Raml-Module-Builder

Copyright (C) 2017 The Open Library Foundation

This software is distributed under the terms of the Apache License, Version 2.0. See the file "LICENSE" for more information.

Introduction

This documentation includes information about the Raml-Module-Builder (RMB) framework and examples of how to use it.

The goal of the project is to abstract away as much boilerplate functionality as possible and allow a developer to focus on implementing business functions. In other words: simplify the process of developing a micro service module. The framework is RAML driven, meaning a developer / analyst declares APIs that the 'to be developed' module is to expose (via RAML files) and declares the objects to be used and exposed by the APIs (via JSON schemas). Once the schemas and RAML files are in place, the framework generates code and offers a number of tools to help implement the module. Note that this framework is both a build and a run-time library.

The framework consists of a number of tools:

• domain-models-api-interfaces -- project exposes tools that receive as input these RAML files and these JSON schemas, and generates java POJOs and java interfaces.

• domain-models-api-aspects -- project exposes tools that enforce strict adherence to the RAML declaration to any API call by exposing validation functionality.

  • for example: a RAML file may indicate that a specific parameter is mandatory or that a query parameter value must be a specific regex pattern. The aspects project handles this type of validation for developers so that it does not need to be re-developed over and over. More on validation below.

• domain-models-runtime -- project exposes a run-time library which should be used to run a module. It is Vert.x based. When a developer implements the interfaces generated by the interfaces project, the run-time library should be included in the developed project and run. The run-time library will automatically map URLs to the correct implemented function so that developers only need to implement APIs, and so all the wiring, validation, parameter / header / body parsing, logging (every request is logged in an apache like format) is handled by the framework. Its goal is to abstract away all boilerplate functionality and allow a module implementation to focus on implementing business functions.

  • The runtime framework also exposes hooks that allow developers to implement one-time jobs, scheduled tasks, etc.

  • Provides tooling (Postgres client, etc.) for developers to use while developing their module.

  • Runtime library runs a Vert.x verticle.

• rules -- Basic Drools functionality allowing module developers to create validation rules via *.drl files for objects (JSON schemas).

Overview

Follow the Introduction section above to generally understand the RMB framework. Review the separate Okapi Guide and Reference. Scan the Basics section below for a high-level overview of RMB. Then follow the Get started with a sample working module section which demonstrates an already constructed example. When that is understood, then move on to the section Creating a new module to get your project started.

Note that actually building this RAML Module Builder framework is not required. (Some of the images below are out-of-date.) The already published artifacts will be incorporated into your project from the repository.

The basics

Implement the interfaces

For example, note the validation annotations generated based on the constraints in the RAML.

• When implementing the interfaces, you must add the @Validate annotation to enforce the annotated constraints declared by the interface.

• Note that a Bib entity was passed as a parameter. The runtime framework transforms the JSON passed in the body into the correct POJO.

Set up your pom.xml

• Add the exec-maven-plugin. This will generate the POJOs and interfaces based on the RAML files.

• Add the aspectj-maven-plugin. This is required if you would like the runtime framework to validate all URLs.

• Add the maven-shade-plugin, indicating the main class to run as RestLauncher and main verticle as RestVerticle. This will create a runnable jar with the runtime's RestVerticle serving as the main class.

• Add the maven-resources-plugin. This will copy your RAML files to the /apidocs directory where they will be made visible online (html view) by the runtime framework.

These are further explained below.

Build and run

Do mvn clean install ... and run :)

The runtime framework will route URLs in your RAML to the correct method implementation. It will validate (if @Validate was used), log, and expose various tools.

Notice that no web server was configured or even referenced in the implementing module - this is all handled by the runtime framework.

Some sample projects:

• https://github.com/folio-org/mod-configuration
• https://github.com/folio-org/mod-notes

and other modules (not all do use the RMB).

Get started with a sample working module

The mod-configuration is a full example which uses the RMB. Clone it, and then investigate:

$ git clone --recursive https://github.com/folio-org/mod-configuration.git
$ cd mod-configuration
$ mvn clean install

• This module implements basic configuration APIs. It contains two sub modules, the configuration server and a configuration client (which can be used to interact with the server in a more OO manner, instead of using URLs).

• Its RAMLs and JSON schemas can be found in the ramls directory. These are also displayed as local API documentation.

• Open the pom.xml in the configuration server module - notice the jars in the dependencies section as well as the plugins section. The ramls directory is declared in the pom.xml and passed to the interface and POJO generating tool via a maven exec plugin. The tool generates source files within the configuration server project. The generated interfaces are implemented within the project in the org.folio.rest.impl package.

• Open the mod-configuration-server/src/main/java/org/folio/rest/impl/ConfigAPI.java class. Notice that there is a function representing each endpoint that is declared in the RAML file. The appropriate parameters (as described in the RAML) are passed as parameters to these functions so that no parameter parsing is needed by the developer. Notice that the ConfigAPI.java contains all the code for the entire module. All handling of URLs, validations, objects, etc. is all either in the RMB jars, or generated for the configuration module by the RMB at build time.

• IMPORTANT NOTE: Every interface implementation - by any module - must reside in package org.folio.rest.impl. This is the package that is scanned at runtime by the runtime framework, to find the needed runtime implementations of the generated interfaces.

Now run the configuration module in standalone mode:

$ java -jar mod-configuration-server/target/mod-configuration-server-fat.jar embed_postgres=true

Now send some requests using 'curl' or 'httpie' (for example to view or set the Logging levels).

At this stage there is not much that can be queried, so stop that quick demonstration now. After explaining general command-line options, etc. we will get your local development server running and populated with test data.

Command-line options

• -Dhttp.port=8080 (Optional -- defaults to 8081)

• -Ddebug_log_package=* (Optional -- Set log level to debug for all packages. Or use org.folio.rest.* for all classes within a specific package, or org.folio.rest.RestVerticle for a specific class.)

• embed_postgres=true (Optional -- defaults to false)

• db_connection=[path] (Optional -- path to an external JSON config file with connection parameters to a PostgreSQL DB)

  • for example Postgres: {"host":"localhost", "port":5432, "maxPoolSize":50, "username":"postgres","password":"mysecretpassword", "database":"postgres", "charset":"windows-1252", "queryTimeout" : 10000}

• drools_dir=[path] (Optional -- path to an external drools file. By default, *.drl files in the resources/rules directory are loaded)

• Other module-specific arguments can be passed via the command line in the format key=value. These will be accessible to implementing modules via RestVerticle.MODULE_SPECIFIC_ARGS map.

• Optional JVM arguments can be passed before the -jar argument, e.g. -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -Xloggc:C:\Git\circulation\gc.log

Environment Variables

RMB implementing modules expect a set of environment variables to be passed in at module startup. The environment variables expected by RMB modules are:

• DB_HOST
• DB_PORT
• DB_USERNAME
• DB_PASSWORD
• DB_DATABASE
• DB_QUERYTIMEOUT
• DB_CHARSET
• DB_MAXPOOLSIZE

See the Environment Variables section of the Okapi Guide for more information on how to deploy environment variables to RMB modules via Okapi.

Local development server

To get going quickly with running a local instance of Okapi, adding a tenant and some test data, and deploying some modules, follow these separate brief instructions.

