Powershell - Invoke-WebRequest to a URL with literal '/' (%2F) in it

Question

I have been trying to access a URL with a / character in it from powershell, using the following command (it's a query to a gitlab server to retrieve a project called "foo/bar"):

Invoke-WebRequest https://server.com/api/v3/projects/foo%2Fbar -Verbose

Now, the odd thing is that using the PowerShell ISE or Visual Studio, the request is OK. When using PowerShell itself, the URL is automatically un-escaped and the request fails. E.g.

In ISE/VS:

$> Invoke-WebRequest https://server.com/api/v3/projects/foo%2Fbar -Verbose
VERBOSE: GET https://server.com/api/v3/projects/foo%2Fbar with 0-byte payload
VERBOSE: received 19903-byte response of content type application/json

StatusCode        : 200
StatusDescription : OK
Content           : .... data ....

In Powershell:

$> Invoke-WebRequest https://server.com/api/v3/projects/foo%2Fbar -Verbose
VERBOSE: GET https://server.com/api/v3/projects/foo/bar with 0-byte payload
Invoke-WebRequest : {"error":"404 Not Found"}
At line:1 char:1
+ Invoke-WebRequest 'https://server.com/api/v3/projects/foo%2Fbar ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand

I have tried adding single and double quotes around the URL, but nothing is helping.

What could be the reason for this behaviour, and how do I make PS not un-escape the URL string?

---

Environment: Windows 7, also tested on Server 2012R2 with same results.

$> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      4.0
WSManStackVersion              3.0
SerializationVersion           1.1.0.1
CLRVersion                     4.0.30319.42000
BuildVersion                   6.3.9600.16406
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0}
PSRemotingProtocolVersion      2.2

Answer 1

Here is an alternate port of https://stackoverflow.com/a/784937/2864740 - it accepts a string and returns a new URI.

function CreateUriWithoutIncorrectSlashEncoding {
    param(
        [Parameter(Mandatory)][string]$uri
    )

    $newUri = New-Object System.Uri $uri

    [void]$newUri.PathAndQuery # need to access PathAndQuery (presumably modifies internal state)
    $flagsFieldInfo = $newUri.GetType().GetField("m_Flags", [System.Reflection.BindingFlags]::Instance -bor [System.Reflection.BindingFlags]::NonPublic)
    $flags = $flagsFieldInfo.GetValue($newUri)
    $flags = $flags -band (-bnot 0x30) # remove Flags.PathNotCanonical|Flags.QueryNotCanonical (private enum)
    $flagsFieldInfo.SetValue($newUri, $flags)

    $newUri
}

Usage:

$uri = CreateUriWithoutIncorrectSlashEncoding "https://server.com/api/v3/projects/foo%2Fbar"