Cannot read property 'did' of undefined.

[ChinmayPatel]

Trying to validate a signed credential, using the code below,

const emailAddressSignedCredential = '{"@context":[{"id":"@id","type":"@type","cred":"https://w3id.org/credentials#","schema":"http://schema.org/","dc":"http://purl.org/dc/terms/","xsd":"http://www.w3.org/2001/XMLSchema#","sec":"https://w3id.org/security#","Credential":"cred:Credential","issuer":{"@id":"cred:issuer","@type":"@id"},"issued":{"@id":"cred:issued","@type":"xsd:dateTime"},"claim":{"@id":"cred:claim","@type":"@id"},"credential":{"@id":"cred:credential","@type":"@id"},"expires":{"@id":"sec:expiration","@type":"xsd:dateTime"},"proof":{"@id":"sec:proof","@type":"@id"},"EcdsaKoblitzSignature2016":"sec:EcdsaKoblitzSignature2016","created":{"@id":"dc:created","@type":"xsd:dateTime"},"creator":{"@id":"dc:creator","@type":"@id"},"domain":"sec:domain","nonce":"sec:nonce","signatureValue":"sec:signatureValue"},{"ProofOfEmailCredential":"https://identity.jolocom.com/terms/ProofOfEmailCredential","schema":"http://schema.org/","email":"schema:email"}],"id":"claimId:3ddfa760e8c02745","issuer":"did:jolo:0e2abe7919a330e13e8c9cac2ef31a52a307880d6fd22e3878de4a6fc7c38f41","issued":"2020-08-03T17:54:44.752Z","type":["Credential","ProofOfEmailCredential"],"expires":"2021-08-03T17:54:44.749Z","proof":{"created":"2020-08-03T17:54:44.751Z","type":"EcdsaKoblitzSignature2016","nonce":"754a9373838c0a6e","signatureValue":"08ba912396a60e51f092a09e91fc0d89e07bc3c99140ca9e5c72b4258ec200e34bcaa8d4c0c0313916fe6481f259b73f8ae6eef49aac946c272a30ced451f991","creator":"did:jolo:0e2abe7919a330e13e8c9cac2ef31a52a307880d6fd22e3878de4a6fc7c38f41#keys-1"},"claim":{"email":"cpatel@keyko.io","id":"did:jolo:0e2abe7919a330e13e8c9cac2ef31a52a307880d6fd22e3878de4a6fc7c38f41"},"name":"Email address"}';

const receivedCredential = JolocomLib.parse.signedCredential(emailAddressSignedCredential);

... and It's giving me the error below.

TypeError: Cannot read property 'did' of undefined
    at Object.exports.validateDigestable (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/jolocom-lib/ts/utils/validation.ts:21:62)
    at _callee2$ (/Users/chinmay/coding/keyko/ssi/server-identity/index.js:87:41)
    at tryCatch (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/babel-polyfill/node_modules/regenerator-runtime/runtime.js:65:40)
    at Generator.invoke [as _invoke] (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/babel-polyfill/node_modules/regenerator-runtime/runtime.js:303:22)
    at Generator.prototype.(anonymous function) [as next] (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/babel-polyfill/node_modules/regenerator-runtime/runtime.js:117:21)
    at step (/Users/chinmay/coding/keyko/ssi/server-identity/index.js:158:191)
    at /Users/chinmay/coding/keyko/ssi/server-identity/index.js:158:361

I've also attempted, fromJSON function by passing the object directly but it still didn't work. This approach gave me an error _jolocomLib.JolocomLib.parse.signedCredential.fromJSON is not a function.

Also, if you are wondering, emailAddressSignedCredential is created using the code below,

emailAddressSignedCredential = await userWallet.create.signedCredential({
      metadata: claimsMetadata.emailAddress,
      claim: { email: process.env.user_email },
      subject: userWallet.did // Our own DID, referred to as a self-issued credential
    }, process.env.user_secret)

Is this the library error or am I not using the library correctly?

[ChinmayPatel]

Also, one more question. How can I view the public claim?

[mnzaki]

JolocomLib.parse.signedCredential is actually just a convenience wrapper around SignedCredential.fromJSON (it is the fromJSON static method). It expects a JSON objects (not stringify()ed!)
I hope you are using typescript, because you can avoid these kinds of errors entirely (the tsserver will point this kind of type mismatch out)

Re: public claim, there is no "public claim", these credentials are created and signed and passed around locally, not registered publicly anywhere.

There is though one credential which we typically store on IPFS, and that's the PublicProfile credential, which is meant to be used as a public profile for "service backend identities". This contains things like a URL and description and image.

[ChinmayPatel]

I agree with the "public claim" question. That was my misunderstanding of the create function. I red the docs further and found out last night. Thanks for the clarification though.

Regarding JolocomLib.parse.signedCredential, the wrapper makes sense. My first attempt, after reading the doc was to attempt just that. I passed the JSON object created using userWallet.create.signedCredential directly to JolocomLib.parse.signedCredential and I receive an error below.

{ jsonld.SyntaxError: Invalid JSON-LD syntax; @context must be an object.
    at api.process (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/jsonld/lib/context.js:160:13)
    at contextsToProcess.forEach.localCtx (/Users/chinmay/coding/keyko/ssi/server-identity/node_modules/jsonld/lib/jsonld.js:328:17)
    at Array.forEach (<anonymous>)
    at /Users/chinmay/coding/keyko/ssi/server-identity/node_modules/jsonld/lib/jsonld.js:327:21
    at process._tickCallback (internal/process/next_tick.js:68:7)
  name: 'jsonld.SyntaxError',
  details: { code: 'invalid local context', context: undefined } }

[mnzaki]

you need to do something like:

const reparsed = JolocomLib.parse.signedCredential(emailAddressSignedCredential.toJSON())

[ChinmayPatel]

Gotcha. I was trying all in one script and that created the confusion.

I've create a PR(jolocom/jolocom-lib#418) for the documentation update from other people running into the same issue. You are welcome to accept or reject it based on your plan ahead.

Thanks for the help.