Understanding The Facebook Live Through Facebook Graph API

First, you have to create facebook app account if you did not create follow this link

1) Go to My Apps.
2) Click "+ Add a New App".
3) Setup a website app

Don't need any changes its permissions or anything. We have to need an app use for facebook graph API through access token.

->Step for getting user short-lived access token

1) Go to the Graph API Explorer link here.
2) Select the application you want to get the access token for (in the "Application" drop-down menu, not the "My Apps" menu).

3) Click "Get Token" -> "Get User Access Token".
4) In the pop-up, under the "Extended Permissions" tab, check "manage_pages".
5) Click "Get Access Token".

-->Url for getting your facebook live videos which you post.

https://graph.facebook.com/v2.12/me?fields=live_videos&access_token={facebook login token}

-->Url for getting reactions, likes, comment of the particular video

https://graph.facebook.com/v2.12/{video-id}?fields=reactions,likes,title,comments

Now I will elaborate the access tokens and OAuth 2.0 to make the concepts clear.

OAuth 2.0

   1. The standard OAuth 2.0 implementation, the first step is to invoke the OAuth Dialog of the service provider (facebook)-

    \GET  http://www.facebook.com/dialog/oauth

       Parameters:

        client_id (APP ID)
	redirect_uri (App's Redirect Url)
	scope (permissions - optional) 

       Returns:- 

    code (appended with the redirect url)

   2. When user successfully authenticated the app, a code is returned by the service provider(facebook) appended with the redirect_url passed. So you'll be redirected to-

       {redirect-url}?code=XXXXXXXXXXXXXXXXX

       We use this code then and request for the access_token-

    \GET  https://graph.facebook.com/oauth/access_token

        Parameters:

        client_id (APP ID)
	client_secret (APP Secret)
	code
	redirect_uri

If you dont need to build this manual flow, you can use the SDKs. It will just application to the outh dialog and if success will give you the access token in response.Facebook provides official SDKs for iOS, Android, Javascript and PHP; also there are other third-party SDKs.

Access Tokens

There are 3 types of access tokens to support different use cases:

User Access Token:-

This type of user-access token is required any time the app calls an API to read and modify or write a specific person's Facebook data on their behalf. 

App Access Token:-

This access tokens are used to makes requests to Facebook APIs on behalf of an app. With this access token we can create, and manage test users, or read your application's insights.

	GET /oauth/access_token?
	     client_id={app-id}
	     &client_secret={app-secret}
	     &grant_type=client_credentials
	or directly from here, or simply use {app-id}|{app-secret}

       /GET  /{page-id}?fields=access_token