Ensure that the sample users are loaded, and that a query is successful:

curl -D - -w '\n' \
  -H "X-Okapi-Tenant: diku" \
  http://localhost:9131/users?active=true

Use the local API documentation to view the RAMLs and conduct some more requests (and remember to specify the "X-Okapi-Tenant: diku" header):

http://localhost:9131/apidocs/index.html?raml=raml/users.raml

Now use a similar method to deploy and enable the mod-configuration module that we started to investigate above.

Use the local API documentation to view the RAMLs, and post some entries, and conduct some requests:

http://localhost:9132/apidocs/index.html?raml=raml/configuration/config.raml

Continue to investigate the mod-configuration example.

After getting started with your new module as explained below, it can be similarly deployed and investigated.

Creating a new module

Step 1: Describe the APIs to be exposed by the new module

Create the new project using the normal layout of files and basic POM file.

Add an area for the RAML, schemas, and examples files, e.g. /ramls. (See notes below.) These define the API endpoints. Get started by using the following familiar example:

ebook.raml

#%RAML 0.8

title: e-BookMobile API
baseUri: http://api.e-bookmobile.com/{version}
version: v1

schemas:
  - book: !include ebook.json

/ebooks:
  /{bookTitle}:
    get:
      queryParameters:
        author:
          displayName: Author
          type: string
          description: An author's full name
          example: Mary Roach
          required: false
        publicationYear:
          displayName: Pub Year
          type: number
          description: The year released for the first time in the US
          example: 1984
          required: false
        rating:
          displayName: Rating
          type: number
          description: Average rating (1-5) submitted by users
          example: 3.14
          required: false
        isbn:
          displayName: ISBN
          type: string
          minLength: 10
          example: 03217360797
      responses:
        200:
          body:
            application/json:
              schema: book
              example: |
                {
                  "bookdata": {
                    "id": "SbBGk",
                    "title": "Stiff: The Curious Lives of Human Cadavers",
                    "description": null,
                    "datetime": 1341533193,
                    "genre": "science",
                    "author": "Mary Roach",
                    "link": "http://e-bookmobile.com/books/Stiff"
                  },
                  "success": true,
                  "status": 200
                }
    put:
      queryParameters:
        access_token:
          displayName: Access Token
          type: string
          description: "Token giving you permission to make call"
          required: true

Create JSON schemas indicating the objects exposed by the module:

ebook.json

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "bookdata": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string"
        },
        "title": {
          "type": "string"
        },
        "description": {
          "type": "null"
        },
        "datetime": {
          "type": "integer"
        },
        "genre": {
          "type": "string"
        },
        "author": {
          "type": "string"
        },
        "link": {
          "type": "string"
        }
      },
      "required": [
        "id",
        "title",
        "description",
        "datetime",
        "genre",
        "author",
        "link"
      ]
    },
    "success": {
      "type": "boolean"
    },
    "status": {
      "type": "integer"
    }
  },
  "required": [
    "bookdata",
    "success",
    "status"
  ]
}

Step 2: Include the jars in your project pom.xml

  <repositories>
    <repository>
      <id>folio-nexus</id>
      <name>FOLIO Maven repository</name>
      <url>https://repository.folio.org/repository/maven-folio</url>
    </repository>
  </repositories>
  <dependencies>
    <dependency>
      <groupId>org.folio</groupId>
      <artifactId>domain-models-runtime</artifactId>
      <version>13.0.0</version>
    </dependency>
  </dependencies>

Step 3: Add the plugins to your pom.xml

Four plugins need to be declared in the POM file:

• The exec-maven-plugin which will generate the POJOs and interfaces based on the RAML files.

• The aspectj-maven-plugin which will pre-compile your code with validation aspects provided by the framework - remember the @Validate annotation. The validation supplied by the framework verifies that headers are passed correctly, parameters are of the correct type and contain the correct content as indicated by the RAML file.

• The maven-shade-plugin which will generate a fat-jar runnable jar. While the shade plugin is not mandatory, it does makes things easier. The important thing to notice is the main class that will be run when running your module. Notice the Main-class and Main-Verticle in the shade plugin configuration.

• The maven-resources-plugin which will copy the RAML files into a directory under /apidocs so that the runtime framework can pick it up and display html documentation based on the RAML files.

Add ramlfiles_path property indicating the location of the RAML directories:

  <properties>
    <ramlfiles_path>${basedir}/ramls</ramlfiles_path>
  </properties>

Add the plugins:

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
          <encoding>UTF-8</encoding>
        </configuration>
      </plugin>

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.5.0</version>
        <executions>
          <execution>
            <id>generate_interfaces</id>
            <phase>generate-sources</phase>
            <goals>
              <goal>java</goal>
            </goals>
            <configuration>
              <mainClass>org.folio.rest.tools.GenerateRunner</mainClass>
              <!-- <executable>java</executable> -->
              <cleanupDaemonThreads>false</cleanupDaemonThreads>
              <systemProperties>
                <systemProperty>
                  <key>project.basedir</key>
                  <value>${basedir}</value>
                </systemProperty>
                <systemProperty>
                  <key>raml_files</key>
                  <value>${ramlfiles_path}</value>
                </systemProperty>
              </systemProperties>
            </configuration>
          </execution>
        </executions>
      </plugin>

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>aspectj-maven-plugin</artifactId>
        <version>1.9</version>
        <configuration>
          <verbose>true</verbose>
          <showWeaveInfo>false</showWeaveInfo>
          <complianceLevel>1.8</complianceLevel>
          <includes>
            <include>**/impl/*.java</include>
            <include>**/*.aj</include>
          </includes>
          <aspectDirectory>src/main/java/org/folio/rest/annotations</aspectDirectory>
          <XaddSerialVersionUID>true</XaddSerialVersionUID>
          <showWeaveInfo>true</showWeaveInfo>
          <aspectLibraries>
            <aspectLibrary>
              <groupId>org.folio</groupId>
              <artifactId>domain-models-api-aspects</artifactId>
            </aspectLibrary>
          </aspectLibraries>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
            </goals>
          </execution>
        </executions>
        <dependencies>
          <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>1.8.9</version>
          </dependency>
          <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjtools</artifactId>
            <version>1.8.9</version>
          </dependency>
        </dependencies>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <version>3.0.1</version>
        <executions>
          <execution>
            <id>copy-resources</id>
            <phase>prepare-package</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <outputDirectory>${basedir}/target/classes/apidocs/raml</outputDirectory>
              <resources>
                <resource>
                  <directory>${ramlfiles_path}</directory>
                  <filtering>true</filtering>
                </resource>
              </resources>
            </configuration>
          </execution>
        </executions>
      </plugin>

      <!-- Replace the baseUri and the protocols in the RAMLs that have been copied to
        apidocs directory so that they can be used via the local html api console. -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-antrun-plugin</artifactId>
        <version>1.8</version>
        <executions>
          <execution>
            <phase>prepare-package</phase>
            <configuration>
              <target>
                <replace token="baseUri: http://api.e-bookmobile.com/{version}"
                  value="baseUri: http://localhost:{http.port}"
                  dir="${basedir}/target/classes/apidocs/raml">
                  <include name="**/*.raml" />
                </replace>
                <replace token="protocols: [ HTTPS ]" value="protocols: [ HTTP ]"
                  dir="${basedir}/target/classes/apidocs/raml">
                  <include name="**/*.raml" />
                </replace>
              </target>
            </configuration>
            <goals>
              <goal>run</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.4</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer
                  implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <manifestEntries>
                    <Main-Class>org.folio.rest.RestLauncher</Main-Class>
                    <Main-Verticle>org.folio.rest.RestVerticle</Main-Verticle>
                  </manifestEntries>
                </transformer>
              </transformers>
              <artifactSet />
              <outputFile>${project.build.directory}/${project.artifactId}-fat.jar</outputFile>
            </configuration>
          </execution>
        </executions>
      </plugin>

Compare the POM with other FOLIO RMB-based modules.

