Apply SPARQL escape helpers on interpolated template variables

Author: erikap

Dockerfile

@@ -1,4 +1,4 @@
-FROM semtech/mu-javascript-template:1.0.0
+FROM semtech/mu-javascript-template:1.1.0
 
 MAINTAINER Erika Pauwels <erika.pauwels@gmail.com>
 

README.md

@@ -39,7 +39,7 @@ Each element in the array will become an API endpoint in the microservice. An ex
 ## Using variables in the export query
 You can also define variables in your SPARQL export query which will be replaced with query param values at runtime. Therefore, we use [ES6's tagged template literals](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals#Tagged_template_literals).
 
-Import the `template` tag function from `/app/template.js` in your `export.js` and apply the tag function on your query. You can then define variables in your SPARQL query using `${'myVariable'}` (note the quotes around the variable name). At runtime the variable will be replaced with the value provided in the `myVariable` query param of the request.
+Import the `template` tag function from `/app/template.js` in your `export.js` and apply the tag function on your query. You can then define variables in your SPARQL query using `${['myVariable', 'type']}`. `myVariable` is the name of the variable that must be replaced. `type` is the datatype of the variable. This must be one of `'string'`, `'uri'`, `'int'`, `'float'`, `'date'`, `'dateTime'`, `'bool'`. At runtime the variable will be replaced with the value provided in the `myVariable` query param of the request.
 
 An example `export.js` including variables file may look as follows:
 

app.js

@@ -4,32 +4,40 @@ import request from 'request';
 import queries from '/config/export';
 
 queries.map(function(config) {
-    app.get(config.path, function(req, res, next) {
-        const options = {
-            method: 'POST',
-            url: process.env.MU_SPARQL_ENDPOINT,
-            encoding: 'utf8',
-            headers: {
-                'Accept': config.format
-            },
-            qs: {
-                format: config.format,
-                // replace placeholders in query with query params if it's a template
-                query: typeof(config.query) === 'string' ? config.query : config.query(req.query)
-            }
-        };
-        
-        request(options, function(error, response, body) {
-            if (error) {
-                console.error(`Something went wrong executing the SPARQL query: ${JSON.stringify(error)}`);
-                next(error);
-            } else if (response.statusCode == 200) {
-                const filename = req.query.file || config.file;
-                if (filename) { res.attachment(filename); }
-                res.send(body);
-            } else {
-                next(new Error(body));
-            }
-        });
-    } );    
+  app.get(config.path, function(req, res, next) {
+    let query = '';
+    try {
+      // replace placeholders in query with query params if it's a template
+      query = typeof(config.query) === 'string' ? config.query : config.query(req.query);
+    } catch (err) {
+      err.status = 400;
+      return next(err);
+    }
+
+    const options = {
+      method: 'POST',
+      url: process.env.MU_SPARQL_ENDPOINT,
+      encoding: 'utf8',
+      headers: {
+        'Accept': config.format
+      },
+      qs: {
+        format: config.format,
+        query: query
+      }
+    };
+
+    request(options, function(error, response, body) {
+      if (error) {
+        console.error(`Something went wrong executing the SPARQL query: ${JSON.stringify(error)}`);
+        return next(error);
+      } else if (response.statusCode == 200) {
+        const filename = req.query.file || config.file;
+        if (filename) { res.attachment(filename); }
+        res.send(body);
+      } else {
+        return next(new Error(body));
+      }
+    });
+  } );    
 });

package.json

@@ -1,10 +1,10 @@
 {
-  "name": "mu-export-js-template",
-  "version": "0.2.0",
+  "name": "export-service",
+  "version": "1.0.0",
   "description": "Microservice to export data using custom defined SPARQL queries",
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/mu-semtech/mu-export-js-template.git"
+    "url": "git+https://github.com/mu-semtech/export-service.git"
   },
   "keywords": [
     "mu-semtech"

template.js

@@ -1,10 +1,16 @@
-export default function template(strings, ...keys) {
-    return (function(values) {
-        var result = [strings[0]];
-        keys.forEach(function(key, i) {
-            var value = values[key];
-            result.push(value, strings[i + 1]);
-        });
-        return result.join('');
+import { sparqlEscape } from 'mu';
+
+export default function template(strings, ...replacements) {
+  return (function(values) { // object with query param values to inline
+    const result = [strings[0]]; // string parts without variables
+    replacements.forEach(function(replacement, i) { // replacement = [key, type]
+      const value = values[replacement[0]];
+      if (value == null) {
+        throw new Error(`No value provided for key ${replacement[0]}`);
+      }
+      const escapedValue = sparqlEscape(value, replacement[1]);
+      result.push(escapedValue, strings[i + 1]);
     });
+    return result.join('');
+  });
 }