SignIn with Facebook

react native facebook login introduction in the last tutorials, you built a user login/logout feature to your app using the parse user parse user class now you will learn how to use facebook fbsdk login to retrieve user data from facebook and log in, sign up or link existent users with it you will also install and configure the react native fbsdk react native fbsdk lib to achieve that the parse user linkwith parse user linkwith method is responsible for signing up and logging in users using any third party authentication method, as long as you pass the right parameters requested by each different provider after linking the user data to a new or existent parse user parse user , parse will store a valid user session in your device future calls to methods like currentasync currentasync will successfully retrieve your user data, just like with regular logins at any time, you can access the complete android project built with this tutorial at our github repositories kotlin example repository java example repository prerequisites to complete this tutorial, you will need a react native app created and connected to back4app complete the previous guides so you can have a better understanding of the parse user class goal to build a user login feature using facebook fbsdk login on parse for a react native app 1 installing dependencies the most popular way to add facebook login on react native is using react native fbsdk react native fbsdk to handle it since this library configuration depends on your development environment, target platform, and preferences, set it up following the official docs https //github com/facebook/react native fbsdk note if you are developing for ios, make sure that your project has support for swift files, containing a bridging header also, pay close attention to where you add the facebook app ids inside your info plist info plist file and if your pods files are correctly generated 2 using fbsdk login with parse let’s now create a new method inside the userlogin userlogin component calling facebook fbsdk authentication modal with loginmanager loginwithpermissions loginmanager loginwithpermissions , requesting permission only to access the user email if the user successfully signs in with facebook, you can then call accesstoken getcurrentaccesstoken accesstoken getcurrentaccesstoken to retrieve the user access token from facebook after that, you still need to get the user id id and email email using a graphrequest graphrequest through fbsdk graphrequestmanager graphrequestmanager javascript 1 const douserloginfacebook = async function () { 2 try { 3 // login using the facebook login dialog asking form email permission 4 return await loginmanager loginwithpermissions(\['email']) then( 5 (loginresult) => { 6 if (loginresult iscancelled) { 7 console log('login cancelled'); 8 return false; 9 } else { 10 // retrieve access token from fbsdk to be able to linkwith parse 11 accesstoken getcurrentaccesstoken() then((data) => { 12 const facebookaccesstoken = data accesstoken; 13 // callback that will be called after fbsdk successfuly retrieves user email and id from fb 14 const responseemailcallback = async ( 15 error, 16 emailresult, 17 ) => { 18 if (error) { 19 console log('error fetching data ' + error tostring()); 20 } else { 21 // format authdata to provide correctly for facebook linkwith on parse 22 const facebookid = emailresult id; 23 const facebookemail = emailresult email; 24 const authdata = { 25 id facebookid, 26 access token facebookaccesstoken, 27 }; 28 // log in or sign up on parse using this facebook credentials 29 let usertologin = new parse user(); 30 // set username and email to match provider email 31 usertologin set('username', facebookemail); 32 usertologin set('email', facebookemail); 33 return await usertologin 34 linkwith('facebook', { 35 authdata authdata, 36 }) 37 then(async (loggedinuser) => { 38 // login returns the corresponding parseuser object 39 alert alert( 40 'success!', 41 `user ${loggedinuser get( 42 'username', 43 )} has successfully signed in!`, 44 ); 45 // to verify that this is in fact the current user, currentasync can be used 46 const currentuser = await parse user currentasync(); 47 console log(loggedinuser === currentuser); 48 // navigation navigate takes the user to the screen named after the one 49 // passed as parameter 50 navigation navigate('home'); 51 return true; 52 }) 53 catch(async (error) => { 54 // error can be caused by wrong parameters or lack of internet connection 55 alert alert('error!', error message); 56 return false; 57 }); 58 } 59 }; 60&#x9; 61 // formats a fbsdk graphrequest to retrieve user email and id 62 const emailrequest = new graphrequest( 63 '/me', 64 { 65 accesstoken facebookaccesstoken, 66 parameters { 67 fields { 68 string 'email', 69 }, 70 }, 71 }, 72 responseemailcallback, 73 ); 74&#x9; 75 // start the graph