pixl-server-user

A basic user login and session management system for the pixl-server framework.

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Readme

Overview
This module is a component for use in pixl-server. It implements a server-side user login and management API, and is built atop the pixl-server-api and pixl-server-storage components. You still need to build a client-side UI to send requests to the API, but this is a great starting point for a webapp back-end.
This document assumes you are already familiar with pixl-server and the following three components:
Usage
Use npm to install the module:
npm install pixl-server pixl-server-storage pixl-server-web pixl-server-api pixl-server-user

Here is a simple usage example. Note that the component's official name is User, so that is what you should use for the configuration key, and for gaining access to the component via your server object.
var PixlServer = require('pixl-server');
var server = new PixlServer({
	
	__name: 'MyServer',
	__version: "1.0",
	
	config: {
		"log_dir": "/var/log",
		"debug_level": 9,
		
		"Storage": {
			"engine": "File",
			"File": {
				"base_dir": "/var/data/myserver"
			}
		},
		
		"WebServer": {
			"http_port": 80,
			"http_htdocs_dir": "/var/www/html"
		},
		
		"API": {
			"base_uri": "/api"
		},
		
		"User": {
			"free_accounts": 0,
			"sort_global_users": 1
		}
	},
	
	components: [
		require('pixl-server-storage'),
		require('pixl-server-web'),
		require('pixl-server-api'),
		require('pixl-server-user')
	]
	
});

server.startup( function() {
	// server startup complete
} );

Notice how we are loading the pixl-server parent module, and then loading our components into the components array, with pixl-server-user at the very bottom:
components: [
	require('pixl-server-storage'),
	require('pixl-server-web'),
	require('pixl-server-api'),
	require('pixl-server-user')
]

This example demonstrates a very simple user manager implementation, which will accept JSON formatted HTTP POSTs to URIs such as /api/user/create and /api/user/login, and will send back serialized JSON responses.
Configuration
The configuration for this component is set by passing in a User key in the config element when constructing the PixlServer object, or, if a JSON configuration file is used, a User object at the outermost level of the file structure. It can contain the following keys:

freeaccounts

The free_accounts property controls whether the create API is "free" (allowed by non-users). Meaning, if this property is set to true, anyone can create an account. If set to false (the default), you must create an administrator account first (see Initial Setup). The administrator must then login, and call admincreate to create user accounts.

sessionexpiredays

The session_expire_days property specifies the number of days that idle sessions should exist before being automatically deleted. The default value is 30 days.

maxfailedloginsperhour

The max_failed_logins_per_hour property specifies the maximum number of failed password attempts to allow per account per hour, before the account is locked out. If an account becomes locked, the only way to unlock it is to reset the password. The default value is 5.

maxforgotpasswordsperhour

The max_forgot_passwords_per_hour property specifies the maximum number of times a user can start the password recovery process. If this is exceeded, the user must wait until the next hour before he/she can try again. The default value is 3.

sortglobalusers

The sort_global_users property, when set to true (also the default value), will keep the global user list sorted alphabetically by username as new users are added. This affects the admingetusers API call, as it will return sorted users for display to administrators.
Note that keeping the global user list sorted is disk intensive, so this is only suitable for small-to-medium servers, up to 10,000 users or so. Any larger and this property should be set to false, in which case users are sorted by their creation date (newest users at the top).

usebcrypt

The use_bcrypt property, when set to true (also the default value), will use the bcrypt-node module to hash passwords. This is an extremely secure but CPU intensive hashing algorithm, which resists brute force attacks. It is recommended, but beware of the additional CPU overhead for creating user accounts and logging in. Password generation and comparison each take about 250ms on my 2012 MacBook Pro.
Note: If you enable this feature on an existing user database, all of your users will need to reset their passwords.

smtphostname

The smtp_hostname property specifies the SMTP (outgoing mail) server to use when sending e-mails. This defaults to the outer pixl-server configuration (it looks for the same smtp_hostname property), or if that is not set it falls back to 127.0.0.1, which will use your local sendmail system. See Emails below for details.

emailtemplates

The email_templates property should be an object containing filesystem paths to e-mail templates, for each of the following e-mails: welcome_new_user, changed_password and recover_password. Example:
"email_templates": {
	"welcome_new_user": "conf/emails/welcome_new_user.txt",
	"changed_password": "conf/emails/changed_password.txt",
	"recover_password": "conf/emails/recover_password.txt"
}

For details, see the Emails section below.

defaultprivileges

The default_privileges property should be an object containing any privileges you want added to new user accounts by default. Privileges are freeform key/value pairs, and up to you to define. Example:
"default_privileges": {
	"admin": 0,
	"view_things": 1,
	"edit_things": 0
}

