Dart

Download an FTP File to a Stream

Demonstrates the Chilkat Ftp2.GetFileToStream method, which downloads a remote file and writes its bytes to a Stream. The first argument is the remote file path and the second is the Stream, which must have a destination sink configured beforehand.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Streaming to a Stream object decouples the download from where the bytes ultimately go — a file (as here, via SinkFile), or a pipe feeding another component such as a decompressor or a hashing routine — and processes the data as it arrives rather than buffering the whole file. That keeps memory flat for large downloads and lets you chain the transfer into a processing pipeline.

Chilkat Dart Downloads

Download Chilkat for Dart

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // Demonstrates the Ftp2.GetFileToStream method, which downloads a remote file and writes its
  // bytes to a Stream.  The 1st argument is the remote file path and the 2nd is the Stream.

  final ftp = CkFtp2();

  ftp.hostname = 'ftp.example.com';
  ftp.username = 'myFtpLogin';

  // Normally you would not hard-code the password in source.  You should instead obtain it
  // from an interactive prompt, environment variable, or a secrets vault.
  ftp.password = 'myPassword';

  try {
    ftp.connect();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Configure the stream's destination sink before downloading.  Here the stream writes to a
  // local file.
  final fileStream = CkStream();
  fileStream.sinkFile = 'qa_output/report.pdf';

  try {
    ftp.getFileToStream('public_html/report.pdf', fileStream);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Downloaded to stream.');

  try {
    ftp.disconnect();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }
}