nvdnkpr / booster

Booster is the fastest way to get a full-fledged REST service up and running in nodejs

#booster

##Overview Booster is the fastest way to get a full-fledged REST service up and running in nodejs!

var booster = require('booster'), express = require('express'), app = express(), db = require('./myDbSetup');

booster.init({app:app,db:db});
booster.resource('post');

app.listen(3000);

Done! You now have a REST service listening on the five standard REST paths for 'post' and connecting to your database.

Want customized controllers? Disable some paths? Nest resources? Model validations? Uniqueness? Read on!

##Installation

npm install booster

Doesn't get easier than that!

##Usage

What does it provide?

booster provides the following basic features:

• REST routing - similar to express-resource
• Easy controllers - with defaults for all patterns
• Standardized models - with validation, optional schemas, and database agnostic interfaces

What does it look like?

var express = require('express'), app = express(), booster = require('booster');

// set up my database
db = dbSetUp();
booster.init({app:app,db:db,controllers:'./controllers',models:'./models'});
booster.resource('post');
booster.resource('comment',{parent:'post'});
booster.resource('note',{parent:'comment'});
booster.resource('test',{base:'/api'});

app.listen(3000);

You now have a RESTful app that listens on the following verb/path/action

GET       /post                           post#index()
GET       /post/:post                     post#show()
POST      /post                           post#create()
PUT       /post/:post                     post#update()
PATCH     /post/:post                     post#patch()
DELETE    /post/:post                     post#destroy()
	GET       /post/:post/comment             comment#index()
	GET       /post/:post/comment/:comment    comment#show()
	POST      /post/:post/comment             comment#create()
	PUT       /post/:post/comment/:comment    comment#update()
	PATCH     /post/:post/comment/:comment    comment#patch()
	DELETE    /post/:post/comment/:comment    comment#destroy()
	GET       /post/:post/comment/:comment/note					note#index()
	GET       /post/:post/comment/:comment/note/:note		note#show()
	POST      /post/:post/comment/:comment/note/:note		note#create()
	PUT       /post/:post/comment/:comment/note/:note   note#update()
	PATCH     /post/:post/comment/:comment/note/:note   note#patch()
	DELETE    /post/:post/comment/:comment/note/:note   note#destroy()
GET       /api/test                       test#index()
GET       /api/test/:test                 test#show()
POST      /api/test                       test#create()
PUT       /api/test/:test                 test#update()
PATCH     /api/test/:test                 test#patch()
DELETE    /api/test/:test                 test#destroy()

and where exactly are those post#index() and comment#show() functions? You can create them or use the defaults:

If you create them, they are in <controllerPath>/post.js and <controllerPath>/comment.js. So post#index() is just the method index() on the module.exports of <controllerPath>/post.js.

And if you don't create them? Well, then booster has built-in defaults!

For example, calling GET /post with no <controllerPath>/post.js defined, or without the index() function defined, will simply load the list of posts from the database and send them all.

Getting started

var booster = require('booster');

That shouldn't surprise anyone!

So what do I do with booster once I have required it?

booster.init(config); // returns booster, so you can chain

And what exactly goes in that config, anyways?

• controllers: path to controller files directory, relative to app root, e.g. ./ctrlr (trailing slash is optional). Default is './routes', but controllers are totally optional.
• models: path to model files director, relative to app root, e.g. ./mymodels (trailing slash is optional). Default is './models', but models are totally optional.
• param: parameters you want to make available to controller functions. Optional. Default is {}.
• db: a database object. Required.
• app: your express app object (you really should have one of these!). Required.

REST Resources

The basic step is defining a REST resource, like so:

booster.resource(name,opts)

For example:

booster.resource('comment');

This sets up a resource named 'comment', expecting a controller (or using the default) for comment, and a model (or using the default) for comment. As shown above, it creates six paths by default:

GET       /comment             comment#index()
GET       /comment/:comment    comment#show()
POST      /comment             comment#create()
PUT       /comment/:comment    comment#update()
PATCH     /comment/:comment    comment#patch()
DELETE    /comment/:comment    comment#destroy()

Name of the rose. I mean resource.

The first (and only required) argument to booster.resource() is the name of the resource. It should be all string, valid alphanumeric, and will ignore all leading and trailing whitespace. It will also ignore anything before the last slash, so:

abc     -> abc
	/abc    -> abc
	a/b/c   -> c
	ca/     -> INVALID

Optional options

opts is just a plain old JavaScript object with options. What goes into those options? That depends what you want to do with this resource.

Base path

If you prefer to have a base path to your resource, so the path is /api/comment, just do:

booster.resource('comment',{base:'/api'});

Which will give you

	GET       /api/comment             comment#index()
GET       /api/comment/:comment    comment#show()
POST      /api/comment             comment#create()
PUT       /api/comment/:comment    comment#update()
PATCH     /api/comment/:comment    comment#patch()
DELETE    /api/comment/:comment    comment#destroy()

If you want all of your routes to have a base path, instead of having to do:

booster.resource('post',{base:'/api'});
booster.resource('comment',{base:'/api'});
booster.resource('user',{base:'/api'});

You could simply do:

booster.init({base:'/api'});
booster.resource('post');
booster.resource('comment');
booster.resource('user');

If you do specify a base on a specific resource after already specifying the global base in init(), the resource-specific base will override the global one.

Nested Resource

If you want to nest a resource, like in the example above, you just need to pass a parent option:

booster.resource('comment',{parent:'post'});

Which will give you

GET       /post/:post/comment             comment#index()
GET       /post/:post/comment/:comment    comment#show()
POST      /post/:post/comment             comment#create()
PUT       /post/:post/comment/:comment    comment#update()
PATCH     /post/:post/comment/:comment    comment#patch()
DELETE    /post/:post/comment/:comment    comment#destroy()

If you include both parent and base, it will ignore base.