The only predefined privilege is admin, which signifies the account is a full administrator. If this property is set to 1 on a user account, then they have access to all the admin-level API calls.
User Accounts
User accounts are stored using the pixl-server-storage component. They are identified using the following path: users/USERNAME where USERNAME is the lower-case name of the user. A typical user record looks like this:
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com",
	"full_name": "Tom Cruise",
	"active": "1",
	"modified": 1433735738,
	"created": 1433705544,
	"password": "1190a32e21627477f807294edfc7e533bb3ec58afbe5247a58474cc57f484031",
	"salt": "7210b89f03013272dffc3ba0b48b4de6a1b10bdc9ead535744297adb022be09e",
	"privileges": {
		"admin": 0,
		"view_things": 1,
		"edit_things": 0
	}
}

The username, email, and full_name values are passed in directly from the APIs (create, update, admincreate and/or adminupdate).
The password goes through a salted hash function first (SHA-256) and the digest is stored instead. The salt is just a randomly generated string, so each user has a different password salt (prevents rainbow table attacks).
The created and modified properties are Epoch timestamps. created is automatically set when the user is first created, and modified is updated each time the user is updated.
The privileges object is automatically copied from the defaultprivileges when the user is first created. It can only be updated by an administrator via the adminupdate API.
In general, as long as these standard properties are preserved, the user records can be extended to store whatever additional data you require for your application. You can manipulate the user data via the Hooks system, by adding your own API calls that read/write the user storage records directly, or by including additional keys in the client data passed to the create, update, admincreate and adminupdate APIs.

Global User List

When new users are first created, their usernames are added to a single master list. This is stored in the pixl-server-storage component under the path: global/users. It contains only usernames and nothing else:
[
	{
		"username": "redbird262"
	},
	{
		"username": "tcruise"
	},
	{
		"username": "whiteduck152"
	},
	{
		"username": "yellowmouse910"
	}
]

This data is used by the admingetusers API call, to render a page of users to a client UI using pagination. You can also fetch data from this list for your own app (newsletter?).
If your configuration has the sortglobalusers key set to true, this list will remain sorted alphabetically as new users are added. Otherwise, new users will be unshifted onto the head of the list (so they will be shown first).

Privileges

Each user record has a privileges object, which can contain anything your application requires. The only property used by the library is admin, which specifies if the user is an administrator or not. Example:
"privileges": {
	"admin": 0,
	"view_things": 1,
	"edit_things": 0
}

The other properties are yours to define (in the defaultprivileges configuration object), and then update with the adminupdate API.
A user cannot set or update his/her own privileges object using the create or update APIs. Only administrators have that ability, using admincreate or adminupdate.
Sessions
When a user logs in with the login API, a new session object is created, and stored via the pixl-server-storage component. Session paths follow this pattern: sessions/SESSION_ID where SESSION_ID is a randomly generated unique ID. Here is an example record:
{
	"id": "099db662412794c89a8480b558cf7655c25863b12b4c23a4d3415905f7c78f5f",
	"username": "jhuckaby",
	"ip": "127.0.0.1",
	"useragent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3",
	"created": 1433705951,
	"modified": 1433705951,
	"expires": 1436297951
}

The id is the randomly generated Session ID. The username is the user who opened the session. The ip and useragent are collected from the HTTP request that opened the session. The created and modified dates are what you would expect. The expires date is when the session expires. This is controlled by the sessionexpiredays configuration parameter.

Resuming Sessions

A session may be "resumed" by calling the resumesession API. This simply validates and extends an existing session, allowing the user to keep using it without requiring them to login again. The session's expires property is extended out to N days past the current date on each resume (where N is sessionexpiredays).
Emails
The user management system can be configured to send e-mails to users based on various events, such as new account signups, changing and resetting passwords. Emails are sent using SMTP, via the pixl-mail package. First, you need to specify a valid SMTP server in your configuration, using the smtphostname property.
Then you need to provide up to three e-mail template files. These are used to generate the headers and body of the e-mails. They use a placeholder substitution system for bits of content such as the user's name. You specify the paths to the e-mail template files using the emailtemplates configuration object:
"email_templates": {
	"welcome_new_user": "conf/emails/welcome_new_user.txt",
	"changed_password": "conf/emails/changed_password.txt",
	"recover_password": "conf/emails/recover_password.txt"
}

To disable an e-mail, simply unset the corresponding configuration property (set it to a blank string, or remove it entirely).
Here are some of the various placeholders you can use in your e-mail templates:
| Placeholder | Description | |-------------|-------------| | [/user/username] | The current username. | | [/user/email] | The current user's e-mail address. | | [/user/full_name] | The current user's full name. | | [/date_time] | The current date/time as a formatted string in the server's timezone. | | [/ip] | The IP address that sent in the current request. | | [/request/headers/useragent] | The current user's user agent (browser). | | [/self_url] | A URL to the current application (root level, with trailing slash). |
Here are details about the various e-mails that can be sent, if template files are provided:

welcomenewuser

This e-mail is sent when new users create an account (or optionally when an administrator creates a user account). Here is an example template:
To: [/user/email]
From: support@myapp.com
Subject: Welcome to MyApp!

