Add optional "forceSequential" flag to batch request payload.

README.md

@@ -57,3 +57,14 @@ Optionally you can assign the query as a third property rather than placing it d
 ```
 
 If an error occurs as a result of one the requests to an endpoint it will be included in the response in the same location in the array as the request causing the issue.  The error object will include an error property that you can interrogate.  At this time the response is a 200 even when a request in the batch returns a different code.
+
+By default, requests in the `"requests"` array will be run concurrently, with the exception of pipelined requests which will be run sequentially.
+To force all batched requests to run sequentially regardless of pipelining, pass in the `forceSequential: true` flag:
+
+```json
+{ "forceSequential": true,
+  "requests": [
+    {"method": "get", "path": "/users/1"},
+    {"method": "get", "path": "/users/2"}
+] }
+```

lib/batch.js

@@ -28,6 +28,7 @@ module.exports.config = function (settings) {
                 results: [],
                 resultsMap: []
             };
+            const { forceSequential } = request.payload;
 
             let errorMessage = null;
 
@@ -71,7 +72,7 @@ module.exports.config = function (settings) {
             }
 
             try {
-                await internals.process(request, requests, payloads, resultsData);
+                await internals.process(request, requests, payloads, resultsData, forceSequential);
             }
             catch (err) {
                 // console.log("ERROR ", err);
@@ -89,23 +90,24 @@ module.exports.config = function (settings) {
                     path: Joi.string().required(),
                     query: [Joi.object().unknown().allow(null),Joi.string()],
                     payload: [Joi.object().unknown().allow(null),Joi.string()]
-                }).label('BatchRequest')).min(1).required()
+                }).label('BatchRequest')).min(1).required(),
+                forceSequential: Joi.bool().label('ForceSequential').optional().default(false)
             }).required().label('BatchRequestPayload')
         },
         auth: settings.auth,
         tags: settings.tags
     };
 };
 
-internals.process = async function (request, requests, payloads, resultsData) {
+internals.process = async function (request, requests, payloads, resultsData, forceSequential) {
 
     const fnsParallel = [];
     const fnsSerial = [];
 
     requests.forEach((requestParts, idx) => {
 
         const payloadParts = payloads[idx];
-        if (internals.hasRefPart(requestParts) || payloadParts.length) {
+        if (forceSequential || internals.hasRefPart(requestParts) || payloadParts.length) {
             return fnsSerial.push(
                 async () => await internals.batch(request, resultsData, idx, requestParts, payloadParts)
             );

test/batch.js

@@ -169,6 +169,17 @@ describe('Batch', () => {
         expect(res[1].name).to.equal('Active Item');
     });
 
+    it('handles sequential requests with forceSequential', async () =>  {
+
+        const res = await Internals.makeRequest(server, '{ "forceSequential": true, "requests": [{"method": "get", "path": "/sequential"}, {"method": "get", "path": "/sequential"}, {"method": "get", "path": "/sequential"}, {"method": "get", "path": "/sequential"}] }');
+
+        expect(res.length).to.equal(4);
+        expect(res[0]).to.equal(1);
+        expect(res[1]).to.equal(2);
+        expect(res[2]).to.equal(3);
+        expect(res[3]).to.equal(4);
+    });
+
     it('supports piping a response into the next request', async () => {
 
         const res = await Internals.makeRequest(server, '{ "requests": [ {"method": "get", "path": "/item"}, {"method": "get", "path": "/item/$0.id"}] }');

test/internals.js

@@ -3,6 +3,14 @@
 const Hapi = require('hapi');
 const Bassmaster = require('../');
 
+const awaitDelay = function (ms) {
+
+    return new Promise((resolve) => {
+
+        return setTimeout(resolve, ms);
+    });
+};
+
 const profileHandler = function (request, h) {
 
     const id = request.query.id || 'fa0dbda9b1b';
@@ -171,6 +179,21 @@ const echoHandler = function (request, h) {
     return request.payload;
 };
 
+const sequentialHandler = async function (request, h) {
+
+    if (!sequentialHandler.callCount) {
+        sequentialHandler.callCount = 1;
+
+        await awaitDelay(500);
+
+        return sequentialHandler.callCount;
+    }
+
+    await awaitDelay(Math.floor(Math.random() * 100));
+
+    return ++sequentialHandler.callCount;
+};
+
 module.exports.setupServer = async function () {
 
     const server = new Hapi.Server();
@@ -205,7 +228,8 @@ module.exports.setupServer = async function () {
                 ]
             }
         },
-        { method: 'GET', path: '/redirect', handler: redirectHandler }
+        { method: 'GET', path: '/redirect', handler: redirectHandler },
+        { method: 'GET', path: '/sequential', handler: sequentialHandler }
     ]);
 
     await server.register(Bassmaster);