add gitignore which ignores node_modules folder in future

ccppjava · ccppjava · commit 9a9e161aaf3b · 2014-01-17T10:38:44.000Z
add two simple node and mongo use case
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/node_mongo/simple-cli.js b/node_mongo/simple-cli.js
@@ -0,0 +1,108 @@
+var MongoClient = require('mongodb').MongoClient
+
+// move connecting into a function to avoid the 'pyramid of doom'
+function getConnection(cb) {
+	MongoClient.connect('mongodb://localhost', function(err, db) {
+		if (err) return cb(err);
+
+		var simpleUser = db.collection('simple');
+
+		// to search by name, index is need to get speed
+		// ref: http://docs.mongodb.org/manual/core/indexes-introduction/
+		simpleUser.ensureIndex({name: true}, function(err) {
+			if (err) return cb(err);
+			cb(null, simpleUser);
+		});
+	});
+}
+
+// an upsert will create a new record OR update an existing record
+// which makes things easier, in mongo, we can do this with a 
+// findAndModify and passing the upsert option to have the update 
+// document returned, we pass the new option as well
+function upsertUser(collection, name, role, cb) {
+	collection.findAndModify({name: name}, {}, {$set: {role: role}},
+		{upsert: true, new: true}, cb);
+}
+
+// instead of finding just one user, we can list all of the documents
+// by passing an empty selector. This returns a 'cursor', which allows
+// us to walk through the documents look at how we do this in process
+function readAll(collection, cb) {
+	collection.find({}, cb);
+}
+
+function readRole(collection, name, cb) {
+	collection.findOne({name: name}, cb);
+}
+
+function printUser(user) {
+	// make sure that we found our user
+	if (!user) {
+		console.log("Couldn't find the user you asked for!")
+	}
+
+	console.log(user.name + ' has the role of ' + user.role);
+}
+
+// the each method allows us to walk through the result set, notice
+// the callback, as every time the callback is called, there is 
+// another chance of an error
+function printUsers(users, cb) {
+	users.each(function(err, user) {
+		if (err) return cb(err);
+		printUser(user);
+	});
+}
+
+function simpleCli(operation, name, role, cb) {
+	getConnection(function(err, collection) {
+		if (err) return cb(err);
+
+		// we need to make sure to close the database, otherwise
+		// the process won't stop
+		function processUser(err, user) {
+			if (err) return cb(user);
+			printUser(user);
+			collection.db.close();
+			cb();
+		}
+
+		// use this function when dealing with lots of users
+		function processUsers(err, users) {
+			if (err) return cb(err);
+			// the callback to each is called for every result
+			// once it returns a null, we know the result is done
+			users.each(function(err, user) {
+				if (err) return cb(err);
+				if (user) {
+					printUser(user);
+				} else {
+					collection.db.close();
+					cb();
+				}
+			});
+		}
+
+		if (operation === 'list') {
+			readAll(collection, processUsers);
+		} else if (operation === 'update') {
+			upsertUser(collection, name, role, processUser);
+		} else if (operation === 'read') {
+			readRole(collection, name, processUser);
+		} else {
+			return cb(new Error('unknown operation!'));
+		}
+	});
+}
+
+var operation = process.argv[2];
+var name = process.argv[3];
+var role = process.argv[4];
+
+simpleCli(operation, name, role, function(err) {
+	if (err) {
+		console.log("Had an error!", err);
+		process.exit(1);
+	}
+});
diff --git a/node_mongo/simple.js b/node_mongo/simple.js
@@ -0,0 +1,37 @@
+// import the mongo driver that help connect to mongo
+var MongoClient = require('mongodb').MongoClient
+
+MongoClient.connect('mongodb://localhost', function(err, db) {
+	// if we didn't connect, throw the error
+	if (err) throw err;
+
+	// in mongo, documents are grouped in collection (like a table)
+	// make one
+	var simpleUser = db.collection("simple");
+
+	// inserting a new document of easy json
+	simpleUser.insert({name: 'ccppjava', role: 'admin'}, function(err, result) {
+		if (err) throw err;
+
+		// all documents in mongo get assigned a unique id, _id
+		// we use this to find the document we just inserted
+		var _id = result[0]._id
+
+		// to update, we write a 'selector', and then the update
+		// notice the use of $set, it is a special operator that
+		// sets the fields in the document, otherwise, we would
+		// wipe out the exisitng document
+		simpleUser.update({_id: _id}, {$set: {role: 'user'}},	function(err){
+			if (err) throw err;
+
+			// finding a documents needs a selector like above
+			simpleUser.findOne({_id: _id}, function(err, doc) {
+				if (err) throw err;
+
+				console.log(doc.name + " has the role of " + doc.role);
+				// close our database so the process will die
+				db.close();
+			});
+		});
+	});
+});
