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Single Page Application with Angular.js, Node.js and CouchDB (Cradle Module)

July 12, 2013 3 Comments

Previously we have posted the article for Single Page Application with Angular.js, Node.js and MongoDB (MongoJS Module).

Current post is a proof of concept towards make a web application with Javascript based Web Server with CouchDB with Angular.js and Node.js.

This time we have tried with CouchDB, by definition which is from Apache CouchDB site

Apache CouchDB™ is a database that uses JSON for documents, JavaScript for MapReduce queries, and regular HTTP for an API

To make this possible, we have selected -

1> Angular.js for client side development – Single Page Application

2> Cross Domain Communication in between Angular.js and Node.js

3> Node.js for server side development

4> Rest based web service creation with express.js

5> Database – CouchDb

6> Node.js Cradle Module Extention (to make communication with CouchDB)

7> Making CouchDB views with Map-Reduce to fetch the data

We have created a Proof of Concept with Javascript based web server, where we have focused on dealing with NoSql (CouchDB) with javascript based framework Node.js and angular.js on client side.

Our initial code can be downloaded here.

Architecture at a glance -

Angular.js Node CouchDB

So here are the steps -

Installation -

A> Download and install Node.js from here.

B> To Develop the application we need to install mongojs module for Node.js

Command – npm install cradle (should be connected to internet)

C> We need to install express.js for node.js

Command – npm install express  (should be connected to internet)

Configuration Code -

Now, we will try to describe the code portion -

 
var application_root = __dirname,
    express = require("express"),
    path = require("path");

Here we have initialised the express.js within javascript variables in respect of Node.js concept.

 
var app = express();

Here we have initialised the express web server in app variable.

 
var databaseUrl = "sampledb";
var cradle = require('cradle');
var connection = new(cradle.Connection)('http://couchadmin:couchadmin@localhost', 5984, {
auth: { username: 'couchadmin', password: 'couchadmin' }
});
var db = connection.database(databaseUrl);

Here we have made the connection to the mongodb database using the Node.js mongojs module extension library.

 
// Config

app.configure(function () {
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(app.router);
  app.use(express.static(path.join(application_root, "public")));
  app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
});

Here we have made the configuration related to express.js

Rest Services Code -

 
app.get('/api', function (req, res) {
  res.header("Access-Control-Allow-Origin", "http://localhost");
  res.send('Our Sample API is up...');
});

Here we have made our first REST based web service and tested whether the express.js is up.

Our sample api will be  - http://127.0.0.1:1212/api (Get Method)
javascriptnosqlbook

 
app.get('/getangularusers', function (req, res) {
	res.header("Access-Control-Allow-Origin", "http://localhost");
	res.header("Access-Control-Allow-Methods", "GET, POST");
        // The above 2 lines are required for Cross Domain Communication(Allowing the methods that come as Cross           // Domain Request
        res.writeHead(200, {'Content-Type': 'application/json'});
        str='[';
        db.view('characters/all', function (err, response) { //Query in CouchDB View
             response.forEach(function (row) {
             str = str + '{ "name" : "' + row.username + '"},' +'\n';
        });
        str = str.trim();
        str = str.substring(0,str.length-1);
        str = str + ']';
        res.end( str);
      });
});

Here we have created another REST api to get all username from user collection and so have done the mongojs query.

CouchDB View Creation

This view creation is to be executed, before running the Angular Client Application to get specific set of data from couchdb.

Also a note, to run this view creation, we should put -

[httpd]
authentication_handlers = {couch_httpd_auth, null_authentication_handler}

in the local.ini file of <<CouchDB Installation folder>>/etc/couchdb folder to execute this map function without being the admin user.

