powershell script: Body of a web request is empty string

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I have the following logic that sets values on a json object ... then tries to convert to a json string, stuff into the Body of an HTTP request. When I attempt the POST the request fails because the body is empty. But the debug print that outputs the $widget just before I attempt the assignment to Body looks valid.

Code Looks like this:

 $widget = (Get-Content './testdata/notification.json') | ConvertFrom-Json

Write-Output $widget.GetType();
Write-Output $sourcedata.GetType();
$widget.requestId = $sourcedata.requestId
$widget.status = "provisioned"
$widget.workspace.id = $sourcedata.workspace.id
$widget.workspace.isReadOnly = "false"
$widget.workspace.isOnDedicatedCapacity = $sourcedata.workspace.isOnDedicatedCapacity
$widget.workspace.name = $sourcedata.workspace.name
$widget.workspace.owners = $sourcedata.workspace.owners

# Convert to Json
$widget | ConvertTo-Json -Depth 5
Write-Output $widget 

$params = @{
    Uri    = "http://localhost:7071/workspace/notification"
    Method = "POST"
    Headers = @{
        'Authorization' = 'Bearer ' + $token
        'Content-Type' = 'application/json'
    }
   'Body'= $widget
}

$notificationResult = Invoke-RestMethod @params

Any tips would be appreciated.

What's interesting is that when I try to print the object type of the widgets object just after I assign it all the values and convert to json, nothing comes back.

 Write-Output $widget.GetType()

returns:

 True     False    PSCustomObject                          System.Object

instead of something like:

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     True     Object[]                                 System.Array
powershell
1 Answers

Even though I don't have too much context on the particulars about your REST api, I think I can spot the problems, as I've experienced a number of variations of it myself.

Problem #1: ConvertTo-JSON is unrolling objects

# When you pipe to ConvertTo-JSON, you're actually saying:
# Give me a JSON object for each item in the list.
$widget | ConvertTo-Json -Depth 5

Solution:

# Assuming there was more than one widget, this will produce a JSON array
ConvertTo-JSON -Depth 5 -InputObject $widget 

# If you need to force it into a JSON array, you can always use the array subexpression:
ConvertTo-JSON -Depth 5 -InputObject @($widget)

Problem #2: Invoke-RestMethod -Body does not auto-convert JSON.

When you call Invoke-RestMethod with -Body $widget $widget is not JSON. Invoke-RestMethod will not magically make your body JSON, since lots of REST apis take formats other than JSON.

Solution: Assign the converted value and pass that instead.

# Convert to Json
$widgetJson = ConvertTo-Json -Depth 5 -InputObject $widget
Write-Output $widget 

$params = @{
    Uri    = "http://localhost:7071/workspace/notification"
    Method = "POST"
    Headers = @{
        'Authorization' = 'Bearer ' + $token
        'Content-Type' = 'application/json'
    }
   'Body'= $widgetJson
}

I don't know if there would be additional problems in your object's structure that would make the REST api complain, but these are two significant issues in your script that I was able to identify from the symptoms you've presented.

Hope this Helps

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