Add wellKnownMediaTypes configuration option

Closes #124

Author: pietercolpaert

README.md

@@ -181,6 +181,7 @@ Optionally, the following parameters can be set in the `JsonLdParser` constructo
 * `skipContextValidation`: If JSON-LD context validation should be skipped. This is useful when parsing large contexts that are known to be valid. _(Default: `false`)_
 * `rdfstar`: If embedded nodes and annotated objects should be parsed according to the [JSON-LD star specification](https://json-ld.github.io/json-ld-star/). _(Default: `true`)_
 * `rdfstarReverseInEmbedded`: If embedded nodes in JSON-LD star can have reverse properties. _(Default: `false`)_
+* `wellKnownMediaTypes`: an array of media types that can also be parsed as JSON-LD. _(Default: `['application/activity+json']`)_
 
 ```javascript
 new JsonLdParser({

lib/JsonLdParser.ts

@@ -106,8 +106,12 @@ export class JsonLdParser extends Transform implements RDF.Sink<EventEmitter, RD
   public static fromHttpResponse(baseIRI: string, mediaType: string,
                                  headers?: Headers, options?: IJsonLdParserOptions): JsonLdParser {
     let context: JsonLdContext | undefined;
-    // Special cases when receiving something else than the JSON-LD media type
-    if (mediaType !== 'application/ld+json') {
+    let wellKnownMediaTypes = ['application/activity+json'];
+    if (options && options.wellKnownMediaTypes) {
+      wellKnownMediaTypes = options.wellKnownMediaTypes;
+    }
+    // Special cases when receiving something else than the JSON-LD media type or the wellKnownMediaTypes
+    if (mediaType !== 'application/ld+json' && !wellKnownMediaTypes.includes(mediaType)) {
       // Only accept JSON or JSON extension types
       if (mediaType !== 'application/json' && !mediaType.endsWith('+json')) {
         throw new ErrorCoded(`Unsupported JSON-LD media type ${mediaType}`,
@@ -672,4 +676,10 @@ export interface IJsonLdParserOptions {
    * Defaults to false.
    */
   rdfstarReverseInEmbedded?: boolean;
+  /**
+   * If the APIs you interact with publish valid JSON-LD on media types that are not application/ld+json,
+   * provide those content-types in this array.
+   * Default to ['application/activity+json']
+   */
+  wellKnownMediaTypes?: string[];
 }

test/JsonLdParser-test.ts

@@ -105,6 +105,11 @@ describe('JsonLdParser', () => {
       expect((<any> parser).options.baseIRI).toEqual('BASE');
     });
 
+    it('should handle an ActivityStreams JSON response in the same way as JSON-LD', () => {
+      const parser = JsonLdParser.fromHttpResponse('BASE', 'application/activity+json');
+      expect((<any> parser).options.baseIRI).toEqual('BASE');
+    });
+
     it('should handle a JSON-LD response and allow option overrides', () => {
       const parser = JsonLdParser.fromHttpResponse('BASE', 'application/ld+json', undefined, { baseIRI: 'base2' });
       expect((<any> parser).options.baseIRI).toEqual('base2');
@@ -116,6 +121,13 @@ describe('JsonLdParser', () => {
           ERROR_CODES.LOADING_DOCUMENT_FAILED))
     });
 
+    it('should error on an application/activity+json without link header if the wellknowntypes do not include it', () => {
+      expect(() => JsonLdParser.fromHttpResponse('BASE', 'application/activity+json', undefined, {
+        wellKnownMediaTypes: []
+      })).toThrow(new ErrorCoded(`Missing context link header for media type application/activity+json on BASE`,
+      ERROR_CODES.LOADING_DOCUMENT_FAILED))
+    });
+
     it('should error on a plain JSON response without link header', () => {
       expect(() => JsonLdParser.fromHttpResponse('BASE', 'application/json'))
         .toThrow(new ErrorCoded(`Missing context link header for media type application/json on BASE`,