Add JSON-LD handler to fetcher

src/fetcher.ts

@@ -54,6 +54,7 @@ import {
   Quad_Predicate,
   Quad_Subject
 } from './tf-types'
+import jsonldParser from './jsonldparser'
 
 const Parsable = {
   'text/n3': true,
@@ -479,6 +480,39 @@ class HTMLHandler extends Handler {
 }
 HTMLHandler.pattern = new RegExp('text/html')
 
+class JsonLdHandler extends Handler {
+  static toString () {
+    return 'JsonLdHandler'
+  }
+  static register (fetcher: Fetcher) {
+    fetcher.mediatypes['application/ld+json'] = {
+      'q': 0.9
+    }
+  }
+  parse (
+    fetcher: Fetcher,
+    responseText: string,
+    options: {
+      req: Quad_Subject
+      original: Quad_Subject
+      resource: Quad_Subject
+    } & Options,
+    response: ExtendedResponse
+  ): ExtendedResponse | Promise<FetchError> {
+    const kb = fetcher.store
+    return new Promise((resolve, reject) => {
+      try {
+        jsonldParser (responseText, kb, options.original.value, resolve)
+      } catch (err) {
+        const msg = 'Error trying to parse ' + options.resource +
+          ' as JSON-LD:\n' + err  // not err.stack -- irrelevant
+        resolve(fetcher.failFetch(options, msg, 'parse_error', response))
+      }
+    })
+  }
+}
+JsonLdHandler.pattern = /application\/ld\+json/
+
 class TextHandler extends Handler {
   static toString () {
     return 'TextHandler'
@@ -578,7 +612,7 @@ class N3Handler extends Handler {
 N3Handler.pattern = new RegExp('(application|text)/(x-)?(rdf\\+)?(n3|turtle)')
 
 const defaultHandlers = {
-  RDFXMLHandler, XHTMLHandler, XMLHandler, HTMLHandler, TextHandler, N3Handler
+  RDFXMLHandler, XHTMLHandler, XMLHandler, HTMLHandler, TextHandler, N3Handler, JsonLdHandler
 }
 
 function isXHTML (responseText) {
@@ -1895,7 +1929,6 @@ export default class Fetcher implements CallbackifyInterface {
     const responseNode = this.saveResponseMetadata(response, options)
 
     const contentType = this.normalizedContentType(options, headers) || ''
-
     let contentLocation = headers.get('content-location')
 
     // this.fireCallbacks('recv', xhr.args)

tests/unit/fetcher-jsonld-test.js

@@ -0,0 +1,43 @@
+import * as rdf from '../../src';
+
+const nock = require('nock')
+import chai from 'chai'
+
+const {expect} = chai
+
+describe('Given a JSON-LD resource', () => {
+
+    const uri = "http://localhost/jsonld#it"
+
+    beforeEach(() => {
+        const docContents = `
+        {
+            "@id": "${uri}",
+            "https://predicate.example": "value"
+        }
+        `
+        nock('http://localhost').get('/jsonld').reply(200, docContents, {
+            'Content-Type': 'application/ld+json',
+        })
+    });
+
+    describe('when it is fetched to the store', () => {
+
+        let fetcher, store;
+        beforeEach(() => {
+            store = rdf.graph();
+            fetcher = rdf.fetcher(store);
+        });
+
+        it('then the triples from the document can be found in the store', async () => {
+            await fetcher.load(uri);
+            const match = store.anyStatementMatching(rdf.sym(uri), rdf.sym('https://predicate.example'), rdf.literal('value'));
+            expect(match.subject.value).to.equal(uri);
+            expect(match.predicate.value).to.equal('https://predicate.example');
+            expect(match.object.value).to.equal('value');
+
+        });
+    });
+
+
+});

tests/unit/fetcher-test.js

@@ -372,7 +372,7 @@ describe('Fetcher', () => {
     it('should set the Accept header', () => {
       options = fetcher.initFetchOptions(uri, options)
 
-      let expectedHeader = 'image/*;q=0.9, */*;q=0.1, application/rdf+xml;q=0.9, application/xhtml+xml, text/xml;q=0.5, application/xml;q=0.5, text/html;q=0.9, text/plain;q=0.5, text/n3;q=1.0, text/turtle;q=1'
+      let expectedHeader = 'image/*;q=0.9, */*;q=0.1, application/rdf+xml;q=0.9, application/xhtml+xml, text/xml;q=0.5, application/xml;q=0.5, text/html;q=0.9, text/plain;q=0.5, text/n3;q=1.0, text/turtle;q=1, application/ld+json;q=0.9'
 
       expect(options.headers['accept']).to.equal(expectedHeader)
     })