golang Network framework gin usage

golang native http library can easily implement 1 http server, but for complex web services, routing resolution, request parameter resolution, object return, etc., native api is not enough, and gin is a fully functional, high performance web network framework, especially suitable for the development of web api

hello world

package main

import "github.com/gin-gonic/gin"

func main() {
  r := gin.New()
  r.GET("/ping", func(c *gin.Context) {
    c.String(200, "hello world")
  })
  r.Run() // listen and serve on 0.0.0.0:8080
}

All of gin's business logic is implemented in the func(c * gin.Context) function as shown in this hello world program, through which requests and returns are passed

Request parameter resolution

gin provides a rich way to get request parameters

(c *Context) Query(key string) string        //  To obtain  GET  parameter 
(c *Context) QueryArray(key string) []string    //  To obtain  GET  Parameters of the array 
(c *Context) DefaultQuery(key, defaultValue string) //  To obtain  GET  Parameter and provide a default value 
(c *Context) Param(key string) string        //  To obtain  Param  Parameters, similar to  "/user/:id"
(c *Context) GetRawData() ([]byte, error)      //  To obtain  body  data 

I don't recommend using any of these functions. I recommend using a structure to describe the request and using bind api to get the request parameters directly

type HelloWorldReq struct {
  Token  string `json:"token"`
  ID    int  `json:"id" uri:"id"`
  Email  string `json:"email" form:"email"`
  Password string `json:"password" form:"password"`
}

req := &HelloWorldReq{
  Token: c.GetHeader("Authorization"),  //  Header field cannot  bind Can be passed  GetHeader  To obtain 
}

//  In the request  Param  Parameter fills in the structure  uri  field 
if err := c.BindUri(req); err != nil {
  return nil, nil, http.StatusBadRequest, fmt.Errorf("bind uri failed. err: [%v]", err)
}

// GET  Request in  Query  Parameters of the filling  form  field 
//  non  GET  The request will be  body  In the  json  or  xml  Deserialize and populate  form  field 
if err := c.Bind(req); err != nil {
  return nil, nil, http.StatusBadRequest, fmt.Errorf("bind failed. err: [%v]", err)
}

http client ip 1 generally in the request header X-ES44en-ES45en and ES46en-ES47en-ES48en, gin provides (c *Context) ClientIP() string to obtain ip

Returns the inclusions

(c *Context) String(code int, format string, values ...interface{}) //  return 1 A string 
(c *Context) JSON(code int, obj interface{})            //  return 1 a  json
(c *Context) Status(code int)                    //  return 1 A status code 

File upload and return

Gets the file from the request

fh, err := ctx.FormFile("file")
if err != nil {
  return err
}

src, err := fh.Open()
if err != nil {
  return err
}
defer src.Close()

Returns the file

(c *Context) File(filepath string)

cros cross-domain

Server returns a field in the head "Access - Control - Allow - Origin", if the fields and request the domain is different, the browser will be browser refused, in fact, the place I understand should be no access to the client, the server should not return a result, the browser that the result is not available, so prompt cross-domain error, but the header fields also can write an address, or write *, is open to all sites, want to multiple website development, we can according to the request of "Origin" field, Dynamically set the "ES79en-ES80en-ES81en-ES82en" field to satisfy the permission to set the "Origin" field in the request, gin has a plug-in github. com/ gin-ES88en /cors is designed to do this, you can set multiple websites in AllowOrigins, you can also set the wildcard (to set AllowWildcard as true)

import "github.com/gin-contrib/cors"

r := gin.New()
r.Use(cors.New(cors.Config{
  AllowOrigins:   []string{"a.example.com", "b.example.com"},
  AllowMethods:   []string{"PUT", "POST", "GET", "OPTIONS"},
  AllowHeaders:   []string{"Origin", "Content-Type", "Content-Length", "Accept-Encoding", "X-CSRF-Token", "Authorization", "Accept", "Cache-Control", "X-Requested-With"},
  AllowCredentials: true,
}))

cookies

// maxAge  Is the expiration time 
// domain  Is the address of a website, if Shared across domains  cookie , can be set to a domain name, 
//    Such as  a.example.com  and  b.example.com That can be  domain  Set to  example.com
// secure  for  https  Set to  true . http  Set to  false
// httpOnly  Set to  false , otherwise,  axios  Is not available  cookie
(c *Context) SetCookie(name, value string, maxAge int, path, domain string, secure, httpOnly bool)

In addition, axios needs to be set to withCredentials: true cookie to return normally

link

github address: https: / / github com/gin - gonic/gin
Code examples: https: / / github com hpifu/tpl go -- http