How to get Powershell Invoke-Restmethod to return body of http 500 code response

Question

Invoke-RestMethod call returns only very unhelpful exception below and does not (as far as I can tell) allow you to collect the body content (JSON object shown in fiddler trace results). This seems a pretty bad implementation if so because http 500 definition is pretty specific that client should return the body of the response to help troubleshoot... Am I missing something?

invoke-restmethod -method Post -uri "https://api-stage.enviance.com/ver2/EqlService.svc/eql" -Body (ConvertTo-Json $eqlhash)  -Headers @{"Authorization"="Enviance $session"}

invoke-restmethod : The remote server returned an error: (500) Internal Server Error. At line:1 char:9...

Fiddler trace below

HTTP/1.1 500 Internal Server Error Connection: close Date: Thu, 12 Sep 2013 17:35:00 GMT Server: Microsoft-IIS/6.0 X-Powered-By: ASP.NET X-AspNet-Version: 2.0.50727 EnvApi-Version: 2.0,2.0 EnvApi-Remaining-Calls: 994,994 EnvApi-Remaining-Interval: 2684,2684 Cache-Control: no-cache Pragma: no-cache Expires: -1 Content-Type: text/csv; charset=utf-8

{"errorNumber":0,"message":"Current user has no rights to retrieve data from table 'CustomFieldTemplate'"}

Rather cryptic note in "what's new in powershell 4.0 suggests (possibly) that this issue is a bug and has been fixed. http://technet.microsoft.com/en-us/library/hh857339.aspx#BKMK_bugs Under Notable bug fixes section: The Invoke-RestMethod cmdlet now returns all available results. — JorgeSandoval, Sep 12 '13 at 23:01

score 114 · Answer 1 · edited May 31 '16 at 15:22

The other answer does get you the response, but you need an additional step to get the actual body of the response, not just the headers. Here is a snippet:

try {
        $result = Invoke-WebRequest ...
}
catch {
        $result = $_.Exception.Response.GetResponseStream()
        $reader = New-Object System.IO.StreamReader($result)
        $reader.BaseStream.Position = 0
        $reader.DiscardBufferedData()
        $responseBody = $reader.ReadToEnd();
}

score 41 · Accepted Answer · answered Nov 30 '13 at 23:02

41

Although an old thread, here an answer to the problem with the cmdlets Invoke-WebRequest and Invoke-RestMethod.

This one has bothered me for quite some time. As all 4xx and 5xx responses are generating an exception, you have to catch that one and then you are able to extract the Response from there though. Use it like this:

$resp = try { Invoke-WebRequest ... } catch { $_.Exception.Response }

Now $resp always contains everything you like.

answered Nov 30 '13 at 23:02

Anonymous

450
6
3

Probably should add -ErrorAction Stop to the Invoke-WebRequest call. – Nathan Hartley Sep 28 '18 at 12:45

score 33 · Answer 3 · edited Nov 15 '18 at 20:46

33

This solution no longer works with PowerShell 6 - it does not support GetResponseStream(). Instead use

try {
    $result = Invoke-WebRequest ...
}
catch {
    $_.ErrorDetails.Message
}

I wrote a short helper function to support PowerShell 6 and earlier:

function ParseErrorForResponseBody($Error) {
    if ($PSVersionTable.PSVersion.Major -lt 6) {
        if ($Error.Exception.Response) {  
            $Reader = New-Object System.IO.StreamReader($Error.Exception.Response.GetResponseStream())
            $Reader.BaseStream.Position = 0
            $Reader.DiscardBufferedData()
            $ResponseBody = $Reader.ReadToEnd()
            if ($ResponseBody.StartsWith('{')) {
                $ResponseBody = $ResponseBody | ConvertFrom-Json
            }
            return $ResponseBody
        }
    }
    else {
        return $Error.ErrorDetails.Message
    }
}

try {
    $result = Invoke-WebRequest ...
}
catch {
    ParseErrorForResponseBody($_)
}

edited Nov 15 '18 at 20:46

Taegost

1,208
1
17
26

answered Jan 08 '18 at 16:52

Florian Feldhaus

5,567
2
38
46

Just what I was looking for. Thanks! – May 07 '19 at 02:49
Perfect solution. ` _.Exception.Response` gives all details about HTTPResponse but does not provide exact error details. `_.ErrorDetails.Message` is perfect error display – Nikhil Redij Jul 03 '19 at 13:08
this seems to accumulate errors from previous runs $Error.ErrorDetails.Message – eglasius Nov 18 '19 at 14:53
PowerShell indeed uses `$Error` as variable to provide a list of recent exceptions. As the function uses a nested scope, that's still fine and the solution works without problems. If you want, rename the variable `$Error` to `$Err` to avoid confusion. I kept it like this for better readability. – Florian Feldhaus Jul 01 '20 at 21:05

score 13 · Answer 4 · answered Oct 28 '14 at 13:05

13

Searching an answer for my problem I found this thread.

