Post to Office365 Group Connector(Webhook) using Powershell

Question

I am trying to post a simple message to a O365 'Incoming Webhook' using powershell. Here is the code:

$url = 'https://outlook.office365.com/webhook/.......'

$body = @"
{
    "text": "Hello World!"
    "title": "Today"
}
"@

Invoke-RestMethod -Uri $url -Method Post -Body $body -ContentType "application/json"

But get this error:

PSMessageDetails      : 
Exception             : System.Net.WebException: The remote server returned an error: (404) Not Found.
                           at Microsoft.PowerShell.Commands.WebRequestPSCmdlet.GetResponse(WebRequest request)
                           at Microsoft.PowerShell.Commands.WebRequestPSCmdlet.ProcessRecord()
TargetObject          : System.Net.HttpWebRequest
CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
ErrorDetails          : Invalid webhook request
InvocationInfo        : System.Management.Automation.InvocationInfo
ScriptStackTrace      : at <ScriptBlock>, <No file>: line 10
PipelineIterationInfo : {}

if i leave out the -Contentype parameter i get this error:

Microsoft.IdentityModel.Clients.ActiveDirectory.AdalServiceException: AADSTS90002: Requested tenant identifier '00000000-0000-0000-0000-000000000000' is not valid. Tenant identifiers may not be an empty GUID.
Trace ID: c4b77459-3915-475e-8125-fa2db9fd11e8
Correlation ID: 0ba64202-db52-4a96-8f44-a87b7f009170
Timestamp: 2016-03-27 07:48:02Z

anyone know how to get this to work?

Answer 1

Thank you for the direction. I was trying to test out an Azure WebHook. It would work on the Test method of the web page; even copied the JSON body from the page to powershell and it wouldn't work. The key was apparently specifying the

-ContentType "application/json"

However, something I found interesting, is that WebHooks in Teams do work with the default content type (which is "application/x-www-form-urlencoded") as the example post Stefan Stranger posted:

Use WebHooks Connect to Send Data from PowerShell to Microsoft Teams

Nice shortcut for them, but looks best to always specify the content type for WebHooks to be safe.

Answer 2

Your message body is not a valid json snippet due to a missing comma after "text" field.

Changed to

$body = @"
{
    "text": "Hello World!",
    "title": "Today"
}
"@

and it works for me.