VaRest URL Call in C++

In this tutorial we will turn this blueprint graph below into C++.

Step 1

You can either download VaRest from github or from Unreal Marketplace.

Download the proper VaRest version for your Project:

https://github.com/ufna/VaRest

Add the files to your Project Plugins Folder:

MyProject/Plugins/VaRest

If you use marketplace just jump to step 2

Step 2

Add VaRest module to MyProject.Build.cs File.

using UnrealBuildTool;

public class CHANGETHIS: ModuleRules
{
	public CHANGETHIS(ReadOnlyTargetRules Target) : base(Target)
	{
		PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;
	
		PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore",  "VaRest" });

		PrivateDependencyModuleNames.AddRange(new string[] {  });

	}
}

Step 3

Time to add some code. I’m using AActor Class.

So first we add some headers into x.h file

#include "VaRestSubsystem.h"
#include "VaRestRequestJSON.h"
#include "VaRestTypes.h"
#include "VaRestJsonObject.h"
#include "VaRestJsonValue.h"

Then we add VaRest Delegate

FVaRestCallDelegate VarestDelegate;

Then comes delegate result function.

Always add UFUNCTION into this or it wont be called by delegate.

void VaRestTest(UVaRestRequestJSON* Request);

This we use to start whole thing

void VaRestInit(FString URL);

Function that gets the subsystem

UVaRestSubsystem* GetVARestSub();

And whole thing.

#pragma once

#include "CoreMinimal.h"
#include "VaRestSubsystem.h"
#include "VaRestRequestJSON.h"
#include "VaRestTypes.h"
#include "VaRestJsonObject.h"
#include "VaRestJsonValue.h"
#include "Subsystems/SubsystemBlueprintLibrary.h"
#include "GameFramework/Actor.h"
#include "ResTest.generated.h"

UCLASS()
class AResTest : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AResTest();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;


	FVaRestCallDelegate VarestDelegate;

//UFUNCTION is really important here
	UFUNCTION(BlueprintCallable, Category = "Tests")
		void VaRestTest(UVaRestRequestJSON* Request);

	UFUNCTION(BlueprintCallable, Category = "Tests")
		void VaRestInit(FString URL);

	UFUNCTION(BlueprintCallable, Category = "Tests")
		UVaRestSubsystem* GetVARestSub();
};

#include "ResTest.h"

// Sets default values
AResTest::AResTest()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void AResTest::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AResTest::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

//Don't add any other parameters into this just what the VaRestDelegate gives
void AResTest::VaRestTest(UVaRestRequestJSON* Request)
{
	FString Response = Request->GetResponseContentAsString(false);

	FString Message = FString();
	
	Message.Append(TEXT("Request went through"));
	Message.Append(TEXT(" Response Length: "));
	Message.Append(FString::FromInt(Response.Len()));

	GEngine->AddOnScreenDebugMessage(-1, 9.f, FColor::Yellow, Message);
}

void AResTest::VaRestInit(FString URL)
{

	UVaRestSubsystem* Varestsub = GetVARestSub();

	if (!::IsValid(Varestsub))
	{
		GEngine->AddOnScreenDebugMessage(-1, 4.f, FColor::Red, TEXT("VArest Subsystem missing"));

		return;
	}

//This will bind VaRestTest function to VarestDelegate, which is how you get the result from CallUrl
	VarestDelegate.BindUFunction(this, FName("VaRestTest"));
       
//This is the Call Url Function
	Varestsub->UVaRestSubsystem::CallURL(URL, EVaRestRequestVerb::POST, EVaRestRequestContentType::x_www_form_urlencoded_url, ((UVaRestJsonObject*)nullptr), VarestDelegate);

}

UVaRestSubsystem* AResTest::GetVARestSub()
{
	UVaRestSubsystem* Subsystem{};


	Subsystem = CastChecked<UVaRestSubsystem>(USubsystemBlueprintLibrary::GetEngineSubsystem(UVaRestSubsystem::StaticClass()), ECastCheckedType::NullAllowed);

	if (::IsValid(Subsystem))
	{
		return Subsystem;
	}

	return nullptr;
}

And that’s it, edit it into your needs, good luck!

If you need to multithread this task check out this:

https://unrealcommunity.wiki/asynctask-function-mfdnmfca