Hey [/user/full_name],

Welcome to MyApp!  Your new account username is "[/user/username]".  You can login to your new account by clicking the following link, or copying & pasting it into your browser:

[/self_url]

Regards,
The MyApp Team

changedpassword

This e-mail is sent whenever a user changes his/her password, either using the update API, or from a password reset. It is not sent when an administrator changes a password.
To: [/user/email]
From: support@myapp.com
Subject: Your MyApp password was changed

Hey [/user/full_name],

Someone recently changed the password on your MyApp account.  If this was you, then all is well, and you can disregard this message.  However, if you suspect your account is being hacked, you might want to consider using the "Forgot Password" feature (located on the login page) to reset your password.

Here is the information we gathered from the request:

Date/Time: [/date_time]
IP Address: [/ip]
User Agent: [/request/headers/user-agent]

Regards,
The MyApp Team

recoverpassword

This e-mail is sent whenever the user requests a password reset, via the forgotpassword API. It should contain a special link consisting of a recovery key, which will allow the user to set a new password for their account. The recovery key is available via the [/recovery_key] placeholder, and should be passed, along with the username and a new password collected from the user, to the resetpassword API.
To: [/user/email]
From: support@myapp.com
Subject: Forgot your MyApp password?

Hey [/user/full_name],

Someone recently requested to have your password reset on your MyApp account.  To make sure this is really you, this confirmation was sent to the e-mail address we have on file for your account.  If you really want to reset your password, please click the link below.  If you cannot click the link, copy and paste it into your browser.

[/self_url]#Login?u=[/user/username]&h=[/recovery_key]

This password reset page will expire after 24 hours.

If you suspect someone is trying to hack your account, here is the information we gathered from the request:

Date/Time: [/date_time]
IP Address: [/ip]
User Agent: [/request/headers/user-agent]

Regards,
The MyApp Team
Initial Setup
When your application is first installed, you need to execute a few setup tasks. These are typically implemented in a setup script, which either runs automatically or manually on the command-line. It should do the following:

Creating an initial administrator

You'll want to create an initial administrator user, who has full permissions. This is typically done by the following code inserted into a command-line script which uses the Standalone Mode of the pixl-server-storage component.
var user = {
	username: username,
	password: password,
	full_name: "Administrator",
	email: "admin@myapp.com"
};

user.active = 1;
user.created = user.modified = Tools.timeNow(true);
user.salt = Tools.generateUniqueID( 64, user.username );
user.password = Tools.digestHex( '' + user.password + user.salt );
user.privileges = { admin: 1 };

storage.put( 'users/' + username, user, function(err) {
	if (err) throw err;
	console.log( "Administrator '"+username+"' created successfully.\n" );
} );

You'll need to import the pixl-tools package for the timeNow(), generateUniqueID() and digestHex() functions used in the example above.

Creating the initial user list

The master user list, which is located in the storage component under global/users is actually automatically created when the first user is added. However, it is recommended that you pre-create this list, so you can set the List Page Size to something higher than the default of 50.
The user list contains only usernames, so the list items are tiny in size. It is therefore much more efficient if the list page size was something more like 100. You cannot change the list page size after the fact, so you must do it at initial server install. To do this, add something like this to your command-line setup / install script:
storage.listCreate( 'global/users', { list_size: 100 }, function(err) {
	if (err) throw err;
	console.log( "Global user list created successfully.\n" );
} );

Storage Maintenance

In order for your sessions (and any other data records that you set expiration dates on) to be properly deleted when they expire, you need to enable maintenance on the storage component. This is done by setting the maintenance storage configuration property to a HH::MM formatted string, indicating the time of day at which it will perform its cleanup:
{
	"maintenance": "04:30" // run daily at 4:30 AM
}