request, which will call the callback after finished 76 new graphrequestmanager() addrequest(emailrequest) start(); 77&#x9; 78 return true; 79 }); 80 } 81 }, 82 (error) => { 83 console log('login fail with error ' + error); 84 return false; 85 }, 86 ); 87 } catch (error) { 88 alert alert('error!', error code); 89 return false; 90 } 91 };1 const douserloginfacebook = async function () promise\<boolean> { 2 try { 3 // login using the facebook login dialog asking form email permission 4 return await loginmanager loginwithpermissions(\['email']) then( 5 (loginresult object) => { 6 if (loginresult iscancelled) { 7 console log('login cancelled'); 8 return false; 9 } else { 10 // retrieve access token from fbsdk to be able to linkwith parse 11 accesstoken getcurrentaccesstoken() then((data object) => { 12 const facebookaccesstoken = data accesstoken; 13 // callback that will be called after fbsdk successfuly retrieves user email and id from fb 14 const responseemailcallback = async ( 15 error string, 16 emailresult object, 17 ) => { 18 if (error) { 19 console log('error fetching data ' + error tostring()); 20 } else { 21 // format authdata to provide correctly for facebook linkwith on parse 22 const facebookid string = emailresult id; 23 const facebookemail string = emailresult email; 24 const authdata object = { 25 id facebookid, 26 access token facebookaccesstoken, 27 }; 28 // log in or sign up on parse using this facebook credentials 29 let usertologin parse user = new parse user(); 30 // set username and email to match provider email 31 usertologin set('username', facebookemail); 32 usertologin set('email', facebookemail); 33 return await usertologin 34 linkwith('facebook', { 35 authdata authdata, 36 }) 37 then(async (loggedinuser parse user) => { 38 // login returns the corresponding parseuser object 39 alert alert( 40 'success!', 41 `user ${loggedinuser get( 42 'username', 43 )} has successfully signed in!`, 44 ); 45 // to verify that this is in fact the current user, currentasync can be used 46 const currentuser parse user = await parse user currentasync(); 47 console log(loggedinuser === currentuser); 48 // navigation navigate takes the user to the screen named after the one 49 // passed as parameter 50 navigation navigate('home'); 51 return true; 52 }) 53 catch(async (error object) => { 54 // error can be caused by wrong parameters or lack of internet connection 55 alert alert('error!', error message); 56 return false; 57 }); 58 } 59 }; 60&#x9; 61 // formats a fbsdk graphrequest to retrieve user email and id 62 const emailrequest = new graphrequest( 63 '/me', 64 { 65 accesstoken facebookaccesstoken, 66 parameters { 67 fields { 68 string 'email', 69 }, 70 }, 71 }, 72 responseemailcallback, 73 ); 74&#x9; 75 // start the graph request, which will call the callback after finished 76 new graphrequestmanager() addrequest(emailrequest) start(); 77&#x9; 78 return true; 79 }); 80 } 81 }, 82 (error string) => { 83 console log('login fail with error ' + error); 84 return false; 85 }, 86 ); 87 } catch (error object) { 88 alert alert('error!', error code); 89 return false; 90 } 91 }; note that after the graphrequest graphrequest succeeds, this function uses parse user linkwith parse user linkwith on a new parse user parse user object to register a new user or log in a previous one with these credentials, passing his facebook authentication data accordingly add this function to your usersignin usersignin component and assign it to your facebook button onpress onpress parameter go ahead and test your new function, you will see that the user will be redirected to your home screen after successfully signing in 3 verifying user sign in and session creation to make sure that the facebook sign in worked, you can look at your parse dashboard and see your new user user (if your facebook authentication data didn’t belong to another user), containing the facebook authdata authdata parameters you can also verify that a valid session was created in the dashboard, containing a pointer to that user user object 4 linking an existing user to fbsdk login another linkwith linkwith possible use is to link an existing user with another auth provider, in this case, facebook add this function that calls linkwith linkwith the same way you did in userlogin userlogin to your hellouser hellouser component or directly to your home screen the only difference here is that instead of calling the method from an empty parse user parse user , you will use it from the logged in user object javascript 1 const douserlinkfacebook = async function () { 2 try { 3 // login using the facebook login dialog asking form email permission 4 return await loginmanager loginwithpermissions(\['email']) then( 5 (loginresult) => { 6 if (loginresult iscancelled) { 7 console log('login cancelled'); 8 return false; 9 } else { 10 // retrieve access token from fbsdk to be able to linkwith