Sharing my toxy-based development proxy.

examples/uiDeveloperNerdvana.js

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+var toxy = require('..');  /** we have to use this line when running in toxy/examples.
+use this elsewhere
+# var toxy = require('toxy');
+**/
+var express = require('express');
+var poisons = toxy.poisons;
+var rules = toxy.rules;
+
+// Create a new toxy proxy
+var proxy = toxy();
+//var Array = require('Array');
+
+/**********
+
+  You probably want to change the dirs, apiRoots and host line.
+
+*************/
+
+var rootPath = __dirname; // start with local directory
+
+var defaultBackend = 'yourbackendhost.com';
+var apiRoots = ['/api','/login']; // URLs beginning with this are intercepted and routed to your backend.
+var staticDirs = [rootPath, rootPath+ '/dist', rootPath+ '/build']; //
+var host = process.env.HOST || defaultBackend;
+var poisonrate = process.env.POISONRATE || 0;
+var maxlatency = process.env.MAXLATENCY || 0;
+var minlatency = process.env.MINLATENCY || maxlatency/2;
+var throttle = process.env.THROTTLE || 0;
+
+
+var app = express(),
+port = process.env.PORT || 8000;
+
+function processRequest(req,res,next) {
+	    console.log(">>>>"+req.url);
+	    next();
+}
+
+function applyPoisons(route)
+{
+	if (poisonrate > 0)
+	{
+	route.poison(poisons.inject({
+	  code: 503,
+	  body: '{"error": "toxy injected error"}',
+	  headers: {'Content-Type': 'application/json'}
+	}))
+  .withRule(rules.probability(poisonrate));
+   }
+   if (maxlatency > 0)
+   {
+   	route.poison(poisons.latency({max:maxlatency, min: minlatency})).withRule(rules.method('GET'));
+   }
+   if (throttle > 0)
+   {
+   	route.poison(poisons.bandwidth({bps: throttle})).withRule(rules.method('GET'));
+   }
+
+}
+
+function processResponse(req,res,next) {
+	    console.log("<<<<<"+req.url);
+	var keys = Object.keys(res._headers),
+		len = keys.length,
+		prop,
+		value;
+		for (i=0; false && i < len;i++)
+		{
+			prop = keys[i];
+			value = res._headers[prop];
+			//console.log("replacing",prop,value);
+
+			/****
+			  Most backend hosts give you a cookie that only works with their domain, by setting
+			  Secure on the cookie.
+			***/
+			if (Array.isArray(value))
+			{
+				for (jx=0; jx < value.length; jx++)
+				{
+					v2 = value[jx];
+					value[jx] = v2.replace(/Secure/g,'');
+				}
+			}
+			else
+			{
+				value.replace(/Secure/g,'');
+				res._headers[prop]=value;
+			}
+		}
+
+        //res.connection.uncork() // needed to make rocky/toxy work with node 4.x
+        next()
+}
+
+// Default server to forward incoming traffic
+/*** Change https to http if your API server isn't https****/
+proxy
+  .forward('https://'+host)
+
+
+for (var ix=0;ix< apiRoots.length;ix++)
+{
+var root = apiRoots[ix]+'/*';
+	console.log('proxying',root);
+	route=proxy
+	  .all(root)
+	  .withRule(rules.method(['POST', 'PUT', 'DELETE','GET']))
+	  .options({ secure: false })
+	.use(processRequest)
+	.transformResponseBody(processResponse)
+	  .host(host);
+	  applyPoisons(route);
+}
+
+
+// Enable the admin HTTP server
+var admin = toxy.admin({ cors: true })
+
+// Add the toxy proxy instance
+admin.manage(proxy)
+
+admin.listen(9000)
+console.log('Admin server listening on port:', 9000)
+
+for (var dx=0; dx< staticDirs.length; dx++)
+{
+  console.log("Serving static content from ", staticDirs[dx])
+  app.use(express.static(staticDirs[dx]));
+}
+app.use(proxy.middleware())
+app.listen(port);
+
+console.log("Environment Variables/Parameters are:");
+console.log("HOST=",host);
+console.log("PORT=",port);
+if (poisonrate > 0)
+	console.log("POISONRATE=",poisonrate," % of time to reply with 5xx instead of data");
+else
+	console.log("POISONRATE= 0");
+	console.log("      no poisoning of requests");
+
+if (maxlatency > 0)
+{
+	console.log("MAXLATENCY=",maxlatency, ' milliseconds');
+	console.log("MINLATENCY=",minlatency, ' milliseconds');
+}
+else
+{
+	console.log("MAXLATENCY=",maxlatency);
+	console.log("     NOT adding latency set at least MAXLATENCY to enable");
+
+}
+
+if (throttle > 0)
+{
+	console.log('THROTTLE=', throttle, ' bps');
+}
+else
+{
+	console.log('THROTTLE=0 bps');
+	console.log('     no throttling will be performed');
+}
+
+console.log('Test it:', 'http://localhost:'+port+'/index.html')

examples/uiDeveloperNerdvana.md

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+# What is UI Developer Nerdvana?
+
+UI Developer Nerdvana is when your *code*-*build*-*test* cycle can be shortened to
+*save*-*refresh*. From *minutes* to *seconds*. Once you have achieved nerdvana, it can be
+very hard to go back to waiting for a lengthy *code*-*build*-*deploy*-*test* process.
+
+`uiDeveloperNerdvana.js` is a sample for `toxy` to help you acheive nerdvana. What it does
+is pretty simple. It looks at the requests coming in, and routes requests beginning with `/api`
+or `/login` to the host of your choice.
+
+In other words, if you're developing in JavaScript, TypeScript, or nearly any other modern
+UI technology where the browser executes your UI code, and the backend code is served by
+somewhere else, you can setup a common backend server for your UI team. Since the UI code
+is executed by the browser anyways; there's no reason to deploy it anywhere. If you're using
+`gulp` or `webpack`, you can use their `watch` features to automatically build. So *Save* becomes
+your *Deploy*.
+
+By changing the backend host, you can test against Production, or a particular QA persons
+machine if they've setup a tricky to reproduce bug.
+
+Nerdvana also implements some poisons for toxy that can be controlled from the command line.
+
+## Ok, so how do I get started?
+
+1. Copy this file to your UI project as `nerdvana.js`.
+2. Add toxy to your package.json in devDependencies, and `npm install` or `yarn`.
+3. Change `defaultBackend` in the code to match the backend host name you want to use.
+4. Change `apiRoots` if you're using something other than `/api` or `/login` as your
+API route in the backend.
+5. If serving your front end content from something other than the current directory, or
+`./build` or `./dist`, modify `staticDirs`.
+6. Setup `watch` in your build system.
+11. Launch the proxy with `node nerdvana.js`
+7. Load your UI by going to the opening page.
+8. Make a change and save it.
+9. Refresh your browser.
+10. *Do Victory Dance*
+
+
+### Advanced Features & Options
+
+Rather than parse a command line, nerdvana will read certain values from the environment
+variables, which can be also set from the command line.
+
+#### Repoint the proxy
+
+
+Ex: `HOST=<new host> node nerdvana.js`. will use the specified host instead of the
+defaultBackend value. Same thing with `PORT=`. This is very useful to point a production or
+a special build of the backend.
+
+#### Cause errors to make sure your UI is robust
+
+`POISONRATE=25` will cause 25% of the API requests to return an error so you can make sure
+your UI will work when people's network connection is unreliable.
+
+`MAXLATENCY=5000` will cause each API call to take 2.5 to 5 seconds to complete, so you can
+debug race conditions, and also see what its like when your user's network connection is slow.