Provided by: liblwp-authen-oauth2-perl_0.20-1_all 
NAME
LWP::Authen::OAuth2 - Make requests to OAuth2 APIs.
VERSION
version 0.20
SYNOPSIS
OAuth 2 is a protocol that lets a user tell a service provider that a consumer has
permission to use the service provider's APIs to do things that require access to the
user's account. This module tries to make life easier for someone who wants to write a
consumer in Perl.
Specifically it provides convenience methods for all of the requests that are made to the
service provider as part of the permission handshake, and after that will proxy off of
LWP::UserAgent to let you send properly authenticated requests to the API that you are
trying to use. When possible, this will include transparent refresh/retry logic for
access tokens expiration.
For a full explanation of OAuth 2, common terminology, the requests that get made, and the
necessary tasks that this module does not address, please see
LWP::Authen::OAuth2::Overview
This module will not help with OAuth 1. See the similarly named but unrelated
LWP::Authen::OAuth for a module that can help with that.
Currently LWP::Authen::OAuth2 provides ready-to-use classes to use OAuth2 with
• Dwolla
LWP::Authen::OAuth2::ServiceProvider::Dwolla
implemented by Adi Fairbank <https://github.com/adifairbank>
• Google
LWP::Authen::OAuth2::ServiceProvider::Google
• Line
LWP::Authen::OAuth2::ServiceProvider::Line
implemented by Adam Millerchip <https://github.com/amillerchip>
• Strava
LWP::Authen::OAuth2::ServiceProvider::Strava
implemented by Leon Wright <https://github.com/techman83>
• Withings
LWP::Authen::OAuth2::ServiceProvider::Withings
implemented by Brian Foley <https://github.com/foleybri>
• Yahoo
LWP::Authen::OAuth2::ServiceProvider::Yahoo
implemented by Michael Stevens <https://github.com/michael-stevens>
You can also access any other OAuth2 service by setting up a plain "LWP::Authen::OAuth2"
object. If you do, and the service provider might be of interest to other people, please
submit a patch so we can include it in this distribution, or release it as a standalone
package.
Here are examples of simple usage.
use LWP::Authen::OAuth2;
# Constructor
my $oauth2 = LWP::Authen::OAuth2->new(
client_id => "Public from service provider",
client_secret => "s3cr3t fr0m svc prov",
service_provider => "Google",
redirect_uri => "https://your.url.com/",
# Optional hook, but recommended.
save_tokens => \&save_tokens,
save_tokens_args => [ $dbh ],
# This is for when you have tokens from last time.
token_string => $token_string.
);
# URL for user to go to to start the process.
my $url = $oauth2->authorization_url();
# The authorization_url sends the user to the service provider to
# say that you want to be authorized. After the user confirms that
# request, the service provider sends the user back to you with a
# code. This might be a CGI parameter, something that the user is
# supposed to paste to you - that's between you and the service
# provider.
# Assuming that you have your code, get your tokens from the service
# provider.
$oauth2->request_tokens(code => $code);
# Get your token as a string you can easily store, pass around, etc.
# If you have a save_tokens callback, that gets passed this string
# whenever the tokens change.
#
# This string bears a suspicious resemblance to serialized JSON.
my $token_string = $oauth2->token_string,
# Access the API. Consult the service_provider's documentation for when
# to use which type of request. Note that argument processing is the
# same as in LWP. Thus the parameters array and headers hash are both
# optional.
$oauth2->get($url, %header);
$oauth2->post($url, \@parameters, %header);
$oauth2->put($url, %header);
$oauth2->delete($url, %header);
$oauth2->head($url, %header);
# And if you need more flexibility, you can use LWP::UserAgent's request
# method
$oauth2->request($http_request, $content_file);
# In some flows you can refresh tokens, in others you have to go through
# the handshake yourself. This method lets you know whether a refresh
# looks possible.
$oauth2->can_refresh_tokens();
# This method lets you know when it is time to reauthorize so that you
# can find out in a nicer way than failing an API call.
$oauth2->should_refresh();
CONSTRUCTOR
When you call "LWP::Authen::OAuth2->new(...)", arguments are passed as a key/value list.
They are processed in the following phases:
Construct service provider
Service provider collects arguments it wants
LWP::Authen::OAuth2 overrides defaults from arguments
Sanity check
Here are those phases in more detail.
Construct service provider
There are two ways to construct a service provider.
Prebuilt class
To load a prebuilt class you just need one or two arguments.
"service_provider => $Foo,"
In the above construct, $Foo identifies the base class for your service
provider. The actual class will be the first of the following two classes
that can be loaded. Failure to find either is an error.
LWP::Authen::OAuth2::ServiceProvider $Foo
$Foo
A list of prebuilt service provider classes is in
LWP::Authen::OAuth2::ServiceProvider as well as instructions for making a new
one.
