Simple Setup & Usage

This is the simplest approach, but it requires that your Client ID and Client Secret be built into your application or are somehow retrievable by your application at run-time. While you can take steps to make extracting these from your project difficult (e.g. only storing encrypted strings which are decrypted at run-time), there will always be a risk that one of your users will be able to locate and extract them.

Your Redirect URI in your registered client should start with http://localhost

The process will work like this:

1. You open the Patreon login and consent page for your user (either using their default web browser or the UMG Web Browser widget).
2. While they are signing in and granting your application access to their data, we start up an HTTP server a. By default the server will listen for a request at http://localhost/login:8080, but you can customize this as you see fit b. Whatever you configure the server to use, you need to ensure that your application's configuration on the Patreon side has a matching Redirect URI, e.g. if you set Callback Route to /patreon and Callback Port to 9999, you must update the settings in Patreon to include a Redirect URI of http://localhost:9999/patreon.

   The Callback Route MUST start with "/" and be longer than just "/" but can otherwise be anything you want.

   The Callback Port MUST be a positive integer, and unless you plan to use port 80 should be larger than 1024

3. After consenting to sharing their data with your application, Patreon will make a request to the built-in HTTP server with a one-time use code we use to obtain an Access Token on behalf of the user.
4. Once we have an access token, we use this to request the user's account information, including any tiers and benefits they are entitled to.
5. You can then use this information as you want, e.g. checking if they are pledged to a specific tier and unlocking some content for them.

That sounds like a lot, but steps 1-3 are encapsulated inside of a single function which can be chained to a second function to handle step 4 for you, leaving only the actual logic for your application in step 5 up to you to implement.

Blueprint

C++

#include "Actions/PerformAuthenticationAsyncAction.h"
#include "Actions/GetPatreonUserInfoAsyncAction.h"
#include "APITokenInfo.h"

#define CLIENT_ID     TEXT("<Your Client ID>")
#define CLIENT_SECRET TEXT("<Your Client Secret>")

void MyClass::DoPatreonLogin() {
  // create an authentication action expecting a callback at http://localhost/login:8080
  UPerformAuthenticationAsyncAction* authAction = UPerformAuthenticationAsyncAction::PerformAuthenticationAsyncAction(
    this, // world context
    CLIENT_ID,
    CLIENT_SECRET
    // callback route defaults to "/login"
    // callback port defaults to 8080
  );

  // register callbacks for results
  authAction->OnComplete.AddDynamic(this, &MyClass::OnAuthenticationComplete);
  authAction->OnFail.AddDynamic(this, &MyClass::OnAuthenticationFailed);
  // kick off action
  authAction->Activate();
}

void MyClass::OnAuthenticationComplete(FAPITokenInfo TokenInfo) {
  // now that we have a token, we can use it to fetch information about the user who just logged in
  UGetPatreonUserInfoAsyncAction* getInfoAction = UGetPatreonUserInfoAsyncAction::GetPatreonUserInfoAsyncAction(
    this, // world context
    TokenInfo
  );

  getInfoAction->OnComplete.AddDynamic(this, &MyClass::OnGetUserInfoComplete);
  getInfoAction->OnFail.AddDynamic(this, &MyClass::OnGetUserInfoFail);
  getInfoAction->Activate();
}

void MyClass::OnAuthenticationFailed() {
  UE_LOG(LogTemp, Error,
    TEXT("Patreon authentication failed: The user may have denied the request for their data")
  );
}

void MyClass::OnGetUserInfoComplete(FPatreonUserInfo UserInfo) {
  // now that we have the user's information,
  //  we can check if they have pledged to a tier with unlockable content
  if (UserInfo.HasTier("Special Tier")) {
    UnlockSecretConent();
  } else  {
    // suggest the user should pledge to the Special Tier ;)
  }
}

void MyClass::OnGetUserInfoFail() {
  UE_LOG(LogTemp, Error,
    TEXT("Fetching user info from Patreon API failed: Was the access token invalid?")
  );
}

For any questions, help, suggestions or feature requests, please feel free to contact me at nbpsup@gmail.com