feat: Validate Accept-DateTime.

src/util/HeaderUtil.ts

@@ -362,6 +362,9 @@ export const parseAcceptLanguage = (input: string): AcceptLanguage[] => {
   return results;
 };
 
+// eslint-disable-next-line max-len
+const rfc1123Date = /^(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun), \d{2} (?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) \d{4} \d{2}:\d{2}:\d{2} GMT$/u;
+
 /**
  * Parses an Accept-DateTime header string.
  *
@@ -369,8 +372,22 @@ export const parseAcceptLanguage = (input: string): AcceptLanguage[] => {
  *
  * @returns An array with a single {@link AcceptDatetime} object.
  */
-export const parseAcceptDateTime = (input: string): AcceptDatetime[] =>
+export const parseAcceptDateTime = (input: string): AcceptDatetime[] => {
-  [{ range: input, weight: 1 }];
+  const results: AcceptDatetime[] = [];
+  const range = input.trim();
+  if (range) {
+    if (!rfc1123Date.test(range)) {
+      logger.warn(
+        `Invalid Accept-DateTime range: ${range}`,
+      );
+      throw new BadRequestHttpError(
+        `Invalid Accept-DateTime range: ${range} does not match the RFC1123 format`,
+      );
+    }
+    results.push({ range, weight: 1 });
+  }
+  return results;
+};
 
 /**
  * Adds a header value without overriding previous values.

test/unit/util/HeaderUtil.test.ts

@@ -3,6 +3,7 @@ import {
   addHeader,
   parseAccept,
   parseAcceptCharset,
+  parseAcceptDateTime,
   parseAcceptEncoding,
   parseAcceptLanguage,
   parseForwarded,
@@ -131,6 +132,24 @@ describe('HeaderUtil', (): void => {
     });
   });
 
+  describe('#parseAcceptDateTime', (): void => {
+    it('parses valid Accept-DateTime Headers.', async(): Promise<void> => {
+      expect(parseAcceptDateTime('Wed, 30 May 2007 18:47:52 GMT')).toEqual([
+        { range: 'Wed, 30 May 2007 18:47:52 GMT', weight: 1 },
+      ]);
+    });
+
+    it('parses empty Accept-DateTime headers.', async(): Promise<void> => {
+      expect(parseAcceptDateTime('')).toEqual([]);
+      expect(parseAcceptDateTime('   ')).toEqual([]);
+    });
+
+    it('rejects invalid Accept-DateTime Headers.', async(): Promise<void> => {
+      expect((): any => parseAcceptDateTime('a/b')).toThrow('Invalid Accept-DateTime range:');
+      expect((): any => parseAcceptDateTime('30 May 2007')).toThrow('Invalid Accept-DateTime range:');
+    });
+  });
+
   describe('#addHeader', (): void => {
     let response: HttpResponse;
 
@@ -168,7 +187,7 @@ describe('HeaderUtil', (): void => {
     });
   });
 
-  describe('parseForwarded', (): void => {
+  describe('#parseForwarded', (): void => {
     it('parses an undefined value.', (): void => {
       expect(parseForwarded()).toEqual({});
     });