Option to ignore JSON media type for link headers

rubensworks · Nov 9, 2020 · d1279e2 · d1279e2
1 parent 012fe50
commit d1279e2
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Showing 2 changed files with 39 additions and 16 deletions.
diff --git a/lib/JsonLdParser.ts b/lib/JsonLdParser.ts
@@ -106,24 +106,29 @@ export class JsonLdParser extends Transform implements RDF.Sink<EventEmitter, RD
           ERROR_CODES.LOADING_DOCUMENT_FAILED);
       }
 
-      // We need exactly one JSON-LD context in the link header
-      if (headers && headers.has('Link')) {
-        headers.forEach((value, key) => {
-          if (key === 'link') {
-            const linkHeader = parseLinkHeader(value);
-            for (const link of linkHeader.get('rel', 'http://www.w3.org/ns/json-ld#context')) {
-              if (context) {
-                throw new ErrorCoded('Multiple JSON-LD context link headers were found on ' + baseIRI,
-                  ERROR_CODES.MULTIPLE_CONTEXT_LINK_HEADERS);
+      // If we can skip checking for the context in the Link headers
+      const skipJSON = mediaType === 'application/json' && !!options?.ignoreJSONMediaType
+
+      if (!skipJSON) {
+        // We need exactly one JSON-LD context in the link header
+        if (headers && headers.has('Link')) {
+          headers.forEach((value, key) => {
+            if (key === 'link') {
+              const linkHeader = parseLinkHeader(value);
+              for (const link of linkHeader.get('rel', 'http://www.w3.org/ns/json-ld#context')) {
+                if (context) {
+                  throw new ErrorCoded('Multiple JSON-LD context link headers were found on ' + baseIRI,
+                    ERROR_CODES.MULTIPLE_CONTEXT_LINK_HEADERS);
+                }
+                context = link.uri;
               }
-              context = link.uri;
             }
-          }
-        });
-      }
-      if (!context) {
-        throw new ErrorCoded(`Missing context link header for media type ${mediaType} on ${baseIRI}`,
-          ERROR_CODES.LOADING_DOCUMENT_FAILED);
+          });
+        }
+        if (!context) {
+          throw new ErrorCoded(`Missing context link header for media type ${mediaType} on ${baseIRI}`,
+            ERROR_CODES.LOADING_DOCUMENT_FAILED);
+        }
       }
     }
 
@@ -548,6 +553,12 @@ export interface IJsonLdParserOptions {
    * Loader for remote contexts.
    */
   documentLoader?: IDocumentLoader;
+  /**
+   * Allows {@link JsonLdParser.fromHttpResponse} to treat responses with
+   * Content-Type: application/json as JSON-LD and not error if they
+   * don't contain a Link header. 
+   */
+  ignoreJSONMediaType?: boolean
   /**
    * If blank node predicates should be allowed,
    * they will be ignored otherwise.

diff --git a/test/JsonLdParser-test.ts b/test/JsonLdParser-test.ts
@@ -36,6 +36,18 @@ describe('JsonLdParser', () => {
         ERROR_CODES.LOADING_DOCUMENT_FAILED))
     });
 
+    it('should handle a plain JSON response when ignoreJSONMediaType is true', () => {
+      const parser = JsonLdParser.fromHttpResponse('BASE', 'application/json', undefined, { ignoreJSONMediaType: true });
+      expect((<any> parser).options.baseIRI).toEqual('BASE');
+    });
+
+
+    it('should error on a JSON extension type even with ignoreJSONMediaType', () => {
+      expect(() => JsonLdParser.fromHttpResponse('BASE', 'text/turtle+json', undefined, { ignoreJSONMediaType: true }))
+        .toThrow(new ErrorCoded(`Missing context link header for media type text/turtle+json on BASE`,
+          ERROR_CODES.LOADING_DOCUMENT_FAILED))
+    });
+
     it('should error on a JSON extension type without link header', () => {
       expect(() => JsonLdParser.fromHttpResponse('BASE', 'text/turtle+json'))
         .toThrow(new ErrorCoded(`Missing context link header for media type text/turtle+json on BASE`,