FBackgroundHttpFileHashHelper | Unreal Engine 5.7 Documentation

API > API/Runtime > API/Runtime/BackgroundHTTPFileHash

Helper that handles generating unique hashed file paths to use store to store BackgroundHTTP work once completed. Can be saved and loaded to/from disk to handle persistence across session when background work is compelted without any usefull program state. NOTE: This is in it's own separate module as some platforms (IOS, etc.) need to include this functionality in ApplicationCore and thus fully adding a dependency to those modules on BackgroundHTTP would not work


Name	FBackgroundHttpFileHashHelper
Type	class
Header File	/Engine/Source/Runtime/Online/BackgroundHTTPFileHash/Public/BackgroundHttpFileHashHelper.h
Include Path	#include "BackgroundHttpFileHashHelper.h"

Syntax

class FBackgroundHttpFileHashHelper

Constructors

Name	Remarks	Include Path	Unreal Specifiers
FBackgroundHttpFileHashHelper()		BackgroundHttpFileHashHelper.h

Variables

Protected

Name	Type	Remarks	Include Path
bHasLoadedURLData	std::atomic< bool >	Used to make sure that we have called LoadData before any operations that depend on it.	BackgroundHttpFileHashHelper.h
bIsDirty	std::atomic< bool >	Tracks if we have changed data since our last call to SaveData()	BackgroundHttpFileHashHelper.h
URLFileMappings	TMap< FString, FURLTempFileMapping >	Stores our FURLTempFileMapping mapped to a Hashed filename.	BackgroundHttpFileHashHelper.h
URLFileMappingsLock	FRWLock	Access lock for URLFileMappings.	BackgroundHttpFileHashHelper.h

Functions

Public

Name	Remarks	Include Path
void DeleteURLMappingsWithoutTempFiles()	Deletes any URLMapping that doesn't have a corresponding Temp file actually on disk.	BackgroundHttpFileHashHelper.h
bool FindMappedURLForTempFilename ( const FString& TempFilename, FString& OutMappedURL ) const	Looks for a URL mapped to the supplied TempFilename. Nullptr returned if one isn't found.	BackgroundHttpFileHashHelper.h
const FString * FindMappedURLForTempFilename ( const FString& TempFilename ) const		BackgroundHttpFileHashHelper.h
const FString & FindOrAddTempFilenameMappingForURL ( const FString& URL )	Looks for a temp filename mapping for the given URL. If one isn't found a new one is generated and returned.	BackgroundHttpFileHashHelper.h
const FString * FindTempFilenameMappingForURL ( const FString& URL ) const		BackgroundHttpFileHashHelper.h
bool FindTempFilenameMappingForURL ( const FString& URL, FString& OutTempFilename ) const	Looks for a temp filename mapping for the given URL. If one isn't found returns nullptr and does NOT generate one.	BackgroundHttpFileHashHelper.h
bool InitFromString ( const FString& StringIn )	Sets the values of this FBackgroundHttpFileHashHelper from the string representation Returns if the parse was successful or not	BackgroundHttpFileHashHelper.h
void LoadData()	Handles loading URL Mapping data from disk. No operation if data has previously been loaded.	BackgroundHttpFileHashHelper.h
void RemoveURLMapping ( const FString& URL )	Removes URL mapping.	BackgroundHttpFileHashHelper.h
void SaveData()	Handles saving URL Mapping data to disk. No operation if data isn't dirty.	BackgroundHttpFileHashHelper.h
FString ToString()	Creates an FString representation of this FBackgroundHttpFileHashHelper's URL mappings. Used for serializing to/from disk.	BackgroundHttpFileHashHelper.h

Static

Name	Remarks	Include Path
static FString GenerateHashedFilenameForURLNoLock ( const FString& URL, uint32 CollisionCount )	Creates a hashed Filename with a modifier for the given collision count.	BackgroundHttpFileHashHelper.h
static FString GetFullPathOfTempFilename ( const FString& TempFilename )	Helper function that returns a full path representation of hte given TempFilename.	BackgroundHttpFileHashHelper.h
static const FString & GetTempFileExtension()	Helper function that returns the file extension used by our BackgroundHTTP temp files.	BackgroundHttpFileHashHelper.h
static const FString & GetTemporaryRootPath()	Get our base directory used to store Temp files.	BackgroundHttpFileHashHelper.h
static const FString & GetURLMappingFilePathNoLock()	Helper function that just returns the filepath we use to save/load our URL mapping data.	BackgroundHttpFileHashHelper.h

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