WebImage.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Misc/DateTime.h"
#include "Containers/UnrealString.h"
#include "Templates/SharedPointer.h"
#include "Delegates/Delegate.h"
#include "Misc/Attribute.h"
#include "Interfaces/IHttpRequest.h"
#include "Interfaces/IHttpResponse.h"
#include "Brushes/SlateDynamicImageBrush.h"
#include "IImageWrapper.h"
 
class IHttpRequest;
struct FSlateBrush;
 
typedef TSharedPtr<IHttpRequest, ESPMode::ThreadSafe> FHttpRequestPtr;
typedef TSharedPtr<class IHttpResponse, ESPMode::ThreadSafe> FHttpResponsePtr;
 
class FWebImage 
    : public TSharedFromThis<FWebImage>
{
public:
    IMAGEDOWNLOAD_API FWebImage();
    IMAGEDOWNLOAD_API ~FWebImage();
 
    DECLARE_DELEGATE_OneParam(FOnImageDownloaded, bool);
 
    inline FWebImage& SetStandInBrush(TAttribute<const FSlateBrush*> StandInBrushIn) { StandInBrush = StandInBrushIn; DownloadedBrush.Reset(); return *this; }
 
    IMAGEDOWNLOAD_API bool BeginDownload(const FString& InUrl, const TOptional<FString>& StandInETag = TOptional<FString>(), const FOnImageDownloaded& DownloadCallback = FOnImageDownloaded());
 
    inline bool BeginDownload(const FString& InUrl, const FOnImageDownloaded& DownloadCallback)
    {
        return BeginDownload(InUrl, TOptional<FString>(), DownloadCallback);
    }
 
    IMAGEDOWNLOAD_API void CancelDownload();
 
public:
 
    IMAGEDOWNLOAD_API TAttribute< const FSlateBrush* > Attr() const;
 
    inline const FSlateBrush* GetBrush() const { return DownloadedBrush.IsValid() ? DownloadedBrush.Get() : StandInBrush.Get(); }
 
    inline const FSlateBrush* GetDownloadedBrush() const { return DownloadedBrush.IsValid() ? DownloadedBrush.Get() : nullptr; }
 
    inline bool IsDownloadPending() const { return PendingRequest.IsValid(); }
 
    inline bool DidDownloadSucceed() const { return bDownloadSuccess; }
 
    inline bool DidDownloadFail() const { return !IsDownloadPending() && !DidDownloadSucceed(); }
 
    inline const FString& GetUrl() const { return Url; }
 
    inline const TOptional<FString>& GetETag() const { return ETag; }
 
private:
    IMAGEDOWNLOAD_API void HttpRequestComplete(FHttpRequestPtr HttpRequest, FHttpResponsePtr HttpResponse, bool bSucceeded);
    IMAGEDOWNLOAD_API bool ProcessHttpResponse(const FString& RequestUrl, FHttpResponsePtr HttpResponse);
 
private:
    FString Url;
 
    TAttribute< const FSlateBrush* > StandInBrush;
 
    TSharedPtr<FSlateDynamicImageBrush> DownloadedBrush;
 
    TSharedPtr<IHttpRequest, ESPMode::ThreadSafe> PendingRequest;
 
    FOnImageDownloaded PendingCallback;
 
    bool bDownloadSuccess;
 
    FDateTime DownloadTimeUtc;
 
    TOptional<FString> ETag;
};