Go语言系列- http编程和mysql

http编程

一、Http协议

1. 什么是协议？

　　协议，是指通信的双方，在通信流程或内容格式上，共同遵守的标准。

2. 什么是http协议？

　　http协议，是互联网中最常见的网络通信标准。

3. http协议的特点

　　①通信流程：断开式（无状态）

　　　　　　　　断开式：http协议每次响应完成后，会断开与客户端的连接

　　　　　　　　无状态：由于服务器断开了之前的连接，就无法知晓连接间的关系

　　②内容格式：消息头和消息体

二、http编程概述

　　HTTP(HyperText Transfer Protocol,超文本传输协议)是互联网上应用最为广泛的一种网络协议，定义了客户端和服务端之间请求和响应的传输标准。Go语言标准库内建提供了net/http包，涵盖了HTTP客户端和服务端的具体实现。使用net/http包，我们可以很方便地编写HTTP客户端或服务端的程序。

特点：

a. Go原生支持http，import(“net/http”)
b. Go的http服务性能和nginx比较接近
c. 几行代码就可以实现一个web服务

三、客户端与服务端

1. 服务端

package main
 
import (
    "fmt"
    "net/http"
)
 
//w, 给客户端回复数据
//r, 读取客户端发送的数据
func HandConn(w http.ResponseWriter, r *http.Request) {
    fmt.Println("r.Method = ", r.Method)
    fmt.Println("r.URL = ", r.URL)
    fmt.Println("r.Header = ", r.Header)
    fmt.Println("r.Body = ", r.Body)
 
    w.Write([]byte("hello go")) //给客户端回复数据
}
 
func main() {
    //注册处理函数，用户连接，自动调用指定的处理函数
    http.HandleFunc("/", HandConn)
 
    //监听绑定
    http.ListenAndServe(":8000", nil)
}

package main

import (
    "fmt"
    "net/http"
)

func Hello(w http.ResponseWriter, r *http.Request) {
    fmt.Println("r.Method = ", r.Method)
    fmt.Println("r.URL = ", r.URL)
    fmt.Println("r.Header = ", r.Header)
    fmt.Println("r.Body = ", r.Body)
    fmt.Println("handle hello")
    fmt.Fprintf(w, "hello ")
}

func login(w http.ResponseWriter, r *http.Request) {
    fmt.Println("handle login")
    fmt.Fprintf(w, "login ")
}

func history(w http.ResponseWriter, r *http.Request) {
    fmt.Println("handle history")
    fmt.Fprintf(w, "history ")
}

func main() {
    http.HandleFunc("/", Hello)
    http.HandleFunc("/user/login", login)
    http.HandleFunc("/user/history", history)
    err := http.ListenAndServe("0.0.0.0:8880", nil)
    if err != nil {
        fmt.Println("http listen failed")
    }
}

http_server.go

2. 客户端

package main
 
import (
    "fmt"
    "net/http"
)
 
func main() {
    //resp, err := http.Get("http://www.baidu.com")
    resp, err := http.Get("http://127.0.0.1:8000")
    if err != nil {
        fmt.Println("http.Get err = ", err)
        return
    }
 
    defer resp.Body.Close()
 
    fmt.Println("Status = ", resp.Status)
    fmt.Println("StatusCode = ", resp.StatusCode)
    fmt.Println("Header = ", resp.Header)
    //fmt.Println("Body = ", resp.Body)
 
    buf := make([]byte, 4*1024)
    var tmp string
 
    for {
        n, err := resp.Body.Read(buf)
        if n == 0 {
            fmt.Println("read err = ", err)
            break
        }
        tmp += string(buf[:n])
    }
 
    //读取网页内容，打印出来
    fmt.Println("tmp = ", tmp)
}

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    res, err := http.Get("https://www.baidu.com/")
    if err != nil {
        fmt.Println("get err:", err)
        return
    }

    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        fmt.Println("get data err:", err)
        return
    }

    fmt.Println(string(data))
}

http_client.go

四、http常见请求方法

HTTP请求的方法：

HTTP/1.1协议中共定义了八种方法（有时也叫“动作”），来表明Request-URL指定的资源不同的操作方式

1、OPTIONS

返回服务器针对特定资源所支持的HTTP请求方法，也可以利用向web服务器发送‘*’的请求来测试服务器的功能性

2、HEAD

向服务器索与GET请求相一致的响应，只不过响应体将不会被返回。这一方法可以再不必传输整个响应内容的情况下，就可以获取包含在响应小消息头中的元信息。

3、GET

向特定的资源发出请求。它本质就是发送一个请求来取得服务器上的某一资源。资源通过一组HTTP头和呈现数据（如HTML文本，或者图片或者视频等）返回给客户端。GET请求中，永远不会包含呈现数据。