"client_type => $name_of_client_type"
Some service providers will keep track of your client type ("webserver"
application, "installed" application, etc), and will treat them differently.
A base service provider class can choose to accept a "client_type" parameter
to let it know what to expect.
Whether this is done, and the allowable values, are up to the service provider
class.
Built on the fly
The behavior of simple service providers can be described on the fly without
needing a prebuilt class. To do that, the following arguments can be filled with
arguments from your service provider:
"authorization_endpoint => $auth_url,"
This is the URL which the user is directed to in the authorization request.
"token_endpoint => $token_url,"
This is the URL which the consumer goes to for tokens.
Various optional fields
LWP::Authen::OAuth2::ServiceProvider documents many methods that are available
to customize the actual requests made, and defaults available. Simple service
providers can likely get by without this, but here is a list of those methods
that can be specified instead in the constructor:
# Arrayrefs
required_init
optional_init
authorization_required_params
authorization_optional_params
request_required_params
request_optional_params
refresh_required_params
refresh_optional_params
# Hashrefs
authorization_default_params
request_default_params
refresh_default_params
Service provider collects arguments it wants
In general, arguments passed into the constructor do not have to be passed into
individual method calls. Furthermore in order to be able to do the automatic
token refresh for you, the constructor must include the arguments that will be
required.
By default you are required to pass your "client_id" and "client_secret". And
optionally can pass a "redirect_uri" and "scope". (The omission of "state" is a
deliberate hint that if you use that field, you should be generating random values
on the fly. And not trying to go to some reasonable default.)
However what is required is up to the service provider.
LWP::Authen::OAuth2 overrides defaults from arguments
The following defaults are available to be overridden in the constructor, or can
be overridden later. In the unlikely event that there is a conflict with the
service provider's arguments, these will have to be overridden later.
"error_handler => \&error_handler,"
Specifies the function that will be called when errors happen. The default is
"Carp::croak".
"is_strict => $bool,"
Is strict mode on? If it is, then excess parameters to requests that are part
of the authorization process will trigger errors. If it is not, then excess
arguments are passed to the service provider as is, who according to the
specification is supposed to ignore them.
Strict mode is the default.
"early_refresh_time => $seconds,"
How many seconds before the end of estimated access token expiration you will
have "should_refresh" start returning true.
"prerefresh => \&prerefresh,"
A handler to be called before attempting to refresh tokens. It is passed the
$oauth2 object. If it returns a token string, that will be used to generate
tokens instead of going to the service provider.
The purpose of this hook is so that, even if you have multiple processes
accessing an API simultaneously, only one of them will try to refresh tokens
with the service provider. (Service providers may dislike having multiple
refresh requests arrive at once from the same consumer for the same user.)
By default this is not provided.
"save_tokens => \&save_tokens,"
Whenever tokens are returned from the service provider, this callback will
receive a token string that can be stored and then retrieved in another
process that needs to construct a $oauth2 object.
By default this is not provided. However if you intend to access the API
multiple times from multiple processes, it is recommended.
"save_tokens_args => [ args ],"
Additional arguments passed to the save_tokens callback function after the
token string. This can be used to pass things like database handles or other
data to the callback along with the token string. Provide a reference to an
array of arguments in the constructure. When the callback is called the
arguments are passed to the callback as an array, so in the example below
$arg1 will be "foo" and $arg2 will be "bar"
...
save_tokens => \&save_tokens,
save_tokens_args => [ "foo", "bar" ],
...
sub save_tokens {
my ($token_string, $arg1, $arg2) = @_;
...
}
"token_string => $token_string,"
Supply tokens generated in a previous request so that you don't have to ask
the service provider for new ones. Some service providers refuse to hand out
tokens too quickly, so this can be important.
"user_agent => $ua,"
What user agent gets used under the hood? Defaults to a new LWP::UserAgent
created on the fly.
Sanity check
Any arguments that are left over are assumed to be mistakes and a fatal warning is
generated.
METHODS
Once you have an object, the following methods may be useful for writing a consumer.
"$oauth2->authorization_url(%opts)"
Generate a URL for the user to go to to request permissions. By default the
"response_type" and "client_id" are defaulted, and all of "redirect_uri", "state" and
"scope" are optional but not required. However in practice this all varies by service
provider and client type, so look for documentation on that for the actual list that you
need.
"$oauth2->request_tokens(%opts)"
Request tokens from the service provider (if possible). By default the "grant_type",
"client_id" and "client_secret" are defaulted, and the "scope" is required. However in
practice this all varies by service provider and client type, so look for documentation on
that for the actual list that you need.
"$oauth2->get(...)"
Issue a "get" request to an OAuth 2 protected URL, just like you would using
LWP::UserAgent to a normal URL.
"$oauth2->head(...)"