Step 4: Build your project

Do mvn clean install

This should:

• Create java interfaces for each added RAML file.

• Each interface will contain functions to be implemented (each function represents an API endpoint declared in the RAML).

• The parameters within each function interface will be annotated with validation annotations that were declared in the RAML. So, if a trait was marked as mandatory, it will be marked as @NOT_NULL. This is not something that needs to be handled by the implementer. This is handled by the framework, which handles validation.

• POJOs -- The JSON schemas will be generated into java objects.

• All generated code can be found in the org.folio.rest.jaxrs package.

Step 5: Implement the generated interfaces

Implement the interfaces associated with the RAML files you created. An interface is generated for every root endpoint in the RAML files. So, for the ebook RAML an org.folio.rest.jaxrs.resource.EbooksResource interface will be generated. Note that the org.folio.rest.jaxrs.resource will be the package for every generated interface.

The implementations must go into the org.folio.rest.impl package because RMB's RestVerticle scans this package for a class that implements the required interface. The class can have any name. RMB then uses reflection to invoke the constructor and the method.

See mod-user's org.folio.rest.impl package for example implementations.

Step 6: Design the RAML files

It is beneficial at this stage to take some time to design and prepare the RAML files for the project. Investigate the other FOLIO modules for guidance. The mod-notes is an exemplar.

Add the shared suite of RAML utility files, as the "raml-util" directory inside your "ramls" directory:

git submodule add https://github.com/folio-org/raml ramls/raml-util

When any schema file refers to an additional schema file, then also use that pathname of the referenced second schema as the "key" name in the RAML "schemas" section, and wherever that schema is utilised in RAML files. Ideally ensure that all such referenced files are below the parent file. It is possible to use a relative path with one set of dot-dots "../" but definitely not more. This is why it is beneficial to place the "raml-util" git submodule inside the "ramls" directory.

NOTE: The schema name of a collection must not end with .json to produce the correct class name. Examples are schemaCollection: noteCollection in note.raml and schemaCollection: addresstypeCollection in addressTypes.raml.

The documentation of HTTP response codes is in HttpStatus.java

The RMB does do some validation of RAML files at compile-time. There are some useful tools to assist with command-line validation, and some can be integrated with text editors, e.g. raml-cop.

RAML-aware text editors are very helpful, such as api-workbench for Atom.

Remember that the POM configuration enables viewing your RAML and interacting with your application via the local API documentation.

NOTE: The FOLIO project is currently using RAML 0.8 version until the RAML 1.0 tools have settled.

NOTE: RAML files must declare at least two endpoints, see RMB-1.

Adding an init() implementation

It is possible to add custom code that will run once before the application is deployed (e.g. to init a DB, create a cache, create static variables, etc.) by implementing the InitAPIs interface. You must implement the init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> resultHandler). Only one implementation per module is supported. Currently the implementation should sit in the org.folio.rest.impl package in the implementing project. The implementation will run during verticle deployment. The verticle will not complete deployment until the init() completes. The init() function can do anything basically, but it must call back the Handler. For example:

public class InitAPIs implements InitAPI {

  public void init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> resultHandler){
    try {
      sayHello();
      resultHandler.handle(io.vertx.core.Future.succeededFuture(true));
    } catch (Exception e) {
      e.printStackTrace();
      resultHandler.handle(io.vertx.core.Future.failedFuture(e.getMessage()));
    }
  }
}

Adding code to run periodically

It is possible to add custom code that will run periodically. For example, to ongoingly check status of something in the system and act upon that. Need to implement the PeriodicAPI interface:

public interface PeriodicAPI {
  /** this implementation should return the delay in which to run the function */
  public long runEvery();
  /** this is the implementation that will be run every runEvery() milliseconds*/
  public void run(Vertx vertx, Context context);

}

For example:

public class PeriodicAPIImpl implements PeriodicAPI {


  @Override
  public long runEvery() {
    return 45000;
  }

  @Override
  public void run(Vertx vertx, Context context) {
    try {
      InitAPIs.amIMaster(vertx, context, v-> {
        if(v.failed()){
          //TODO - what should be done here?
        }
      });
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

There can be multiple implementations of the periodic hook, all will be called by the RMB framework.

Adding a hook to run immediately after verticle deployment

It is possible to add custom code that will be run immediately after the verticle running the module is deployed.

public interface PostDeployVerticle {

  /** this implementation will be run immediately after the verticle is initially deployed. Failure does not stop
   * deployment success. The implementing function MUST call the resultHandler to pass back
   * control to the verticle, like so: resultHandler.handle(io.vertx.core.Future.succeededFuture(true));
   * if not, this function will hang the verticle during deployment */
  public void init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> resultHandler);

}

An implementation example:

public class InitConfigService implements PostDeployVerticle {

  @Override
  public void init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> handler) {

    System.out.println("Getting secret key to decode DB password.");
    /** hard code the secret key for now - in production env - change this to read from a secure place */
    String secretKey = "b2%2BS%2BX4F/NFys/0jMaEG1A";
    int port = context.config().getInteger("http.port");
    AdminClient ac = new AdminClient("localhost", port, null);
    ac.postSetAESKey(secretKey, reply -> {
      if(reply.statusCode() == 204){
        handler.handle(io.vertx.core.Future.succeededFuture(true));
      }
      else{
        handler.handle(io.vertx.core.Future.failedFuture(reply.statusCode() + ", " + reply.statusMessage()));
      }
    });
  }

}

Adding a shutdown hook

It is possible to add custom code that will run just before the verticle is undeployed and the JVM stopped. This will occur on graceful shutdowns, but can not be guaranteed to run if the JVM is forcefully shutdown.

The interface to implement:

public interface ShutdownAPI {

  public void shutdown(Vertx vertx, Context context, Handler<AsyncResult<Void>> handler);

}

An implementation example:

public class ShutdownImpl implements ShutdownAPI {

  @Override
  public void shutdown(Vertx vertx, Context context, Handler<AsyncResult<Void>> handler) {
    try {
      AuditLogger.getInstance().publish(new LogRecord(Level.INFO, "closing audit logger"));
      AuditLogger.getInstance().close();
      handler.handle(io.vertx.core.Future.succeededFuture());
    }
    catch (Exception e) {
      e.printStackTrace();
      handler.handle(io.vertx.core.Future.failedFuture(e.getMessage()));
    }
  }
}

Note that when implementing the generated interfaces it is possible to add a constructor to the implementing class. This constructor will be called for every API call. This is another way you can implement custom code that will run per request.

Implementing file uploads

The RMB (RAML-Module-Builder) supports several methods to upload files and data. The implementing module can use the multipart/form-data header or the application/octet-stream header to indicate that the HTTP request is an upload content request.

