feat: integrate cloudevents module

package.json

@@ -10,6 +10,7 @@
   "types": "build/src/invoker.d.ts",
   "dependencies": {
     "body-parser": "^1.18.3",
+    "cloudevents": "^3.0.1",
     "express": "^4.16.4",
     "minimist": "^1.2.0",
     "on-finished": "^2.3.0"

src/cloudevents.ts

@@ -13,43 +13,15 @@
 // limitations under the License.
 
 import * as express from 'express';
-import { CloudEventsContext } from './functions';
+import { CloudEvent, Receiver } from 'cloudevents';
 
 /**
- * Checks whether the incoming request is a CloudEvents event in binary content
- * mode. This is verified by checking the presence of required headers.
- *
- * @link https://github.com/cloudevents/spec/blob/master/http-protocol-binding.md#3-http-message-mapping
- *
- * @param req Express request object.
- * @return True if the request is a CloudEvents event in binary content mode,
- *     false otherwise.
- */
-export function isBinaryCloudEvent(req: express.Request): boolean {
-  return !!(
-    req.header('ce-type') &&
-    req.header('ce-specversion') &&
-    req.header('ce-source') &&
-    req.header('ce-id')
-  );
-}
-
-/**
- * Returns a CloudEvents context from the given CloudEvents request. Context
- * attributes are retrieved from request headers.
+ * Returns a CloudEvent from the given CloudEvents HTTP request.
  *
  * @param req Express request object.
- * @return CloudEvents context.
+ * @return The CloudEvent
  */
-export function getBinaryCloudEventContext(
-  req: express.Request
-): CloudEventsContext {
-  const context: CloudEventsContext = {};
-  for (const name in req.headers) {
-    if (name.startsWith('ce-')) {
-      const attributeName = name.substr('ce-'.length);
-      context[attributeName] = req.header(name);
-    }
-  }
-  return context;
+export function getCloudEvent(req: express.Request): CloudEvent {
+  const headers = req.headers as { [key: string]: string };
+  return Receiver.accept(headers, req.body);
 }

src/functions.ts

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import * as express from 'express';
+import { CloudEventV1Attributes } from 'cloudevents';
 
 export interface HttpFunction {
   // tslint:disable-next-line:no-any express interface.
@@ -28,11 +29,11 @@ export interface EventFunctionWithCallback {
 }
 export interface CloudEventFunction {
   // tslint:disable-next-line:no-any
-  (cloudevent: CloudEventsContext): any;
+  (cloudevent: CloudEventV1Attributes): any;
 }
 export interface CloudEventFunctionWithCallback {
   // tslint:disable-next-line:no-any
-  (cloudevent: CloudEventsContext, callback: Function): any;
+  (cloudevent: CloudEventV1Attributes, callback: Function): any;
 }
 export type HandlerFunction =
   | HttpFunction
@@ -66,43 +67,4 @@ export interface CloudFunctionsContext {
   resource?: string;
 }
 
-/**
- * The CloudEvents v1.0 context object for the event.
- *
- * @link https://github.com/cloudevents/spec/blob/master/spec.md#context-attributes
- */
-export interface CloudEventsContext {
-  /**
-   * Type of occurrence which has happened.
-   */
-  type?: string;
-  /**
-   * The version of the CloudEvents specification which the event uses.
-   */
-  specversion?: string;
-  /**
-   * The event producer.
-   */
-  source?: string;
-  /**
-   * ID of the event.
-   */
-  id?: string;
-  /**
-   * Timestamp of when the event happened.
-   */
-  time?: string;
-  /**
-   * A link to the schema that the event data adheres to.
-   */
-  schemaurl?: string;
-  /**
-   * Content type of the event data.
-   */
-  contenttype?: string;
-
-  // tslint:disable-next-line:no-any CloudEvents extension attributes.
-  [key: string]: any;
-}
-
-export type Context = CloudFunctionsContext | CloudEventsContext;
+export type Context = CloudFunctionsContext | CloudEventV1Attributes;

src/invoker.ts

@@ -28,7 +28,7 @@ import * as onFinished from 'on-finished';
 
 import { FUNCTION_STATUS_HEADER_FIELD } from './types';
 import { logAndSendError } from './logger';
-import { isBinaryCloudEvent, getBinaryCloudEventContext } from './cloudevents';
+import { getCloudEvent } from './cloudevents';
 import {
   HttpFunction,
   EventFunction,
@@ -144,11 +144,7 @@ function wrapCloudEventFunction(
         }
       }
     );
-    let cloudevent = req.body;
-    if (isBinaryCloudEvent(req)) {
-      cloudevent = getBinaryCloudEventContext(req);
-      cloudevent.data = req.body;
-    }
+    const cloudevent = getCloudEvent(req);
     // Callback style if user function has more than 2 arguments.
     if (userFunction!.length > 2) {
       const fn = userFunction as CloudEventFunctionWithCallback;
@@ -197,17 +193,11 @@ function wrapEventFunction(
         }
       }
     );
-    let data = event.data;
+    const data = event.data;
     let context = event.context;
-    if (isBinaryCloudEvent(req)) {
-      // Support CloudEvents in binary content mode, with data being the whole
-      // request body and context attributes retrieved from request headers.
-      data = event;
-      context = getBinaryCloudEventContext(req);
-    } else if (context === undefined) {
-      // Support legacy events and CloudEvents in structured content mode, with
-      // context properties represented as event top-level properties.
-      // Context is everything but data.
+    if (context === undefined) {
+      // Support legacy events with context properties represented as event
+      // top-level properties. Context is everything but data.
       context = event;
       // Clear the property before removing field so the data object
       // is not deleted.