Invoke-RestMethod OutFile Empty When PassThru Used

Question

Using PowerShell 4.0 and Invoke-RestMethod cmdlet. I'm having trouble with the -OutFile and -PassThru options. Whenever I add the -PassThru option, my -OutFile is created but the contents are Empty!

According to the Invoke-RestMethod Documentation, both an output file and pipeline object should be available when these options are used together. "-OutFile Saves the response body in the specified output file. [...] To send the results to a file and to the pipeline, use the Passthru parameter."

Here's a test to repeat the problem I'm having. Here I'm calling a rest api attempting to BOTH save response to file AND deserialize into a powershell object.

"POWERSHELL VERSION $($host.Version.ToString())"
$date = Invoke-RestMethod "http://date.jsontest.com" -OutFile "OutFile.txt" -PassThru
Get-Content "OutFile.txt"
# FILE IS EMPTY!!! PASSTHRU SEEMS TO RESULT IN EMPTY FILE
$date
# powershell object has the date received from api

Here are two tests to verify the normal functionality of Invoke-RestMethod WITHOUT the PassThru option

# ... Test # 1, call rest api and deserialize into powershell object
$date = Invoke-RestMethod "http://date.jsontest.com"
$date
# Output shows the date retrieved from sample restful service
# ... Test # 2, call rest api and save response body directly to a file
Invoke-RestMethod "http://date.jsontest.com" -OutFile "OutFile.txt"
Get-Content "OutFile.txt"
# Output shows contents of rest api response body (json text)

I think these tests should help others see the trouble I'm having. My question is whether there is something I'm missing to make this work, or whether this may be a bug with the cmdlet? I've Googled a bit for solution and no obvious reports of this issue. I'm wanting to use -OutFile as part of a workaround for another Invoke-RestMethod issue related to content encoding as described at Bug? Invoke-RestMethod and UTF-8 data. The -PassThru option is helpful for me to look at the returned data and terminate iteration on a multi-request (paged) odata result set.

Answer 1

I believe the -PassThru switch redirects all output to the console only, and I think that is why your file is empty. However, since you have it a variable you could add one more line like so. . .

Write-Output -InputObject $date | Out-File -FilePath "OutFile.txt"