I wouldn't recommend writing this library by hand when there are plenty of
libraries to pick from.
Take a look at "Client libraries" athttp://oauth.net/2/
and there are plenty more.
On Wed, Sep 30, 2015 at 3:58 PM, Saravanakumar A Srinivasan <
I am working on implementing (see Github commit at  for more details)
an Express middleware to authenticate incoming requests using OAuth bearer
access token. We want to make sure our implementation follows the OAuth 2.0
Authorization Framework specification when processing client requests.
While reading the specification I came across a section where the spec
lists error codes to use when we get an invalid request. In there, the
invalid_request error code seems to suggest that we need to validate
required request parameters for a particular request before we authenticate
the user and return HTTP response code 400 with appropriate error code and
error message. It also mentions that we need to return HTTP response code
401, when a request does not contain any authentication information. So it
sounds odd for me to validate the request parameters before we validate the
authentication of the request.
Saravanakumar Srinivasan (Assk),
Bay Area Lab, 1001, E Hillsdale Blvd, Ste 400, Foster City, CA - 94404.
Phone: 650 645 8251 (T/L 367-8251)