baucis

baucis v0.5.8

Baucis is Express middleware that creates configurable REST APIs using Mongoose schemata.

Like Baucis and Philemon of old, this library provides REST to the weary traveler. The goal is to create a JSON REST API for Mongoose & Express that matches as closely as possible the richness and versatility of the HTTP 1.1 protocol.

Baucis uses semver.

David Rijckaert - Philemon and Baucis Giving Hospitality to Jupiter and Mercury

Usage

To install:

npm install baucis

An example of creating a REST API from a couple Mongoose schemata:

var Vegetable = new mongoose.Schema({ name: String });
var Fruit = new mongoose.Schema({ name: String });

// Note that Mongoose middleware will be executed as usual
Vegetable.pre('save', function () { ... });

// Register the schemata
mongoose.model('vegetable', Vegetable);
mongoose.model('fruit', Fruit);

// Create the API routes
baucis.rest('vegetable');
baucis.rest('fruit');

// Create the app and listen for API requests
var app = express();
app.use('/api/v1', baucis());
app.listen(80);

Later, make requests:

HTTP Verb	/vegetables	/vegetables/:id
GET	Get all or a subset of documents	Get the addressed document
POST	Creates new documents and sends them back. You may post a single document or an array of documents.	n/a
PUT	n/a	Update the addressed document
DELETE	Delete all or a subset of documents	Delete the addressed object

HTTP Headers

Header Field	Notes
ETag	Used for HTTP caching based on response body. Supported out-of-the-box by Express.
Last-Modified	Used for HTTP caching. Can be set automatically by Baucis. Pass lastModified: 'foo' to baucis.rest in order to set the path to be used (currently it must be a Date). GET requests to the collection set this to the latest date out of all documents returned by the query.
Accept	Set to application/json for all responses.
Allow	Set automatically, correctly removing HTTP verbs when those verbs have been disabled by e.g. passing put: false to baucis.rest. Example: Allow: HEAD, GET, POST.
Location	Set to the URL of the created/edited entity for PUT and POST responses.
Link	If relations: true is passed to baucis.rest, this header will be set with various related links for all responses. As of v0.5.4, first, last, next, and previous links are added when paging through a collection with limit/skip.

Examples

• Example REST API server built with Node and Baucis
• Examples with Backbone
• Examples with jQuery

Query Options

Name	Description
conditions	Set the Mongoose query's find or remove arguments
skip	Don't send the first n matched documents in the response
limit	Limit the response document count to n
select	Set which fields should be selected for response documents
sort	Sort response documents by the given criteria. sort: 'foo -bar'' sorts the collection by foo in ascending order, then by bar in descending order.
populate	Set which fields should be populated for response documents. See the Mongoose population documentation for more information.

It is not permitted to use the select query option or the select option of populate with a +path. This is to allow a mechanism for hiding fields from client software.

You can deselect paths in the schema definition using select: false or in the controller options using select: '-foo' and your server middleware will able to select these fields as usual using query.select, while preventing the client from selecting the field.

baucis.rest

baucis.rest returns an instance of the controller created to handle the schema's API routes.

var controller = baucis.rest({ ... });

For simple controllers, only the schema name need be passed.

var controller = baucis.rest('robot');

Controllers are Express apps; they may be used as such.

var controller = baucis.rest('robot');

// Add middleware before API routes
controller.use('/qux', function (request, response, next) {
  // Do something cool…
  next();
});

controller.get('/readme', function (request, response, next) {
  // Send a readme document about the resource (for example)
  next();
});

// Do other stuff...
controller.set('some option name', 'value');
controller.listen(3000);

Customize them with plain old Express/Connect middleware, including pre-existing modules like passport. Middleware can be registered like so:

controller.request(function (request, response, next) {
  if (request.isAuthenticated()) return next();
  return response.send(401);
});

Baucis adds middleware registration functions for three stages of the request cycle:

Name	Description
request	This stage of middleware will be called after baucis applies defaults based on the request, but before the Mongoose query is generated
query	This stage of middleware will be called after baucis applies defaults to the Mongoose query object, but before the documents or count are retrieved from the database. The query can be accessed in your custom middleware via request.baucis.query. Query middleware cannot be added explicitly for POST and will be ignored when added for POST implicitly.
documents	This stage of middleware will be called after baucis executes the query, but before the documents or count are sent in the response. The documents/count can be accessed in your custom middleware via request.baucis.documents.

Each of these functions has three forms:

To apply middleware to all API routes, just pass the function or array to the method for the appropriate stage:

controller.request(function (request, response, next) {
  if (request.isAuthenticated()) return next();
  return response.send(401);
});

controller.documents(function (request, response, next) {
  if (typeof request.baucis.documents === 'number') return next();
  if (!Array.isArray(request.baucis.documents)) return next();

  request.baucis.documents.pop();
  next();
});

To add middleware that applies only to specific HTTP verbs, use the second form. It adds a paramater that must contain a space-delimted list of HTTP verbs that the middleware should be applied to.

controller.query('head get put', function (request, response, next) {
  request.baucis.query.sort('-created');
  next();
});

The final form is the most specific. The first argument lets you specify whether the middleware applies to document instances (paths like /foos/:id) or to collection requests (paths like /foos).

controller.request('instance', 'head get del', middleware);
controller.request('collection', 'post', middleware);

Controller Options

Name	Description
singular	The name of the schema, as registered with mongoose.model.
plural	This will be set automatically using the lingo module, but may be overridden by passing it into baucis.rest.
basePath	Defaults to /. Used for embedding a controller in another controller.
publish	Set to false to not publish the controller's endpoints when baucis() is called.
select	Select or deselect fields for all queries e.g. 'foo +bar -password'
findBy	Use another field besides _id for entity queries.
lastModified	Set the Last-Modified HTTP header using the given field. Currently this field must be a Date.
head, get, post, put, del	May be set to false to disable those HTTP verbs completely for the controller

An example of embedding a controller within another controller

var subcontroller = baucis.rest({
  singular: 'bar',
  basePath: '/:fooId/bars',
  publish: false
});

subcontroller.query(function (request, response, next) {
  // Only retrieve bars that are children of the given foo
  request.baucis.query.where('parent', request.params.fooId);
  next();
});

// Didn't publish, so have to manually initialize
subcontroller.initialize();

var controller = baucis.rest('foo');

// Embed the subcontroller at /foos/:fooId/bars
controller.use(subcontroller);

Contact

• http://kun.io/
• @wprl

© 2012-2013 William P. Riley-Land