Post to slack returns 400 because JSON is in hashtable format-CodePudding

I am writing a powershell script to post a message to slack :

Param
(
    [Parameter(Mandatory = $true)]$newrelicAppName,
    [Parameter(Mandatory = $true)]$releasenumber,
    [Parameter(Mandatory = $true)]$RequestedBy,
    [Parameter(Mandatory = $true)]$SourceVersion
)

$uriSlack = "https://hooks.slack.com/services/MYDATA"

$jsonBase = @{}
$blocksList = New-Object System.Collections.ArrayList

$fieldsList = New-Object System.Collections.ArrayList
$Null = $fieldsList.Add(@{"type"="mrkdwn";"text"="*Release Number* $releasenumber";})
$Null = $fieldsList.Add(@{"type"="mrkdwn";"text"="*Requested By* $RequestedBy";})
$Null = $fieldsList.Add(@{"type"="mrkdwn";"text"="*Source Version* $SourceVersion";})

$textData = @{"type"="plain_text";"text"="Release completed for $($newrelicAppName)";}
$dividerData = @{"type"="divider";}

$Null = $blocksList.Add(@{"type"="header"; "text"=$textData})
$Null = $blocksList.Add(@{"type"="divider"})
$Null = $blocksList.Add(@{"type"="section"; "fields"=$fieldsList;})

$blocksList | ConvertTo-Json -Depth 4

$Null = $jsonBase.Add("blocks",$blocksList)

write-output $jsonBase.GetType()

try {
    Invoke-RestMethod -uri $uriSlack -Method Post -body $jsonBase -ContentType 'application/json' | Out-Null
} catch {
    Write-Output $_
    Write-Error "Update to Slack went wrong..."
}

This currently returns a 400 message :

Invoke-RestMethod : The remote server returned an error: (400) Bad Request

And if I looks at the GetType() output, I can see that the $jsonBase is actually still a HashTable:

IsPublic IsSerial Name                                     BaseType                                                                                                                                                                   
-------- -------- ----                                     --------                                                                                                                                                                   
True     True     Hashtable                                System.Object

I thought that adding the -Depth 4 to the conversion would fix this, but apparently not! If I copy the output of $jsonBase into postman and post the plain text, it works. So I know it is something to do with the generated JSON, and not the format of the message. Any ideas?

CodePudding user response：

You can explicitly convert the body payload to JSON by doing:

Invoke-RestMethod ... -Body ($jsonBase |ConvertTo-Json -Depth 4)