golang (10): web connection database & Development

http Programming

1 ) Go native support http: Import ( " NET / http " )
 2 ) Go's http service performance and nginx closer to
 3 ) a few lines of code to implement a web service

http server

// sample code: 
Package main 

Import ( 
    " FMT " 
    " NET / HTTP " 
) 

FUNC the Hello (http.ResponseWriter W, R & lt * http.Request) { 
    fmt.Println ( " Hello World \ n- " ) 
    fmt.Fprintf (W, " Hello World " )     // returns the response 
} 


FUNC main () { 
    http.HandleFunc ( " / " , the Hello)         // route; first parameter is the path, the second argument is the view function 
    err: = http.ListenAndServe ( " 0.0.0.0:8080 " , nil)         //Listens and waits for requests 
    IF ERR! = Nil { 
        fmt.Println ( " HTTP Listened failed " ) 
    } 
}

http client

// sample code: 
Package main 

Import ( 
    " FMT " 
    " NET / HTTP " 
    " IO / ioutil " 
) 

FUNC main () { 
    RET, ERR: = http.Get ( " https://www.baidu.com/ " )     // send GET request to a server; data returned in ret.Body inside 
    IF ERR =! nil { 
        fmt.Println ( " GET ERR: " , ERR)
         return 
    } 

    data, ERR: = ioutil.ReadAll (ret.Body )     // returned data are ret.Body inside 
    IF ERR! =  nil {
        fmt.Println ("get data err:",err)
        return
    }

    fmt.Printf("Type:%T\n",data)
    fmt.Println(string(data))
}


// 运行结果：
[root@NEO example01_http_client]# go run main/main.go
Type:[]uint8
<html>
<head>
    <script>
        location.replace(location.href.replace("https://","http://"));
    </script>
</head>
<body>
    <noscript><meta http-equiv="refresh" content="0;url=http://www.baidu.com/"></noscript>
</body>
</html>
[root@NEO example01_http_client]#

http common request methods

. 1 ) the Get Request
 2 ) Post request
 . 3 ) of Put request
 . 4 ) the Delete request
 . 5 ) Head Request -> Request header page only

Sends a HEAD request

// 示例代码：
package main

import (
    "fmt"
    "net/http"
)

var urls = []string{
    "http://www.baidu.com",
    "http://www.google.com",
    "http://www.taobao.com",
}

func main(){
    for _,v := range urls{
        resp,err := http.Head(v)    // 发送 Head 请求
        if err != nil {
            fmt.Printf("head %s failed,err:%v\n",v,err)
            continue
        }
        fmt.Printf("head success,status:%v\n",resp.Status)        // resp.Status --> 状态码
    }
}

// 运行结果：
[root@NEO example01_http_head_request]# go run main/main.go
head success,status:200 OK
head http://www.google.com failed,err:Head http://www.google.com: dial tcp 75.126.2.43:80: connect: connection timed out
head success,status:200 OK
[root@NEO example01_http_head_request]# 


// 自定义超时时间
// 示例代码：
package main

import (
    "fmt"
    "net/http"
    "time"
    "net"
)

var urls = []string{
    "http://www.baidu.com",
    "http://www.google.com",
    "http://www.taobao.com",
}

func main(){
    for _,v := range urls{
        c := http.Client{        // 自定义客户端
            Transport: &http.Transport{
                The Dial: FUNC (Network, addr String ) (net.Conn, error) { 
                    timeout: = time.Second * 2         // custom timeout 
                    return net.DialTimeout (Network, addr, timeout) 
                }, 
            }, 
        }     

        Start: = Time.now () 
        RESP, ERR: = c.Head (V)     // with defined from the client sends a request 
        end: = Time.now () 
        interval the: = end.Sub (Start) 
        fmt.Println ( " interval the: " , interval The)
         // RESP, ERR: = http.Head (v)    // send request Head 
        IF ERR =! Nil { 
            fmt.Printf ( " head% S failed, ERR: V% \ n- " , V, ERR)
             Continue 
        } 
        fmt.Printf ( " head Success, Status:% V \ n- " , resp.Status)         // resp.Status -> status code 
    } 
} 


// run results: 
[@ NEO example01_http_head_request the root] # Go main rUN / main.go 
interval The: 171 is .062376ms 
head Success, status: 200 is the OK 
interval The: 2 .000789206s 
head HTTP: //www.google.com failed,err:Head http://www.google.com: dial tcp 69.63.184.142:80: i/o timeout
interval: 749.542763ms
head success,status:200 OK
[root@NEO example01_http_head_request]#

http common status codes:

http.StatusContinue = 100
http.StatusOK = 200
http.StatusFound = 302
http.StatusBadRequest = 400
http.StatusUnauthorized = 401
http.StatusForbidden = 403
http.StatusNotFound = 404
http.StatusInternalServerError = 500

Form processing:

// 示例代码：
package main
import (
    "io"
    "net/http"
)


// 常量 form 是一段 html 代码
const form = `<html><body><form action="#" method="post" name="bar">
                    <input type="text" name="in"/>
                    <input type="text" name="in"/>
                     <input type="submit" value="Submit"/>
             </form></html></body>`

func SimpleServer(w http.ResponseWriter, request *http.Request) {        // 请求信息都在 request 中
    io.WriteString(w, "<h1>hello, world</h1>")        // 返回给客户端一段html代码
}

func FormServer(w http.ResponseWriter, request *http.Request) {
    w.Header().Set("Content-Type", "text/html")            // w.Head (). Set (key, val) ---> Set response header
    Switch request.method {                                 // request.method -> Request Method 
    Case  " the GET " : 
        io.WriteString (W, form)             // the return form form to the client 
    Case  " the POST " : 
        request.ParseForm ()         // required to parse form 
        io.WriteString (W, request.Form [ " in " ] [ 0 ])         // request.Form [ "in"] is an array 
        io.WriteString (W, " \ n- " )
        io.WriteString (W, request.FormValue ( " in " ))         // request.FormValue ( "in") ---> Get values in the form (name when repeated, rounded to the nearest a); this recommended 
    } 
} 
main FUNC () { 
    http.HandleFunc ( " / test1 " , SimpleServer) 
    http.HandleFunc ( " / test2 " , FormServer)
     IF ERR: = http.ListenAndServe ( " : 8088 " !, nil); ERR = nil { 
    } 
}

golang (10): web connection database & Development

http Programming

Guess you like