Getting started

Install JSON Server

npm install -g json-server

Create a db.json file with some data

{
  "posts": [
    { "id": 1, "title": "mock json", "author": "typicode" }
  ],
  "comments": [
    { "id": 1, "body": "some comment", "postId": 1 }
  ],
  "profile": { "name": "typicode" }
}

Start JSON Server

emo --watch db.json

Start websocket server

 emo db.json --ws 

  const ws = new WebSocket('ws://localhost:4000/io')
  ws.onopen = function(evt) { 
    console.log("Connection open ..."); 
    ws.send("Hello WebSockets!");
  };

  ws.onmessage = function(evt) {
    console.log( "Received Message: " + evt.data);
    // ws.close();
  };

  ws.onclose = function(evt) {
    console.log("Connection closed.");
  }; 

  const handleSend = () => { // quick feedback
    ws.send(JSON.stringify({
      userResponse: 'FEEDBACK'
    }));
  }

Now if you go to http://localhost:3000/posts/1, you'll get

{ "id": 1, "title": "mock-server", "author": "code" }

Also when doing requests, it's good to know that:

• If you make POST, PUT, PATCH or DELETE requests, changes will be automatically and safely saved to db.json using lowdb.
• Your request body JSON should be object enclosed, just like the GET output. (for example {"name": "Foobar"})
• Id values are not mutable. Any id value in the body of your PUT or PATCH request will be ignored. Only a value set in a POST request will be respected, but only if not already taken.
• A POST, PUT or PATCH request should include a Content-Type: application/json header to use the JSON in the request body. Otherwise it will return a 2XX status code, but without changes being made to the data.

Routes

Based on the previous db.json file, here are all the default routes. You can also add other routes using --routes.

Plural routes

GET    /posts
GET    /posts/1
POST   /posts
PUT    /posts/1
PATCH  /posts/1
DELETE /posts/1

Singular routes

GET    /profile
POST   /profile
PUT    /profile
PATCH  /profile

Filter

Use . to access deep properties

GET /posts?title=json-server&author=typicode
GET /posts?id=1&id=2
GET /comments?author.name=typicode

Paginate

Use _page and optionally _limit to paginate returned data.

In the Link header you'll get first, prev, next and last links.

GET /posts?_page=7
GET /posts?_page=7&_limit=20

10 items are returned by default

Sort

Add _sort and _order (ascending order by default)

GET /posts?_sort=views&_order=asc
GET /posts/1/comments?_sort=votes&_order=asc

For multiple fields, use the following format:

GET /posts?_sort=user,views&_order=desc,asc

Slice

Add _start and _end or _limit (an X-Total-Count header is included in the response)

GET /posts?_start=20&_end=30
GET /posts/1/comments?_start=20&_end=30
GET /posts/1/comments?_start=20&_limit=10

Works exactly as Array.slice (i.e. _start is inclusive and _end exclusive)

Operators

Add _gte or _lte for getting a range

GET /posts?views_gte=10&views_lte=20

Add _ne to exclude a value

GET /posts?id_ne=1

Add _like to filter (RegExp supported)

GET /posts?title_like=server

Full-text search

Add q

GET /posts?q=internet

Relationships

To include children resources, add _embed

GET /posts?_embed=comments
GET /posts/1?_embed=comments

To include parent resource, add _expand

GET /comments?_expand=post
GET /comments/1?_expand=post

To get or create nested resources (by default one level, add custom routes for more)

GET  /posts/1/comments
POST /posts/1/comments

Database

GET /db

Homepage

Returns default index file or serves ./public directory

GET /

Extras

Add custom routes

Create a routes.json file. Pay attention to start every route with /.

{
  "/api/*": "/$1",
  "/:resource/:id/show": "/:resource/:id",
  "/posts/:category": "/posts?category=:category",
  "/articles?id=:id": "/posts/:id"
}

Start JSON Server with --routes option.

emo db.json --routes routes.json

Now you can access resources using additional routes.

/api/posts # → /posts
/api/posts/1  # → /posts/1
/posts/1/show # → /posts/1
/posts/javascript # → /posts?category=javascript
/articles?id=1 # → /posts/1

Add middlewares

You can add your middlewares from the CLI using --middlewares option:

// hello.js
module.exports = (req, res, next) => {
  res.header('X-Hello', 'World')
  next()
}

emo db.json --middlewares ./hello.js
emo db.json --middlewares ./first.js ./second.js

CLI usage

emo [options] <source>

Options:
  --port, -p         Set port                                    [default: 3000]
  --host, -H         Set host                             [default: "localhost"]
  --watch, -w        Watch file(s)                                     [boolean]
  --routes, -r       Path to routes file
  --middlewares, -m  Paths to middleware files                           [array]
  --static, -s       Set static files directory
  --read-only, --ro  Allow only GET requests                           [boolean]
  --no-cors, --nc    Disable Cross-Origin Resource Sharing             [boolean]
  --no-gzip, --ng    Disable GZIP Content-Encoding                     [boolean]
  --snapshots, -S    Set snapshots directory                      [default: "."]
  --delay, -d        Add delay to responses (ms)
  --id, -i           Set database id property (e.g. _id)         [default: "id"]
  --foreignKeySuffix, --fks  Set foreign key suffix, (e.g. _id as in post_id)
                                                                 [default: "Id"]
  --quiet, -q        Suppress log messages from output                 [boolean]
  --help, -h         Show help                                         [boolean]
  --version, -v      Show version number                               [boolean]

Examples:
  emo db.json
  emo file.js
  emo http://example.com/db.json

Config

可通过配置修改的变量 emo c ls 展示配置 emo c set key value 修改变量配置

{
  res: '{"code": 0, "data": null}', // 等同于result: '{"code": 0, "data": null}'
  q: 'q',
  _start: "_start",
  _end: "_end",
  _page: "_page",
  _sort: "_sort",
  _order: "_order",
  _limit: "_limit",
  _embed: "_embed",
  _expand: "_expand",
  listKey: "list",
  totaKey: "total"
}