After the recent changes in the Facebook developers interface, we would like to provide informarmation in this article about how you can create a Facebook Log in App, get the APP ID Secret and configure the Facebook login (in the product of ours supporting this functionality).
Basically in order to enable the log in for the users with a Facebook account, you need to create a Facebook log in app, get the APP ID and Secret and set them on the Settings->Configuration Options page in the administration panel (in the fields "Facebook APP ID" and "Facebook APP Secret").
The first step is to go to https://developers.facebook.com/setup , log in with your account and click on the green "Add a New App" button at the top right corner.
There you need to enter the app name in the Display Name field (it could be your site name or any other name you prefer) and click on the blue button at the bottom "Create APP ID".
This will bring you to the next step, where you have to choose "Facebook Login".
On the next step, for "Select the platform for this app", please choose Web -
After selecting "Web", a new screen will pop up and it will ask you for "Tell us what the URL of your site is" and there you have to enter your website domain, for example yourdomain.com
There will be a next step popping up "Set up the Facebook SDK for Javascript", but you may skip it and directly go to Settings>Basics in the menu to the left.
There to activate the APP, you set the button "Make APP Public" to YES - when doing that, it will ask you to enter a Privacy Policy url, so if you already have a Privacy Policy page, you can paste the page url (in general from the administration panel of our products, you can easily create new pages from Site Content->Pages or Website->Management depending on the admin panel version you are using, so if you wish, you may also create a new Privacy Policy page from there).
The last step in the configuration is to go to Facebook Login->Settings in the left menu and there in the field Valid OAuth Redirect URIs, enter https://www.yourdomain.com/index.php?mod=facebook_login (where at the place of yourdomain.com, you have to enter your real website domain name)
Please note that as of April 2018, for all the new apps created the setting Enforce HTTPS you could see above this field is set to YES and it's not possible to switch to NO - so all requests are only done with https and you'll need to install SSL on your site in order that your site is accessible with https. For older apps, at this moment (May, 2018) it's still possible to use http urls and to change the value of Enfore HTTPS and make it YES (only https calls) or NO (http calls allowed).
Finally you have to go to Settings->Basic, from where you can see and copy your new Facebook APP ID and Secret, and paste the values on the Settings->Configurations options in the admin panel in order to activate the Facebook user log in on your site.