For more information, please see the Daily Maintenance section of the pixl-server-storage component docs.
API
All the APIs provided by this package are registered under the user namespace. So, coupled with the standard base URI of /api (configurable), the endpoint for the user create API is /api/user/create, user update is /api/user/update, and so on.
Unless otherwise specified, all APIs return a JSON formatted response, consisting of at least a code property. If code is 0, then the API was a success. If code is non-zero, then an error occurred. In this case see the description property for the error message.
Most APIs require an active session (the only exceptions are create and login). The user's Session ID should be stored client-side, and passed in using any of the following methods:
  • An HTTP Cookie with the name: session_id
  • An HTTP request header: X-Session-ID
  • A top-level JSON property in the POST data: session_id
  • A URL query string parameter: session_id

Here is the full list of APIs:

create

Create a new user: POST /api/user/create
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com",
	"full_name": "Tom Cruise",
	"password": "topGun!"
}

The create API creates a new user account, but is only accessible if the freeaccounts configuration property is set to true. No session is required for this. The required JSON properties in the POST data are username (must be alphanumeric), email, full_name and password. Any unknown properties are also stored in the user record.
Example successful response:
{
	"code": 0
}

login

Validate user and create a new session: POST /api/user/login
{
	"username": "tcruise",
	"password": "topGun!"
}

The login API validates the user account exists and is active, and makes sure the provided password matches the hash-digested one we have on file. If everything checks out, a new session is created, and the Session ID is passed back to the client, along with the user record (sans password and salt).
Example successful response:
{
	"code": 0,
	"username": "tcruise",
	"user": {
		"username": "tcruise",
		"email": "tcruise@hollywood.com",
		"full_name": "Tom Cruise",
		"password": "topGun!",
		"privileges": {
			"admin": 0,
			"view_things": 1,
			"edit_things": 0
		}
	},
	"session_id": "099db662412794c89a8480b558cf7655c25863b12b4c23a4d3415905f7c78f5f"
}

The returned session_id can then be used for subsequent API calls.

logout

Delete user session: POST /api/user/logout
The logout API deletes an existing user session, effectively logging the user out. No JSON data is required in the request, as long as the Session ID is specified in some way (see API). After this API returns, the client should destroy the Session ID, and return the user to the home or login screens.
Example successful response:
{
	"code": 0
}

resumesession

Recover existing session: POST /api/user/resume_session
The resume_session API reloads an existing user session, effectively allowing the user to resume a previous session. No JSON data is required in the request, as long as the Session ID is specified in some way (see API).
Example successful response:
{
	"code": 0,
	"username": "tcruise",
	"user": {
		"username": "tcruise",
		"email": "tcruise@hollywood.com",
		"full_name": "Tom Cruise",
		"password": "topGun!"
	},
	"session_id": "099db662412794c89a8480b558cf7655c25863b12b4c23a4d3415905f7c78f5f"
}

The returned session_id can then be used for subsequent API calls.

update

Update user data: POST /api/user/update
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com",
	"full_name": "Tom Cruise",
	"old_password": "topGun!",
	"new_password": "daysOfThunder!"
}

The update API updates an existing user account. Note that the username provided in the JSON POST data must match that of the active session. A user may only update his/her own profile. To change the account password, provide a new one in new_password. Any unknown properties will be stored with the user record.
Note that the current account password must always be specified in old_password, even if a new password is not being provided.
The API response also includes a copy of the updated user record, so you can refresh the client-side UI.
Example successful response:
{
	"code": 0,
	"user": {
		"username": "tcruise",
		"email": "tcruise@hollywood.com",
		"full_name": "Tom Cruise",
		"privileges": {
			"admin": 0,
			"view_things": 1,
			"edit_things": 0
		}
	}
}

delete

Delete user account: POST /api/user/delete
{
	"username": "tcruise",
	"password": "topGun!"
}

The delete API permanently deletes a user account, and logs the user out (destroys the active session). Both the username and password of the account must be provided by the client, and an active session ID must be found (the user must be logged in). After this API returns, the client should destroy the Session ID, and return the user to the home or login screens.
Example successful response:
{
	"code": 0
}

forgotpassword

Send e-mail to reset password: POST /api/user/forgot_password
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com"
}

The forgot_password API initiates the password recovery process for a user. This is designed to be sent without an active session (user is logged out), and requires a username and email. The username must match an active account, and the e-mail must match the address on file for the account (case-insensitive).
If everything checks out, the user is sent a recoverpassword e-mail with further instructions. Namely, the e-mail should contain a link that includes a special recovery key. This is then used in the resetpassword API to complete the process. The recovery key is stored under the path password_recovery/KEY where KEY is the unique recovery key.
Example successful response:
{
	"code": 0
}

resetpassword

Complete the password reset process: POST /api/user/reset_password
{
	"username": "tcruise",
	"key": "3a43167a326b1eccd1c752f72064875656d80144b6f9527a185f2f6ac0c04003",
	"new_password": "missionImpossble!"
}