Option 1

A multipart RAML declaration may look something like this:

/uploadmultipart:
    description: Uploads a file
    post:
      description: |
          Uploads a file
      body:
        multipart/form-data:
          formParameters:
            file:
              description: The file to be uploaded
              required: true
              type: file

The body content would look something like this:

------WebKitFormBoundaryNKJKWHABrxY1AdmG
Content-Disposition: form-data; name="config.json"; filename="kv_configuration.sample"
Content-Type: application/octet-stream

<file content 1>

------WebKitFormBoundaryNKJKWHABrxY1AdmG
Content-Disposition: form-data; name="sample.drl"; filename="Sample.drl"
Content-Type: application/octet-stream

<file content 2>

------WebKitFormBoundaryNKJKWHABrxY1AdmG

There will be a MimeMultipart parameter passed into the generated interfaces. An implementing module can access its content in the following manner:

int parts = entity.getCount();
for (int i = 0; i < parts; i++) {
        BodyPart part = entity.getBodyPart(i);
        Object o = part.getContent();
}

where each section in the body (separated by the boundary) is a "part".

An octet/stream can look something like this:

 /uploadOctet:
    description: Uploads a file
    post:
      description: |
          Uploads a file
      body:
        application/octet-stream:

The interfaces generated from the above will contain a parameter of type java.io.InputStream representing the uploaded file.

Option 2

The RMB allows for content to be streamed to a specific implemented interface. For example, to upload a large file without having to save it all in memory:

• Mark the function to handle the upload with the org.folio.rest.annotations.Stream annotation @Stream.
• Declare the RAML as receiving application/octet-stream (see Option 1 above)

The RMB will then call the function every time a chunk of data is received. This means that a new Object is instantiated by the RMB for each chunk of data, and the function of that object is called with the partial data included in a java.io.InputStream object.

PostgreSQL integration

By default an embedded PostgreSQL is included in the runtime, but is not run by default. To change that add embed_postgres=true to the command line (java -jar mod-configuration-server-fat.jar embed_postgres=true). Connection parameters to a non-embedded PostgreSQL can be placed in resources/postgres-conf.json or passed via the command line.

The runtime framework exposes a PostgreSQL async client which offers CRUD operations in an ORM type fashion. https://github.com/folio-org/raml-module-builder/blob/master/domain-models-runtime/src/main/java/org/folio/rest/persist/PostgresClient.java

Important Note: The PostgreSQL client currently implemented assumes JSONB tables in PostgreSQL. This is not mandatory and developers can work with regular PostgreSQL tables but will need to implement their own data access layer.

Important Note: The embedded Postgres can not run as root.

Important Note: The embedded Postgres relies on the en_US.UTF-8 (*nix) / american_usa (win) locale. If this locale is not installed the Postgres will not start up properly.

Currently the expected format is:

create table <schema>.<table_name> (
  _id SERIAL PRIMARY KEY,
  jsonb JSONB NOT NULL
);

This means that all the fields in the JSON schema (representing the JSON object) are the "jsonb" (column) in the Postgres table.

There is one exception to this. Lets take an example of an auditing table which wants to store changes to a specific table. Every row in the audit table will contain the operation, date, and the current content (jsonb) in the table being audited.

For example:

_id	orig_id	operation	jsonb	creation_date
12345	11111	insert	{json with current data}	1/1/2010
67890	22222	delete	{json with previous data}	1/1/2010
12321	11111	update	{json with current data}	1/1/2010

When querying such a table, you would want to get back all columns, not just the id and the jsonb columns.

To achieve this, the declared JSON schema would need to contain a "jsonb" field. For example: JSON schema representing the entire auditing table row:

{
  "$schema":"http://json-schema.org/draft-04/schema#",
  "type":"object",
  "properties":{
    "_id":{
      "type":"string"
    },
    "orig_id":{
      "type":"string"
    },
    "operation":{
      "type":"string"
    },
    "jsonb":{
      "type": "object",
        "properties": {
          "content": {
            "id": "contentData",
            "type": "array",
            "items": {
              "type": "object",
              "$ref" : "config"
          }
        }
      }
    },
    "creation_date":{
      "type":"string"
    }
  }
}

where the "jsonb" field references a JSON schema that will exist in the "jsonb" column in the table.

The example above refers to querying only. As of now, saving a record will only save the "jsonb" and "id" fields (the above example uses triggers to populate the operation, creation data, and original id).

Credentials

When running in embedded mode, credentials are read from resources/postgres-conf.json. If a file is not found, then the following configuration will be used by default:

port: 6000
host: 127.0.0.1
username: username
password: password
database: postgres

Securing DB Configuration file

As previously mentioned, the Postgres Client supplied by the RMB looks for a file called postgres-conf.json. However, leaving a file which contains the DB password to a superuser in plain text on the server is not a good idea. It is possible to encrypt the password in the file. The encryption should be an AES encryption (symmetric block cipher). This encryption is done with a secret key.

Meaning: password in plain text + secret key = encrypted password

The RMB comes with an AES class that supports generating secret keys, encrypting and decrypting them, https://github.com/folio-org/raml-module-builder/blob/master/domain-models-runtime/src/main/java/org/folio/rest/security/AES.java

Note that the use of this class is optional.

To work with an encrypted password the RMB exposes an API that can be used to set the secret key (stored only in memory). When creating the DB connection the RMB will check to see if the secret key has been set. If the secret key has been set, the RMB will decrypt the password with the secret key, and use the decrypted password to connect to the DB. Otherwise it will assume an un-encrypted password, and will connect using that password as-is. A module can also set the secret key via the static method AES.setSecretKey(mykey)

The needed steps are:

• Generate a key
• Encrypt a password
• Include that password in the config file
• Either call AES.setSecretKey(mykey) or the admin/set_AES_key API (to load the secret key into memory)

A good way for a module to set the secret key is by using the post deployment hook interface in the RMB.

public class InitConfigService implements PostDeployVerticle {
  @Override
  public void init(Vertx vertx, Context context, Handler<AsyncResult<Boolean>> handler) {
    System.out.println("Getting secret key to decode DB password.");
    //** hard code the secret key  - in production env - read from a secure place *//
    String secretKey = "b2%2BS%2BX4F/NFys/0jMaEG1A";
    int port = context.config().getInteger("http.port");
    AdminClient ac = new AdminClient("localhost", port, null);
    ac.postSetAESKey(secretKey, reply -> {
      if(reply.statusCode() == 204){
        handler.handle(io.vertx.core.Future.succeededFuture(true));
      }
      else{
        handler.handle(io.vertx.core.Future.failedFuture(reply.statusCode() + ", " + reply.statusMessage()));
      }
    });
    handler.handle(io.vertx.core.Future.succeededFuture(true));
  }
}

Foreign keys constraint

PostgreSQL does not directly support a foreign key constraint (referential integrity) of a field inside the JSONB. Create an additional column with the foreign key constraint and setup a trigger to keep it in sync with the value inside the JSONB.

Example:

CREATE TABLE item (
  _id UUID PRIMARY KEY,
  jsonb JSONB NOT NULL,
  permanentLoanTypeId UUID REFERENCES loan_type,
  temporaryLoanTypeId UUID REFERENCES loan_type
);
CREATE OR REPLACE FUNCTION update_item_references()
RETURNS TRIGGER AS $$
BEGIN
  NEW.permanentLoanTypeId = NEW.jsonb->>'permanentLoanTypeId';
  NEW.temporaryLoanTypeId = NEW.jsonb->>'temporaryLoanTypeId';
  RETURN NEW;
END;
$$ language 'plpgsql';
CREATE TRIGGER update_item_references
  BEFORE INSERT OR UPDATE ON item
  FOR EACH ROW EXECUTE PROCEDURE update_item_references();

The overhead of this trigger and foreign key constraint reduces the number of UPDATE transactions per second on this table by about 10% (when tested against an external stand alone Postgres database). See https://github.com/folio-org/raml-module-builder/blob/master/domain-models-runtime/src/test/java/org/folio/rest/persist/ForeignKeyPerformanceIT.java for the performance test. Doing the foreign key check manually by sending additional SELECT queries takes much more time than 10%.