You can nest as many layers deep as you want:

booster.resource('comment',{parent:'post'});
booster.resource('note',{parent:'comment'});

GET       /post/:post/comment             comment#index()
GET       /post/:post/comment/:comment    comment#show()
POST      /post/:post/comment             comment#create()
PUT       /post/:post/comment/:comment    comment#update()
PATCH     /post/:post/comment/:comment    comment#patch()
DELETE    /post/:post/comment/:comment    comment#destroy()
GET       /post/:post/comment/:comment/note					note#index()
GET       /post/:post/comment/:comment/note/:note		note#show()
POST      /post/:post/comment/:comment/note/:note		note#create()
PUT       /post/:post/comment/:comment/note/:note   note#update()
PATCH     /post/:post/comment/:comment/note/:note   note#patch()
DELETE    /post/:post/comment/:comment/note/:note   note#destroy()

Required Parent Param

Sometimes, you want to require that a nested resource has a property that matches the parent.

For example, if I am creating a new nested comment on post 2 as follows:

POST /post/2/comment {author:"john",content:"This is a comment"}

I might want the content to require the name of the parent as a property:

{author:"john",content:"This is a comment",post:"2"}

booster can enforce this if you tell it to! When sitting up a nested resource, just set the parentProperty to true as follows:

booster.resource('comment',{parent:'post',parentProperty:true});

If parentProperty is set to true, booster will insist that the posted body contains a property with the same name as the parent, and that its value precisely matches the value of the parent parameter. In other words, it will insist that req.params[parent] === req.body[parent]. If not, it will reject it with a 400 error.

This rule is enforced for all POST, PUT and PATCH.

If you have:

booster.resource('post');
booster.resource('comment',{parent:'post',parentProperty:true});

each of the following examples, it will show what works and what doesn't

POST   /post/3/comment    {post:"4"}  // FAIL: "4" !== "3"
POST   /post/3/comment    {post:"3"}  // PASS: "3" === "3"
POST   /post/3/comment    {}          // FAIL: missing "post" property
PUT    /post/3/comment/4  {post:"4"}  // FAIL: "4" !== "3"
PUT    /post/3/comment/4  {post:"3"}  // PASS: "3" === "3"
PUT    /post/3/comment/4  {}          // FAIL: missing "post" property and PUT means replace entirely
PATCH  /post/3/comment/4  {post:"4"}  // FAIL: "4" !== "3"
PATCH  /post/3/comment/4  {post:"3"}  // PASS: "3" === "3"
PATCH  /post/3/comment/4  {}          // PASS: missing "post" property, but PATCH is only an update, not a replace

Note that for POST or PUT, where the body is the entire new or replacement object, the property must exist, else it fails. However, for PATCH, where it only replaces those explicit fields, it the parent property is missing, it passes.

In the case of POST and PUT, if you want the field to default to the value of the parent property - in our above example, {post:"3"} - you can tell booster, "Hey, the field has to match, but if it isn't there at all, fill it in for me." Just tell the resource, in addition to setting parentProperty to true, set parentDefault to true as well:

booster.resource('post');
booster.resource('comment',{parent:'post',parentProperty:true,parentDefault:true});

In that case, all of the above examples where missing post caused the route to fail with a 400 will now pass, and the value will be set:

POST   /post/3/comment    {}          // PASS: will be sent to the model as {post:"3"}
PUT    /post/3/comment/4  {}          // PASS: will be sent to the model as {post:"3"}

Note that if you have a property set to {mutable:false} and the same property is {parentDefault:true}, it might conflict when doing a PUT. POST will never be a problem, since it does not yet exist, and PATCH is not a problem, since it only updates the given fields.

For example, what if the data in the database is:

{id:"1",post:"3",content:"Hello, I am here"}

and you initialize as

booster.resource('comment',{parent:'post',parentProperty:true,parentDefault:true});

If you do

PUT /post/3/comment/1  {content:"Now I am not"}

booster will look at the update (PUT) to comment with the id "1", see that it requires the parent property ("post") but that it isn't present, so it will add {post:"3"} before updating the model. This is the equivalent of:

PUT /post/3/comment/1  {content:"Now I am not",post:"3"}

This is great, but what if you defined the comment model making post immutable:

module.exports = {
	fields: {
		content:{required:true,mutable:true},
		post: {required:true,mutable:false},
		id: {required:true,mutable:false}
	}
}

After all, you do not want someone accidentally moving a comment from one post to another! But then the update of

PUT /post/3/comment/1  {content:"Now I am not",post:"3"}

will cause a 400 error, since it is trying to update the post property, and that one is immutable!

Not to worry; booster inteillgently handles this. If you actually try to update post, it will throw a 400. But if you did not set it, and you have parentDefault set, it will not set it unless the field is mutable.

Resource Property

What if you don't want to create a whole new resource, but have a separate property as part of a resource? For example, if you want to be able to PUT /post/:post/title and so change the title directly?

It already works! Yes, that's right. If you already created the resource booster.resource('post'), then unless you created a nested resource of exactly the same name, GET /post/:post/title will get you the title from /post/:post Similarly, you can PUT /post/:post/title to change it. But, no you cannot POST or PATCH it; they don't make much sense.

And you get all of the validations of models for free!

