Why does this PowerShell Invoke-RestMethod POST throw an exception?

Question

I have following PowerShell script that throws an exception as follows. How can I Invoke-RestMethod -Method Post with authorization $bearerHeader?

$content = New-Object System.Net.Http.StreamContent $snapshot;
$content.CopyToAsync($snapshot);
try {
    $encodedPath = [Text.Encoding]::ASCII.GetBytes($this.snapshotPath)
    $hmacsha = New-Object System.Security.Cryptography.HMACSHA512
    $hmacsha.key = [Convert]::FromBase64String($this.apikey);
    $bearerToken = $hmacsha.ComputeHash($encodedPath)

    $bearerToken = [Convert]::ToBase64String($bearerToken)
    $bearerToken = $bearerToken.Split('=')[0]
    $bearerToken = $bearerToken.Replace('*', '-')
    $bearerToken = $bearerToken.Replace('+', '_')

    $bearerHeader = @{ "Authorization" = ("Bearer", $bearerToken -join " ") }
    $url = ($this.baseAddress, $this.snapshotPath -join "");
    $resp = Invoke-RestMethod -Method Post -Uri $this.snapshotPath -ContentType "application/octet-stream" -Body $content -Headers $bearerToken
} catch [Exception] {
    Write-Host "Exception: "$_.Exception.Message -ForegroundColor Red;
}

Cannot convert the "uZZETvpJdAIqIH_235oFjan3wS_M582332jmiJjm23jJvJxJwHm0JtWSkhg5qj_7jGDI_s3IFx2ozx5wyQXCA" value of type "System.String" to type "System.Collections.IDictionary".

Invoke-RestMethod ... -Headers $bearerToken -> Invoke-RestMethod ... -Headers $bearerHeader — Ansgar Wiechers
Sorry, what do you mean by this? I don't understand. Could you be little more descriptive? — masiboo
One is what you currently have and the other is what you should have. Pretty clear. You currently pass $bearerToken in the -Headers parameter but you should be passing $bearerHeader. — EBGreen

Mark Wragg Mark Wragg · Accepted Answer · 2018-01-12T19:39:24

Per the comments, this:

$resp = Invoke-RestMethod -Method Post -Uri $this.snapshotPath -ContentType "application/octet-stream" -Body $content -Headers $bearerToken

Needs to be:

$resp = Invoke-RestMethod -Method Post -Uri $this.snapshotPath -ContentType "application/octet-stream" -Body $content -Headers $bearerHeader

The -Headers parameter expects a hashtable as its input, which your code creates as $bearerHeader but then you are not using it.

Why does this PowerShell Invoke-RestMethod POST throw an exception?

1 Answers