4、POST

向指定资源提交数据进行处理请求（例如提交表单或者上传文件）。数据被包含在请求体中。POST请求可能会导致新的资源的建立和/或已有资源的修改。 Loadrunner中对应POST请求函数：web_submit_data,web_submit_form

5、PUT

向指定资源位置上传其最新内容

6、DELETE

请求服务器删除Request-URL所标识的资源

7、TRACE

回显服务器收到的请求，主要用于测试或诊断

8、CONNECT

HTTP/1.1协议中预留给能够将连接改为管道方式的代理服务器。

注意：

1）方法名称是区分大小写的，当某个请求所针对的资源不支持对应的请求方法的时候，服务器应当返回状态码405（Mothod Not Allowed）；当服务器不认识或者不支持对应的请求方法时，应返回状态码501（Not Implemented）。
2）HTTP服务器至少应该实现GET和HEAD/POST方法，其他方法都是可选的，此外除上述方法，特定的HTTP服务器支持扩展自定义的方法。

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

常见状态码

get 和 post区别

　　区别：

　　　　get请求无消息体，只能携带少量数据

　　　　post请求有消息体，可以携带大量数据

　　携带数据的方式：

　　　　get请求将数据放在url地址中

　　　　post请求将数据放在消息体中

GET请求请提交的数据放置在HTTP请求协议头中，而POST提交的数据则放在实体数据中；
GET方式提交的数据最多只能有1024字节，而POST则没有此限制。

五、Head请求

package main

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

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

func main() {

	for _, v := range url {
		c := http.Client{
			Transport: &http.Transport {
				Dial:func(network, addr string) (net.Conn, error){
					timeout := time.Second*2
					return net.DialTimeout(network, addr, timeout)
				},
			},
		}
		resp, err := c.Head(v)
		if err != nil {
			fmt.Printf("head %s failed, err:%v
", v, err)
			continue
		}

		fmt.Printf("head succ, status:%v
", resp.Status)
	}
}

　六、表单及panic处理

package main

import (
	"io"
	"log"
	"net/http"
)

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></body></html>`

func SimpleServer(w http.ResponseWriter, request *http.Request) {
	io.WriteString(w, "<h1>hello, world</h1>")
	panic("test test")
}

func FormServer(w http.ResponseWriter, request *http.Request) {
	w.Header().Set("Content-Type", "text/html")
	switch request.Method {
	case "GET":
		io.WriteString(w, form)
	case "POST":
		request.ParseForm()
		io.WriteString(w, request.Form["in"][1])
		io.WriteString(w, "
")
		io.WriteString(w, request.FormValue("in"))
	}
}
func main() {
	http.HandleFunc("/test1", logPanics(SimpleServer))
	http.HandleFunc("/test2", logPanics(FormServer))
	if err := http.ListenAndServe(":8088", nil); err != nil {
	}
}

func logPanics(handle http.HandlerFunc) http.HandlerFunc {
	return func(writer http.ResponseWriter, request *http.Request) {
		defer func() {
			if x := recover(); x != nil {
				log.Printf("[%v] caught panic: %v", request.RemoteAddr, x)
			}
		}()
		handle(writer, request)
	}
}

　七、模板

　　1. 替换 {{.字段名}}

if 判断
if 常见操作
{{.}}
{{with .Var}}... {{end}}

　　2. 循环

　　{{range.}}... {{end}}

模板示例1：

package main

import (
    "fmt"
    "os"
    "text/template"
)

type Person struct {
    Name  string
    Title string
    age   string
}

func main() {
    t, err := template.ParseFiles("day10/template/index.html")
    if err != nil {
        fmt.Println("parse file err:", err)
        return
    }
    p := Person{Name: "Mary", age: "31", Title: "我的个人网站"}
    if err := t.Execute(os.Stdout, p); err != nil {
        fmt.Println("There was an error:", err.Error())
    }
}

main.go

<html>
    <head>
        <title>{{.Title}}</title>
    </head>
    <body>
        <p> hello, {{.Name}}</p>
        <p> {{.}}</p>
    </body>
 </html>

index.html

<html>
    <head>
        <title>我的个人网站</title>
    </head>
    <body>
        <p> hello, Mary</p>
        <p> {Mary 我的个人网站 31}</p>
    </body>
</html>