The reset_password API completes the forgot password / reset password workflow, by actually changing the account password to a new one. This API requires a special recovery key (key) which is obtained from the recoverpassword e-mail sent via the forgotpassword API. The username must also match what is in the recovery record. Specify the desired new account password in new_password.
Example successful response:
{
	"code": 0
}

admincreate

Create user as an administrator: POST /api/user/admin_create
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com",
	"full_name": "Tom Cruise",
	"password": "topGun!",
	"privileges": {
		"admin": 0,
		"view_things": 1,
		"edit_things": 0
	},
	"send_email": true
}

The admin_create API creates a new user account, but it is only accessible to administrators. Also, this is the only way to create user accounts if the freeaccounts configuration parameter is set to false.
The main difference between admin_create and create is that admin_create allows you to specify privileges. So you can use this to create users with any privileges you want, including other administrators (just set admin to 1).
The send_email property is a boolean flag indicating whether the user should be sent the usual welcome e-mail, or not.
Example successful response:
{
	"code": 0
}

adminupdate

Update any user as an administrator: POST /api/user/admin_update
{
	"username": "tcruise",
	"email": "tcruise@hollywood.com",
	"full_name": "Tom Cruise",
	"new_password": "oblivion!",
	"privileges": {
		"admin": 0,
		"view_things": 1,
		"edit_things": 0
	}
}

The admin_update API updates any user, but it is only accessible to administrators. Using this you can set any user properties on any account, including privileges, and reset passwords without also providing the current password (as is the case with the standard update API).
The API response also includes a copy of the updated user record, so you can refresh the client-side UI.
Example successful response:
{
	"code": 0,
	"user": {
		"username": "tcruise",
		"email": "tcruise@hollywood.com",
		"full_name": "Tom Cruise",
		"privileges": {
			"admin": 0,
			"view_things": 1,
			"edit_things": 0
		}
	}
}

admindelete

Delete any user as an administrator: POST /api/user/admin_delete
{
	"username": "tcruise"
}

The admin_delete API permanently deletes a user account, but it is only accessible to administrators. Only the username of the account must be provided by the client.
Example successful response:
{
	"code": 0
}

admingetuser

Fetch a user record as an administrator: POST /api/user/admin_get_user
{
	"username": "tcruise"
}

You can alternatively use HTTP GET for this API: GET /api/user/admin_get_user?username=USERNAME
The admin_get_user API fetches a single user record, for the purpose of displaying form fields in a UI for editing. It is only accessible to administrators. Specify the desired username, and the user record will be returned (sans password and salt).
Example successful response:
{
	"code": 0,
	"user": {
		"username": "tcruise",
		"email": "tcruise@hollywood.com",
		"full_name": "Tom Cruise",
		"privileges": {
			"admin": 0,
			"view_things": 1,
			"edit_things": 0
		}
	}
}

admingetusers

Fetch multiple users as an administrator: POST /api/user/admin_get_users
{
	"offset": 0,
	"limit": 50
}

You can alternatively use HTTP GET for this API: GET /api/user/admin_get_users?offset=0&limit=50
The admin_get_users API fetches multiple users from the master user list, given an offset from the top of the list, and a limit specifying the number of users you want. Using these two parameters you can design a pagination system. The API response always includes the master list length, so you can calculate how many "pages" there are.
The API response will contain a rows array consisting of one element per user, and a list object containing metadata about the master user list as a whole (this is where you can get the total list length, for calculating pagination links).
Example successful response:
{
	"code": 0,
	"rows": [
		{
			"username": "beautifulkoala110",
			"active": 1,
			"full_name": "Maurizio Ijsselstein",
			"email": "maurizio.ijsselstein32@example.com",
			"privileges": {
				"admin": 0,
				"edit_events": 0,
				"edit_plugins": 0
			},
			"modified": 1433735643,
			"created": 1433735643
		},
		{
			"username": "crazypeacock161",
			"active": 1,
			"full_name": "Franklin Duncan",
			"email": "franklin.duncan29@example.com",
			"privileges": {},
			"modified": 1433733408,
			"created": 1433733408
		},
		{
			"username": "goldenpeacock287",
			"active": 1,
			"full_name": "Danielle George",
			"email": "danielle.george99@example.com",
			"privileges": {
				"admin": 0,
				"edit_events": 0,
				"edit_plugins": 0
			},
			"modified": 1433735637,
			"created": 1433735637
		}
	],
	"list": {
		"first_page": 0,
		"last_page": 0,
		"length": 3,
		"page_size": 50,
		"type": "list"
	}
}
Adding Your Own APIs
To add your own APIs, you should use the pixl-server-api component. You can call either addHandler() to register a single API handler method, or addNamespace() to declare an entire class as an API namespace (this is what the user component does). Example:
server.API.addHandler( 'my_custom_api', function(args, callback) {
	// custom request handler for our API
	callback({
		code: 0,
		description: "Success!"
	});
} );

See the pixl-server-api documentation for more details.

