feat: Support link and slug headers in SimpleBodyParser

src/ldp/http/SimpleBodyParser.ts

@@ -1,5 +1,6 @@
 import { HttpRequest } from '../../server/HttpRequest';
 import { DATA_TYPE_BINARY } from '../../util/ContentTypes';
+import { UnsupportedHttpError } from '../../util/errors/UnsupportedHttpError';
 import { BinaryRepresentation } from '../representation/BinaryRepresentation';
 import { RepresentationMetadata } from '../representation/RepresentationMetadata';
 import { BodyParser } from './BodyParser';
@@ -17,24 +18,53 @@ export class SimpleBodyParser extends BodyParser {
   // Note that the only reason this is a union is in case the body is empty.
   // If this check gets moved away from the BodyParsers this union could be removed
   public async handle(input: HttpRequest): Promise<BinaryRepresentation | undefined> {
-    const contentType = input.headers['content-type'];
-
-    if (!contentType) {
+    if (!input.headers['content-type']) {
       return;
     }
 
-    const mediaType = contentType.split(';')[0];
-
-    const metadata: RepresentationMetadata = {
-      raw: [],
-      profiles: [],
-      contentType: mediaType,
-    };
-
     return {
       dataType: DATA_TYPE_BINARY,
       data: input,
-      metadata,
+      metadata: this.parseMetadata(input),
     };
   }
+
+  private parseMetadata(input: HttpRequest): RepresentationMetadata {
+    const mediaType = input.headers['content-type']!.split(';')[0];
+
+    const metadata: RepresentationMetadata = {
+      raw: [],
+      contentType: mediaType,
+    };
+
+    const { link, slug } = input.headers;
+
+    if (slug) {
+      if (Array.isArray(slug)) {
+        throw new UnsupportedHttpError('At most 1 slug header is allowed.');
+      }
+      metadata.slug = slug;
+    }
+
+    // There are similarities here to Accept header parsing so that library should become more generic probably
+    if (link) {
+      metadata.linkRel = {};
+      const linkArray = Array.isArray(link) ? link : [ link ];
+      const parsedLinks = linkArray.map((entry): { url: string; rel: string } => {
+        const [ , url, rest ] = /^<([^>]*)>(.*)$/u.exec(entry) ?? [];
+        const [ , rel ] = /^ *; *rel="(.*)"$/u.exec(rest) ?? [];
+        return { url, rel };
+      });
+      parsedLinks.forEach((entry): void => {
+        if (entry.rel) {
+          if (!metadata.linkRel![entry.rel]) {
+            metadata.linkRel![entry.rel] = new Set();
+          }
+          metadata.linkRel![entry.rel].add(entry.url);
+        }
+      });
+    }
+
+    return metadata;
+  }
 }