Swagger + Gin = SwaGin

If you use Fiber, you can try my another similar project Fibers.

Introduction

SwaGin is a web framework based on Gin and Swagger, which wraps Gin and provides built-in swagger api docs and request model validation.

Why I build this project?

Previous I have used FastAPI, which gives me a great experience in api docs generation, because nobody like writing api docs.

Now I use Gin but I can't found anything like that, I found swag but which write docs with comment is so stupid. So there is SwaGin.

Installation

go get -u github.com/long2ice/swagin

Online Demo

You can see online demo at https://swagin.long2ice.io/docs or https://swagin.long2ice.io/redoc.

And you can reference all usage in examples.

Usage

Build Swagger

Firstly, build a swagger object with basic information.

package examples

import (
  "github.com/getkin/kin-openapi/openapi3"
  "github.com/long2ice/swagin/swagger"
)

func NewSwagger() *swagger.Swagger {
  return swagger.New("SwaGin", "Swagger + Gin = SwaGin", "0.1.0",
    swagger.License(&openapi3.License{
      Name: "Apache License 2.0",
      URL:  "https://github.com/long2ice/swagin/blob/dev/LICENSE",
    }),
    swagger.Contact(&openapi3.Contact{
      Name:  "long2ice",
      URL:   "https://github.com/long2ice",
      Email: "[email protected]",
    }),
    swagger.TermsOfService("https://github.com/long2ice"),
  )
}

Write API

Then write a router function.

package examples

type TestQuery struct {
  Name string `query:"name" validate:"required" json:"name" description:"name of model" default:"test"`
}

func TestQuery(c *gin.Context, req TestQueryReq) error {
  return c.JSON(req)
}

// TestQueryNoReq if there is no req body and query
func TestQueryNoReq(c *gin.Context) {
  c.JSON(http.StatusOK, "{}")
}

Note that the attributes in TestQuery? SwaGin will validate request and inject it automatically, then you can use it in handler easily.

Write Router

Then write router with some docs configuration and api.

package examples

var query = router.New(
  TestQuery,
  router.Summary("Test Query"),
  router.Description("Test Query Model"),
  router.Tags("Test"),
)

// if there is no req body, you need use router.NewX
var query = router.NewX(
  TestQueryNoReq,
  router.Summary("Test Query"),
  router.Description("Test Query Model"),
  router.Tags("Test"),
)

Security

If you want to project your api with a security policy, you can use security, also they will be shown in swagger docs.

Current there is five kinds of security policies.

• Basic
• Bearer
• ApiKey
• OpenID
• OAuth2

package main

var query = router.New(
  TestQuery,
  router.Summary("Test query"),
  router.Description("Test query model"),
  router.Security(&security.Basic{}),
)

Then you can get the authentication string by context.MustGet(security.Credentials) depending on your auth type.

package main

func TestQuery(c *gin.Context) {
  user := c.MustGet(security.Credentials).(*security.User)
  fmt.Println(user)
  c.JSON(http.StatusOK, t)
}

Mount Router

Then you can mount router in your application or group.

package main

func main() {
  app := swagin.New(NewSwagger())
  queryGroup := app.Group("/query", swagin.Tags("Query"))
  queryGroup.GET("", query)
  queryGroup.GET("/:id", queryPath)
  queryGroup.DELETE("", query)
  app.GET("/noModel", noModel)
}

Start APP

Finally, start the application with routes defined.

package main

import (
  "github.com/gin-contrib/cors"
  "github.com/long2ice/swagin"
)

func main() {
  app := swagin.New(NewSwagger())
  app.Use(cors.New(cors.Config{
    AllowOrigins:     []string{"*"},
    AllowMethods:     []string{"*"},
    AllowHeaders:     []string{"*"},
    AllowCredentials: true,
  }))

  queryGroup := app.Group("/query", swagin.Tags("Query"))
  queryGroup.GET("", query)
  queryGroup.GET("/:id", queryPath)
  queryGroup.DELETE("", query)

  formGroup := app.Group("/form", swagin.Tags("Form"))
  formGroup.POST("/encoded", formEncode)
  formGroup.PUT("", body)

  app.GET("/noModel", noModel)
  app.POST("/body", body)
  if err := app.Run(); err != nil {
    panic(err)
  }
}

That's all! Now you can visit http://127.0.0.1:8080/docs or http://127.0.0.1:8080/redoc to see the api docs. Have fun!

Disable Docs

In some cases you may want to disable docs such as in production, just put nil to swagin.New.

app = swagin.New(nil)

SubAPP Mount

If you want to use sub application, you can mount another SwaGin instance to main application, and their swagger docs is also separate.

package main

func main() {
  app := swagin.New(NewSwagger())
  subApp := swagin.New(NewSwagger())
  subApp.GET("/noModel", noModel)
  app.Mount("/sub", subApp)
}

ThanksTo

• kin-openapi, OpenAPI 3.0 implementation for Go (parsing, converting, validation, and more).
• Gin, an HTTP web framework written in Go (Golang).

License

This project is licensed under the Apache-2.0 License.