Validating The Session

To validate the current session, you can call the loadSession() method on the user component. It should be accessible from your own component's API methods using this syntax:
this.server.User.loadSession(args, function(err, session, user) {
	if (err) {
		// an error occurred
	}
	else {
		// valid session and user
	}
} );
Hooks
Hooks allow you to intercept any API call, potentially make changes to the data, and/or throw an error and stop the API from proceeding.
All the "before" hooks require you to fire a callback. If you pass an error to the callback, the API is aborted and the error sent back to the client. In this way you can interrupt and abort any API. If you pass nothing to the callback, the API call can proceed. All the "after" hooks are passive (no callback), and happen after the response has already been sent back to the client.
To register a hook, call the registerHook() method, and provide the hook name (see below) and your own callback function:
this.server.User.registerHook( 'before_create', function(args, callback) {
	// do something here
	callback();
} );

All hooks are passed an args object containing the following:
| Property | Description | |----------|-------------| | args.user | The current user object, if available (depends on the hook). | | args.session | The current session object, if available (depends on the hook). | | args.request | The core Node.js server request object. | | args.response | The core Node.js server response object. | | args.ip | This will be set to the user's public IP address. | | args.ips | This will be set to an array of all the user's IP addresses. | | args.query | An object containing key/value pairs from the URL query string. | | args.params | All the HTTP POST parameters as key/value pairs. | | args.files | All the uploaded files as key/object pairs (see args.files). | | args.cookies | All the HTTP Cookies parsed into key/value pairs. | | args.server | The pixl-server object which handled the request. |
This is largely the same as the args object passed to HTTP request handlers in the pixl-server-web component. For more details, see the args section of those docs.
Here is the list of supported hooks:

beforecreate

The before_create hook is fired just before a new user is created in the create API. The args object passed to your callback will contain the new user object as it is being constructed, which contains all the parameters sent from the client. Using this you could implement your own validation on addition parameters passed by the UI.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

aftercreate

The after_create hook is fired just after a new user is created, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforelogin

The before_login hook is fired just before a user logs in, via the login API. The args object passed to your callback will contain the user object that represents the user performing the login.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterlogin

The after_login hook is fired just after a user has successfully logged in, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforelogout

The before_logout hook is fired just before a user logs out, via the logout API. The args object passed to your callback will contain the user object that represents the user performing the logout, as well as the session that is going to be destroyed.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterlogout

The after_logout hook is fired just after a user has successfully logged out, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforeresumesession

The before_resume_session hook is fired just before a user resumes a session, via the resumesession API. The args object passed to your callback will contain the relevant user object.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterresumesession

The after_resume_session hook is fired just after a user has successfully logged in, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforeupdate

The before_update hook is fired just before a user record is updated, via the update API. The args object passed to your callback will contain the user object that represents the user performing the update, as well as the active session object.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterupdate

The after_update hook is fired just after a user has successfully been updated, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforedelete

The before_delete hook is fired just before a user record is deleted, via the delete API. The args object passed to your callback will contain the user object that represents the user performing the update, as well as the active session object.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterdelete

The after_delete hook is fired just after a user has successfully been deleted, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforeforgotpassword

The before_forgot_password hook is fired just before a user begins the password reset workflow, via the forgotpassword API. The args object passed to your callback will contain the relevant user object.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterforgotpassword

The after_forgot_password hook is fired just after a user has successfully been e-mailed, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.

beforeresetpassword

The before_reset_password hook is fired just before a user resets their password, via the resetpassword API. The args object passed to your callback will contain the relevant user object.
Your function is also passed a callback as the 2nd argument. You must invoke this callback to complete the hook, and return control to the API. Pass an error to the callback to abort the API and pass the error along to the client.

afterresetpassword

The after_reset_password hook is fired just after a user has successfully reset their password, and the response has been sent back to the client. This is a passive hook, and does not require a callback to be fired.
Transaction Log
The user management system makes use of the pixl-server event log, by logging both debug messages and transactions. See below for examples of all the transaction log entries.
All transactions will have the code column set to transaction, and the msg column usually set to the username. The data column usually contains a JSON object with various information such as the user record and/or HTTP headers.
For more details on the server event log format, see the Logging section of the pixl-server docs.

