loopback/rest.md at 112029556a1a21df0dfcf45098b11ad55b6e9bca

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REST API

The REST API allows clients to interact with the LoopBack models using HTTP. The clients can be a web browser, a JavaScript program, a mobile SDK, a curl script, or anything that can act as an HTTP client.

LoopBack automatically binds a model to a list of HTTP endpoints that provide REST APIs for model instance data manipulations (CRUD) and other remote operations.

We'll use a simple model called Location (locations for rental) to illustrate what REST APIs are exposed by LoopBack.

By default, the REST APIs are mounted to /<pluralFormOfTheModelName>, for example, /locations, to the base URL such as http://localhost:3000/.

CRUD remote methods

For a model backed by a data source that supports CRUD operations, you'll see the following endpoints:

Model.create: POST /locations
Model.upsert: PUT /locations
Model.exists: GET /locations/:id/exists
Model.findById: GET /locations/:id
Model.find: GET /locations
Model.findOne: GET /locations/findOne
Model.deleteById: DELETE /locations/:id
Model.count: GET /locations/count
Model.prototype.updateAttributes: PUT /locations/:id

Custom remote methods

To expose a JavaScript method as REST API, we can simply describe the method as follows:

loopback.remoteMethod(
  Location.nearby,
  {
    description: 'Find nearby locations around the geo point',
    accepts: [
      {arg: 'here', type: 'GeoPoint', required: true, description: 'geo location (lat & lng)'},
      {arg: 'page', type: 'Number', description: 'number of pages (page size=10)'},
      {arg: 'max', type: 'Number', description: 'max distance in miles'}
    ],
    returns: {arg: 'locations', root: true},
    http: {verb: 'POST', path: '/nearby'}
  }
);

The remoting is defined using the following properties:

description: Description of the REST API
accepts: An array of parameters, each parameter has a name, a type, and an optional description
returns: Description of the return value
http: Binding to the HTTP endpoint, including the verb and path

Request Format

For POST and PUT requests, the request body must be JSON, with the Content-Type header set to application/json.

Encode the JSON object as query string

LoopBack uses the syntax from node-querystring to encode JSON objects or arrays as query string. For example,

user[name][first]=John&user[email]=callback@strongloop.com
==>
{ user: { name: { first: 'John' }, email: 'callback@strongloop.com' } }

user[names][]=John&user[names][]=Mary&user[email]=callback@strongloop.com
==>
{ user: { names: ['John', 'Mary'], email: 'callback@strongloop.com' }}

items=a&items=b
==> { items: ['a', 'b'] }

For more examples, please check out node-querystring

Response Format

The response format for all requests is a JSON object or array if present. Some responses have an empty body.

Whether a request succeeded is indicated by the HTTP status code. A 2xx status code indicates success, whereas a 4xx status code indicates request related issues. 5xx status code reports server side problems.

The response for an error is in the following format:

{
"error": {
    "message": "could not find a model with id 1",
    "stack": "Error: could not find a model with id 1\n ...",
    "statusCode": 404
    }
}

###Generated APIs

###create

Create a new instance of the model and persist it into the data source

####Definition

POST /locations

####Arguments

data The model instance data

####Example Request curl -X POST -H "Content-Type:application/json"
-d '{"name": "L1", "street": "107 S B St", "city": "San Mateo", "zipcode": "94401"}'
http://localhost:3000/locations

####Example Response

####Potential Errors

None

###upsert

Update an existing model instance or insert a new one into the data source

####Definition

PUT /locations

####Arguments

data The model instance data

####Example Request curl -X PUT -H "Content-Type:application/json"
-d '{"name": "L1", "street": "107 S B St", "city": "San Mateo", "zipcode": "94401"}'
http://localhost:3000/locations

####Example Response

####Potential Errors

None

###exists

Check whether a model instance exists by id in the data source

####Definition

GET /locations/exists

####Arguments

id The model id

####Example Request curl http://localhost:3000/locations/exists/88

####Example Response

{
    "exists": true
}

####Potential Errors

None

###findById

Find a model instance by id from the data source

####Definition

GET /locations/{id}

####Arguments

id The model id

####Example Request curl http://localhost:3000/locations/88

####Example Response

{
    "id": "88",
    "street": "390 Lang Road",
    "city": "Burlingame",
    "zipcode": 94010,
    "name": "Bay Area Firearms",
    "geo": {
        "lat": 37.5874391,
        "lng": -122.3381437
    }
}

####Potential Errors

None

###find

Find all instances of the model matched by filter from the data source

####Definition

GET /locations

####Arguments

filter The filter that defines where, order, fields, skip, and limit

where Object { key: val, key2: {gt: 'val2'}} The search criteria
- Format: {key: val} or {key: {op: val}}
- Operations:
  - gt: >
  - gte: >=
  - lt: <
  - lte: <=
  - between
  - inq: IN
  - nin: NOT IN
  - neq: !=
  - like: LIKE
  - nlike: NOT LIKE
include String, Object or Array Allows you to load relations of several objects and optimize numbers of requests.
- Format:
  - 'posts': Load posts
  - ['posts', 'passports']: Load posts and passports
  - {'owner': 'posts'}: Load owner and owner's posts
  - {'owner': ['posts', 'passports']}: Load owner, owner's posts, and owner's passports
  - {'owner': [{posts: 'images'}, 'passports']}: Load owner, owner's posts, owner's posts' images, and owner's passports
order String The sorting order
- Format: 'key1 ASC, key2 DESC'
limit Number The maximum number of instances to be returned
skip Number Skip the number of instances
offset Number Alias for skip
fields Object|Array|String The included/excluded fields
['foo'] or 'foo' - include only the foo property
['foo', 'bar'] - include the foo and bar properties
{foo: true} - include only foo
{bat: false} - include all properties, exclude bat

