How to download file

Sometimes you need to download additional files (installers, libraries, resources, etc.) required by your build process.

There is a number of ways you can use to download file in AppVeyor environment:

Invoke-WebRequest cmdlet

HTTP

$source = "http://yoursite.com/file.xml"
$destination = "c:\application\data\newdata.xml"
Invoke-WebRequest $source -OutFile $destination

FTP

$source = "ftp://yoursite.com/file.xml"
$destination = "c:\application\data\newdata.xml"
Invoke-WebRequest $source -OutFile $destination -Credential ftpUser

Examples taken from this blog post.

WebClient class

You can use the following PowerShell code to download file using System.Net.WebClient class which is part of .NET Framework:

(New-Object Net.WebClient).DownloadFile('<file_url>', '<local_file_name>')

Where:

  • <file_url> - URL of remote file
  • <local_file_name> - full local path to downloaded file

Start-FileDownload cmdlet

AppVeyor build session has built-in Start-FileDownload cmdlet for downloading files. There are some advantages of using this cmdlet instead of WebClient class:

  • It maintains current directory context
  • It allows specifying request timeout.

Command syntax:

Start-FileDownload <url> [-FileName <string>] [-Timeout <int>]

Timeout value is milliseconds. Default timeout is 300000 (5 minutes).

For example, the following command downloads remote file to the current folder with installer.msi name:

Start-FileDownload 'http://www.myserver.com/packages/installer.msi'

Example usage in appveyor.yml:

install:
  - ps: Start-FileDownload 'http://www.myserver.com/packages/installer.msi'

If you are getting the following error while downloading

Start-FileDownloadInternal : Error downloading remote file: One or more errors occurred.
Inner Exception: The request was aborted: Could not create SSL/TLS secure channel.

this most probably means that build worker and server could not agree on SSL protocol, because server does not support modern protocol with highest security. If you understand this security risk and trust that server, you can relax SSL client settings in build PowerShell session by the following statement called before Start-FileDownload

[Net.ServicePointManager]::SecurityProtocol = 'Ssl3, Tls, Tls11, Tls12'

AppVeyor command-line utility

AppVeyor command-line utility (appveyor.exe) which is a part of Build Agent API provides DownloadFile command which behaves similar to Start-FileDownload cmdlet.

Command syntax:

appveyor DownloadFile <url> [-FileName <string>] [-Timeout <int>]

Example:

appveyor DownloadFile http://www.myserver.com/packages/installer.msi

Curl

Curl (curl.exe) comes bundled with Git and is therefore also available on the build workers. Users on Unix-like operating systems may be more familiar with this command.

Command syntax:

curl [-fsSL...] [-o <output-filename>] [-m <timeout-in-seconds>] <url>

For scripting, using -fsS (or -fsSL) is recommended. For more info on what the flags do, see the curl manual. Be aware that if neither -o nor -O are given, curl will dump the data to standard output.

Example:

curl -fsS -o installer.msi http://www.myserver.com/packages/installer.msi
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