Construct params based on resource string in event payload. (#154)

Author: laurenzlong

spec/cloud-functions.spec.ts

@@ -53,9 +53,6 @@ describe('makeCloudFunction', () => {
       },
       eventType: 'providers/provider/eventTypes/event',
       resource: 'resource',
-      params: {
-        foo: 'bar',
-      },
       data: 'data',
     };
 
@@ -67,10 +64,37 @@ describe('makeCloudFunction', () => {
       },
       eventType: 'providers/provider/eventTypes/event',
       resource: 'resource',
+      data: 'data',
+      params: {},
+    });
+  });
+});
+
+describe('makeParams', () => {
+
+  const cloudFunctionArgs: MakeCloudFunctionArgs<any> = {
+    provider: 'mock.provider',
+    eventType: 'mock.event',
+    resource: 'projects/_/instances/pid/ref/{foo}/nested/{bar}',
+    handler: () => null,
+  };
+
+  const testEvent: Event<string> = {
+    resource: 'projects/_/instances/pid/ref/a/nested/b',
+    data: 'data',
+  };
+
+  it('should construct params from the event resource', () => {
+    let args: any = _.assign({}, cloudFunctionArgs, {handler: (e) => e});
+    let cf = makeCloudFunction(args);
+
+    return expect(cf(testEvent)).to.eventually.deep.equal({
+      resource: 'projects/_/instances/pid/ref/a/nested/b',
+      data: 'data',
       params: {
-        foo: 'bar',
+        foo: 'a',
+        bar: 'b',
       },
-      data: 'data',
     });
   });
 });

src/cloud-functions.ts

@@ -24,6 +24,7 @@ import { apps } from './apps';
 import * as _ from 'lodash';
 import { Request, Response } from 'express';
 export { Request, Response };
+const WILDCARD_REGEX = new RegExp('{[^/{}]*}', 'g');
 
 /** An event to be handled in a developer's Cloud Function */
 export interface Event<T> {
@@ -72,6 +73,22 @@ export interface MakeCloudFunctionArgs<EventData> {
   after?: (raw: Event<any>) => void;
 }
 
+function _makeParams (event: Event<any>, triggerResource: string): { [option: string]: any } {
+  let wildcards = triggerResource.match(WILDCARD_REGEX);
+  let params = {};
+  if (wildcards) {
+    let triggerResourceParts = _.split(triggerResource, '/');
+    let eventResourceParts = _.split(event.resource, '/');
+    _.forEach(wildcards, wildcard => {
+      let wildcardNoBraces = wildcard.slice(1,-1);
+
+      let position = _.indexOf(triggerResourceParts, wildcard);
+      params[wildcardNoBraces] = eventResourceParts[position];
+    });
+  }
+  return params;
+};
+
 /** @internal */
 export function makeCloudFunction<EventData>({
   provider,
@@ -88,7 +105,7 @@ export function makeCloudFunction<EventData>({
       .then(() => {
         let typedEvent: Event<EventData> = _.cloneDeep(event);
         typedEvent.data = dataConstructor(event);
-        typedEvent.params = event.params || {};
+        typedEvent.params = _makeParams(event, resource) || {};
         return handler(typedEvent);
       }).then(result => {
         if (after) { after(event); }