Add idempotency (#6748)

* added idempotency router and middleware

* added idempotency rules for routes classes, functions, jobs, installaions, users

* fixed typo

* ignore requests without header

* removed unused var

* enabled feature only for MongoDB

* changed code comment

* fixed inconsistend storage adapter specification

* Trigger notification

* Travis CI trigger

* Travis CI trigger

* Travis CI trigger

* rebuilt option definitions

* fixed incorrect import path

* added new request ID header to allowed headers

* fixed typescript typos

* add new system class to spec helper

* fixed typescript typos

* re-added postgres conn parameter

* removed postgres conn parameter

* fixed incorrect schema for index creation

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* temporarily disabling index creation to fix postgres issue

* trying to fix postgres issue

* fixed incorrect auth when writing to _Idempotency

* trying to fix postgres issue

* Travis CI trigger

* added test cases

* removed number grouping

* fixed test description

* trying to fix postgres issue

* added Github readme docs

* added change log

* refactored tests; fixed some typos

* fixed test case

* fixed default TTL value

* Travis CI Trigger

* Travis CI Trigger

* Travis CI Trigger

* added test case to increase coverage

* Trigger Travis CI

* changed configuration syntax to use regex; added test cases

* removed unused vars

* removed IdempotencyRouter

* Trigger Travis CI

* updated docs

* updated docs

* updated docs

* updated docs

* update docs

* Trigger Travis CI

* fixed coverage

* removed code comments

src/middlewares.js

@@ -4,9 +4,11 @@ import auth from './Auth';
 import Config from './Config';
 import ClientSDK from './ClientSDK';
 import defaultLogger from './logger';
+import rest from './rest';
+import MongoStorageAdapter from './Adapters/Storage/Mongo/MongoStorageAdapter';
 
 export const DEFAULT_ALLOWED_HEADERS =
-  'X-Parse-Master-Key, X-Parse-REST-API-Key, X-Parse-Javascript-Key, X-Parse-Application-Id, X-Parse-Client-Version, X-Parse-Session-Token, X-Requested-With, X-Parse-Revocable-Session, Content-Type, Pragma, Cache-Control';
+  'X-Parse-Master-Key, X-Parse-REST-API-Key, X-Parse-Javascript-Key, X-Parse-Application-Id, X-Parse-Client-Version, X-Parse-Session-Token, X-Requested-With, X-Parse-Revocable-Session, X-Parse-Request-Id, Content-Type, Pragma, Cache-Control';
 
 const getMountForRequest = function (req) {
   const mountPathLength = req.originalUrl.length - req.url.length;
@@ -406,6 +408,52 @@ export function promiseEnforceMasterKeyAccess(request) {
   return Promise.resolve();
 }
 
+/**
+ * Deduplicates a request to ensure idempotency. Duplicates are determined by the request ID
+ * in the request header. If a request has no request ID, it is executed anyway.
+ * @param {*} req The request to evaluate.
+ * @returns Promise<{}>
+ */
+export function promiseEnsureIdempotency(req) {
+  // Enable feature only for MongoDB
+  if (!(req.config.database.adapter instanceof MongoStorageAdapter)) { return Promise.resolve(); }
+  // Get parameters
+  const config = req.config;
+  const requestId = ((req || {}).headers || {})["x-parse-request-id"];
+  const { paths, ttl } = config.idempotencyOptions;
+  if (!requestId || !config.idempotencyOptions) { return Promise.resolve(); }
+  // Request path may contain trailing slashes, depending on the original request, so remove
+  // leading and trailing slashes to make it easier to specify paths in the configuration
+  const reqPath = req.path.replace(/^\/|\/$/, '');
+  // Determine whether idempotency is enabled for current request path
+  let match = false;
+  for (const path of paths) {
+    // Assume one wants a path to always match from the beginning to prevent any mistakes
+    const regex = new RegExp(path.charAt(0) === '^' ? path : '^' + path);
+    if (reqPath.match(regex)) {
+      match = true;
+      break;
+    }
+  }
+  if (!match) { return Promise.resolve(); }
+  // Try to store request
+  const expiryDate = new Date(new Date().setSeconds(new Date().getSeconds() + ttl));
+  return rest.create(
+    config,
+    auth.master(config),
+    '_Idempotency',
+    { reqId: requestId, expire: Parse._encode(expiryDate) }
+  ).catch (e => {
+    if (e.code == Parse.Error.DUPLICATE_VALUE) {
+      throw new Parse.Error(
+        Parse.Error.DUPLICATE_REQUEST,
+        'Duplicate request'
+      );
+    }
+    throw e;
+  });
+}
+
 function invalidRequest(req, res) {
   res.status(403);
   res.end('{"error":"unauthorized"}');