What if you don't want this to happen? Just set it in the controller:

module.exports = {
	getProperty: null // disable `GET /post/:post/property`
	setProperty: null // disable `PUT /post/:post/property`
}

Custom Properties

OK, so the above works great if you want /post/1/title to map to title of post 1, or /post/10/author to map to author of post 10. But what if you want all of the above and you want to map some special properties to their own handlers. For example, if a user is:

{id:"1",firstname:"john",lastname:"smith"}

so you want the following to work (and hey, booster already said you get it for free):

GET /user/1/firstname -> "john"
	GET /user/1/lastname -> "smith"
	GET /user/1 -> {id:"1",firstname:"john",lastname:"smith"}

But you also want to be able to do:

GET /user/1/groups -> [10,12,2678]

In other words, that special property groups is really not a property of a user object, but has its own logic. On the other hand, it behaves mightily like a property: it uses PUT and GET, and has meaning only in the context of a specific user. It isn't a first-class resource (the group and the user are), but that array of group IDs comes from somewhere else!

You know that I'm going to say, "it's easy!", right?

All you need to do is put in place that special controller file, and add properties to it.

module.exports = {
	properties: {
		groups: {
			get: function(req,res,next) {
				// do all of your get logic here
				// LOGIC A
			},
			set: function(req,res,next) {
				// do all of your set logic here
				// LOGIC B
			}
		},
		roles: {
			get: function(req,res,next) {
				// LOGIC C
			}
		},
		strange: {
			set: function(req,res,next) {
				// LOGIC D
			}
		}
	}
};

So when booster hits a property of a resource, like /user/1/someProperty, it says, if all of the following is true, use your function, else treat it just like a regular property:

(controller file exists) AND 
	  (controller has "properties" key) AND 
		  ("properties" key has appropriate property name) AND 
			  (  (property name has "get" key as function if request was GET) OR 
				   (property name has "get" key as function if request was PUT)  )

Going back to the above example, here is what will happen with each type of request and why:

GET /user/1/title -> get the property "title" of the object; properties.title not defined
GET /user/1/groups -> use function for LOGIC A; properties.groups.get defined
PUT /user/1/groups -> use function for LOGIC B; properties.groups.set defined
GET /user/1/roles -> use function for LOGIC C; properties.roles.get defined
PUT /user/1/roles -> get property "roles" of the object; properties.roles.set not defined
GET /user/1/strange -> get property "strange" of the object; properties.strange.get not defined
PUT /user/1/strange -> use function for LOGIC D; properties.strange.set defined

Resource as a Property (RaaP?)

Actually, it is even easier! A really common pattern is where a property of one resource is actually a reference to another resource that has some find restrictions. Take a look at the following:

GET /group         -> get all of the groups
	GET /group/10      -> get group whose ID is 10
GET /user/1/name   -> get the name of user 1, normal property
	GET /user/1/groups -> Get all of the groups of which user "1" is a member, like GET /group?{user:1}

Since this is such a common pattern, let's make it easier for you!

booster.resource('group');
booster.resource('user',{resource:{group:["get"]}});

That is exactly the same as the following:

booster.resource('group');
booster.resource('user');

// and inside routes/user.js :
module.exports = {
	properties: {
		group: {
			get: function(req,res,next) {
				// get the groups of the user from the separate groups list and send them off
				req.booster.models.group.find({user:req.params.user},function (err,data) {
					if (err) {
						res.send(400,err);
					} else if (data && _.size(data) > 0) {
						res.send(200,data[0]);
					} else {
						next();
					}
				});
				
			}
		}
	}
}

But come on, is that not so much easier? You want to write 17 lines instead of 2, and in 2 different files? Go ahead. But I think 2 lines is just cooler.

Root path

If you want to have the resource called at the root path, you just need to pass a root option:

booster.resource('comment',{root:true})

Which will give you

GET       /             comment#index()
GET       /:comment     comment#show()
POST      /             comment#create()
PUT       /:comment     comment#update()
PATCH     /:comment     comment#patch()
DELETE    /:comment     comment#destroy()

Notice that the resource itself is still comment, but the path does not include the name comment.

Controllers

The default controller provides the standard actions: index, show, create, update, patch, destroy. It interacts with the models of the same name (see models, below), and lists all of them, shows one, creates a new one, updates an existing one, or destroys one.

If you want to override one or more of the actions, just create a file with that name in controllerPath directory, either the default path or the one you provided when initializing booster. Each function should match express route signature. If you want to eliminate a route entirely, override it with a null. See the example below.

// <controllerPath>/post.js
module.exports = {
	index: function(req,res,next) {
		// do lots of stuff here
	}
	// because we only override index, all of the rest will just use the default
	update: null
	// because we actively made update null, the update() function and its corresponding PUT /post/:post will be disabled and return 404
};

You can also take a shortcut to eliminating a route, using the except configuration parameter:

booster.resource('post',{except:"index"}); // will create all the routes except GET /post
booster.resource('post',{except:["update","patch"]}); // will create all the routes except PATCH /post/:post and PUT /post/:post

Note that if you are eliminating only one, you can put it in an array, or just as a string.

What does the default controller do?

Well, it looks like this but with real error-handling. Look at the source code in github if you want the real nitty-gritty.

module.exports = {
	index: function(req,res,next) {
		var data = model.find();
		res.send(200,data);
	},
	show: function(req,res,next) {
		var data = model.get(req.param(resource)); // 'resource' is the name you provided when you called booster.resource(name);
		res.send(200,data);
	},
	create: function(req,res,next) {
		model.create(req.body,function(){
			res.send(201);
		});
	},
	update: function(req,res,next) {
		model.update(req.body.id,req.body,function(){
			res.send(200);
		});
	},
	patch: function(req,res,next) {
		model.patch(req.body.id,req.body,function(){
			res.send(200);
		});
	},
	destroy: function(req,res,next) {
		model.destroy(req.param.id,function(){
			res.send(200);
		});
	}
};

It just calls the basic model functions.

