Wait for a HTTP request to be completed at game exit

Development Programming & Scripting
,
1

Hi,

When the game exits, I need to send a HTTP request and to wait for its completion (with a timeout of a couple of seconds) before allowing the game to actually exit.

I could create the http request in the Shutdown method of a module / game instance and call Wait() on the OnProcessRequestComplete delegate of the HttpRequest.

But it would block the game main thread…

Is there a better solution?

2

Perhaps try the varest plugin. It has a latent request node which you can bind success and failure to events. (Apply URL is a latent function)

3

@3dRaven

I forgot to mention that I need to make the http request in C++. VaRest seems to dedicated to blueprints.
Moreover, how could it help me to run an http request at game exit?

Thank you

4

You would need to have the logic built in a way where the user triggers a quit game command => Game does http request => receives reply => calls quit game function.

If you are thinking of catching an ALT + F4 then it would be practically impossible.
The only way that could ever be done is if you had a parallel program that would ping the game and upon not receiving a reply do the request. (sort of like a watchdog in a microcontroller)

I’ll check the stock http requests in c++ and see if there is any async functions.

5

header

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h" 
#include "Interfaces/IHttpRequest.h" 
#include "HTTPRequestActor.generated.h"


DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(FHttpRequestFinished, bool, Finished, FString, Message);
/**
 * 
 */
UCLASS(Blueprintable)
class QREQ_API AHTTPRequestActor : public AActor
{
	GENERATED_BODY()

public:

	UFUNCTION(BlueprintCallable)
	void QuitRequest(FString UrlAddressAsString, FString OutputString);
	
	

	void OnGetUsersResponse(FHttpRequestPtr Request, FHttpResponsePtr Response, bool bWasSuccessful);

	UPROPERTY(BlueprintAssignable)
	FHttpRequestFinished RequestFinishedDelegate;

};

.CPP

// Fill out your copyright notice in the Description page of Project Settings.


#include "HTTPRequestActor.h"
#include "HttpModule.h" 
#include "Kismet/GameplayStatics.h"
#include "Kismet/KismetSystemLibrary.h"
#include "Interfaces/IHttpResponse.h"

void AHTTPRequestActor::QuitRequest(FString UrlAddressAsString, FString OutputString) {

    TSharedRef<IHttpRequest> HttpRequest = FHttpModule::Get().CreateRequest();

    HttpRequest->SetVerb("POST");
    HttpRequest->SetHeader("Content-Type", "application/json");
    HttpRequest->SetURL(*FString::Printf(TEXT("%s"), *UrlAddressAsString));
    HttpRequest->SetContentAsString(OutputString);
    HttpRequest->OnProcessRequestComplete().BindUObject(this, &AHTTPRequestActor::OnGetUsersResponse);    
    HttpRequest->ProcessRequest();
}


void AHTTPRequestActor::OnGetUsersResponse(FHttpRequestPtr Request, FHttpResponsePtr Response, bool bWasSuccessful) 
{
    if (bWasSuccessful)
    {
        TSharedPtr<FJsonObject> JsonObject = MakeShareable(new FJsonObject());        
        TSharedRef<TJsonReader<TCHAR>> JsonReader = TJsonReaderFactory<TCHAR>::Create(Response->GetContentAsString());
        FJsonSerializer::Deserialize(JsonReader, JsonObject);

        FString string_value_read = JsonObject->GetStringField("success");
        if (string_value_read == "true") {
            RequestFinishedDelegate.Broadcast(true, "Success");
            
            bool IgnorePlatformRestrictions = true;
            if (APlayerController* pc = UGameplayStatics::GetPlayerController(GetWorld(), 0)) {
                UKismetSystemLibrary::QuitGame(GetWorld(), pc, EQuitPreference::Quit, IgnorePlatformRestrictions);
            }

        }
        else {
            RequestFinishedDelegate.Broadcast(false, "Key not found response: " + Response.Get()->GetContentAsString());
            // Request failed
        }
    }
    else {
        FString Message = "Request failed [" + FString::FromInt(Response.Get()->GetResponseCode()) + "] " + Response.Get()->GetContentAsString();
        RequestFinishedDelegate.Broadcast(false, Message);
    }
}

You will need to modify

FString string_value_read = JsonObject->GetStringField("success");
if (string_value_read == "true") {
}

to the needed validation you want from the request response.

You can also bind to an exposed delegate RequestFinishedDelegate and quit that way
(you would have to remove the hard-coded quit)

Example project:
QReq.zip (125.8 KB)

You may want to expose the quit condition as a pin. Not sure what you need so kept it simple.

Executed via QuitRequest