Tenant API

The Postgres Client support in the RMB is schema specific, meaning that it expects every tenant to be represented by its own schema. The RMB exposes three APIs to facilitate the creation of schemas per tenant (a type of provisioning for the tenant). Post, Delete, and 'check existence' of a tenant schema. Note that the use of this API is optional.

The RAML defining the API:

https://github.com/folio-org/raml/blob/3e5a4a58e141fb9d4a6968723df50e0f0b8d8de1/ramls/tenant.raml

The Post Tenant API

RMB will look for a file at /resources/templates/db_scripts/ called schema.json

The file contains an array of tables and views to create for a tenant on registration (tenant api post)

An example can be found here:

• https://github.com/folio-org/raml-module-builder/blob/master/domain-models-runtime/src/main/resources/templates/db_scripts/examples/schema.json.example

Entries in the json file to be aware of:

For each table:

1. tableName - name of the table that will be generated - this is the table that should be referenced from the code
2. generateId - whether to auto generate the id of entries for this table - (will add the following to the id column DEFAULT gen_random_uuid())
3. fromModuleVersion - this field indicates the version in which the table was created / updated in. When a tenant update is requested - only versions older than the indicated version will generate the declared table. This ensures that if a module upgrades from an older version, the needed tables will be generated for it, however, subsequent upgrades from versions equal or later than the version indicated for the table will not re-generate the table.

• Note that this is enforced for all tables, views, indexes, FK, triggers, etc... - via the IF NOT EXISTS sql Postgres statement

4. mode - should be used only to indicate delete
5. withMetadata - will generate the needed triggers to populate the metadata section in the json on update / insert
6. likeIndex - indicate which fields in the json will be queried using the LIKE - needed for fields that will be faceted on

• the tOps indicates the table operation - ADD means to create this index, DELETE indicates this index should be removed

7. ginIndex - generate an inverted index on the json
8. withAuditing - create an auditing table with triggers populating the audit table whenever an insert, update, or delete occurs on the table

• the name of the audit table will be audit_{tableName}
• The auditingSnippet section allows some customizations to the auditing function by allowing custom sqls in the declare section and the body (for either insert / update / delete)

9. foreignKeys - adds / removes foreign keys (trigger populating data in a column based on a field in the json and creating a FK constraint)
10. uniqueIndex - create a unique index on a field in the json
11. customSnippetPath - a relative path to a file with custom sql commands for this specific table
12. deleteFields / addFields - delete (or add with a default value), a field at the specified path for all json entries in the table
13. populateJsonWithId - when the id is auto generated, and the id must be stored in the json as well

The views section is a bit more self explanatory as it indicates a viewName and the two tables (and a column per table) to join by.

The script section allows a module to run custom SQLs before table / view creation/updates and after all tables/views have been created/updated.

The fields in the script section include:

1. run - either before or after the tables / views are generated
2. snippet - the SQL to run
3. fromModuleVersion - same as fromModuleVersion for table

The tables / views will be generated in the schema named tenantid_modulename

The x-okapi-tenant header passed in to the API call will be used to get the tenant id. The value used for the module name is the artifactId found in the pom.xml (the parent artifactId is used if one is found).

Posting a new tenant can optionally include a body. The body should contain a JSON conforming to the https://github.com/folio-org/raml/blob/master/schemas/moduleInfo.schema schema. The module_to entry is mandatory if a body is included in the request, indicating the version module for this tenant. The module_from entry is optional and indicates an upgrade for the tenant to a new module version.

Encrypting Tenant passwords

As of now (this may change in the future), securing a tenant's connection to the database via an encrypted password can be accomplished in the following way:

• Set the secret key (as described in the Securing DB Configuration file section)

The PASSWORD will be replaced with the following: encrypt(tenant id with secret key) = new tenant's password The new tenant's password will replace the default PASSWORD value (which is the tenantid_modulename) The RMB Postgres client will use the secret key and the passed in tenant id to calculate the tenant's password when DB connections are needed for that tenant. Note that if you use the tenant API and set the secret key - the decrypting of the password will be done by the Postgres Client for each tenant connection.

The RMB comes with a TenantClient to facilitate calling the API via URL. To post a tenant via the client:

TenantClient tClient = null;
tClient = new TenantClient("localhost", port, "mytenantid");
tClient.post( response -> {
  response.bodyHandler( body -> {
    System.out.println(body.toString());
    async.complete();
  });
});

The Delete Tenant API

When this API is called RMB will basically drop the schema for the tenant (CASCADE) as well as drop the user

Some Postgres Client examples

Examples:

Saving a POJO within a transaction:

PoLine poline = new PoLine();

...

postgresClient.save(beginTx, TABLE_NAME_POLINE, poline , reply -> {...

Querying for similar POJOs in the DB (with or without additional criteria):

Criterion c = new Criterion(new Criteria().addField("_id").setJSONB(false).setOperation("=").setValue("'"+entryId+"'"));

postgresClient.get(TABLE_NAME_POLINE, PoLine.class, c,
              reply -> {...

The Criteria object which generates where clauses can also receive a JSON Schema so that it can cast values to the correct type within the where clause.

Criteria idCrit = new Criteria("ramls/schemas/userdata.json");

Query Syntax

The RMB can receive parameters of different types. Modules can declare a query parameter and receive it as a string parameter in the generated API functions.

The RMB exposes an easy way to query, using CQL (https://github.com/folio-org/cql2pgjson-java). This enables a seamless integration from the query parameters to a prepared "where" clause to query with.

//create object on table.field
CQL2PgJSON cql2pgJson = new CQL2PgJSON("tablename.jsonb");
//cql wrapper based on table.field and the cql query
CQLWrapper cql = new CQLWrapper(cql2pgJson, query);
//query the db with the cql wrapper object
PostgresClient.getInstance(context.owner(), tenantId).get(CONFIG_COLLECTION, Config.class,
          cql, true,

The CQLWrapper can also get an offset and limit:

new CQLWrapper(cql2pgJson, query).setLimit(new Limit(limit)).setOffset(new Offset(offset));

A CQL querying example:

http://localhost:<port>/configurations/entries?query=scope.institution_id=aaa%20sortBy%20enabled

Metadata

RMB is aware of the metadata.schema. When a request (POST / PUT) comes into an RMB module, RMB will check if the passed in json's schema declares a reference to the metadata schema. If so, RMB will populate the json with a metadata section with the current user and the current time. RMB will set both update and create values to the same date/time and to the same user, as accepting this information from the request may be unreliable. The module should persist the creation date and the created by values after the initial POST. For an example of this using triggers see metadata.sql

Facet Support

RMB also allows easy faceting of result sets. The grouping / faceting is done in the database. To add faceting to your API.