Access models inside the controllers

If you need to access the model classes inside the controllers, no problem. They are always available on a request at req.booster.models. Each named resource has its own object.

booster.resource('user');

index: function(req,res,next) {
	var User = req.booster.models.user;
}

Note: req.booster is available in all express routes, not just those inside booster controllers. For example:

booster.resource('user');

app.get('/foo',function(req,res,next){
	req.booster.models.user(); // this works here!
});

Parameters to controller functions

And what if you want to pass some parameters to controller functions? For example, what if one of your controller functions needs to send emails, and you just happen to have a sendmail object in your app that knows how to do just that?

Well, you could require() it in each controller, but that really is rather messy, requires multiple configurations and calls (not very DRY), and would work much better if you could just inject the dependency.

booster supports that type of dependency injection. If you have configuration parameters you want available to your controllers, they are available, in true express style, on the req object as req.booster.param. You inject them by using the param property when calling booster.init()

booster.init({param:{sendmail:fn}});

index: function(req,res,next) {
	req.booster.param.sendmail();
	// do lots of stuff here
}

Filters

Now, what if you don't want to entirely override the controller function, but perhaps put in a filter. You could easily just do:

module.exports = {
	show: function(req,res,next) {
		// handle everything here
	}
}

But you didn't want to have to recreate all of the model calls, error handling, all of the benefits of the default controller. You really just wanted to inject some middleware prior to the default show() being called!

Booster gives you two really good options for this: all global filter, and filters for individual ones.

Global 'before' option for controllers

If you are writing controller method overrides, and you want a function that will always be executed before the usual index/show/update/create/destroy, just add an all function.

module.exports = {
	all: function(req,res,next) {
		// stuff here will always be done *before* the usual middleware methods
		next();
	}
};

Individual filters

If you want an individual filter to run on only one specific routing, e.g. user.index() or user.show(), you do the following:

module.exports = {
	filter: {
		show: function(res,res,next) {
			// do your filtering here
			// succeeded?
			next();
			// failed?
			res.send(400);
			// or else
			next(error);
		}
	}
};

Of course, you will ask, why the split language? Why is all a first-level property, but each other filter is below the filter property? Well, all can go in either space. Both of the following are valid:

module.exports = {
	// this one will get executed first
	all: function(res,res,next) {
		next();
	},
	filter: {
		// then this one
		all: function(res,res,next) {
			next();
		},
		// and this one last
		show: function(req,res,next) {
		}
	}
};

The order of execution is:

1. all()
2. filter.all()
3. filter.show() (or any other specific one)

Post-Processors

A common use case is one where you want to do some post-processing before sending the response back to the client, for example, if you create with POST /users but before sending back that successful 201, you want to set up some activation stuff, perhaps using activator. Like with filters, you could override a controller method, like create, but then you lose all of the benefits.

The solution here is post-processors, methods that are called after a successful controller method, but before sending back the 200 or 201. Does booster support post-processors? Of course it does! (why are you no surprised?)

Like filters, post-processors are added as properties of the controller object.

module.exports = {
	// use "post" to indicate post-processors
	post: {
		all: function(req,res,next) {},  // "all" will always be called
		create: function(req,res,next) {}, // "create" will be called after each "create"
	}
};

The order of execution is:

1. post.all()
2. post.create() (or any other specific one)

Post-processor signatures look slightly different than most handlers, since they need to know what the result of the normal controller method was.

function(req,res,next,status,body) {
};

req, res, next are the normal arguments to a route handler. status is the status code and body is the body returned by the controller method, if any.

Your post-processor filter has 3 options:

• Do nothing: if it does not alternate the response at all, just call next() as usual.
• Error: as usual, you can always call next(error) to invoke expressjs's error handler.
• Change the response: if it want to alternate the response, call res.send() or anything else.

And what about all of our models? What do we do with them?

Models

Models are just standard representations of back-end data from the database. Like controllers, models are completely optional. If you don't provide a model file, the default will be used. If you prefer to design your own, create it in modelPath directory, either the default or the one you provided when initializing booster.

So what is in a model? Actually, a model is an automatically generated JavaScript object handler. It is driven by a config file in which you tell it which you tell booster, for this particular model, how to manage data: name in the database, id field, validations, what should be unique, etc.

• name: what the name of this model should be in your database. Optional. Defaults to the name of the file, which is the name of the resource you created in booster.resource('name').
• fields: what fields this model should have, and what validations exist around those fields
• unique: what unique fields need to exist for this model
• id: what the ID field is. We need this so that we can use "unique" comparisons and other services. Optional. Defaults to "id".
• presave: a function to be executed immediately prior to saving a model via update or create. Optional.
• extend: an object, with functions that will extend the model. Optional. See below.

An actual model instance is just a plain old javascript object (POJSO). The data returned from the database to a controller should be a POJSO, as should the data sent back.

name

The name is just an identifier for this model, and is optional. It defaults to the name of the file, which is the name of the resource you created.

It is used, however, as the value of the table passed to all the database calls. See below under Persistence.

fields

The fields is a list of all of the required fields and properties that are used for this model. It includes the following:

• required: boolean, if the field is required. Ignored for PUT updates. Default false
• createblank: boolean, if this field is optional during creation. ignored if required === false. Default false
• mutable: boolean, if the field can be changed by a client request. Default true
• visible: this field is one of: public (visible to all), private (visible only for explicit private viewers), secret (never sent off the server)
• validation: validations to which to subject this field

Example:

fields = {
	id: {required: true, createoptional: true, mutable: false, visible: "public"},
	name: {required: true, mutable:false, visible: "public", validation:["notblank","alphanumeric"]},
	email: {required: true, mutable:true, visible: "public", validation:"email"}
}

The required boolean is ignored in two cases:

1. PUT update: This makes sense. You might be updating a single field, why should it reject it just because you didn't update them all? If the name and email fields are required, but you just want to update email, you should be able to PUT the follwing {email:"[email protected]"} without triggering any "missing field required" validation errors.
2. POST create and createoptional === true: If you flag a field as required, but also flag it as createoptional, then if you are creating it, validations will ignore the required flag. Well, that's why you set it up as createoptional in the first place, right?

