1. All about social networking

2. What is it exactly??
twitter is a free social networking and micro-blogging service
At twitter you can follow somebody you like. people can follow you for any reason.
Since its creation in 2006 by jack dorsey, twitter has gained notability and popularity worldwide.
Twitter application programming interfaces are being widely used by third party applications running on different servers to allow their users to interact with twitter.

3. Flavors of twitter API’s
Twitter offers two types of API’s
Search API’s
REST API’s
The Search API methods give developers methods to interact with Twitter Search and trends data.
Returns tweets that match a specified query.
Tweets are text-based posts of up to 140 characters displayed on the author's profile page and delivered to the author's subscribers who are known as followers.
Returns the top ten topics that are currently trending on Twitter.
The Twitter REST API methods allow developers to access core Twitter data
Access user information
Update Status messages
Access timelines

4. Rate limiting in Twitter API’s
The Twitter API only allows clients to make a limited number of calls in a given hour. This policy affects the two APIs in different ways.
Talking about REST API
The default rate limit for calls to the REST API is 150 requests per hour.
Rate limiting only applies to methods that request information with the HTTP GET command
WHITELISTING can be done for application and IP address by filling out WHITELISTING form.
You can thus make 2000 calls per hour
Talking about Search API
The Search API is rate limited by IP address.
The number is quite a bit higher than 150 per hour
Twitter does not disclose this number in order to discourage the unnecessary usage of Search.
Consistent failure to avoid the rate-limiter will signal Twitter to automatically blacklist your application

5. How application works??

6. Oauth flow..

7. What happened in last slide? Well that was Oauth authentication
But what exactly is Oauth authentication? I heard this for the first time.

8. What is OAuth? A simple open standard for secure API authentication.

9. Specifically OAuth is... Need to log in to access parts of a website
Authentication
Need to log in to access parts of a website
ex: bookmark a link, post a photo, add a friend, view a private message
Token-based Authentication
Logged-in user has a unique token used to access
data from the site

10. Who is involved?

11. Who is it for?
Service Providers - have an web API that needs authorization for certain functions
Consumers - want to use an API that requires (or encourages) Oauth.

12. Goals…. Be Secure secure for end users
easy to implement security features for website developers
3rd party developers don’t have access to passwords
balance security with ease of use

13. Goals…. Be Open any website can implement Oauth
any 3rd party developer can use Oauth
open source client libraries

14. OAuth Setup
Service provider gives documentation of authorization URLs and methods
Consumer registers an application with the service provider

15. Sign in with Twitter
It is the pattern of authentication that allows users to connect their Twitter account with third-party services
It utilizes Oauth
Although the flow is very similar, the authorization URL and workflow differs slightly as described below.
The normal flow dictates that applications send request tokens to oauth/authorize in Twitter's implementation of the OAuth Specification. To take advantage of Sign in with Twitter, applications should send request tokens in the oauth_token paramater to oauth/authenticate instead.

16. Twitter URL’s for getting tokens
Getting Request Token
Getting Access Token

17. Register a Consumer Application
Go to the following link

18. You will see something like this

19. Description of fields Application name
Provide a name for your application
Description
Provide a brief description of your application
Application website
URL pointing to your application
Organization
For which organization are you providing this application
Website
Website of the organization
Application type
Type of your application. Check browser for our purposes
Callback URL
The URL where twitter shall redirect user after gaining authorization from user.
Default access type
Choose access types
use twitter for login
Mark this field if you wish to do so.

20. After registration?? Basic Steps Note down application consumer key
Note down application consumer secret
Consumer key and consumer secret will be used to authenticate your application, when user will try to use it.
Start building application

21. Getting request token
You will require to make call to along with following GET parameters
oauth_consumer_key
This is they key you obtained after registering you application
oauth_signature
String constructed using chosen signature method
oauth_signature_method
supported method is "HMAC- SHA1”
oauth_timestamp
seconds since unix epoch ( use time() function in php )
oauth_nonce
random string per timestamp
used to stop replay atacks
oauth_version
1.0 is used as a value

22. Authorization from user
Response of previous request is a request token and request secret
Redirect user to along with oauth_token parameter in GET field.
oauth_token is the request token we got from previous step.
If user provides access to the application, twitter sends acccess token and access secret to our callback url
we provide callback url while registering our application
Save the access token and access secret in sessions for making subsequent requests for resources

23. Making API calls
After we have got access token, we are now free to make various rest calls that required authentication
Many REST API calls in twitter do not require authentications
Check out for the list of API’s that are available with twitter.
If API call requires authorization, access token is sent along in authorization header of the call to a particular REST resource.

24. Format for response Developer chooses the format for response XML JSON
You are free to choose any format while making request to any API.
Eg. If you are requesting for any resource say .
Making call to get user’s followers in xml format we can write the request url like this.

25. Dealing with response
Once we get response in our desired format. We will require to extract information from that.
If your desired format is XML, you can use inbuilt PHP function simplexml_load_string($content); to convert the response contained in $content into array.
This array will contain different fields of response at its all indexes.
Loop through the array to get the value for various fields of response.

26. Example API calls and responses
We want to get list of friends of a user along with their status in xml format
Make call to with one of following GET parameters
id.  Optional.  The ID or screen name of the user for whom to request a list of friends. 
user_id.  Optional.  Specfies the ID of the user for whom to return the list of friends.
screen_name.  Optional.  Specfies the screen name of the user for whom to return the list of friends
cursor. Optional. Breaks the results into pages. A single page contains 100 users. This is recommended for users who are following many users. Provide a value of  -1 to begin paging. Provide values as returned to in the response body's next_cursor and previous_cursor attributes to page back and forth in the list.
Example: 
Example: 

27. Useful resources To know more about signing procedures visit
To know more about getting request tokens visit
Visit to know more about Oauth
Visit to know more about Twitter API’s

28. Thank You