Application Programming Interface (API):

An Application Programming Interface is a set of commands, routines and tools to create software applications

Twython:

Twython is the Python library providing an easy (and up-to-date) way to access Twitter data.

First, you can head over to https://dev.twitter.com/apps  and register an application.

After Registering, get your applications ConsumerKey and Consumer Secret from Application details tab.

Now you’re ready to start authentication!

Authentication:

Authentication is the process of verifying the identity of a user by obtaining some sort of credentials, use those credentials to verify the user's identity.

Authentication using OAuth 1 and OAuth2

OAuth 1 is for user making requests for tweeting, following people, sending DMs, etc.

OAuth 2 is for application authenticated calls (when you don’t want to authenticate a user and make read-only calls to Twitter, i.e. searching, reading a public users timeline)

0Auth 1 is the most common type used for authentication

If your web application is having users sign up with their Twitter account and interact with their timelines, updating their status, OAuth 1 authentication is used

If you’re not interested in authenticating a user and plan on making read-only calls, OAuth2 authentication is used

Authorisation:

Authorisation is the process of allowing an authenticated users to access the resources by checking whether the user has access rights to the system. Authorization helps you to control access rights by granting specific permissions to an authenticated user.

OAuth 1 (User Authentication)

First you should import Twython

from twython import Twython

Now, you should create a Twython instance with your consumer key and consumer secret

APP_KEY = 'YOUR_APP_KEY'

APP_SECRET = 'YOUR_APP_SECRET'

twitter = Twython(APP_KEY, APP_SECRET)

auth = twitter.get_authentication_tokens(callback_url='http://mysite.com/callback')

Only pass callback_url to get_authentication_tokens if your application is a Web Application

For Desktop and Mobile Applications callback_url is not required

From the auth variable, save the oauth_token_secret.

OAUTH_TOKEN = auth['oauth_token']

OAUTH_TOKEN_SECRET = auth['oauth_token_secret']

Now,Send the user to the authentication url, you can obtain it by accessing

auth['auth_url']

Handling the Callback

After they authorize your application to access some of their account details, they'll be redirected to the callback url you specified in get_authentication_tokens

After authorize you will get the oauth_verifier in the url with this oauth_verifier you can get oauth_token and oauth_token_secret 

oauth_verifier = request.GET['oauth_verifier']

Now that you have the oauth_verifier stored to a variable, you’ll want to create a new instance of Twython and grab the final user tokens

twitter = Twython(APP_KEY,APP_SECRET,OAUTH_TOKEN,OAUTH_TOKEN_SECRET)

final_step = twitter.get_authorized_tokens(oauth_verifier)

OAUTH_TOKEN = final_step['oauth_token']
OAUTH_TOKEN_SECRET = final_step['oauth_token_secret']

update_status(parameters):

update_status is used for updting the status of user on twitter

parameters:

status(required): The text of your status updates, typically up to 140 characters.

in_reply_to_status_id(optional): The ID of an existing status that the update is in reply to.

Example:

twitter = Twython(TW_CONSUMER_KEY, TW_CONSUMER_SECRET, OAUTH_TOKEN, OAUTH_TOKEN_SECRET)

update = twitter.update_status(status=”Your Status Here”)