golang gin 框架常用案例

一、html渲染

• 使用 LoadHTMLGlob()

• package main
  
  import (
  	"github.com/gin-gonic/gin"
  	"net/http"
  )
  
  func main() {
  	r := gin.Default()
  	r.LoadHTMLGlob("static/templates/*")
  	r.GET("/", func(c *gin.Context) {
  		c.HTML(http.StatusOK, "index.html",
  			gin.H{"title": "golang web"})
  	})
  	r.Run(":8000")
  }
  

• static/templates/index.html
  
  
  
      {{ .title }}
  
  
  

二、表单绑定

• package main
  
  import (
  	"github.com/gin-gonic/gin"
  	"github.com/gin-gonic/gin/binding"
  )
  
  type LoginForm struct {
  	User     string `form:"user" binding:"required"`
  	Password string `form:"password" binding:"required"`
  }
  
  func main() {
  	r := gin.Default()
  	r.POST("/login", func(c *gin.Context) {
  		// 你可以使用显式绑定声明绑定 multipart form：
  		// c.ShouldBindWith(&form, binding.Form)
  		// 或者简单地使用 ShouldBind 方法自动绑定：
  		var form LoginForm
  		// 在这种情况下，将自动选择合适的绑定
  		if c.ShouldBindWith(&form, binding.Form) == nil {
  			if form.User == "user" && form.Password == "password" {
  				c.JSON(200, gin.H{"status": "you are logged in"})
  			} else {
  				c.JSON(401, gin.H{"status": "unauthorized"})
  			}
  		}
  	})
  	r.Run(":8000")
  }
  
  /**
  *   Trying 127.0.0.1:8000...
  * Connected to localhost (127.0.0.1) port 8000 (#0)
  > POST /login HTTP/1.1
  > Host: localhost:8000
  > User-Agent: curl/7.83.1
  > Accept: */*
  > Content-Length: 248
  > Content-Type: multipart/form-data; boundary=------------------------e350eab01c4dd2e0
  >
  * We are completely uploaded and fine
  * Mark bundle as not supporting multiuse
  < HTTP/1.1 200 OK
  < Content-Type: application/json; charset=utf-8
  < Date: Mon, 24 Oct 2022 04:28:05 GMT
  < Content-Length: 30
  <
  {"status":"you are logged in"}* Connection #0 to host localhost left intact
  */
  

三、xml/json/yaml/protobuf渲染

• package main
  
  import (
     "github.com/gin-gonic/gin"
     "github.com/gin-gonic/gin/testdata/protoexample"
     "net/http"
  )
  
  type message struct {
     Code int    `json:"code"`
     Msg  string `json:"msg"`
     Data string `json:"data"`
  }
  
  func main() {
     r := gin.Default()
     r.GET("/json", func(c *gin.Context) {
        c.SecureJSON(200, message{
           Code: 200,
           Msg:  "成功",
           Data: "{\"name\":\"小哥\"}",
        })
     })
     r.GET("/xml", func(c *gin.Context) {
        c.XML(http.StatusOK, gin.H{"message": "xml", "status": http.StatusOK})
     })
  
     r.GET("/yaml", func(c *gin.Context) {
        c.YAML(http.StatusOK, gin.H{"message": "yaml", "status": http.StatusOK})
     })
  
     r.GET("/protobuf", func(c *gin.Context) {
        reps := []int64{int64(1), int64(2)}
        label := "test"
        // protobuf 的具体定义写在 testdata/protoexample 文件中。
        data := &protoexample.Test{
           Label: &label,
           Reps:  reps,
        }
        // 请注意，数据在响应中变为二进制数据
        c.ProtoBuf(http.StatusOK, data)
     })
     r.Run(":8000")
  }
  