Validations

Validations are one of:

• Predefined validations that you can use to check the field
• An arbitrary function that you can define to validate and even manipulate the field

Predefined validations

Predefined validations are a single string or an array of strings that name validations to which to subject each model before sending persisting them to the database or accepting them from the database.

The following validations exist as of this writing:

• notblank: Is not null, undefined or a string made up entirely of whitespace
• notpadded: Does not start or end with whitespace
• email: Is a valid email pattern. Does not actually check the email address. For example, [email protected] is a valid email pattern, but I am pretty sure that the address is not in use.
• integer: must be a valid integer
• alphanumeric: must be a valid alphanumeric a-zA-Z0-9
• string: must be a string
• boolean: must be a boolean true or false
• array: must be an array
• integerArray: must be an array, every element of which must be a valid integer
• stringArray; must be an array, every element of which must be a valid alphanumeric
• unique: must be an array, no element of which may be repeated more than once
• minimum:<n>: must be a string of minimum length n

If two or more validations are provided in an array, then all of the validations must pass (AND).

unique

If you want to check, before saving an object, that certain fields are unique - e.g. you don't want to create two objects with the same email - you can tell booster to check for you. It uses the db.find() function, creating a search to check.

The unique field is an array, the elements of which are either strings or arrays of strings. Let's look at a few examples:

One field

If you want just one field to be unique, like email, then just put it there:

unique: ["email"]

If you create a model of type user {name:"john",email:"[email protected]"}, and have the above unique parameter, then before saving, booster will do the following:

db.find('user',{email:"[email protected]"},callback);

Only if it finds no matches at all, will it proceed to save/update/create the model.

Two fields, both of which must be unique

If you want to make sure that two fields are not repeated, like email and user, then put them both in:

unique: ["email","name"]

If you create a model of type user {name:"john",email:"[email protected]"}, and have the above unique parameter, then before saving, booster will do the following:

db.find('user',{email:"[email protected]","name":"john","_join":"OR"},callback);

Only if it finds no matches at all, will it proceed to save/update/create the model.

Two fields, which must be unique in combination

If you want to make sure that two fields are unique in combination, for example if firstName can be repeated, and lastName can be repeated, but the combination cannot, then put them in their own array.

unique: [["email","name"]]

If you create a model of type user {firstName:"John",lastName:"Smith"}, and have the above unique parameter, then before saving, booster will do the following:

db.find('user',{email:"[email protected]","name":"john","_join":"AND"},callback);

Only if it finds no matches at all, will it proceed to save/update/create the model.

Validation Functions

Sometimes, the pre-defined validations just are not enough. You want to define your own validation functions. No problem! Instead of a string or array of strings, simply define a function, like so:

module.exports = {
	fields: {
		id: {required:true, validation: "integer"},
		name: {required:true, validation: "alphanumeric"},
		password: {required:true, validation: function(name,field,mode,attrs){
			// do whatever checks and changes you want here
		}}
	}
}

The validation function provides several parameters:

• name: name of the model class you are validating, e.g. 'user' or 'post', helpful for generic functions.
• field: name of the field you are validating, helpful for generic functions.
• mode: what we were doing to get this mode for validating, helpful if you need to validate some things on save, but not load. One of: find get update create 'patch`` (which are the exact db methods. Smart, eh?)
• attrs: the JavaScript object you are validating.
• callback: OPTIONAL. Async callback.

And what should the validation function return? It can return one of three things:

• true: the validation passed, go ahead and do whatever else you were going to do
• false: the validation did not pass, call the callback with an error indicating
• object: the validation might or might not have passed, but we want to do some more work:

The returned object should have the following properties:

• valid: true or false if the validation passed
• value: if this exists, then the value of this key on the object should be changed to the provided value before moving on. See the example below.
• message: if the validation failed (valid === false), then this is the message to be passed

Sync/Async

Note that a validation function can be synchronous or asynchronous.

• Sync: If the arity (number of arguments) of a validation function is four, then it is treated as synchronous, and the validation return is the return value of the function.
• Async: If the arity of a validation function is five, then it is treated as asynchronous, and the fifth argument is the callback function. The callback function should have one argument exactly, the true/false/object that would be returned.

Note that sync is likely to be deprecated in future versions.

The classic example for this is a password field. Let's say the user updated their password, we don't just want to validate the password as alphanumeric or existing, we want to do two special things:

1. We want to validate that the password is at least 8 characters (which john's new password is not)
2. We want to one-way hash the password before putting it in the database

Our validation function will look like this:

module.exports = {
	fields: {
		id: {required:true, validation: "integer"},
		name: {required:true, validation: "alphanumeric"},
		password: {required:true, validation: function(name,field,attrs){
			var valid, newpass = attrs[field];
			// in create or update, we are OK with no password, but check length and hash it if it exists
			if (mode === "create" || mode === "update") {
				if (newpass === undefined) {
					valid = true;
				} else if (newpass.length < 8>) {
					valid = {valid:false,message:"password_too_short"};
				} else {
					valid = {valid:true, value: hashPass(newpass)}; // we want it set to "assde232shwsww1323"
				}
			} else {
				// in get or find mode, we accept whatever the password is
				valid = true;
			}
			return(valid);
		}}
	}
}

So if the user sends us:

PUT /user/123 {id:"10",name:"john",password:"poorpw"}		

then the response from the validation function will be {valid:false,message:"password_too_short"}, the update() will fail, and the error passed back to the calling controller and hence function will be "password_too_short".

