senia-psm / facebook4s

Async Scala SDK for the Facebook Graph API.

facebook4s

Prerequisites

Scala 2.12.x

SBT 0.13.x

Installation

[Link to a header] Add the following line to your sbt dependencies:

"com.github.vooolll" %% "facebook4s" % "0.1.5"

Note: make sure that you have in your build.sbt

resolvers += Resolver.sonatypeRepo("releases")

Usage

Configuration

Add your client id(application id) and application secret to your environment variables:

export FACEBOOK_CLIENT_ID='your client id'
export FACEBOOK_APP_SECRET='your application secret'
export FACEBOOK_REDIRECT_URI='http://localhost:9000/redirect'

or you can use typesafe config, typically known as application.conf

facebook {
  clientId = "your client id"
  redirectUri = "http://localhost:9000/redirect"
  appSecret = "your application secret"
}

Create FacebookClient

In order to use api you need to create FacebookClient all api is available via this object

import api.FacebookClient

val facebookClient = FacebookClient()

In example above FacebookClient will use configured parameters, see Configuration.

If you want to specify client id and application secret explicitly you can do it as expected:

import api.FacebookClient

val facebookClient = FacebookClient("your client id", "your app secret")

or you can use types to your advantage:

import api.FacebookClient
import domain.{FacebookClientId, FacebookAppSecret}

val facebookClient = FacebookClient(FacebookClientId("your client id"), FacebookAppSecret("your app secret"))

Getting authentication uri

FacebookClient can be used to get authentication url for client. It is starting point if you want to use api.

import api.FacebookClient
import domain.permission.FacebookPermissions.FacebookUserPosts

val facebookClient = FacebookClient()

val urlWithCodeAsQueryParam = facebookClient.authUrl(Seq(FacebookUserPosts))

println(url) // prints url client needs to request to get credentials (client code by default)

Or you can tell to FacebookClient that you want to receive access token instead of client code by passing specific argument:

import domain.permission.FacebookPermissions.FacebookUserPosts
import domain.oauth.FacebookToken

val urlWithTokenAsQueryParam = facebookClient.authUrl(Seq(FacebookUserPosts), FacebookToken)

Exchanging client code to access token

After client code received, it can be exchanged to access token.

import api.FacebookClient
import scala.util.{Success, Failure}

val facebookClient = FacebookClient()
val clientCode = "code from request"

facebookClient.userAccessToken(clientCode) onComplete {
  case Success(token) => println(token)
  case Failure(e) => println(e.getMessage)
}

Exchange short lived to long lived token

In order to access api you typically need user access token, it is often obtained by client application, so assuming you already have one:

val shortLivedAccessToken = "user access token"

Then you may exchange it to long lived access token, you need to create FacebookClient object:

import api.FacebookClient
import scala.util.{Success, Failure}

val facebookClient = FacebookClient()

facebookClient.extendUserAccessToken(shortLivedAccessToken) onComplete {
 case Success(longLivedToken) => println(longLivedToken)
 case Failure(e) => println(e.getMessage)
}

Exchange long-lived token to client code

It is possible to obtain client code using api call and long lived token from previous auth:

import api.FacebookClient
import scala.util.{Success, Failure}

val facebookClient = FacebookClient()

val longLivedTokeValue = "long-lived-token-value"

facebookClient.clientCode(longLivedTokeValue) onComplete {
 case Success(code) => println(code)
 case Failure(e) => println(e.getMessage)
}

After obtaining client code you can send it to client over secure channel

Obtaining app access token

In some cases you may need your application access token, you can get it using appAccessToken api call:

import api.FacebookClient
import scala.util.{Success, Failure}

val facebookClient = FacebookClient()

facebookClient.appAccessToken() onComplete {
 case Success(appAccessToken) => println(appAccessToken)
 case Failure(e) => println(e.getMessage)
}

Api references

• FacebookClient
• FacebookAccessToken
• AppAccessToken
• UserAccessToken
• FacebookClientId
• FacebookClientCode
• FacebookRedirectUri
• FacebookAppSecret
• FacebookVersion
• FacebookOauthError

License

Facebook4s is released under the Apache 2 License.

Credits

Authors