These solution worked for me, but I had to add two new line:

 $reader.BaseStream.Position = 0
 $reader.DiscardBufferedData()

Thanks!

answered Oct 28 '14 at 13:05

Cisco Cabe

584
5
10

1

I had to do this also, I added these lines before $responseBody = $reader.ReadToEnd(); – trevorism Apr 24 '15 at 12:04

score 6 · Answer 5 · answered Sep 21 '20 at 23:05

I have been using Invoke-RestMethod exclusively - and since it might be a wrapper for Invoke-WebRequest, the following information might be useful.

You need to catch the exception and then get the response stream from Response like so.

    try
    {
        $response = Invoke-RestMethod Method Get uri "$($uri)" -Headers $headers
        return $response
    }
    catch
    {
        Write-Host "Exception details: "
        $e = $_.Exception
        Write-Host ("`tMessage: " + $e.Message)
        Write-Host ("`tStatus code: " + $e.Response.StatusCode)
        Write-Host ("`tStatus description: " + $e.Response.StatusDescription)

        Write-Host "`tResponse: " -NoNewline
        $memStream = $e.Response.GetResponseStream()
        $readStream = New-Object System.IO.StreamReader($memStream)
        while ($readStream.Peek() -ne -1) {
            Write-Host $readStream.ReadLine()
        }
        $readStream.Dispose();
    }

Reference: https://social.technet.microsoft.com/Forums/windowsserver/en-US/7d838d53-bfd5-4706-b0df-c4bee2d00412/using-memorystream-and-textreader

It worked perfectly for me. My only change was in the line "Write-Host ("`tStatus code: " + $e.Response.StatusCode)"... I added ".value__" to "$e.Response.StatusCode)": "$e.Response.StatusCode.value__" for getting the status code number — Diego Arias, Feb 15 '21 at 16:57

score 4 · Answer 6 · edited May 05 '21 at 15:19

Please note as an extension to the answer provider by Florial Feldhaus the $_.ErrorDetails.Message is not the original response body. An HTML tag removal regex is used to make the response easier to read github link. Since the stream is disposed on line 1535 there is currently no way to retrieve the original response body.

The work around is to use the dotnet HttpClient to get the original response instead of using the Invoke-WebRequest cmdlet

$url = "http://localhost"
$client = [System.Net.Http.HttpClient]::new()
$request = [System.Net.Http.HttpRequestMessage]::new([System.Net.Http.HttpMethod]::Post, $url)
$request.Content = [System.Net.Http.StringContent]::new("Hello World", [System.Text.Encoding]::UTF8, "plain/text")

$result = $client.SendAsync($request).GetAwaiter().GetResult()
$content = $result.Content.ReadAsStringAsync().GetAwaiter().GetResult()

Write-Verbose $content -Verbose

The powershell core github issue is here

There are a few issues with this response, unless the intent was to provide a PowerShell 6/Core answer. **1)** This doesn't work in PowerShell 5.x without first loading `System.Net.Http.dll` assembly class: eg. `[void][System.Reflection.Assembly]::LoadFile("C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.Net.Http.dll")` **2)*** Line 3 is missing the `$url` variable in the `[System.Net.Http.HttpRequestMessage]::new()` Constructor. **3)** Line 4 will generate an Exception within PowerShell 5.x with`[System.Net.Http.HttpMethod]::GET` verb. — Chris Lynch, Sep 03 '19 at 17:36

score 3 · Answer 7 · answered Feb 06 '23 at 16:55

Because this is one of the first hits on google, here is answer for powershell core 6.0.0/7.0.0

Invoke-RestMethod and Invoke-WebRequest supports -SkipHttpErrorCheck switch:

This parameter causes the cmdlet to ignore HTTP error statuses and continue to process responses. The error responses are written to the pipeline just as if they were successful.

If this switch is used then Cmdlets does not throw error when failing status code is received.

Also Invoke-RestMethod now has command line parameters -StatusCodeVariable and -ResponseHeadersVariable that can be used to extract and save response status code and headers

-ResponseHeadersVariable was added on v6.0.0 and -SkipHttpErrorCheck/ResponseStatusVariable on v7.0.0

How to get Powershell Invoke-Restmethod to return body of http 500 code response

7 Answers7

Linked