NAME

LWP::Authen::OAuth2::ServiceProvider::Google - Google OAuth2

VERSION

version 0.20

SYNOPSIS

See LWP::Authen::OAuth2 for basic usage. The one general note is that "scope" is "scope" is optional in the specification, but required for Google. Beyond that Google supports many client types, and their behavior varies widely.

See <https://developers.google.com/accounts/docs/OAuth2> for Google's own documentation. The documentation here is a Cliff Notes version of that, so look there for any necessary clarification.

REGISTERING

Before you can use OAuth 2 with Google you need to register yourself as a client. For that, go to <https://code.google.com/apis/console>. Follow their directions to create a project, choose your "flow" (which is called your "client_type" in this document - look ahead for advice on available types), and then you'll be given a "client_id" and "client_secret". If you're in the Login, WebServer or Client client types you'll also need to register a "redirect_uri" with them, which will need to be an "https://..." URL under your control.

At that point you have all of the facts that you need to use this module. Be sure to keep your "client_secret" secret - if someone else gets it and starts abusing it, Google reserves the right to block you.

This module only handles the authorization step, after which it is up to you to figure out how to use whatever API you want to access.

CLIENT TYPES

Google offers many client types. Here is the status of each one in this module:

Login

This is for applications that want to let Google manage their logins. See <https://developers.google.com/accounts/docs/OAuth2Login> for Google's documentation.

This is not yet supported, and would require the use of JSON Web Tokens to support.

Web Server Application

This is intended for applications running on web servers, with the user sitting behind a browser interacting with you. See <https://developers.google.com/accounts/docs/OAuth2WebServer> for Google's documentation.

It can be specified in the constructor with:

    client_type => "web server",

however that is not necessary since it is also the assumed default if no client_type is specified.

After registering yourself as a client with Google, you will need to specify the "redirect_uri" as an https URL under your control. If you just need this for one or two accounts there is no need to actually build anything at that URL - just go through the authorization as those accounts and grab your "code" from the URL. If you will support many, making that URL useful is your responsibility.

With this client type you are not guaranteed a refresh token, so the constructor does not require "client_id" and "client_secret". (Passing them there is still likely to be convenient for you.) However there are several optional arguments available to "$oauth2->authorization_url(...)" that are worth taking note of:

"access_type": Pass "access_type => "offline"," to "$oauth2-"request_tokens(...)> to request offline access. This means that you get a "refresh_token" which can be used to refresh the access token without help from the user. The intent of this option is to support things like software that delays posting a blog entry until a particular time.
In light testing this did not work for me until I passed the next argument, but then it worked perfectly.
"approval_prompt": Pass "approval_prompt => "force"," to "$oauth2-"request_tokens(...)> to force the user to see the approval screen. The default behavior without this is that the user sees the approval screen the first time through, and on subsequent times just gets an immediate redirect.
"login_hint": If you think you know who the user is, you can pass an email in this parameter to let Google know which account you are trying to access. Google thinks this may be helpful if someone is logged into multiple accounts at the same time.

Client-side Application

This client type is only for JavaScript applications. See <https://developers.google.com/accounts/docs/OAuth2UserAgent> for Google's documentation.

This is not supported since Perl is not JavaScript.

Installed Application

This client type is for applications that run on the user's machine, which can control a browser. See <https://developers.google.com/accounts/docs/OAuth2InstalledApp> for Google's documentation.

It can be specified in the constructor with:

    client_type => "installed",

On the first time it is the client's responsibility to open a browser and send the user to "$oauth2-"authorization_url(...)>. If you pass in "redirect_uri => "http://localhost:$port"," then your application is expected to be listening on that port. If you instead pass in "redirect_uri => "urn:ietf:wg:oauth:2.0:oob"," then the code you need will be in the "title" inside of the page the browser is redirected to, and you'll need to grab it from there.

The returned tokens always give you a refresh token, so you only have to go through this once per user.

The only special authorization argument is "login_hint", which means the same thing that it does for webserver applications.

Devices

This client_type is for applications that run on the user's machine, which do not control a browser. See <https://developers.google.com/accounts/docs/OAuth2ForDevices> for Google's documentation.

This client_type is not supported because I have not yet thought through how to handle the required polling step of setting up permissions.

Service Account

This client_type is for applications that login to the developer's account using the developer's credentials. See <https://developers.google.com/accounts/docs/OAuth2ServiceAccount> for Google's documentation.

This is not yet supported, and would require the use of JSON Web Tokens to support.

AUTHORS

Ben Tilly, <btilly at gmail.com>
Thomas Klausner <domm@plix.at>

COPYRIGHT AND LICENSE

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.