四、文件上传

• package main
  
  import (
  	"fmt"
  	"github.com/gin-gonic/gin"
  	"log"
  	"net/http"
  )
  
  func main() {
  	r := gin.Default()
  	r.MaxMultipartMemory = 8 << 20 // 8 MiB
  	r.POST("/upload", func(c *gin.Context) {
  		form, _ := c.MultipartForm()
  		files := form.File["upload[]"]
  
  		for _, file := range files {
  			log.Println(file.Filename)
  			dst := "./" + file.Filename
  			// 上传文件至指定目录
  			c.SaveUploadedFile(file, dst)
  		}
  		c.String(http.StatusOK, fmt.Sprintf("%d files uploaded!", len(files)))
  	})
  	r.Run(":8000")
  
  	/**
  	curl -X POST http://localhost:8000/upload -F "upload[]=@./X_80.png"
  	  -H "Content-Type: multipart/form-data"
  	*/
  }
  
  

五、从reader读取器中读取

• package main
  
  import (
  	"github.com/gin-gonic/gin"
  	"net/http"
  )
  
  func main() {
  	r := gin.Default()
  	r.GET("/someDataFromReader", func(c *gin.Context) {
  		response, err := http.Get("https://www.linuxprobe.com/wp-content/uploads/2022/05/00SLU5M6ZFYOXWK_E2.png")
  		if err != nil || response.StatusCode != http.StatusOK {
  			c.Status(http.StatusServiceUnavailable)
  			return
  		}
  
  		reader := response.Body
  		contentLength := response.ContentLength
  		contentType := response.Header.Get("Content-Type")
  
  		extraHeaders := map[string]string{
  			"Content-Disposition": `attachment; filename="gopher.png"`,
  		}
  
  		c.DataFromReader(http.StatusOK, contentLength, contentType, reader, extraHeaders)
  	})
  	r.Run(":8000")
  }
  
  

六、优雅的关闭服务器

• package main
  
  import (
  	"context"
  	"github.com/gin-gonic/gin"
  	"log"
  	"net/http"
  	"os"
  	"os/signal"
  	"time"
  )
  
  func main() {
  	r := gin.Default()
  	r.GET("/someDataFromReader", func(c *gin.Context) {
  		response, err := http.Get("https://www.linuxprobe.com/wp-content/uploads/2022/05/00SLU5M6ZFYOXWK_E2.png")
  		if err != nil || response.StatusCode != http.StatusOK {
  			c.Status(http.StatusServiceUnavailable)
  			return
  		}
  
  		reader := response.Body
  		contentLength := response.ContentLength
  		contentType := response.Header.Get("Content-Type")
  
  		extraHeaders := map[string]string{
  			"Content-Disposition": `attachment; filename="gopher.png"`,
  		}
  
  		c.DataFromReader(http.StatusOK, contentLength, contentType, reader, extraHeaders)
  	})
  	//r.Run(":8000")
  	serve := &http.Server{
  		Addr:    ":8000",
  		Handler: r,
  	}
  	go func() {
  		if err := serve.ListenAndServe(); err != nil {
  			log.Fatalf("listen:%s\n", err)
  		}
  	}()
  	q := make(chan os.Signal)
  	signal.Notify(q, os.Interrupt, os.Kill)
  	<-q
  	log.Println("server shutdown...")
  	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
  	defer cancel()
  	if err := serve.Shutdown(ctx); err != nil {
  		log.Fatalf("server shutdown:%s",err)
  	}
  	
  
  }
  
  

七、使用http restful 风格

• package main
  
  import (
  	"github.com/gin-gonic/gin"
  	"net/http"
  )
  
  type message struct {
  	Code int 
  	Msg string
  	Data string
  }
  func main() {
  	r := gin.Default()
  	r.GET("/get", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.POST("/post", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.PUT("/put", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.DELETE("/delete", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.PATCH("/patch", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.HEAD("/head", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.OPTIONS("/option", func(c *gin.Context) {
  		c.JSON(http.StatusOK,message{
  			Code: 200,
  			Msg:  "成功",
  			Data: "data ",
  		})
  	})
  	r.Run(":8000")
  
  }