Overview#
Form Post Response Mode (
form_post) is the
Response_mode parameter which indicates is an
OAuth 2.0 Response_mode where
Authorization Response parameters are encoded as
HTML form values that are auto-submitted in the
User-agent, and thus are transmitted via the
HTTP POST method to the
Client, with the result parameters being encoded in the body using the
application/x-www-form-urlencoded format.
The action attribute of the form MUST be the OAuth Client's redirect_uri. The method of the form attribute MUST be POST.
Because the Authorization Response is intended to be used only once, the Authorization Server MUST instruct the User-agent (and any intermediaries) not to store or reuse the content of the Authorization Response.
Any technique supported by the user-agent MAY be used to cause the submission of the form, and any form content necessary to support this MAY be included, such as submit controls and client-side scripting commands. However, the OAuth Client MUST be able to process the message without regard for the mechanism by which the form submission was initiated.
As described in
OAuth 2.0 Multiple Response Type Encoding Practices OAuth.Responses, there are security implications to encoding response values in the
URI Query string and in the
URI Fragment Identifiers value. Some of these concerns can be addressed by using the Form Post Response Mode. In particular, it is safe to return
Authorization Response parameters whose default
Response_modes are the query encoding or the fragment encoding using the
form_post Response_mode.
More Information#
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