Enhanced support for batch endpoints (#3042)

* Allow to have different endpoint on publicserverURL and serverURL when batching

* nits

src/batch.js

@@ -1,7 +1,8 @@
-var Parse = require('parse/node').Parse;
-
+const Parse = require('parse/node').Parse;
+const url = require('url');
+const path = require('path');
 // These methods handle batch requests.
-var batchPath = '/batch';
+const batchPath = '/batch';
 
 // Mounts a batch-handler onto a PromiseRouter.
 function mountOnto(router) {
@@ -10,6 +11,48 @@ function mountOnto(router) {
   });
 }
 
+function parseURL(URL) {
+  if (typeof URL === 'string') {
+    return url.parse(URL)
+  }
+  return undefined;
+}
+
+function makeBatchRoutingPathFunction(originalUrl, serverURL, publicServerURL) {
+  serverURL = serverURL ? parseURL(serverURL) : undefined;
+  publicServerURL = publicServerURL ? parseURL(publicServerURL): undefined;
+
+  let apiPrefixLength = originalUrl.length - batchPath.length;
+  let apiPrefix = originalUrl.slice(0, apiPrefixLength);
+
+  let makeRoutablePath = function(requestPath) {
+      // The routablePath is the path minus the api prefix
+    if (requestPath.slice(0, apiPrefix.length) != apiPrefix) {
+      throw new Parse.Error(
+          Parse.Error.INVALID_JSON,
+          'cannot route batch path ' + requestPath);
+    }
+    return path.join('/', requestPath.slice(apiPrefix.length));
+  }
+
+  if (serverURL && publicServerURL 
+        && (serverURL.path != publicServerURL.path)) {
+    let localPath = serverURL.path;
+    let publicPath = publicServerURL.path;
+      // Override the api prefix
+    apiPrefix = localPath;
+    return function(requestPath) {
+        // Build the new path by removing the public path
+        // and joining with the local path
+      let newPath = path.join('/', localPath, '/' , requestPath.slice(publicPath.length));
+        // Use the method for local routing
+      return makeRoutablePath(newPath);
+    }
+  }
+
+  return makeRoutablePath;
+}
+
 // Returns a promise for a {response} object.
 // TODO: pass along auth correctly
 function handleBatch(router, req) {
@@ -26,19 +69,13 @@ function handleBatch(router, req) {
   if (!req.originalUrl.endsWith(batchPath)) {
     throw 'internal routing problem - expected url to end with batch';
   }
-  var apiPrefixLength = req.originalUrl.length - batchPath.length;
-  var apiPrefix = req.originalUrl.slice(0, apiPrefixLength);
+
+  const makeRoutablePath = makeBatchRoutingPathFunction(req.originalUrl, req.config.serverURL, req.config.publicServerURL);
 
   const promises = req.body.requests.map((restRequest) => {
-    // The routablePath is the path minus the api prefix
-    if (restRequest.path.slice(0, apiPrefixLength) != apiPrefix) {
-      throw new Parse.Error(
-        Parse.Error.INVALID_JSON,
-        'cannot route batch path ' + restRequest.path);
-    }
-    var routablePath = restRequest.path.slice(apiPrefixLength);
+    const routablePath = makeRoutablePath(restRequest.path);
     // Construct a request that we can send to a handler
-    var request = {
+    const request = {
       body: restRequest.body,
       config: req.config,
       auth: req.auth,
@@ -58,5 +95,6 @@ function handleBatch(router, req) {
 }
 
 module.exports = {
-  mountOnto: mountOnto
+  mountOnto,
+  makeBatchRoutingPathFunction
 };