Azure App Service Facebook - facebook

Question

I've migrated from Azure Mobile Service to an App Service but I'm having difficulty working out how best to implement extended Facebook auth.
In my old implementation I inherited from FacebookLoginProvider and fetched the token from the claims. I then added the CustomFacebookLoginProvider to my login providers. I then use the token to fetch more information about the user (their date of birth, friends and gender). With this information I created a user object and saved it to my DB.
Does anyone have any suggestions on how best to recreate this in App Service as I can't find any documentation.

Answer 1

As far as how to set up Facebook authentication, you can find documentation here (and it sounds like you've already figured out this much):
https://azure.microsoft.com/en-us/documentation/articles/app-service-mobile-how-to-configure-facebook-authentication/
Now that Facebook authentication is set up, you can refer to the following which shows how to obtain user information:
https://azure.microsoft.com/en-us/documentation/articles/app-service-mobile-dotnet-backend-how-to-use-server-sdk/#user-info
// Get the credentials for the logged-in user.
var credentials =
await this.User
.GetAppServiceIdentityAsync<FacebookCredentials>(this.Request);
if (credentials.Provider == "Facebook")
{
// Create a query string with the Facebook access token.
var fbRequestUrl = "https://graph.facebook.com/me?access_token="
+ credentials.AccessToken;
// Create an HttpClient request.
using (var client = new System.Net.Http.HttpClient())
{
// Request the current user info from Facebook.
using (var resp = await client.GetAsync(fbRequestUrl))
{
resp.EnsureSuccessStatusCode();
// Do something here with the Facebook user information.
var fbInfo = await resp.Content.ReadAsStringAsync();
}
}
}
Note that you must add a using statement for System.Security.Principal to make the GetAppServiceIdentityAsync extension method work.
For more information on which Facebook user properties you can query, see the Facebook documentation here: https://developers.facebook.com/docs/graph-api/reference/user. Note that you may need to specify which user properties you want as an additional fields query string parameter on your call to the Facebook graph.

Answer 2

The only change I had to make when switching from Mobile Service to Mobile App was to change the end of the callback URL in the developer portal to use /.auth/login/facebook/callback instead of /signin-facebook and it worked exactly the same way as before.
Note that this is for a Windows app with a .NET backend; you didn't specify what you're using so your mileage may vary.

Answer 3

I've been using the following approach to obtain the Facebook Access Token in the iOS app.
App Services includes the Facebook Access Token in the request header, refer to https://azure.microsoft.com/en-in/documentation/articles/app-service-api-authentication/.
To get to the access token, create a Custom API in the Azure Portal, e.g. facebookUserInfo, with the following code:
module.exports = {
"get": function (request, response, next) {
response.send(200, { facebookAccessToken: request.headers['x-ms-token-facebook-access-token'] });
}};
In the iOS app, use the following code to query the custom API:
let client = self.table!.client
if client.currentUser != nil {
client.invokeAPI("facebookUserInfo", body: nil, HTTPMethod: "GET", parameters: nil, headers: nil, completion: { (result, response, error) -> Void in
if let resultDict = result {
if let facebookAccessToken = resultDict["facebookAccessToken"]! {
print(facebookAccessToken)
}
}
}
}

Answer 4

By Using the Easy Auth feature of Azure App Services, I dont need to worry about authentication.
I have a blogpost on this. I have explained on how we can use the FB GraphApi's to query FB data. Here is the link: https://blogs.msdn.microsoft.com/kaushal/2017/06/08/using-easy-auth-to-query-facebook-information-via-graph-api/
I have the sample code deployed on Github. Here is the link: https://github.com/kaushalp/Facebook-GraphApi-with-EasyAuth