actionhero OAuth2 provider

Create a OAuth2 provider/server with actionhero

Install:
``bash
npm install actionhero-oauth2-provider
`

create a new initializer inside your actionhero project.

e.g. oauth2.js with the following content
`js
var OAuth2Provider = require('actionhero-oauth2-provider');

var provider = new OAuth2Provider();

provider.on('validate_user', function(api, connection, next){
var authorize_url = connection.params.authorize_url;
if(/the user is logged in./){
next();
}else{
//redirect to the login page
res.writeHead(303, {Location: '/login'});
res.end();
next(false);
}
});

provider.on('validate_client', function(api, connection, next){
var client_id = connection.params.client_id;

if(/client_id valid?/){
next();
}else{
connection.error = 'invalid client id!';
next(false);
}
});


provider.on('validate_grant', function(api, connection, next){
var client_id = connection.params.client_id;
var user_id = connection.session.user_id;

if(/grants exists?/){
next();
}else{
//redirect
res.writeHead(303, {Location: '/grant'});
res.end();
next(false);
}
});


provider.on('validate_code', function(api, connection, next){
var client_id = connection.params.client_id;
var code = connection.params.code;

if(/code is valid?/){
next();
}else{
connection.error = 'invalid code!';
next(false);
}
});


provider.on('validate_access_token', function(api, connection, next){
var client_id = connection.params.client_id;
var access_token = connection.params.access_token;

if(/access_token is valid?/){
//set session variables here if needed
next();
}else{
connection.error = 'invalid access_token!';
next(false);
}
});


provider.on('save_code', function(api, connection, next){
var user_id = connection.session.user_id;
var client_id = connection.params.client_id;
var code = connection.params.code;

//save code here
next();
});


provider.on('destroy_code', function(api, connection, next){
var client_id = connection.params.client_id;
var code = connection.params.code;

//destroy code here
next();
});

provider.on('save_access_token', function(api, connection, next){
var client_id = connection.params.client_id;
var code = connection.params.code;
var access_token = connection.params.access_token;

//save access_token here
next();
});


//export the initializer for actionhero
exports.oauth2 = provider.initializer;
``