/
cloudevents.ts
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/
cloudevents.ts
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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import * as express from 'express';
import {CloudEventsContext} from './functions';
/**
* Custom exception class to represent errors durring event conversions.
*/
export class EventConversionError extends Error {}
// CloudEvent service names.
export const CE_SERVICE = {
FIREBASE_AUTH: 'firebaseauth.googleapis.com',
FIREBASE_DB: 'firebasedatabase.googleapis.com',
FIREBASE: 'firebase.googleapis.com',
FIRESTORE: 'firestore.googleapis.com',
PUBSUB: 'pubsub.googleapis.com',
STORAGE: 'storage.googleapis.com',
};
/**
* 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.
*
* @param req Express request object.
* @return CloudEvents context.
*/
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
) as keyof CloudEventsContext;
context[attributeName] = req.header(name);
}
}
// Populate the traceparent header.
if (req.header('traceparent')) {
context.traceparent = req.header('traceparent');
}
return context;
}