feat: add simple preference parser

src/ldp/http/SimplePreferenceParser.ts

@@ -0,0 +1,42 @@
+import { HttpRequest } from '../../server/HttpRequest';
+import { PreferenceParser } from './PreferenceParser';
+import { RepresentationPreference } from '../representation/RepresentationPreference';
+import { RepresentationPreferences } from '../representation/RepresentationPreferences';
+
+export class SimplePreferenceParser extends PreferenceParser {
+  public constructor() {
+    super();
+  }
+
+  public async canHandle(): Promise<void> {
+    return undefined;
+  }
+
+  public async handle(input: HttpRequest): Promise<RepresentationPreferences> {
+    const type = this.parseHeader(input.headers.accept);
+    const charset = this.parseHeader(input.headers['accept-charset'] as string);
+    const language = this.parseHeader(input.headers['accept-language']);
+
+    // Datetime can have commas so requires separate rules
+    let datetime;
+    if (input.headers['accept-datetime']) {
+      datetime = [{ value: input.headers['accept-datetime'] as string }];
+    }
+
+    return { type, charset, datetime, language };
+  }
+
+  private parseHeader(header: string): RepresentationPreference[] {
+    if (!header) {
+      return undefined;
+    }
+
+    return header.split(',').map((preference): RepresentationPreference => {
+      const parts = preference.split(';');
+      if (parts.length === 1) {
+        return { value: parts[0].trim() };
+      }
+      return { value: parts[0].trim(), weight: parseFloat(parts[1].trim().slice('q='.length)) };
+    });
+  }
+}