usercreate

The user_create transaction log entry has the new username in the msg column, and the user's new record (sans password and salt), as well as the requesting IP and HTTP headers in the data column. Example:
[1433735672.387][2015-06-07 20:54:32][joeretina-2.local][User][transaction][user_create][yellowmouse910][{"user":{"username":"yellowmouse910","active":1,"full_name":"Anni Wirtanen","email":"anni.wirtanen78@example.com","privileges":{"admin":0,"edit_events":0,"edit_plugins":0},"modified":1433735672,"created":1433735672},"ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"188","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9692031.124279869.137249571.141495047.141407019.4"}}]

userlogin

The user_login transaction log entry has the username in the msg column, and the user's IP and HTTP headers in the data column. Example:
[1433828230.675][2015-06-08 22:37:10][joeretina-2.local][User][transaction][user_login][jhuckaby][{"ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-language":"en-us","accept-encoding":"gzip, deflate","cache-control":"max-age=0","content-type":"application/json","origin":"http://127.0.0.1:3012","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","content-length":"81","connection":"keep-alive","cookie":"__utma=9692031.124294869.137439571.141495047.141907019.4"}}]

userlogout

The user_logout transaction log entry has the username in the msg column, and the user's IP and HTTP headers in the data column. Example:
[1433705600.912][2015-06-07 12:33:20][joeretina-2.local][User][transaction][user_logout][jhuckaby][{"ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"8ab04848093c063718fe5064e90ffad3dc2cbe48ad2a961f06e3ce4512ee84be","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"81","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9699231.124294869.137239571.141895047.141407019.4"}}]

userupdate

The user_update transaction log entry has the username in the msg column, and the user's updated record (sans password and salt), as well as the requesting IP and HTTP headers in the data column. Example:
[1433735738.641][2015-06-07 20:55:38][joeretina-2.local][User][transaction][user_update][tcruise][{"user":{"username":"tcruise","email":"tcruise@hollywood.com","full_name":"Tom Cruise","active":"1","modified":1433735738,"created":1433705544,"privileges":{"admin":1,"edit_events":1,"edit_plugins":0},"joetest":12345},"ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"164","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9692031.124274869.137239571.141895047.141907019.4"}}]

userdelete

The user_delete transaction log entry has the username in the msg column, and the user's IP and HTTP headers in the data column. Example:
[1433735602.883][2015-06-07 20:53:22][joeretina-2.local][User][transaction][user_delete][zgoldenlion329][{"ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"29","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9699231.124274869.137249571.141485047.144907019.4"}}]

userforgotpassword

The user_forgot_password transaction log entry has the username in the msg column, and the user's recovery key in the data column as a property named key in the encoded JSON text. Example:
[1433735131.978][2015-06-07 20:45:31][joeretina-2.local][User][transaction][user_forgot_password][redsnake609][{"key":"7210b89f03013272dffc3ba0b48b4de6a1b10bdc9ead535744297adb022be09f","ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"26","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9699031.124294869.172439571.141895047.141407019.4"}}]

