Powershell HTTP POST File Upload for REST api

Question

I am new to Powershell and having trouble sending a file via an HTTP POST request. Everything is working perfectly except for sending/uploading the file. Is this possible using my existing code?

Here is my code:



    # VARIABLES
    $myFile = "c:\sample_file.csv"
    $updateUrl = "http://www.example.com/processor"
    $postData  =  "field1=value1"
    $postData += "&field2=value2"
    $postData += "&myFile=" + $myFile

    # EXECUTE FUNCTION
    updateServer -url $updateUrl -data $postData



    function updateServer {
        param(
            [string]$url = $null,
            [string]$data = $null,
            [System.Net.NetworkCredential]$credentials = $null,
            [string]$contentType = "application/x-www-form-urlencoded",
            [string]$codePageName = "UTF-8",
            [string]$userAgent = $null
        );

        if ( $url -and $data ){
            [System.Net.WebRequest]$webRequest = [System.Net.WebRequest]::Create($url);
            $webRequest.ServicePoint.Expect100Continue = $false;
            if ( $credentials ){
                $webRequest.Credentials = $credentials;
                $webRequest.PreAuthenticate = $true;
            }
            $webRequest.ContentType = $contentType;
            $webRequest.Method = "POST";
            if ( $userAgent ){
                $webRequest.UserAgent = $userAgent;
            }

            $enc = [System.Text.Encoding]::GetEncoding($codePageName);
            [byte[]]$bytes = $enc.GetBytes($data);
            $webRequest.ContentLength = $bytes.Length;
            [System.IO.Stream]$reqStream = $webRequest.GetRequestStream();
            $reqStream.Write($bytes, 0, $bytes.Length);
            $reqStream.Flush();

            $resp = $webRequest.GetResponse();
            $rs = $resp.GetResponseStream();
            [System.IO.StreamReader]$sr = New-Object System.IO.StreamReader -argumentList $rs;
            $sr.ReadToEnd();
        }
    }

The file upload is not working. The server receives all parameters fine except the file itself. — Davy Nixon
– Davy Nixon, Commented Feb 14, 2013 at 4:13

Community · Accepted Answer · 2017-05-23 11:59:11Z

2

Two thoughts. First it seems you're uploading the filename but not the file's contents. Second, if you upload the file's contents within the POST you're likely going to need to URL encode the data using something like [System.Web.HttpUtility]::UrlEncode(). Also, check out my answer to this related SO question.

edited May 23, 2017 at 11:59

CommunityBot

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answered Feb 14, 2013 at 2:30

Keith Hill

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1 Comment

Davy Nixon Over a year ago

Yes, with the code above I was uploading the filename. I also tried using <pre><code>filecontent=([IO.File]::ReadAllText('c:\file.txt')) </code</pre> and it seems to upload the file contents, but the existing form processor expects a file as normally uploading through an http form.

Davy Nixon · Accepted Answer · 2013-02-14 16:52:30Z

0

I found the solution to this problem here. I think I may have come across this when I was building my script originally or a snippet of it somewhere else as it is nearly identical to what I have except more thorough.

answered Feb 14, 2013 at 16:52

Davy Nixon

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