1. Add the faceting RAML trait to your RAML and reference it from the endpoint (using the is:[])
   • facet query parameter format: facets=a.b.c or facets=a.b.c:10 (they are repeating). For example ?facets=active&facets=personal.lastName
2. Add the resultInfo.schema to your RAML and reference it within your collection schemas. For example:

 "type": "object",
  "properties": {
    "items": {
      "id": "items",
      "type": "array",
      "items": {
        "type": "object",
        "$ref" : "item.json"
      }
    },
    "resultInfo": {
      "type": "object",
      "$ref": "raml-util/schemas/resultInfo.schema"
    }

3. When building your module, an additional parameter will be added to the generated interfaces of the faceted endpoints. List<String> facets. You can simply convert this list into a List of Facet objects using the RMB tool as follows: List<FacetField> facetList = FacetManager.convertFacetStrings2FacetFields(facets, "jsonb"); and pass the facetList returned to the postgresClient's get() methods.

NOTE: Creating an index on potential facet fields may be required so that performance is not greatly hindered

Json Schema fields

It is possible to indicate that a field in the json is a readonly field when declaring the schema. "readonly": true. From example:

    "resultInfo": {
      "$ref": "raml-util/schemas/resultInfo.schema",
      "readonly" : true
    }

A readonly field is not allowed to be passed in as part of the request. A request that contains data for a field that was declared as readonly will throw a validation error by RMB.

This is part of a framework exposed by RMB which allows creating a field and associating a validation constraint on that field.

To add a custom field, add a system property (in the configuration) to the plugin definition (in the pom.xml) running the <mainClass>org.folio.rest.tools.GenerateRunner</mainClass>

for example:

<systemProperty>
    <key>jsonschema.customfield</key>
    <value>{"fieldname" : "readonly" , "fieldvalue": true , "annotation" : "javax.validation.constraints.Null"}</value>
</systemProperty>

the jsonschema.customfield key can contain multiple json values (delimited by a ;). Each json indicates a field name + a field value to match against - and a validation annotation to apply. So, getting back to the readonly field, the example above indicates that a field in the json schema that has been tagged with the readonly field can not contain data when passed in as part of the request. A list of available annotations: https://docs.oracle.com/javaee/7/api/javax/validation/constraints/package-summary.html

Drools integration

The RMB framework automatically scans the /resources/rules path in an implemented project for *.drl files. A directory can also be passed via the command line drools_dir. The rule files are loaded and are applied automatically to all objects passed in the body (post, put) by the runtime framework. This works in the following manner:

• A POST / PUT request comes in with a body
• The body for the request is mapped to a generated POJO
• The POJO is inserted into the RMB's Drools session
• All rules are run against the POJO

This allows for more complex validation of objects.

• For example, two specific fields can logically be null, but not at the same time. That can easily be implemented with a Drool, as those types of validations are harder to create in a RAML file.

• The rules project also exposes the drools session and allows validation within the implemented APIs. See the tests in the rules project.

For example: (Sample.drl)

package com.sample

import org.folio.rest.jaxrs.model.Patron;

rule "Patron needs one ID at the least"

    no-loop

    when
        p : Patron( patronBarcode  == null, patronLocalId == null )
    then
        throw new java.lang.Exception("Patron needs one ID field populated at the least");
end

It is also possible to create a Drools session in your code, and load rules into the session in a more dynamic way. For example:

import org.folio.rulez.Rules;
...
List<String> ruleList = generateDummyRule();
Rules rules = new Rules(ruleList);
ksession = rules.buildSession();
...
Messages message = new Messages();
ksession.insert(message);
ksession.fireAllRules();
Assert.assertEquals("THIS IS A TEST", message.getMessage());

An additional option to use the Drools framework in the RMB is to load rules dynamically. For example, a module may decide to store Drool .drl files in a database. This enables a module to allow admin users to update rules in the database and then load them into the RMB validation mechanism for use at runtime.

      Rules rules = new Rules(List<String> rulesLoaded);
      ksession = rules.buildSession();
      RestVerticle.updateDroolsSession(ksession);

Messages

The runtime framework comes with a set of messages it prints out to the logs / sends back as error responses to incorrect API calls. These messages are language-specific. In order to add your own message files, place the files in your project under the /resources/messages directory.

Note that the format of the file names should be either:

• [name]_[lang_2_letters].properties (e.g.: APIMessages_de.properties)
• [lang_2_letters]_messages.prop (e.g.: en_messages.prop)

For example: In the circulation project, the messages file can be found at /circulation/src/main/resources/en_messages.prop with the following content:

20002=Operation can not be calculated on a Null Amount
20003=Unable to pay fine, amount is larger than owed
20004=The item {0} is not renewable
20005=Loan period must be greater than 1, period entered: {0}

The circulation project exposes these messages as enums for easier usage in the code:

package org.folio.utils;

import org.folio.rest.tools.messages.MessageEnum;

public enum CircMessageConsts implements MessageEnum {

  OperationOnNullAmount("20002"),
  FinePaidTooMuch("20003"),
  NonRenewable("20004"),
  LoanPeriodError("20005");

  private String code;
  private CircMessageConsts(String code){
    this.code = code;
  }
  public String getCode(){
    return code;
  }
}

Usage:

private final Messages messages = Messages.getInstance();

messages.getMessage(lang, CircMessageConsts.OperationOnNullAmount);

Note: parameters can also be passed when relevant. The raml-module-builder runtime also exposes generic error message enums which can be found at /domain-models-runtime/src/main/java/org/folio/rest/tools/messages/MessageConsts.java

Documentation of the APIs

The runtime framework includes a web application which exposes RAMLs in a view-friendly HTML format. The maven-resources-plugin plugin described earlier copies the RAML files into the correct directory in your project, so that the runtime framework can access it and show local API documentation.

So for example, when running the sample working module then its API documentation is at:

http://localhost:8081/apidocs/index.html?raml=raml/configuration/config.raml

If instead your new module is running on the default port, then its API documentation is at:

http://localhost:8081/apidocs/index.html?raml=raml/ebook.raml

The RMB also automatically provides other documentation, such as the "Admin API":

http://localhost:8081/apidocs/index.html?raml=raml/admin.raml

All current API documentation is also available at dev.folio.org/doc/api

Logging

RMB uses the Log4J logging library. Logs that are generated by RMB will print all log entries in the following format: %d{dd MMM yyyy HH:mm:ss:SSS} %-5p %C{1} %X{reqId} %m%n

A module that wants to generate log4J logs in a different format can create a log4j.properties file in the /resources directory.

The log levels can also be changed via the /admin API provided by the framework. For example:

Get log level of all classes:

(GET) http://localhost:8081/admin/loglevel

Change log level of all classes to FINE:

(PUT) http://localhost:8081/admin/loglevel?level=FINE

A java_package parameter can also be passed to change the log level of a specific package. For example:

http://localhost:8081/admin/loglevel?level=INFO&java_package=org.folio.rest.persist.PostgresClient

http://localhost:8081/admin/loglevel?level=INFO&java_package=org.folio.rest.persist

Monitoring

The runtime framework via the /admin API exposes (as previously mentioned) some APIs to help monitor the service (setting log levels, DB information). Some are listed below (and see the full set):

• /admin/jstack -- Stack traces of all threads in the JVM to help find slower and bottleneck methods.
• /admin/memory -- A jstat type of reply indicating memory usage within the JVM on a per pool basis (survivor, old gen, new gen, metadata, etc.) with usage percentages.
• /admin/slow_queries -- Queries taking longer than X seconds.
• /admin/cache_hit_rates -- Cache hit rates in Postgres.
• /admin/table_index_usage -- Index usage per table.
• /admin/postgres_table_size -- Disk space used per table.
• /admin/postgres_table_access_stats -- Information about how tables are being accessed.
• /admin/postgres_load -- Load information in Postgres.
• /admin/postgres_active_sessions -- Active sessions in Postgres.
• /admin/health -- Returns status code 200 as long as service is up.
• /admin/module_stats -- Summary statistics (count, sum, min, max, average) of all select / update / delete / insert DB queries in the last 2 minutes.