Issue a "head" request to an OAuth 2 protected URL, just like you would using
LWP::UserAgent to a normal URL.
"$oauth2->post(...)"
Issue a "post" request to an OAuth 2 protected URL, just like you would using
LWP::UserAgent to a normal URL.
"$oauth2->delete(...)"
Issue a "delete" request to an OAuth 2 protected URL, similar to the previous examples.
(This shortcut is not by default available with LWP::UserAgent.)
"$oauth2->put(...)"
Issue a "put" request to an OAuth 2 protected URL, similar to the previous examples.
(This shortcut is not by default available with LWP::UserAgent.)
"$oauth2->request(...)"
Issue any "request" that you could issue with LWP::UserAgent, except that it will be
properly signed to go to an OAuth 2 protected URL.
"$oauth2->make_api_call($uri, $params, $headers)"
This is a convenience method which makes a call to an OAuth2 API endpoint given by $uri,
and returns the JSON response decoded to a hash. If the $params hashref arg is set, its
contents will be JSON encoded and sent as POST request content; otherwise it will make a
GET request. Optional $headers may be sent which will be passed through to
"$oauth->get()" or "$oauth->post()".
If the call succeeds, it will return the response's JSON content decoded as hash, or if no
response body was returned, a value of 1 to indicate success. On failure returns undef,
and error message is available from "$oauth2->api_call_error()".
"$oauth2->api_call_error()"
If an error occurred in "$oauth2->make_api_call()", this method will return it. The error
message comes from "HTTP::Response->error_as_HTML()".
"$oauth2->api_url_base()"
Returns the base URL of the service provider, which is sometimes useful to be used in the
content of OAuth2 API calls.
"$oauth2->can_refresh_tokens"
Is sufficient information available to try to refresh tokens?
"$oauth2->should_refresh()"
Is it time to refresh tokens?
"$oauth2->set_early_refresh_time($seconds)"
Set how many seconds before the end of token expiration the method "should_refresh" will
start turning true. Values over half the initial expiration time of access tokens will be
ignored to avoid refreshing too often. This defaults to 300.
"$oauth2->expires_time()"
Returns the raw epoch expiration time of the current access token. Typically this is 3600
seconds greater than the time of token creation.
"$oauth2->set_is_strict($mode)"
Set strict mode on/off. See the discussion of "is_strict" in the constructor for an
explanation of what it does.
"$oauth2->set_error_handler(\&error_handler)"
Set the error handler. See the discussion of "error_handler" in the constructor for an
explanation of what it does.
"$oauth2->set_prerefresh(\&prerefresh)"
Set the prerefresh handler. See the discussion of "prerefresh_handler" in the constructor
for an explanation of what it does.
"$oauth2->set_save_tokens($ua)"
Set the save tokens handler. See the discussion of "save_tokens" in the constructor for
an explanation of what it does.
"$oauth2->set_user_agent($ua)"
Set the user agent. This should respond to the same methods that a LWP::UserAgent
responds to.
"$oauth2->user_agent()"
Get the user agent. The default if none was explicitly set is a new LWP::UserAgent
object.
Contributors
• Leon Wright <https://github.com/techman83>
• Thomas Klausner <https://github.com/domm>
• Alex Dutton <https://github.com/alexdutton>
• Chris <https://github.com/TheWatcher>
• Adi Fairbank <https://github.com/adifairbank>
• Adam Millerchip <https://github.com/amillerchip>
• Andre Bras <https://github.com/whity>
ACKNOWLEDGEMENTS
Thanks to Rent.com <http://www.rent.com> for their generous support in letting me develop
and release this module. My thanks also to Nick Wellnhofer <wellnhofer@aevum.de> for
Net::Google::Analytics::OAuth2 which was very enlightening while I was trying to figure
out the details of how to connect to Google with OAuth2.
Thanks to
• Thomas Klausner <https://github.com/domm> for reporting that client type specific
parameters were not available when the client type was properly specified
• Alex Dutton <https://github.com/alexdutton> for making "ServiceProvider" work without
requiring subclassing.
• Leon Wright <https://github.com/techman83> for adding a Strava Service Provider and
various bug fixes
• Adi Fairbank <https://github.com/adifairbank> for adding a Dwolla Service Provider
and some other improvements
• Adam Millerchip <https://github.com/amillerchip> for adding a Line Service Provider
and some refactoring
• Michael Stevens <https://github.com/mstevens> for adding a "Yahoo |
https://developer.yahoo.com" Service Provider and some dist cleanup
• Nick Morrott for fixing some documentation typos
AUTHORS
• Ben Tilly, <btilly at gmail.com>
• Thomas Klausner <domm@plix.at>
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 - 2022 by Ben Tilly, Rent.com, Thomas Klausner.
This is free software; you can redistribute it and/or modify it under the same terms as
the Perl 5 programming language system itself.