Added simple web-service example

examples/web-service/app.js

@@ -0,0 +1,92 @@
+
+/**
+ * Module dependencies.
+ */
+
+var express = require('../../lib/express');
+
+var app = express.createServer();
+
+/**
+ * Generate our unique identifier.
+ */
+
+function uid() {
+  return [
+      Math.random() * 0xffff | 0
+    , Math.random() * 0xffff | 0
+    , Math.random() * 0xffff | 0
+    , Date.now()
+  ].join('-');
+}
+
+// map of valid api keys, typically mapped to
+// account info with some sort of database like redis.
+// api keys do _not_ serve as authentication, merely to
+// track API usage or help prevent malicious behavior etc.
+
+var apiKeys = [uid(), uid(), uid()];
+
+console.log('valid keys:\n ', apiKeys.join('\n  '));
+
+// these two objects will serve as our faux database
+
+var repos = [
+    { name: 'express', url: 'http://github.com/visionmedia/express' }
+  , { name: 'stylus', url: 'http://github.com/learnboost/stylus' }
+  , { name: 'cluster', url: 'http://github.com/learnboost/cluster' }
+];
+
+var users = [
+    { name: 'tobi' }
+  , { name: 'loki' }
+  , { name: 'jane' }
+];
+
+var userRepos = {
+    tobi: [repos[0], repos[1]]
+  , loki: [repos[1]]
+  , jane: [repos[2]]
+};
+
+// if we wanted to supply more than JSON, we could
+// use something similar to the content-negotiation
+// example.
+
+// here we validate the API key,
+// by mounting this middleware to /api/v1
+// meaning only paths prefixed with "/api/v1"
+// will cause this middleware to be invoked
+
+app.use('/api/v1', function(req, res, next){
+  var key = req.query['api-key'];
+
+  // key isnt present
+  if (!key) return res.send('api key required', 401);
+
+  // key is invalid
+  if (!~apiKeys.indexOf(key)) return res.send('invalid api key', 401);
+
+  // all good, store req.key for route access
+  req.key = key;
+  next();
+});
+
+// we now can assume the api key is valid,
+// and simply expose the data
+
+app.get('/api/v1/users', function(req, res, next){
+  res.send(users);
+});
+
+app.get('/api/v1/repos', function(req, res, next){
+  res.send(repos);
+});
+
+app.get('/api/v1/user/:name/repos', function(req, res, next){
+  var name = req.params.name;
+  res.send(userRepos[name]);
+});
+
+app.listen(3000);
+console.log('Express server listening on port 3000');