Overriding Out of The Box RMB APIs

It is possible to over ride APIs that the RMB provides with custom implementations. For example: To override the /health API to return a relevant business logic health check for a specific module do the following:

1. extend the AdminAPI class that comes with the RMB framework - public class CustomHealthCheck extends AdminAPI and over ride the getAdminHealth function. The RMB will route the URL endpoint associated with the function to the custom module's implementation.

Example:

public class CustomHealthCheck extends AdminAPI {

  @Override
  public void getAdminHealth(Map<String, String> okapiHeaders,
      Handler<AsyncResult<Response>> asyncResultHandler, Context vertxContext) throws Exception {

    super.getAdminHealth(okapiHeaders,  res -> {
      System.out.println(" --- this is an over ride of the health API by the config module "+res.result().getStatus());
      asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetAdminHealthResponse.withOK()));
    }, vertxContext);
  }

  @Override
  public void getAdminModuleStats(Map<String, String> okapiHeaders,
      Handler<AsyncResult<Response>> asyncResultHandler, Context vertxContext) throws Exception {

    super.getAdminModuleStats(okapiHeaders,  res -> {

      JsonObject o = new JsonObject(res.result().getEntity().toString());

      System.out.println(" --- this is an over ride of the Module Stats API by the config module ");
      asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetAdminModuleStatsResponse.
        withPlainOK( o.encodePrettily() )));
    }, vertxContext);
  }
}

Client Generator

The framework can generate a Client class for every RAML file with a function for every API endpoint in the RAML.

To generate a client API from your RAML add the following plugin to your pom.xml

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.5.0</version>
        <executions>
          <execution>
            <id>generate_client</id>
            <phase>process-classes</phase>
            <goals>
              <goal>java</goal>
            </goals>
            <configuration>
              <mainClass>org.folio.rest.tools.ClientGenerator</mainClass>
              <cleanupDaemonThreads>false</cleanupDaemonThreads>
              <systemProperties>
                <systemProperty>
                  <key>client.generate</key>
                  <value>true</value>
                </systemProperty>
                <systemProperty>
                  <key>project.basedir</key>
                  <value>${basedir}</value>
                </systemProperty>
                <systemProperty>
                  <key>json.type</key>
                  <value>postgres</value>
                </systemProperty>
              </systemProperties>
            </configuration>
          </execution>
        </executions>
      </plugin>

For the monitoring APIs exposed by the runtime framework, changing the log level via the client would look like this:

    AdminClient aClient = new AdminClient("localhost", 8083, "myuniversityId");
    aClient.putLoglevel(Level.FINE, "org.folio",  apiResponse -> {
      System.out.println(apiResponse.statusCode());
    });

Requesting a stack trace would look like this:

    AdminClient aClient = new AdminClient("localhost", 8083, "myuniversityId");
    aClient.getJstack( trace -> {
      trace.bodyHandler( content -> {
        System.out.println(content);
      });
    });

Querying multiple modules via HTTP

The RMB has some tools available to help:

• Make HTTP requests to other modules
• Parse JSON responses received (as well as any JSON for that matter)
• Merge together / Join JSON responses from multiple modules
• Build simple CQL query strings based on values in a JSON

HTTP Requests

The HttpModuleClient2 class exposes a basic HTTP Client. The full constructor takes the following parameters

• host
• port
• tenantId
• keepAlive - of connections (default: true)
• connTO - connection timeout (default: 2 seconds)
• idleTO - idle timeout (default: 5 seconds)
• autoCloseConnections - close connection when request completes (default: true)
• cacheTO - cache of endpoint results timeout (in minutes, default: 30)

    HttpModuleClient hc = new HttpModuleClient("localhost", 8083, "myuniversity_new2", false);
    Response response = hc.request("/groups");

It is recommended to use the HttpClientFactory to get an instance of the HttpModuleClient2. The factory will then return either the actual HttpModuleClient2 class or an instance of the HttpClientMock2. To return an instance of the mock client, set the mock mode flag in the vertx config. One way to do this: new DeploymentOptions().setConfig(new JsonObject().put(HttpClientMock2.MOCK_MODE, "true")); See mock_content.json for an example of how to associate a url with mocked data and headers

The client returns a Response object. The Response class has the following members:

• endpoint - url the response came from
• code - http returned status code for request
• (JsonObject) body - the response data
• (JsonObject) error - in case of an error - The error member will be populated. The error object will contain the endpoint, the statusCode, and the errorMessage
• (Throwable) exception - if an exception was thrown during the API call

The HttpModuleClient2 request function can receive the following parameters:

• HttpMethod - (default: GET)
• endpoint - API endpoint
• headers - Default headers are passed in if this is not populated: Content-type=application/json, Accept: plain/test
• RollBackURL - URL to call if the request is unsuccessful [a non 2xx code is returned]. Note that if the Rollback URL call is unsuccessful, the response error object will contain the following three entries with more info about the error (rbEndpoint, rbStatusCode, rbErrorMessage)
• cachable - Whether to cache the response
• BuildCQL object - This allows you to build a simple CQL query string from content within a JSON object. For example: Response userResponse = hc.request("/users", new BuildCQL(groupsResponse, "usergroups[*].id", "patron_group")); This will create a query string with all values from the JSON found in the path usergroups[*].id and will generate a CQL query string which will look something like this: ?query=patron_group==12345+or+patron+group==54321+or+patron_group==09876... See BuildCQL for configuration options.

The Response class also exposes a joinOn function that allow you to join / merge the received JSON objects from multiple requests.

public Response joinOn(String withField, Response response, String onField, String insertField, String intoField, boolean allowNulls)

The Join occurs with the response initiating the joinOn call:

• withField - the field within the response whose value / values will be used to join
• response - the response to join this response with
• onField - the field in the passed in response whose value / values will be used to join
• insertField - the field in the passed in response to push into the current response (defaults to the onField value if this is not passed in)
• intoField - the field to populate within this response
• allowNulls - whether to populate with null if the field requested to push into the current response is null - if set to false - then the field will not be populated with a null value.

Example:

join:

(response1) {"a": "1","b": "2"}

with:

(response2) {"arr2":[{"id":"1","a31":"1"},{"id":"1","a31":"2"},{"id":"1","a32":"4"},{"id":"2","a31":"4"}]}

returns: {"a":"1","b":["1","2"]}

with the following call: response1.joinOn("a", response2, "arr2[*].id", "a31", "b", false)

Explanation: Join response1 on field "a" with response2 on field "arr2[*].id" (this means all IDs in the arr2 array. If a match is found take the value found in field "a31" and place it in field "b". Since in this case a single entry (response1) matches multiple entries from response2 - an array is created and populated. If this was a one-to-one match, then only the single value (whether a JSON object, JSON array, any value) would have been inserted.

Parsing

The RMB exposes a simple JSON parser for the vert.x JSONObject. The parser allows getting and setting nested JSON values. The parser allows retrieving values / nested values in a simpler manner. For example:

a.b -- Get value of field 'b' which is nested within a JSONObject called 'a'

a.c[1].d -- Get 'd' which appears in array 'c[1]'

a.'bb.cc' -- Get field called 'bb.cc' (use '' when '.' in name)

a.c[*].a2 -- Get all 'a2' values as a List for each entry in the 'c' array

See the JsonPathParser class for more info.