This particular feature has taken some time to be discovered by us.

 
app.get('/createview', function (req, res) { // Before running the Angular Application, the view must be created
	db.save('_design/characters', { // Main View Family Name
      all: { // A particular set of data selection by javascript map-reduce
          map: function (doc) {
              if (doc.username) emit(doc.username, doc); // specific code to execute map function on each document
          }
      }
   });
});

Our sample api will be  - http://127.0.0.1:1212/getangularusers (Get Method)

 
app.post('/insertangularcouchuser', function (req, res){
  console.log("POST: ");
  res.header("Access-Control-Allow-Origin", "http://localhost");
  res.header("Access-Control-Allow-Methods", "GET, POST");
  // The above 2 lines are required for Cross Domain Communication(Allowing the methods that come as Cross 
  // Domain Request
  console.log(req.body);
  console.log(req.body.mydata);
  var jsonData = JSON.parse(req.body.mydata);
  var doc = {email: jsonData.email, password: jsonData.password, username: jsonData.username};
  db.save('\''+Math.random()+'\'', doc, function (err, res) {
      if (err) {
          // Handle error
          res += ' SAVE ERROR: Could not save record!!\n';
      } else {
          // Handle success
          res += ' SUCESSFUL SAVE\n';
      }
   });
});

Here we have made a POST request to create an user via REST calling.

Our sample api will be  - http://127.0.0.1:1212/insertangularcouchuser(Post Method)

 
// Launch server
app.listen(1212);

We have made the server to listen at 1212 port.

Now run node appcouchdbangular.js from command shell. This is our node.js specific code file.

References :

1> http://wiki.apache.org/couchdb/Setting_up_an_Admin_account

2> http://guide.couchdb.org/draft/security.html

3> https://github.com/cloudhead/cradle

Angular.js part -

Below is the code in Angular Controller -

 
'use strict';

var myApp = angular.module('myApp', []); // Taking Angular Application in Javascript Variable

// Below is the code to allow cross domain request from web server through angular.js
myApp.config(['$httpProvider', function($httpProvider) {
        $httpProvider.defaults.useXDomain = true;
        delete $httpProvider.defaults.headers.common['X-Requested-With'];
    }
]);

/* Controllers */

function UserListCtrl($scope, $http, $templateCache) {

  var method = 'POST';
  var inserturl = 'http://localhost:1212/insertangularcouchuser';// URL where the Node.js server is running
  $scope.codeStatus = "";
  $scope.save = function() {
    // Preparing the Json Data from the Angular Model to send in the Server. 
    var formData = {
      'username' : this.username,
      'password' : this.password,
	  'email' : this.email
    };

	this.username = '';
	this.password = '';
	this.email = '';

	var jdata = 'mydata='+JSON.stringify(formData); // The data is to be string.

	$http({ // Accessing the Angular $http Service to send data via REST Communication to Node Server.
            method: method,
            url: inserturl,
            data:  jdata ,
            headers: {'Content-Type': 'application/x-www-form-urlencoded'},
            cache: $templateCache
        }).
        success(function(response) {
		console.log("success"); // Getting Success Response in Callback
                $scope.codeStatus = response.data;
		console.log($scope.codeStatus);

        }).
        error(function(response) {
		console.log("error"); // Getting Error Response in Callback
                $scope.codeStatus = response || "Request failed";
		console.log($scope.codeStatus);
        });
	$scope.list();// Calling the list function in Angular Controller to show all current data in HTML
        return false;
  };	

  $scope.list = function() {
	  var url = 'http://localhost:1212/getangularusers';// URL where the Node.js server is running	
	  $http.get(url).success(function(data) {
		$scope.users = data;
	  });
          // Accessing the Angular $http Service to get data via REST Communication from Node Server 
  };

  $scope.list();
}

Angular Template and HTML

 <html lang="en" ng-app="myApp">
.....

We have referred the Angular Application in above code

 <body ng-controller="UserListCtrl">
.....

We have referred the Angular Controller in above code

Search: <input ng-model="user">
<div class="span10">
    <!--Body content-->
    <ul class="users">
        <li ng-repeat="user in users | filter:user ">
            {{user.name}}
        </li>
    </ul>
</div>

We have used the ng-repeat tag to take the users data model from REST communication and shown in HTML

 
<form name="myform" id="myform1" ng-submit="save()">
    <fieldset>
        <legend>New User</legend>
            <div class="control-group">
                <center><input type="text" placeholder="User…" ng-model="username" size=50 required/></center>
                <center><input type="text" placeholder="Password…" ng-model="password" size=50 required/></center>
                <center><input type="text" placeholder="Email…" ng-model="email" size=50 required/></center>
            </div>
    </fieldset>
    <p>
         <div><center><button type="submit" >Save now...</button></center></div>
    </p>
</form>

We have used the ng-submit tag to send the user data model from REST communication and sent to node server to save in CouchDB.

Reader can download the complete source-code in GitHub.

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