Renjith K R

In this guide, I will show you how to create a simple web chat application with Facebook authentication using Firebase and Jquery.

Firebase

Firebase is a scalable, real-time back for your application. It allows developers to build rich, collaborative applications without the hassle of managing servers or writing server-side code.

Setup Facebook Authentication

Create a new Facebook application from your Facebook account. Click the Add a New App button in the top right of that page and select Website as your platform. Then choose an App ID and click Create New Facebook App ID. Select your app's category and click Create App ID. In the top right, click Skip Quick Start.

In your Facebook app configuration, click on the Settings tab on the left-hand navigation menu. Then go to the Advanced tab at the top and scroll down to the Security section. At the bottom of that section, add 'https://auth.firebase.com/v2//auth/facebook/callback' to your Valid OAuth redirect URIs and click Save Changes at the bottom of the page.

Then go to your firebase account, at https://.firebaseio.com. Click Login & Auth in the left side menu. Select the Facebook tab and check the Enable Facebook Authentication and copy the Facebook application credentials (App ID and Secret).

You can also read this Facebook Authentication guide.

Running the chat

To run the application, you need to have a web server. http-server has everything we need.To install the http-server, from the console, execute:

npm install http-server -g

If you don’t have Node.js and npm installed, you can read this Installing Node.js and updating npm guide.

Once you have http-server installed, you can download/clone the app from Github. Then open firegroupchat.js in your favourite text editor and replace `` with your firebase app to point to your Firebase. Now you have your Terminal open and navigate to your fireGroupChat directory, and execute this command:

http-server -a localhost

The code

First, we need to authenticate user. You can use the getAuth() method to synchronously check authentication state. If user does’t have any existing session, you can prompt the user to login and then invoke the Facebook login popup (e.g. after they have clicked a "Login" button) with the following snippet.

var ref = new Firebase("https://.firebaseio.com"); ref.authWithOAuthPopup("facebook", function(error, authData) { if (error) { console.log("Login Failed!", error); } else { console.log("Authenticated successfully with payload:", authData); } });

When the user successfully logs in, save the user's profile into Firebase with following code.

ref.child("users").child(authData.uid).set({ uid: authData.uid, provider: authData.provider, name: authData.facebook.displayName, img: authData.facebook.cachedUserProfile.picture.data.url });

Next, we retrieve all the chat messages from Firebase with following code.

ref.child("chats").on("child_added", function(snapshot) { var chat = snapshot.val(); // generate the html with chat messages.. });

And the final step is to send your message to Firebase server.

ref.child("chats").push({ uid: authData.uid, name: authData.facebook.displayName, img: authData.facebook.cachedUserProfile.picture.data.url, msg: msg, date: Firebase.ServerValue.TIMESTAMP });

This post will guide you through installing django with virtualenv on osx. This is a beginner’s guide for users working on django framework  with postgresql.

Install Homebrew

First, we need to install Homebrew. Homebrew allows us to install and compile software packages easily from source.

Open Terminal and run the following command:

ruby <(curl -fsSkL raw.github.com/mxcl/homebrew/go)

You want to always ensure that you’re running the newest version of Homebrew. Update brew to the latest version with:

brew update

Install Python

With Homebrew, getting Python is quite easy:

brew install python

This will also install package management tools like pip.

Install Virtualenv and Virtualenvwrapper

A Virtual Environment is a tool to keep the dependencies required by different projects in separate places, by creating virtual Python environments for them.

Install virtualenv and virtualenvwrapper via pip:

pip install virtualenv pip install virtualenvwrapper

In your home directory make a folder called .virtualenvs

mkdir ~/.virtualenvs

You now need to have your shell loadup the virtualenvwrapper.sh script. To do this add following lines into your .bash_login file.

source /usr/local/bin/virtualenvwrapper.sh

Then restart your terminal and create a new virtual environment by using

mkvirtualenv yourvirtualenv

Then start working on virtual environment by

workon yourvirtualenv

if you want deactivate use the same

deactivate

Install PostgreSQL

brew install postgresql

Install Psycopg2

This will connect django with postgres. Don’t forgot to install inside your virtualenv.

pip install psycopg2

Start Postgresql Server manually:

pg_ctl -D /usr/local/var/postgres -l /usr/local/var/postgres/server.log start

To stop:

pg_ctl -D /usr/local/var/postgres stop -s -m fast

Actually, for some unknown reason, I found the issue was actually because the postgresql role hadn’t been created.

Try running:

createuser -s -r postgres

Create and drop your database using

createdb mytestdb drop mytestdb

Note: There is no default password for user ‘postgres’.

Install Django

Finally install django inside your virtualenv using pip