How to run curl commands from PowerShell with CurlDotNet

To run a curl command from PowerShell with CurlDotNet, load the DLL once with Add-Type, then call [CurlDotNet.Curl]::Execute('curl ...'). You get a .NET object back with .StatusCode, .Headers and .Body, and you can pipe .Body to ConvertFrom-Json. The command runs in-process, so PowerShell’s native-command quoting rules never touch it.

Setup is covered in installing CurlDotNet for PowerShell.

Run a command and read the result

Add-Type -Path "$HOME/.curldotnet/9.8.0/lib/net8.0/CurlDotNet.dll"

$r = [CurlDotNet.Curl]::Execute('curl -H "Accept: application/json" https://httpbin.org/json')

$r.StatusCode                  # 200
$r.IsSuccess                   # True
$r.Headers['Content-Type']     # application/json (keys are case-insensitive)
$data = $r.Body | ConvertFrom-Json
$data.slideshow.title          # Sample Slide Show

List every response header with $r.Headers.GetEnumerator() | Sort-Object Key | Format-Table Key, Value.

Use single quotes or a single-quoted here-string

PowerShell expands $variables and backtick escapes inside double-quoted strings before CurlDotNet sees them. Put the command in single quotes, or in a single-quoted here-string for multi-line commands copied from docs:

$cmd = @'
curl -X POST https://httpbin.org/post `
  -H "Content-Type: application/json" `
  -d '{"name":"Ada","role":"admin"}'
'@
$r = [CurlDotNet.Curl]::Execute($cmd)
($r.Body | ConvertFrom-Json).json.name    # Ada

The backtick continuations, and bash-style \ continuations, are joined by CurlDotNet’s parser. The closing '@ must start at the beginning of its line.

Secrets from environment variables

CurlDotNet expands $env:NAME (and $NAME) itself, so the token stays out of the string and out of your history. Like a shell, it expands them unquoted or inside the command’s double quotes, not inside its single quotes:

$env:API_TOKEN = 'abc123'
$r = [CurlDotNet.Curl]::Execute('curl -H "Authorization: Bearer $env:API_TOKEN" https://httpbin.org/bearer')
$r.StatusCode   # 200

Save files with absolute paths

.NET resolves relative paths against the process directory, which Set-Location does not change. Build the path from $PWD:

$out = Join-Path $PWD 'logo.png'
$r = [CurlDotNet.Curl]::Execute("curl -L -o `"$out`" https://httpbin.org/image/png")
$r.OutputFiles       # the path; $r.Body is empty, as curl prints nothing with -o
(Get-Item $out).Length

This one uses a double-quoted string on purpose, so $out is expanded, with backtick-escaped quotes around the path.

Async calls and the fluent builder

$r = [CurlDotNet.Curl]::ExecuteAsync('curl https://httpbin.org/get').GetAwaiter().GetResult()

$builder = [CurlDotNet.Core.CurlRequestBuilder]::Get('https://httpbin.org/headers')
$b = $builder.WithHeader('X-Demo', '1').WithUserAgent('ps-script/1.0').Execute()
$b.StatusCode

Handle errors

HTTP errors such as 404 come back as a result with IsSuccess set to False. Network failures throw. PowerShell wraps .NET exceptions, so unwrap them:

try {
    $r = [CurlDotNet.Curl]::Execute('curl -m 5 https://no-such-host.invalid/')
} catch {
    $e = $_.Exception.GetBaseException()
    "$($e.GetType().Name) (curl code $($e.CurlErrorCode)): $($e.Message)"
}

Notes