On the other hand, if the user sends us a good password:

PUT /user/123 {id:"10",name:"john",password:"longerpwisgood"}

Then the response from the validation function will be {valid:true,value:"assde232shwsww1323"}. The final record stored in the database will be:

{id:"10",name:"john",password:"assde232shwsww1323"}

Direct Access

You can directly access the predefined validations as:

var validator = require('booster').validator;

The validator is called with the item to validate and the validation:

validator("abcd","email"); //false
validator("abcd","alphanumeric"); // true

Visibility

Sometimes, you have fields that should always be sent; other times, there are fields that should only be sent to "private" viewers (whatever that means). Other times there are fields that should only be visible on the server and never sent out.

Determining who has the rights to see such fields is the job of authorization; check out cansecurity But the model has to support some knowledge of which fields have which visibility.

By default, when you get() a model object using model.get() or model.find(), it sends you all of the fields. In many cases, that is just fine. But what if you want to be able to filter those fields?

booster provides just this capability using the visible tag in the fields. booster supports three different levels of visibility:

• public: always visible. For example, a username. The default.
• private: visible only to those who should have access (you determine that by your authorization scheme. Did I mention cansecurity ?) For example, a birthday.
• secret: never sent off the server. For example, a password.

Tagging a field as public, private or secret does two things. First, if you filter() it, then you can control it.

user = req.booster.models.user;
user.get("10",function(err,res){
	var allPublic, publicAndPrivate, publicPrivateAndSecret;
	publicAndPrivate = user.filter(res,"private"); // show public and private fields, but not secret
	publicPrivateAndSecret = user.filter(res,"secret"); // show public, private and secret fields - same as res
	allPublic = user.filter(res,"secret"); // show only public fields
});

If I were going to validate a user's password, and then send their info out, I would probably do something like this:

user = req.booster.models.user;
user.get("10",function(err,res){
	var allPublic, publicAndPrivate, publicPrivateAndSecret;
	publicPrivateAndSecret = user.filter(res,"secret"); // show public, private and secret fields - same as res
	if (validatePassword(publicPrivateAndSecret.password,req.param("password"))) {
		// user is now logged in
		// filter out secret information	
		publicAndPrivate = user.filter(res,"private"); // show public and private fields, but not secret
		res.send(200,publicAndPrivate);
	}
});

Second, the default controllers (not the models), filter it, unless you explicitly request it not to, using the query parameter _csview. Just set it to the value you want, e.g. _csview=private will show fields tagged "private" and those tagged "public" (or untagged, which is the same thing), but not those tagged "secret". Not setting _csview (or setting it to _csview=public will show public fields only.

Sending _csview=secret will be ignored!

Controllers:

GET /user/:user // defaults to getting just public or untagged fields
GET /user/:user&_csview=private // returns private and public fields

Models:

req.booster.models.user.get("10",function(err,res){
	// res contains all fields: private, public, secret or untagged
});

presave

Sometimes, you need to do some processing in the model before saving it to the server. For example, if you are saving a reservation for a table, you might want to check that the table actually exists and that no other reservation is in place for that table. You can easily check the existence of another reservation for that table at that time by using unique:

module.exports = {
	fields: {
		// lots of fields here
	},
	unique: [["table","time"]] // makes sure that the combination of table and time is unique
}

How do we do a presave?

module.exports = {
	presave: function(attrs,models,callback) {
		// do whatever processing you need here
	}
}

The signature of a presave function is: function(attrs,models,callback), where:

• attrs: the model you will be saving, a simple JavaScript object
• models: an object with all of the model classes, so you can do searches on other classes. See below.
• callback: the callback you should call back (get it?) when your presave() is done. Classic signature of callback(err,res). If err is anything other than null, undefined or false, the save will not proceed, and the errors will be passed to the callback of the original function that called model.save() or model.update().

Using our above example with tables and reservations, you need to be able to perform a search on table before you can let the reservation go through. Not a problem. Our example skips lots of validations.

module.exports = {
	fields: {id: {required:true}, table: {required:true}, user: {required:true}, time: {required:true}},
	id: "id",
	unique: [["table","time"]], // makes the combination of table and time unique
	presave: function(attrs,models,callback) {
		models.table.get(attrs.table,function(err,res) {
			if (err) {
				callback(err);
			} else if (!res || res.length !== 1){
				// we could not find one matching table, uh oh
				callback("No such table!");
			} else {
				// we had no problems, found exactly one matching table
				callback();
			}
		});
	}
}

Extend

Every model class has a few pre-defined methods (listed in detail in the next section). However, if you want additional custom methods, you can add them here.

Why would you want them? Well, what if you want to do some unique processing, e.g. hashing passwords. You might want to be able to do:

booster.models.user.hashPassword(pass);

Here is an example user.js model file:

module.export = {
	fields: {
		"id":{required:true},
		"name":{required:true},
		"fullname":{required:true},
		"email":{required:true},
		"password":{required:true,visible:"secret"}
	},extend: {
		checkPassword: function (check,valid,callback) {
			bcrypt.compare(check,valid,function (err,res) {
				callback(res);
			});
		},
		hashPass: function (pass,callback) {
			bcrypt.genSalt(WORKFACTOR,function (err,salt) {
				bcrypt.hash(pass,salt,function (err,hash) {
					callback(hash);
				});
			});
		}
	}
};

In the above example, in addition to the usual get, find, create, etc. model functions, you can call booster.models.user.checkPassword("abc","asasqgsqb24h2whsq",callback); and see if "abc" hashes to "asasqgsqb24h2whsq".