userpasswordreset

The user_password_reset transaction log entry has the username in the msg column, and the user's recovery key in the data column as a property named key in the encoded JSON text. Example:
[1433735131.978][2015-06-07 20:45:31][joeretina-2.local][User][transaction][user_password_reset][redsnake609][{"key":"7210b89f03013272dffc3ba0b48b4de6a1b10bdc9ead535744297adb022be09f","ip":"127.0.0.1","headers":{"host":"127.0.0.1:3012","accept":"text/plain, */*; q=0.01","x-session-id":"fb531a0886313888c3c08ba8a82031fb7a37b8d9ea979151f65f88b1a4f90b83","x-requested-with":"XMLHttpRequest","accept-encoding":"gzip, deflate","accept-language":"en-us","content-type":"application/json","origin":"http://127.0.0.1:3012","content-length":"26","user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/600.6.3 (KHTML, like Gecko) Version/8.0.6 Safari/600.6.3","referer":"http://127.0.0.1:3012/","connection":"keep-alive","cookie":"__utma=9692031.124794869.137249571.141495047.141407019.4"}}]
External User Login Systems
If you already have an existing user login system, perhaps a company-wide SSO (single sign-on) system, you can provide a simple REST API bridge in order to link to it from this module. Meaning, you can use your own external system for user login and identification, and pass the user information back to this module securely in the background, effectively synchronizing the two databases. Then this module transparently logs the user in and creates a session as per usual.
The general workflow is:
  1. A user loads your Node.js web application in a browser.
  2. Your client-side JavaScript code detects that the user has no active session cookie for your app, or it has expired.
  3. Instead of showing a usual login form, your client-side code makes an API call to: user/external_login.
  4. The user/external_login code makes a server-to-server HTTP GET request to a URL that you specify.
* The code sends along all the cookies sent from the browser to your API.
* If your API returns user information, it is used to update the local user data and log the user in right away.
* If your API returns a redirect URL, this is passed back to the browser along with our return URL.
The basic idea is that your external API is queried for user information instead of displaying a login page to the user. Any cookies from the browser are passed along to your API (it assumes you store a cookie on the top-level domain on which you are also serving your app). If your API then returns valid user information, it is immediately updated in local storage, and the user is immediately logged in. However, if your API doesn't recognize the user, then it can provide a redirect URL to navigate the browser to (i.e. your own external login page, separate from your app).
The first step is configuring your client-side JavaScript code. You should go through the normal process of detecting a session cookie, and if found, use the user/resumesession API to resume the session as per usual. But if no cookie is found or the session is expired, then instead of showing the user a standard login form, send another HTTP POST call to user/external_login. The browser should include any relevant cookies.
The next step is activating the external login feature by specifying a fully-qualified URL to your API endpoint, which will provide the user bridge. This should go into the external_user_api configuration parameter. Example:
{
	"external_user_api": "http://mycompany.com/usermanager/login-from-app.php"
}

When called via HTTP GET, your API is expected to return one of two JSON responses: an actual user record, or a redirect URL. Here are the two responses explained, with examples:

Returning User Information

If you detect that user is already logged in via your system (i.e. the cookies passed along to your API correspond to an active session) then you should return a JSON record that describes the user. It should contain the following:
{
	"code": 0,
	"username": "jsmith",
	"user": {
		"full_name": "John Smith",
		"email": "test@email.com",
		"avatar": "http://mycompany.com/users/jsmith/avatar.png",
		"privileges": {
			"admin": 1
		}
	}
}

Here are descriptions of the JSON properties:
| Property Name | Description | |---------------|-------------| | code | This represents the error code, and should be set to 0 upon success. | | username | The username of the user, which should contain only alphanumeric characters, dashes and periods. | | user | An object containing more information about the user. | | full_name | The user's first and last names as a single combined string. | | email | The user's e-mail address. | | avatar | This is optional, and may contain a fully-qualified URL to an avatar image for the user. | | privileges | An object containing a set of privileges for the user. See Privileges above. |
At this point the user information will be saved to local data storage, and the user will be logged in (a new session will be created, and the session ID returned to the client).
The API response back to the browser will be identical to the one sent by the user/resumesession call. Your client-side code should be expecting a user record, and a new user session ID, to store in a cookie or browser localStorage.

Redirecting to a Login Page

If you detect that the user is not logged in (i.e. no cookie), or their session has expired, then you will need to trigger a browser redirect, so the user can enter their username and password into your external login page. To do this, send back a JSON record formatted like this:
{
	"code": 0,
	"location": "http://mycompany.com/usermanager/login.php?return="
}

So here you need to specify a fully-qualified URL to your own login form page where the user can enter their username and password. Please include the URL in the location JSON parameter, rather than sending a HTTP 302. Also, your login page URL needs to accept an encoded "return URL" appended to the end. This is so your login system knows where to redirect back to upon successful login. The return URL will be added automatically before the final URL is sent back to the browser for the client-side redirect.
Your client-side app code needs to detect the location property when it is returned, and redirect the browser to the URL provided. Since this API call is typically initiated via AJAX / XHR, a standard HTTP 302 server response will not trigger a browser window redirect, so some JavaScript code is required to interpret the response and redirect the user.
The idea here is that after the user logs in successfully via your login page, they'll have a session cookie created. So when they arrive back at your Node.js app, we'll start the same user verification process again, and request your external_user_api URL via HTTP GET again. But this time, the user will have a valid cookie, so your API should return actual user information (see Returning User Information above), and the user will finally be logged in properly.

Logging Out

When an external user management system is integrated, and the user clicks the "Logout" button in the UI, after the internal session is deleted they will be redirected to your external_user_api URL straight from the browser, but with a logout=1 query string parameter appended. Example:
http://mycompany.com/usermanager/login-from-app.php?logout=1

It is expected that your bridge API will then redirect the user to the appropriate logout page so their session can be deleted and cookies cleaned up.
License
The MIT License (MIT)
Copyright (c) 2015 - 2016 Joseph Huckaby.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.