502 Bad Gateway when calling JWT Auth API

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Leigh M asked Feb 21, '23 Leigh M commented Feb 22, '23

502 Bad Gateway when calling JWT Auth API

I keep getting a 502 Bad Gateway error when attempting to obtain an access token using JWT, but am not sure why this is happening.

Powershell code:

$RC_SERVER_URL="https://platform.devtest.ringcentral.com"
$RC_CLIENT_ID="T2......" # Copied from the app I created
$RC_CLIENT_SECRET="v8d......" # Copied from the app I created
$RC_JWT_TOKEN = "eyJra....." # Created under My Account > Credentials and given specific authorization to the app Client ID above

# as per https://developers.ringcentral.com/guide/authentication/jwt-flow#technical-discussion
$splat = @{
    Method  = "POST"
    Uri     = $RC_SERVER_URL + "/restapi/oauth/token"
    ContentType = 'application/x-www-form-urlencoded'
    headers = @{   
        Accept = 'application/json'
        Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes("${RC_CLIENT_ID}:${RC_CLIENT_SECRET}"))
    }
    body    = @{
        grant_type = 'urn:ietf:params:oauth:grant-type:jwt-bearer'
        assertion = $RC_JWT_TOKEN
    }
}

$Response = Invoke-RestMethod @splat

The object looks good and isn't missing anything:

$splat
Name                           Value
----                           -----
ContentType                    application/x-www-form-urlencoded
Method                         POST
body                           {assertion, grant_type}
headers                        {Accept, Authorization}
Uri                            https://platform.devtest.ringcentral.com/restapi/oauth/token

PS C:\scripts\Get-RingCentralData> $splat.headers
Name                           Value
----                           -----
Accept                         application/json
Authorization                  Basic VAAyAF...

PS C:\scripts\Get-RingCentralData> $splat.body
Name                           Value
----                           -----
assertion                      eyJra...
grant_type                     urn:ietf:params:oauth:grant-type:jwt-bearer

The response I get when executing this is:

$Response = Invoke-RestMethod @splat
Invoke-RestMethod : The remote server returned an error: (502) Bad Gateway.
At line:1 char:13
+ $Response = Invoke-RestMethod @splat
+             ~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand

Any ideas why this might be happening?

rest api authentication

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Answer 1 · 2023-02-21T21:51:33Z

Phong Vu answered Feb 21, '23 Leigh M commented Feb 22, '23

I am not an expert in Powershell. But, why the content-type is not in the headers?

ContentType = 'application/x-www-form-urlencoded'
    headers = @{   
        Accept = 'application/json'
        Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes("${RC_CLIENT_ID}:${RC_CLIENT_SECRET}"))
    }

Should it be like this?

headers = @{   
        ContentType = 'application/x-www-form-urlencoded'
        Accept = 'application/json'
        Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes("${RC_CLIENT_ID}:${RC_CLIENT_SECRET}"))
    }

3

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Attachments: Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.

Leigh M commented · Feb 21, 2023 at 11:18 PM

Powershell's Invoke-RestMethod cmdlet has a -ContentType argument. It effectively puts it into the headers for you.

I just tried inserting it directly into the headers instead of using the -ContentType argument, but the result is the same (502 Bad Gateway)

0 ·

Phong Vu ♦♦ Leigh M commented · Feb 22, 2023 at 12:26 AM

I guess now it's because of wrong header encoding. Try this

headers = @{   
    ContentType = 'application/x-www-form-urlencoded; charset=UTF-8'
    Accept = 'application/json'
    Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes("${RC_CLIENT_ID}:${RC_CLIENT_SECRET}"))
}

1 ·

Leigh M Phong Vu ♦♦ commented · Feb 22, 2023 at 03:05 AM

Changing to UTF8 solved the issue. Thanks a lot, Phong Vu!

0 ·

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