An example

//create a client
HttpClientInterface client = HttpClientFactory.getHttpClient(okapiURL, tenant);
//make a request
CompletableFuture<Response> response1 = client.request(url, okapiHeaders);
//chain a request to the previous request, the placeholder {users[0].username}
//means that the value appearing in the first user[0]'s username in the json returned
//in response1 will be injected here
//the handlePreviousResponse() is a function you code and will receive the response
//object (containing headers / body / etc,,,) of response1 so that you can decide what to do
//before the chainedRequest is issued - see example below
//the chained request will not be sent if the previous response (response1) has completed with
//an error
response1.thenCompose(client.chainedRequest("/authn/credentials/{users[0].username}",
    okapiHeaders, null, handlePreviousResponse());

    Consumer<Response> handlePreviousResponse(){
        return (response) -> {
            int statusCode = response.getCode();
            boolean ok = Response.isSuccess(statusCode);
            //if not ok, return error
        };
    }

//if you send multiple chained Requests based on response1 you can use the
//CompletableFuture.allOf() to wait till they are all complete
//or you can chain one request to another in a pipeline manner as well

//you can also generate a cql query param as part of the chained request based on the
//response of the previous response. the below will create a username=<value> cql clause for
//every value appearing in the response1 json's users array -> username
response1.thenCompose(client.chainedRequest("/authn/credentials", okapiHeaders, new BuildCQL(null, "users[*].username", "username")),...

//join the values within 2 responses - injecting the value from a field in one json into the field of another json when a constraint between the two jsons exists (like field a from json 1 equals field c from json 2)
//compare all users->patron_groups in response1 to all usergroups->id in groupResponse, when there is a match, push the group field in the specific entry of groupResonse into the patron_group field in the specific entry in the response1 json
response1.joinOn("users[*].patron_group", groupResponse, "usergroups[*].id", "group", "patron_group", false);
//close the http client
hClient.closeClient();

A Little More on Validation

Query parameters and header validation

Object validations

function example

  @Validate
  @Override
  public void getConfigurationsEntries(String query, int offset, int limit,
      String lang,java.util.Map<String, String>okapiHeaders,
      Handler<AsyncResult<Response>> asyncResultHandler, Context context) throws Exception {

    CQLWrapper cql = getCQL(query,limit, offset);
    /**
    * http://host:port/configurations/entries
    */
    context.runOnContext(v -> {
      try {
        System.out.println("sending... getConfigurationsTables");
        String tenantId = TenantTool.calculateTenantId( okapiHeaders.get(RestVerticle.OKAPI_HEADER_TENANT) );

        PostgresClient.getInstance(context.owner(), tenantId).get(CONFIG_TABLE, Config.class,
          new String[]{"*"}, cql, true,
            reply -> {
              try {
                if(reply.succeeded()){
                  Configs configs = new Configs();
                  List<Config> config = (List<Config>) reply.result()[0];
                  configs.setConfigs(config);
                  configs.setTotalRecords((Integer)reply.result()[1]);
                  asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetConfigurationsEntriesResponse.withJsonOK(
                    configs)));
                }
                else{
                  log.error(reply.cause().getMessage(), reply.cause());
                  asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetConfigurationsEntriesResponse
                    .withPlainBadRequest(reply.cause().getMessage())));
                }
              } catch (Exception e) {
                log.error(e.getMessage(), e);
                asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetConfigurationsEntriesResponse
                  .withPlainInternalServerError(messages.getMessage(
                    lang, MessageConsts.InternalServerError))));
              }
            });
      } catch (Exception e) {
        log.error(e.getMessage(), e);
        String message = messages.getMessage(lang, MessageConsts.InternalServerError);
        if(e.getCause() != null && e.getCause().getClass().getSimpleName().endsWith("CQLParseException")){
          message = " CQL parse error " + e.getLocalizedMessage();
        }
        asyncResultHandler.handle(io.vertx.core.Future.succeededFuture(GetConfigurationsEntriesResponse
          .withPlainInternalServerError(message)));
      }
    });
  }

Advanced Features

1. RMB handles all routing, so this is abstracted from the developer. However, there are cases where third party functionality may need access to routing information. Once again, this is not to be used for routing, but in order to pass in routing information to a third party (one such example is the pac4j vertx saml client). RMB allows a developer to receive the Vertx RoutingContext object as a parameter to a generated function by indicating the endpoint represented by the function in the pom.xml (uses a comma delimiter for multiple paths).

  <properties>
    <generate_routing_context>/rmbtests/test</generate_routing_context>
  </properties>

Some REST examples

Have these in the headers - currently not validated hence not mandatory:

• Accept: application/json,text/plain
• Content-Type: application/json;

Example 1: Add a fine to a patron (post)

http://localhost:8080/patrons/56dbe25ea12958478cec42ba/fines
{
  "fine_amount": 10,
  "fine_outstanding": 0,
  "fine_date": 1413879432,
  "fine_pay_in_full": true,
  "fine_pay_in_partial": false,
  "fine_note": "aaaaaa",
  "item_id": "56dbe160a129584dc8de7973",
  "fine_forgiven": {
 "user": "the cool librarian",
 "amount": "none"
  },
  "patron_id": "56dbe25ea12958478cec42ba"
}

Example 2: Get fines for patron with id

http://localhost:8080/patrons/56dbe25ea12958478cec42ba/fines

Example 3: Get a specific patron

http://localhost:8080/patrons/56dbe25ea12958478cec42ba

Example 4: Get all patrons

http://localhost:8080/patrons

Example 5: Delete a patron (delete)

http://localhost:8080/patrons/56dbe791a129584a506fb41a

Example 6: Add a patron (post)

http://localhost:8080/patrons
{
 "status": "ACTIVE",
 "patron_name": "Smith,John",
 "patron_barcode": "00007888",
 "patron_local_id": "abcdefd",
 "contact_info": {
  "patron_address_local": {
   "line1": "Main Street 1",
   "line2": "Nice building near the corner",
   "city": "London",
   "state_province": "",
   "postal_code": "",
   "address_note": "",
   "start_date": "2013-12-26Z"
  },
  "patron_address_home": {
   "line1": "Main Street 1",
   "line2": "Nice building near the corner",
   "city": "London",
   "state_province": "",
   "postal_code": "",
   "address_note": "",
   "start_date": "2013-12-26Z"
  },
  "patron_address_work": {
   "line1": "Main Street 1",
   "line2": "Nice building near the corner",
   "city": "London",
   "state_province": "",
   "postal_code": "",
   "address_note": "",
   "start_date": "2013-12-26Z"
  },
  "patron_email": "johns@mylib.org",
  "patron_email_alternative": "johns@mylib.org",
  "patron_phone_cell": "123456789",
  "patron_phone_home": "123456789",
  "patron_phone_work": "123456789",
  "patron_primary_contact_info": "patron_email"
 },
 "total_loans": 50,
 "total_fines": "100$",
 "total_fines_paid": "0$",
 "patron_code": {
  "value": "CH",
  "description": "Child"
 }
}

Additional information

Other modules.

See project RMB at the FOLIO issue tracker.

Other FOLIO Developer documentation is at dev.folio.org