apig is an RESTful API server generator.

• Input: Model definitions based on gorm annotated struct
• Output: RESTful JSON API server using gin including tests and documents

• Contents
• How to build and install
• How to use
  • 1. Generate boilerplate
  • 2. Write model code
  • 3. Generate controllers, tests, documents etc. based on models.
  • 4. Build and run server
• Usage
  • new command
  • gen command
  • API Document
• API server specification
  • Endpoints
  • Available URL parameters
  • Data Type
  • Pagination
  • Versioning
• License

Go 1.6 or higher is required.

After installing required version of Go, you can build and install apig by

$ go get -d -u github.com/wantedly/apig
$ cd $GOPATH/src/github.com/wantedly/apig
$ make
$ make install

make generates binary into bin/apig. make install put it to $GOPATH/bin.

First, creating by apig new command.

$ apig new -u wantedly apig-sample

generates Golang API server boilerplate under $GOPATH/src/gihhub.com/wantedly/apig-sample. apig supports two database engines; SQLite (sqlite) and PostgreSQL (postgres). You can specify this by -d, -database option.

Available command line options of apig new command are:

Second, write model definitions under models/. For example, user and email model is like below:

// models/user.go
package models

import "time"

type User struct {
	ID        uint       `gorm:"primary_key;AUTO_INCREMENT" json:"id" form:"id"`
	Name      string     `json:"name" form:"name"`
	Emails    []Email    `json:"emails" form:"emails"`
	CreatedAt *time.Time `json:"created_at" form:"created_at"`
	UpdatedAt *time.Time `json:"updated_at" form:"updated_at"`
}

// models/email.go
package models

type Email struct {
	ID      uint   `gorm:"primary_key;AUTO_INCREMENT" json:"id" form:"id"`
	UserID  uint   `json:"user_id" form:"user_id"`
	Address string `json:"address" form:"address"`
	User    *User  `json:"user form:"user`
}

This models are based on gorm structure. Please refer gorm document to write detailed models.

Third, run the command:

apig gen

It creates all necessary codes to provide RESTful endpoints of models.

Finally, just build as normal go code.

$ go get ./...
$ go build -o bin/server

After that just execute the server binary. For the first time, you may want to use AUTOMIGRATE=1 when running the server.

$ AUTOMIGRATE=1 bin/server

When AUTOMIGRATE=1, the db tables are generated automatically. After that, you can run the server just executing the command:

$ bin/server

The server runs at http://localhost:8080.

By default, use the port 8080. If you change the port, set environment variables.

$ PORT=3000 bin/server

The server runs at http://localhost:3000.

new command tells apig to generate API server skeleton.

$ apig new NAME

gen command tells apig to generate files (routes, controllers, documents...) from gorm model files you wrote.

You MUST run this command at the directory which was generated by new command.

$ apig gen

API Documents are generated automatically in docs/ directory in the form of API Blueprint.

docs
├── email.apib
├── index.apib
└── user.apib

Aglio is an API Blueprint renderer. Aglio can be installed by

$ npm install -g aglio

You can generate HTML files and run live preview server.

// html file
$ aglio -i index.apib  -o index.html

// running server on localhost:3000
$ aglio -i index.apib --server

index.apib includes other files in your blueprint.

Each resource has 5 RESTful API endpoints. Resource name is written in the plural form.

API server accepts the form of JSON or Form.

application/json

curl -X POST http://localhost:8080/resources \
     -H "Content-type: application/json" \
     -d '{"field":"value"}'

application/x-www-form-urlencoded

curl -X POST http://localhost:8080/users \
     -d 'field=value'

multipart/form-data

curl -X POST http://localhost:8080/users \
     -F 'field=value'

Response data type is always application/json.

API server supports 2 pagination types.

Retrieve items by specifying page number and the number of items per page.

For example:

http://example.com/api/users?limit=5&page=2

+---------+---------+---------+---------+---------+---------+---------+
| ID: 5   | ID: 6   | ID: 7   | ID: 8   | ID: 9   | ID: 10  | ID: 11  |
+---------+---------+---------+---------+---------+---------+---------+
          |                                                 |
 Page 1 ->|<-------------------- Page 2 ------------------->|<- Page 3

Response header includes Link header.

Link:   <http://example.com/api/users?limit=5&page=3>; rel="next",
        <http://example.com/api/users?limit=5&page=1>; rel="prev"

Retrieve items by specifying range from a certain point.

For example:

http://example.com/api/users?limit=5&last_id=100&order=desc

+---------+---------+---------+---------+---------+---------+---------+
| ID: 94  | ID: 95  | ID: 96  | ID: 97  | ID: 98  | ID: 99  | ID: 100 |
+---------+---------+---------+---------+---------+---------+---------+
          |               5 items (ID < 100)                |
          |<------------------------------------------------|

Response header includes Link header.

Link:   <http://example.com/api/users?limit=5&last_id=95&order=desc>; rel="next"

API server uses Semantic Versioning for API versioning.

There are 2 methods to specify API version.

Generally we recommend to include API version in Accept header.

Accept: application/json; version=1.0.0

You can also include API version in URL parameter. This is userful for debug on browser or temporary use,

http://example.com/api/users?v=1.0.0

This method is prior to request header method.