Model Methods

No, I don't mean ways to display clothing for photography!

What methods are there on the models themselves? And when would you want to use them? Primarily, you will use them if you define your own controller functions. The model classes, as discussed above, provide all of the validations and unique data checking. Each model class provides several simple methods for persisting the models:

• get: retrieve one object by ID. Signature: get(key,callback)
• find: retrieve one or more objects by search parameters. Signature: find(search,callback)
• update: update replace one or more objects. Signature: update(key,model,callback)
• patch: update without replace one or more objects. Signature: patch(key,model,callback)
• create: create a new object. Signature: create(model,callback)
• destroy: destroy an object. Signature: destroy(key,callback)

You retrieve model classes, if you need them for controllers (but you can always rely on the default), from req.booster.models or your defined booster.models. For example, if you called booster.resource('user'), then the user class is at req.booster.models.user and booster.models.user.

The model will call validations in the following cases:

• get: will validate the single retrieved object, if any, after getting from database
• find: will validate each and every retrieved object, if any, after finding in database
• update: will validate the object prior to sending to the database
• patch: will validate the object prior to sending to the database
• create: will validate the object prior to sending to the database

Callbacks

The signature of every callback is:

callback(err,res);

The err will always be undefined or null if there is no error, and an error message if there is an error. The error message can be a String, Array, Object or anything that might be passed by the underlying database. If the error is due to something built-in, like validations or unique requirements, the error message will follow a very specific pattern. See below.

The res is the returned data. It is generally determined by your underlying db that you passed to booster.init(). However, it is expected to follow a particular pattern:

// get a single item, return a single item
model.get("25",function(err,res){
	// res = {id:"25",name:"john",email:"[email protected]"}
});

// find 0, 1 or more items, return an array
model.find({name:"john"},function(err,res){
	// res = [{id:"25",name:"john",email:"[email protected]"},{id:"30",name:"john",email:"[email protected]"}]
});

// update, create or destroy an item, return the key of the updated item
model.update("25",{name:"jim"},function(err,res){
	// res = "25"
});
model.create({name:"jim"},function(err,res){
	// res = "51"
});
model.destroy("25",function(err,res){
	// res = "25"
});

When validations fail, the callback will contain the error message(s). However, the object itself that failed will still be sent in the response. This should make it far easier to debug.

Errors

When a call to a model method has an error, it returns the error as follows.

• db errors: just passed on as is
• validation errors: see below

Validation Errors

The err fields in the callback for validation errors, depends on how many records were validated, and how many errors on each field.

In general, each record validated will return a single object if there were any validation errors. So:

• If I do a PUT /resource/:resource, which calls update() on a single record, then any validation errors will return a single object.
• If I do a PATCH /resource/:resource, which calls update() on a single record, then any validation errors will return a single object.
• If I do a GET /resource/:resource, which calls get(), which retrieves a single record, then any validation errors will return a single object.
• If I do a POST /resource, which calls create(), which creates a single record, then any validation errors will return a single object.
• If I do a GET /resource, which calls find(), which retrieves one or more records, then any validation errors will return an array of objects, one entry in the array for each failed validation.

And what does the validation error object look like? Simple: each key is a field that field validation; each value is the validation error. For example:

{email:"email",id:"integer",name:"alphanumeric"}

In the above example, you validated a single record, it failed because the email field's value was not a valid email (it failed our predefined email validation), the id field was not a valid integer, and the name field was not a valid alphanumeric.

For another example:

[{email:"email",id:"integer"},{name:"alphanumeric"}]

You validated at least two records, only possible with a GET /resource, two records failed. The first because of invalid email field and invalid id field, the second because of an invalid name field.

OK, so what are the possible values for the messages indicating what was wrong with a particular field?

• single pre-defined validation: if a field failed one pre-defined validation, even if multiple were possible (remember, you could put multiple validations on a field as an array, e.g. {name:["alphanumeric","required"]}), then the value will be the name of the pre-defined validation that failed, e.g. {email:"email",id:"integer"}
• multiple pre-defined validations: if a field failed multiple pre-defined validations, then the value will be an array of the names of the pre-defined validations that failed, e.g. {email:["email","alphanumeric"]}
• validation function: if a field fails one of your validation functions, then it depends what your function returned:
• • it returned a simple false, the message will be "invalid", e.g. {password: "invalid"}
• • it returned an object with valid.valid = false, and valid.message is undefined or null, the message will be "invalid", e.g. {password: "invalid"}
• • it returned an object with valid.valid = false and valid.message is defined and not null, the message will be the value of valid.message, e.g. , e.g. {password: "some_custom_message"}

Just Models?

What if you, for some strange and odd reason (well, it cannot be that odd if we actually had demand to build it in here), you want just the models, but not the paths?

Pretty easy, just do:

booster.model('post');

Done! You get validations, unique checking, all of the fun stuff, but no paths are created.

Persistence

Of course, the thing you want to do most with models is persist them - send them to a database and retrieve them from a database.

