$user = "example@gmail.com"
$pass= "examplepassword"
$secpasswd = ConvertTo-SecureString $user -AsPlainText -Force
$cred = New-Object System.Management.Automation.PSCredential ($pass, $secpasswd)
Invoke-RestMethod 'https://www.googleapis.com/gmail/v1/users/me/messages/0' -Method Delete -Credentials $cred
So, my problem here is twofold.
I originally tried using Invoke-WebRequest to delete gmail emails via the Google API with a http delete request. However, this did not work because Powershell 2.0 does not support Invoke-WebRequest.
Thereafter, I turned to attempting to utilize Invoke-RestMethod after experimentation with IMAP and POP3, which both required external dependencies (Adding .dlls to the machines I am working with is not optimal).
Therefore, if someone could show me the appropriate way to delete an email via the Google API in Powershell, I would appreciate it. I have provided some sample code as to what I am working with above. Please excuse any mistakes it may contain, as I am relatively new to Powershell, and my experience remains limited in working with RESTful services.
The GMail API is going to require Oauth2 authentication unless this is a gsuit / domain admin / GMail account in which case you can use a service account for authentication. In either case you cant use login and password.
My powershell knowledge is very limited have you considered doing this directly though the mail server IMAP and SMTP and not using the API. No idea if that's possible or not with powershell
Update:
I was able to do it using Invoke-WebRequest you will still need to get an access token first.
Invoke-WebRequest -Uri "https://www.googleapis.com/gmail/v1/users/me/messages/0?access_token=$accesstoken"-Method Get | ConvertFrom-Json
seams to also work
Invoke-RestMethod -Uri "https://www.googleapis.com/gmail/v1/users/me/messages/0?access_token=$accesstoken"-Method Get
Put up a the code for OAuth on GitHub if your interested: Google Oauth Powershell
来源：https://stackoverflow.com/questions/41236955/deleting-gmail-emails-via-google-api-using-powershell-v2-0