For example,

'/weapons': Weapons
'/weapons/2': A weapon by id
'/weapons?filter[limit]=2&filter[offset]=5': Paginated Weapons
'/weapons?filter[where][name]=M1911': Weapons with name M1911
'/weapons?filter[where][audibleRange][lt]=10': Weapons with audioRange < 10
'/weapons?filter[fields][name]=1&filter[fields][effectiveRange]=1': Only name and effective ranges
'/weapons?filter[where][effectiveRange][gt]=900&filter[limit]=3': The top 3 weapons with a range over 900 meters
'/weapons?filter[order]=audibleRange%20DESC&filter[limit]=3': The loudest 3 weapons
'/locations': Locations
'/locations/nearby?here[lat]=37.587409&here[lng]=-122.338225': Locations nearby
'/locations?filter[where][geo][near]=153.536,-28.1&filter[limit]=3': The 3 closest locations to a given geo point
'/locations/87/inventory': The inventory for store 87

####Example Request curl http://localhost:3000/locations

####Example Response

[
  {
    "id": "87",
    "street": "7153 East Thomas Road",
    "city": "Scottsdale",
    "zipcode": 85251,
    "name": "Phoenix Equipment Rentals",
    "geo": {
      "lat": 33.48034450000001,
      "lng": -111.9271738
    }
  },
  {
    "id": "88",
    "street": "390 Lang Road",
    "city": "Burlingame",
    "zipcode": 94010,
    "name": "Bay Area Firearms",
    "geo": {
      "lat": 37.5874391,
      "lng": -122.3381437
    }
  }
]

####Potential Errors

None

###findOne

Find first instance of the model matched by filter from the data source

####Definition

GET /locations/findOne

####Arguments

filter The filter that defines where, order, fields, skip, and limit. It's same as find's filter argument. Please see find for more details.

####Example Request curl http://localhost:3000/locations/findOne?filter[where][city]=Scottsdale

####Example Response

{
  "id": "87",
  "street": "7153 East Thomas Road",
  "city": "Scottsdale",
  "zipcode": 85251,
  "name": "Phoenix Equipment Rentals",
  "geo": {
    "lat": 33.48034450000001,
    "lng": -111.9271738
  }
}

####Potential Errors

None

###deleteById

Delete a model instance by id from the data source

####Definition

DELETE /locations/{id}

####Arguments

id The model id

####Example Request curl -X DELETE http://localhost:3000/locations/88

####Example Response

####Potential Errors

None

###count

Count instances of the model matched by where from the data source

####Definition

GET /locations/count

####Arguments

where The criteria to match model instances

####Example Request curl http://localhost:3000/locations/count

####Example Response

{
    count: 6
}

####Potential Errors

None

###nearby

Find nearby locations around the geo point

####Definition

GET /locations/nearby

####Arguments

here geo location object with lat and lng properties
page number of pages (page size=10)
max max distance in miles

####Example Request curl http://localhost:3000/locations/nearby?here[lat]=37.587409&here[lng]=-122.338225

####Example Response

[
  {
    "id": "88",
    "street": "390 Lang Road",
    "city": "Burlingame",
    "zipcode": 94010,
    "name": "Bay Area Firearms",
    "geo": {
      "lat": 37.5874391,
      "lng": -122.3381437
    }
  },
  {
    "id": "89",
    "street": "1850 El Camino Real",
    "city": "Menlo Park",
    "zipcode": 94027,
    "name": "Military Weaponry",
    "geo": {
      "lat": 37.459525,
      "lng": -122.194253
    }
  }
]

####Potential Errors

None

###updateAttributes

Update attributes for a model instance and persist it into the data source

####Definition

PUT /locations/{id}

####Arguments

data An object containing property name/value pairs
id The model id

####Example Request curl -X PUT -H "Content-Type:application/json" -d '{"name': "L2"}'
http://localhost:3000/locations/88

####Example Response

####Potential Errors

404 No instance found for the given id

###getInventory

Follow the relations from location to inventory to get a list of inventory items for a given location

####Definition

GET /locations/{id}/inventory

####Arguments

where The search criteria for inventory items
id The id for the location model

####Example Request curl http://localhost:3000/locations/88/inventory

####Example Response

[
  {
    "productId": "2",
    "locationId": "88",
    "available": 10,
    "total": 10
  },
  {
    "productId": "3",
    "locationId": "88",
    "available": 1,
    "total": 1
  }
]

####Potential Errors

None

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REST API

CRUD remote methods

Custom remote methods

Request Format

Encode the JSON object as query string

Response Format

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