So how do you persist? You call the correct methods on the model classes, which in turn call them on your db singleton.

db

The db database object provides the abstraction layer to support any kind of database for persisting your models. Since models are just POJSO, you can send them to the database as they are. Your database driver - that db object you gave to booster when you inited it, is expected to provide the following functionality:

• get: retrieve one object by ID. Signature: get(table,key,callback)
• find: retrieve one or more objects by search parameters. Signature: find(table,search,callback)
• update: update replace one or more objects. Signature: update(table,key,model,callback)
• patch: update without replace one or more objects. Signature: patch(table,key,model,callback)
• create: create a new object. Signature: create(table,model,callback)
• destroy: destroy an object. Signature: destroy(table,key,callback)

Notice that these exactly mirror the functions provided by model classes. This should not be surprising. The model handles all of the validation around the actual data, and delegates the database functions to db.

Some common notes about the signatures:

• table: Every method has a table parameter. This is not necessarily a table name; it could be a database name or anything else. It is a unique string used for all models of this type, taken from the model config. Defaults to the name of the model type, e.g. 'post'.
• callback: Every method has a callback parameter. The signature is in line with most expressjs functions: callback(err,res). If there are errors, they should be passed in the err parameter, else it should be false or null. Data retrieved should be passed as res and should be one of: a JavaScript object; an array of JavaScript objects; null.

get

Get a single object from the database.

get(table,key,callback)

• table: The table for this model. See above.
• key: The unique ID of the model being retrieved.
• callback: The callback for this get(). res in the callback should be a single JavaScript object or null.

Example (couchdb):

get: function(table,key,callback) {
  db.database(prefix+table).get(key,function(err,doc){
    var d1 = [], ret;
    _.each(doc||[],function(elm){
      if (elm && elm.doc !== null && elm.doc !== undefined) {
        d1.push(elm.doc);
      }
    });
    callback(err,d1.length > 0 ? d1[0] : null);
	});
}

Finding 0 objects is not considered an error. If the get was legitimate, and you managed to reach the database and do a search, but found no entry with that key, then you should callback(null,null). err is reserved for errors.

find

Find one or more objects from the database based on search parameters.

find(table,search,callback)

• table: The table for this model. See above.
• search: an object that describes the search.
• callback: The callback for this find(). res in the callback should be an array of JavaScript objects or null.

Example (couchdb):

find: function(table,search,callback) {
	// construct the view from the search
  db.database(prefix+table).view(view,opts,function(err,doc){
    var d1 = [], ret;
    _.each(doc||[],function(elm){
      if (elm && elm.doc !== null && elm.doc !== undefined) {
        d1.push(elm.doc);
      }
    });
    callback(err,d1.length > 0 ? d1 : null);
	});
}

Finding 0 objects is not considered an error. If the get was legitimate, and you managed to reach the database and do a search, but found no entry with that key, then you should callback(null,null) or callback(null,[]). err is reserved for errors.

update

Update with replace (just like HTTP PUT) one object in the database.

update(table,key,model,callback)

• table: The table for this model. See above.
• key: the unique key for the object you are updating
• val: the model to update, as a JavaScript object. By default, will send the entire model.
• callback: The callback for this update(). res in the callback is ignored

Example (couchdb):

update: function(table,key,model,callback) {
	db.database(prefix+table).save(key,model,function(err,res){
		callback(err);
	});
}

Parameters to the callback() should follow the following rules:

1. If there were true errors: callback(err)
2. If the item was updated: callback(null,key). Sending back the key as the data is an indication that the data was updated.
3. If the item was not found, e.g. the key does not point to a valid database record: callback(null,null). Sending back nothing (null or undefined) in the res field indicates that there was nothing found.

patch

Update without replace (just like HTTP PATCH) one object in the database.

patch(table,key,model,callback)

• table: The table for this model. See above.
• key: the unique key for the object you are updating
• val: the model to update, as a JavaScript object
• callback: The callback for this update(). res in the callback is ignored

Example (couchdb):

patch: function(table,key,model,callback) {
	db.database(prefix+table).save(key,model,function(err,res){
		callback(err);
	});
}

Parameters to the callback() should follow the following rules:

1. If there were true errors: callback(err)
2. If the item was updated: callback(null,key). Sending back the key as the data is an indication that the data was updated.
3. If the item was not found, e.g. the key does not point to a valid database record: callback(null,null). Sending back nothing (null or undefined) in the res field indicates that there was nothing found.

create

Create a new object in the database.

create: function(table,val,callback)

• table: The table for this model. See above.
• val: the model data to persist, as a JavaScript object
• callback: The callback for this create(). res should be the ID/key of the newly created object

Example (couchdb):

create: function(table,val,callback) {
  // generate a UUID
  db.uuids(1,function(err,uuid){
    if (err || !uuid.length || uuid.length < 1) {
      callback(err);
    } else {
      key = uuid[0];
      db.database(prefix+table).save(key,val,function(err,res){
        callback(err,key);
      });
    }
  });
}

Parameters to the callback() should follow the following rules:

1. If there was not created due to errors: callback(err)
2. If the item was created: callback(null,key). The newly created key should be sent to indicate success and create a reference.

destroy

Remove an object from the database.

destroy(table,key,extra,callback)

• table: The table for this model. See above.
• key: the key of the object you are destroying
• extra: any extra data you need to perform the destroy. E.g. some doc-oriented databases also require a revision.
• callback: The callback for this destroy(). res will be ignored

Example (couchdb):

destroy: function(table,key,extra,callback) {
  db.database(prefix+table).remove(key,extra,function(err,res){
    callback(err);
  });
}

Parameters to the callback() should follow the following rules:

1. If there were true errors: callback(err)
2. If the item was deleted: callback(null,key). Sending back the key as the data is an indication that the item was removed.
3. If the item was not found, e.g. the key does not point to a valid database record: callback(null,null). Sending back nothing (null or undefined) in the res field indicates that there was nothing found.

Licensing

booster is released under the MIT License http://www.opensource.org/licenses/mit-license.php

Author

Avi Deitcher https://github.com/deitch