fix: do not require an HTTP body on incoming binary event messages

This commit modifies the HTTP receivers/parsers to allow for the incoming body
of an HTTP request to be empty if the event message is sent using the binary
mode. In structured mode, a `ValidationError` will still be thrown, since the
entire event must be encoded in the HTTP body.

Signed-off-by: Lance Ball <lball@redhat.com>

Author: lance

Diff for: src/transport/http/binary_receiver.ts

@@ -32,10 +32,11 @@ export class BinaryHTTPReceiver {
    * @returns {CloudEvent} an instance of CloudEvent representing the incoming request
    * @throws {ValidationError} of the event does not conform to the spec
    */
-  parse(payload: string | Record<string, unknown>, headers: Headers): CloudEvent {
-    if (!payload) throw new ValidationError("payload is null or undefined");
+  parse(payload: string | Record<string, unknown> | undefined | null, headers: Headers): CloudEvent {
     if (!headers) throw new ValidationError("headers is null or undefined");
-    isStringOrObjectOrThrow(payload, new ValidationError("payload must be an object or a string"));
+    if (payload) {
+      isStringOrObjectOrThrow(payload, new ValidationError("payload must be an object or a string"));
+    }
 
     if (
       headers[CONSTANTS.CE_HEADERS.SPEC_VERSION] &&
@@ -61,11 +62,15 @@ export class BinaryHTTPReceiver {
       }
     }
 
-    const parser = parserByContentType[eventObj.datacontenttype as string];
-    if (!parser) {
-      throw new ValidationError(`no parser found for content type ${eventObj.datacontenttype}`);
+    let parsedPayload;
+
+    if (payload) {
+      const parser = parserByContentType[eventObj.datacontenttype as string];
+      if (!parser) {
+        throw new ValidationError(`no parser found for content type ${eventObj.datacontenttype}`);
+      }
+      parsedPayload = parser.parse(payload);
     }
-    const parsedPayload = parser.parse(payload);
 
     // Every unprocessed header can be an extension
     for (const header in sanitizedHeaders) {

Diff for: src/transport/http/structured_receiver.ts

@@ -31,7 +31,7 @@ export class StructuredHTTPReceiver {
    * @returns {CloudEvent} a new CloudEvent instance for the provided headers and payload
    * @throws {ValidationError} if the payload and header combination do not conform to the spec
    */
-  parse(payload: Record<string, unknown> | string, headers: Headers): CloudEvent {
+  parse(payload: Record<string, unknown> | string | undefined | null, headers: Headers): CloudEvent {
     if (!payload) throw new ValidationError("payload is null or undefined");
     if (!headers) throw new ValidationError("headers is null or undefined");
     isStringOrObjectOrThrow(payload, new ValidationError("payload must be an object or a string"));

Diff for: src/transport/receiver.ts

@@ -59,7 +59,10 @@ export class Receiver {
    * @param {Object|JSON} body The body of the HTTP request
    * @return {CloudEvent} A new {CloudEvent} instance
    */
-  accept(headers: Headers, body: string | Record<string, unknown> | CloudEventV1 | CloudEventV03): CloudEvent {
+  accept(
+    headers: Headers,
+    body: string | Record<string, unknown> | CloudEventV1 | CloudEventV03 | undefined | null,
+  ): CloudEvent {
     const cleanHeaders: Headers = sanitize(headers);
     const mode: Mode = getMode(cleanHeaders);
     const version = getVersion(mode, cleanHeaders, body);
@@ -103,7 +106,7 @@ function getMode(headers: Headers): Mode {
 function getVersion(
   mode: Mode,
   headers: Headers,
-  body: string | Record<string, unknown> | CloudEventV03 | CloudEventV1,
+  body: string | Record<string, unknown> | CloudEventV03 | CloudEventV1 | undefined | null,
 ) {
   if (mode === Mode.BINARY) {
     // Check the headers for the version
@@ -113,7 +116,7 @@ function getVersion(
     }
   } else {
     // structured mode - the version is in the body
-    return typeof body === "string" ? JSON.parse(body).specversion : body.specversion;
+    return typeof body === "string" ? JSON.parse(body).specversion : (body as CloudEvent).specversion;
   }
   return Version.V1;
 }

Diff for: test/integration/http_receiver_test.ts

@@ -39,6 +39,30 @@ describe("HTTP Transport Binding Receiver for CloudEvents", () => {
       expect((event.data as Record<string, string>).lunch).to.equal("sushi");
     });
 
+    it("Accepts binary events when the data property is undefined", () => {
+      const binaryHeaders = {
+        "content-type": "application/json; charset=utf-8",
+        "ce-specversion": specversion,
+        "ce-id": id,
+        "ce-type": type,
+        "ce-source": source,
+      };
+      const event = receiver.accept(binaryHeaders, undefined);
+      expect(event.data).to.be.undefined;
+    });
+
+    it("Accepts binary events when the data property is null", () => {
+      const binaryHeaders = {
+        "content-type": "application/json; charset=utf-8",
+        "ce-specversion": specversion,
+        "ce-id": id,
+        "ce-type": type,
+        "ce-source": source,
+      };
+      const event = receiver.accept(binaryHeaders, null);
+      expect(event.data).to.be.undefined;
+    });
+
     it("Converts the JSON body of a structured event to an Object", () => {
       const payload = {
         id,

Diff for: test/integration/receiver_binary_03_tests.ts

@@ -9,18 +9,6 @@ const receiver = new BinaryHTTPReceiver(Version.V03);
 
 describe("HTTP Transport Binding Binary Receiver for CloudEvents v0.3", () => {
   describe("Check", () => {
-    it("Throw error when payload arg is null or undefined", () => {
-      // setup
-      const payload = undefined;
-      const attributes = {};
-
-      // act and assert
-      expect(receiver.parse.bind(receiver, (payload as unknown) as string, attributes)).to.throw(
-        ValidationError,
-        "payload is null or undefined",
-      );
-    });
-
     it("Throw error when attributes arg is null or undefined", () => {
       // setup
       const payload = {};

Diff for: test/integration/receiver_binary_1_tests.ts

@@ -10,18 +10,6 @@ const receiver = new BinaryHTTPReceiver(Version.V1);
 
 describe("HTTP Transport Binding Binary Receiver for CloudEvents v1.0", () => {
   describe("Check", () => {
-    it("Throw error when payload arg is null or undefined", () => {
-      // setup
-      const payload = null;
-      const attributes = {};
-
-      // act and assert
-      expect(receiver.parse.bind(receiver, (payload as unknown) as string, attributes)).to.throw(
-        ValidationError,
-        "payload is null or undefined",
-      );
-    });
-
     it("Throw error when attributes arg is null or undefined", () => {
       // setup
       const payload = {};