Windows Native Toolkit | Server Transfer Library

Use this library for downloads, patchers, launchers, internal tools, and simple FTP-based content pipelines.

Python examples use Unreal's reflected API names through the unreal module. Functions that return handles or use delegates are shown using Unreal Python binding conventions.

Transfer Model

These nodes remain delegate-based instead of latent. Each transfer returns an FNetworkTransferHandle that you can keep and pass into Cancel Network Transfer.

Download File (HTTP/HTTPS)

Downloads a file from an HTTP or HTTPS URL into a local folder. The node resolves the output file name from the URL and writes the file when the request completes successfully.

Pin	Direction	Purpose
`URL`	Input	Full file URL such as `https://site.com/files/archive.zip`.
`SaveDirectory`	Input	Existing or creatable destination folder.
`OnProgress`	Input	Delegate that receives progress from `0.0` to `1.0` when the server reports content length.
`OnComplete`	Input	Delegate that receives `true` when the file was downloaded and written successfully.
`Return Value`	Output	`FNetworkTransferHandle` used for cancellation.

C++ Example

#include "ServerHelper.h"

FOnTransferProgress ProgressDelegate;
FOnTransferComplete CompleteDelegate;

const FNetworkTransferHandle Handle =
    UServerHelper::DownloadFileHTTP(URL, SaveDirectory, ProgressDelegate, CompleteDelegate);

Python Example

import unreal

# Note: Progress and Complete delegates are omitted for simplicity
handle = unreal.ServerHelper.download_file_http(url, save_directory, None, None)

Download Advanced

Downloads an HTTP or HTTPS file with overwrite control, byte-level progress, result details, and optional partial-file cleanup.

Pin	Direction	Purpose
`URL`	Input	Full HTTP or HTTPS file URL.
`SaveDirectory`	Input	Existing or creatable destination folder.
`FileNameOverride`	Input	Optional output file name. Leave empty to resolve the name from the URL.
`bOverwrite`	Input	Allows replacing an existing destination file.
`bDeletePartialOnFail`	Input	Deletes the target file when the request fails after a file was created.
`OnProgress`	Input	Delegate that receives transferred bytes and total bytes when known.
`OnComplete`	Input	Delegate that receives `FNetworkTransferResult`.
`Return Value`	Output	`FNetworkTransferHandle` used for cancellation.

FNetworkTransferResult fields:

bSuccess
StatusCode
SavedFilePath
BytesTransferred
TotalBytes
SHA1

C++ Example

#include "ServerHelper.h"

FOnTransferBytes ProgressDelegate;
FOnTransferResult CompleteDelegate;

const FNetworkTransferHandle Handle = UServerHelper::DownloadAdvanced(
    URL,
    SaveDirectory,
    TEXT("Patch.zip"),
    true,
    true,
    ProgressDelegate,
    CompleteDelegate);

Python Example

import unreal

handle = unreal.ServerHelper.download_advanced(
    url,
    save_directory,
    "Patch.zip",
    True,
    True,
    None,
    None,
)

Upload File Using FTP

Uploads one local file to an FTP directory. The node URL-encodes the file name before appending it to the target FTP folder URL.

Pin	Direction	Purpose
`URL`	Input	FTP folder URL such as `ftp://example.com/uploads/`.
`User`	Input	FTP user name.
`Password`	Input	FTP password.
`LocalFilePath`	Input	Full local path to the file that should be uploaded.
`OnProgress`	Input	Delegate that receives progress from `0.0` to `1.0`.
`OnComplete`	Input	Delegate that receives `true` when the upload completed successfully.
`Return Value`	Output	`FNetworkTransferHandle` used for cancellation.

C++ Example

#include "ServerHelper.h"

FOnTransferProgress ProgressDelegate;
FOnTransferComplete CompleteDelegate;

const FNetworkTransferHandle Handle =
    UServerHelper::UploadFileFTP(URL, User, Password, LocalFilePath, ProgressDelegate, CompleteDelegate);

Python Example

import unreal

handle = unreal.ServerHelper.upload_file_ftp(url, user, password, local_file_path, None, None)

Download File Using FTP

Downloads one file from an FTP URL into a local folder. The node resolves the local file name from the FTP URL and removes partially written files when the transfer fails or is canceled.

Pin	Direction	Purpose
`URL`	Input	Full FTP file URL such as `ftp://example.com/packages/build.zip`.
`User`	Input	FTP user name.
`Password`	Input	FTP password.
`SaveDirectory`	Input	Existing or creatable destination folder.
`OnProgress`	Input	Delegate that receives progress from `0.0` to `1.0`.
`OnComplete`	Input	Delegate that receives `true` when the download completed successfully.
`Return Value`	Output	`FNetworkTransferHandle` used for cancellation.

C++ Example

#include "ServerHelper.h"

FOnTransferProgress ProgressDelegate;
FOnTransferComplete CompleteDelegate;

const FNetworkTransferHandle Handle =
    UServerHelper::DownloadFileFTP(URL, User, Password, SaveDirectory, ProgressDelegate, CompleteDelegate);

Python Example

import unreal

handle = unreal.ServerHelper.download_file_ftp(url, user, password, save_directory, None, None)

Cancel Network Transfer

Requests cancellation for an active transfer handle.

Pin	Direction	Purpose
`Handle`	Input	Transfer handle returned by one of the server-transfer nodes.

Cancellation stops the request when the backend honors the cancel flag. It does not delete already uploaded remote data, and it does not remove successful downloads.

C++ Example

#include "ServerHelper.h"

UServerHelper::CancelTransfer(Handle);

Python Example

import unreal

unreal.ServerHelper.cancel_transfer(handle)

Server Transfer Library

Download File (HTTP/HTTPS)

Download Advanced

Upload File Using FTP

Download File Using FTP

Cancel Network Transfer

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