parse 11 accesstoken getcurrentaccesstoken() then((data) => { 12 const facebookaccesstoken = data accesstoken; 13 // callback that will be called after fbsdk successfuly retrieves user email and id from fb 14 const responseemailcallback = async ( 15 error, 16 emailresult, 17 ) => { 18 if (error) { 19 console log('error fetching data ' + error tostring()); 20 } else { 21 // format authdata to provide correctly for facebook linkwith on parse 22 const facebookid = emailresult id; 23 const authdata = { 24 id facebookid, 25 access token facebookaccesstoken, 26 }; 27 let currentuser = await parse user currentasync(); 28 return await currentuser 29 linkwith('facebook', { 30 authdata authdata, 31 }) 32 then(async (loggedinuser) => { 33 // login returns the corresponding parseuser object 34 alert alert( 35 'success!', 36 `user ${loggedinuser get( 37 'username', 38 )} has successfully linked his facebook account!`, 39 ); 40 // to verify that this is in fact the current user, currentasync can be used 41 currentuser = await parse user currentasync(); 42 console log(loggedinuser === currentuser); 43 return true; 44 }) 45 catch(async (linkwitherror) => { 46 // error can be caused by wrong parameters or lack of internet connection 47 alert alert('error!', linkwitherror message); 48 return false; 49 }); 50 } 51 }; 52&#x9; 53 // formats a fbsdk graphrequest to retrieve user email and id 54 const emailrequest = new graphrequest( 55 '/me', 56 { 57 accesstoken facebookaccesstoken, 58 parameters { 59 fields { 60 string 'email', 61 }, 62 }, 63 }, 64 responseemailcallback, 65 ); 66&#x9; 67 // start the graph request, which will call the callback after finished 68 new graphrequestmanager() addrequest(emailrequest) start(); 69&#x9; 70 return true; 71 }); 72 } 73 }, 74 (error) => { 75 console log('login fail with error ' + error); 76 return false; 77 }, 78 ); 79 } catch (error) { 80 alert alert('error!', error code); 81 return false; 82 } 83 };1 const douserlinkfacebook = async function () promise\<boolean> { 2 try { 3 // login using the facebook login dialog asking form email permission 4 return await loginmanager loginwithpermissions(\['email']) then( 5 (loginresult object) => { 6 if (loginresult iscancelled) { 7 console log('login cancelled'); 8 return false; 9 } else { 10 // retrieve access token from fbsdk to be able to linkwith parse 11 accesstoken getcurrentaccesstoken() then((data object) => { 12 const facebookaccesstoken = data accesstoken; 13 // callback that will be called after fbsdk successfuly retrieves user email and id from fb 14 const responseemailcallback = async ( 15 error string, 16 emailresult object, 17 ) => { 18 if (error) { 19 console log('error fetching data ' + error tostring()); 20 } else { 21 // format authdata to provide correctly for facebook linkwith on parse 22 const facebookid string = emailresult id; 23 const authdata object = { 24 id facebookid, 25 access token facebookaccesstoken, 26 }; 27 let currentuser parse user = await parse user currentasync(); 28 return await currentuser 29 linkwith('facebook', { 30 authdata authdata, 31 }) 32 then(async (loggedinuser parse user) => { 33 // login returns the corresponding parseuser object 34 alert alert( 35 'success!', 36 `user ${loggedinuser get( 37 'username', 38 )} has successfully linked his facebook account!`, 39 ); 40 // to verify that this is in fact the current user, currentasync can be used 41 currentuser = await parse user currentasync(); 42 console log(loggedinuser === currentuser); 43 return true; 44 }) 45 catch(async (linkwitherror object) => { 46 // error can be caused by wrong parameters or lack of internet connection 47 alert alert('error!', linkwitherror message); 48 return false; 49 }); 50 } 51 }; 52&#x9; 53 // formats a fbsdk graphrequest to retrieve user email and id 54 const emailrequest = new graphrequest( 55 '/me', 56 { 57 accesstoken facebookaccesstoken, 58 parameters { 59 fields { 60 string 'email', 61 }, 62 }, 63 }, 64 responseemailcallback, 65 ); 66&#x9; 67 // start the graph request, which will call the callback after finished 68 new graphrequestmanager() addrequest(emailrequest) start(); 69&#x9; 70 return true; 71 }); 72 } 73 }, 74 (error string) => { 75 console log('login fail with error ' + error); 76 return false; 77 }, 78 ); 79 } catch (error object) { 80 alert alert('error!', error code); 81 return false; 82 } 83 }; assign this function to a facebook button onpress onpress parameter on your home screen test your new function, noting that the parse user parse user object authdata value will be updated with the new auth provider data verify if the user has indeed updated in your parse server dashboard conclusion at the end of this guide, you learned how to log in or sign up parse users on react native using facebook fbsdk login with react native fbsdk react native fbsdk in the next guide, we will show you how to perform useful user queries