add 'tcat' utility (a la netcat) for quick cli tchannel

package.json

@@ -8,7 +8,8 @@
   "main": "index.js",
   "homepage": "https://github.com/uber/tcurl",
   "bin": {
-    "tcurl": "index.js"
+    "tcurl": "index.js",
+    "tcat": "tcat.js"
   },
   "bugs": {
     "url": "https://github.com/uber/tcurl/issues",

tcat.js

@@ -0,0 +1,76 @@
+#!/usr/bin/env node
+
+// Copyright (c) 2015 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+'use strict';
+
+// trivial tchannel listener interface, a la netcat
+
+var console = require('console');
+var process = require('process');
+
+var minimist = require('minimist');
+var TChannel = require('tchannel');
+
+function main(args) {
+    /*eslint no-console: 0 */
+    var opts = minimist(args, {alias: {peer: ['p'], help: ['h']}});
+    if (opts.help || opts.h) {
+        displayHelp(0);
+    }
+
+    args = opts._.slice(2);
+    if (args.length !== 2 || !opts.peer) {
+        console.error('Must specify full endpoint.\n');
+        displayHelp(1);
+    }
+
+    var host = opts.peer.split(':')[0];
+    var port = opts.peer.split(':')[1];
+    var service = args[0];
+    var endpoint = args[1];
+
+    if (!host || !port) {
+        console.error('Invalid HostPort.\n');
+        displayHelp(1);
+    }
+
+    var server = new TChannel();
+    server
+        .makeSubChannel({serviceName: service})
+        .register(endpoint, onRequest);
+    server.listen(+port, host);
+
+    function onRequest(req, res, arg2, arg3) {
+        res.headers.as = 'raw';
+        console.log(arg2.toString());
+        res.sendOk();
+    }
+}
+
+function displayHelp(exitValue) {
+    /*eslint no-process-exit: 0*/
+    console.log('tcat -p <host:port> <service> <endpoint>');
+    process.exit(exitValue);
+}
+
+if (require.main === module) {
+    main(process.argv);
+}