I'm creating a headless API that's going to drive an Angular front end. I'm having a bit of trouble figuring out how I should handle user authentication though.
Obviously the API should run over SSL, but the question that's coming up is how should I send the request that contains the user's password: over GET or POST. It's a RESTFUL API, so what I'm doing is retrieving information meaning it should get a GET request. But sending the password over get means it's part of the URI, right? I know even a GET request is encrypted over HTTPS, but is that still the correct way? Or is this a case to break from RESTFUL and have the data in the body or something (can a GET request have data in the body?).
If you pass the credentials in a request header, you will be fine with either a GET or POST request. You have the option of using the established Authorization header with your choice of authentication scheme, or you can create custom headers that are specific to your API.
When using header fields as a means of communicating credentials, you do not need to fear the credentials being written to the access log as headers are not included in that log. Using header fields also conforms to REST standards, and should actually be utilized to communicate any meta-data relevant to the resource request/response. Such meta-data can include, but is not limited to, information like: collection size, pagination details, or locations of related resources.
In summary, always use header fields as a means of authentication/authorization.