模板示例2

package main

import (
    "fmt"
    "html/template"
    "io"
    "net/http"
)

var myTemplate *template.Template

type Result struct {
    output string
}

func (p *Result) Write(b []byte) (n int, err error) {
    fmt.Println("called by template")
    p.output += string(b)
    return len(b), nil
}

type Person struct {
    Name  string
    Title string
    Age   int
}

func userInfo(w http.ResponseWriter, r *http.Request) {
    fmt.Println("handle hello")
    //fmt.Fprintf(w, "hello ")
    var arr []Person
    p := Person{Name: "Mary001", Age: 10, Title: "我的个人网站"}
    p1 := Person{Name: "Mary002", Age: 10, Title: "我的个人网站"}
    p2 := Person{Name: "Mary003", Age: 10, Title: "我的个人网站"}
    arr = append(arr, p)
    arr = append(arr, p1)
    arr = append(arr, p2)

    resultWriter := &Result{}
    io.WriteString(resultWriter, "hello world")
    err := myTemplate.Execute(w, arr)
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println("template render data:", resultWriter.output)
    //myTemplate.Execute(w, p)
    //myTemplate.Execute(os.Stdout, p)
    //file, err := os.OpenFile("C:/test.log", os.O_CREATE|os.O_WRONLY, 0755)
    //if err != nil {
    //    fmt.Println("open failed err:", err)
    //    return
    //}

}

func initTemplate(filename string) (err error) {
    myTemplate, err = template.ParseFiles(filename)
    if err != nil {
        fmt.Println("parse file err:", err)
        return
    }
    return
}

func main() {
    initTemplate("day10/template_http/index.html")
    http.HandleFunc("/user/info", userInfo)
    err := http.ListenAndServe("0.0.0.0:8880", nil)
    if err != nil {
        fmt.Println("http listen failed")
    }
}

main.go

<html>
    <head>
    </head>
    <body>
        <p>hello world</p>
        <table border="1">
        {{range .}}
            <tr>
                <td>{{.Name}}</td> <td>{{.Age}}</td><td>{{.Title}}</td>
            </tr>
         {{end}}
        </table>
    </body>
</html>

index.html

Mysql编程

新建测试表

CREATE TABLE person (
    user_id int primary key auto_increment,
    username varchar(260),
    sex varchar(260),
    email varchar(260)
);

CREATE TABLE place (
    country varchar(200),
    city varchar(200),
    telcode int
)

1. 连接mysql

database, err := sqlx.Open("mysql", "root:@tcp(127.0.0.1:3306)/test")

2. insert操作

r, err := Db.Exec("insert into person(username, sex, email)values(?, ?, ?)", "stu001", "man", "stu01@qq.com")

package main

import (
    "fmt"

    _ "github.com/go-sql-driver/mysql"
    "github.com/jmoiron/sqlx"
)

type Person struct {
    UserId   int    `db:"user_id"`
    Username string `db:"username"`
    Sex      string `db:"sex"`
    Email    string `db:"email"`
}

type Place struct {
    Country string `db:"country"`
    City    string `db:"city"`
    TelCode int    `db:"telcode"`
}

var Db *sqlx.DB

func init() {
    database, err := sqlx.Open("mysql", "root:0000@tcp(127.0.0.1:3306)/test")
    if err != nil {
        fmt.Println("open mysql failed,", err)
        return
    }
    Db = database
}

func main() {
    r, err := Db.Exec("insert into person(username, sex, email)values(?, ?, ?)", "stu001", "man", "stu01@qq.com")
    if err != nil {
        fmt.Println("exec failed, ", err)
        return
    }
    id, err := r.LastInsertId()
    if err != nil {
        fmt.Println("exec failed, ", err)
        return
    }

    fmt.Println("insert succ:", id)
}

mysql_insert

3. select操作

err := Db.Select(&person, "select user_id, username, sex, email from person where user_id=?", 1)

package main

import (
    "fmt"

    _ "github.com/go-sql-driver/mysql"
    "github.com/jmoiron/sqlx"
)

type Person struct {
    UserId   int    `db:"user_id"`
    Username string `db:"username"`
    Sex      string `db:"sex"`
    Email    string `db:"email"`
}

type Place struct {
    Country string `db:"country"`
    City    string `db:"city"`
    TelCode int    `db:"telcode"`
}

var Db *sqlx.DB

func init() {

    database, err := sqlx.Open("mysql", "root:0000@tcp(127.0.0.1:3306)/test")
    if err != nil {
        fmt.Println("open mysql failed,", err)
        return
    }

    Db = database
}

func main() {

    var person []Person
    err := Db.Select(&person, "select user_id, username, sex, email from person where user_id=?", 1)
    if err != nil {
        fmt.Println("exec failed, ", err)
        return
    }

    fmt.Println("select succ:", person)
}

mysql_select

4. update操作

_, err := Db.Exec("update person set username=? where user_id=?", "stu0001", 1)

package main

import (
    "fmt"

    _ "github.com/go-sql-driver/mysql"
    "github.com/jmoiron/sqlx"
)

type Person struct {
    UserId   int    `db:"user_id"`
    Username string `db:"username"`
    Sex      string `db:"sex"`
    Email    string `db:"email"`
}

type Place struct {
    Country string `db:"country"`
    City    string `db:"city"`
    TelCode int    `db:"telcode"`
}

var Db *sqlx.DB

func init() {

    database, err := sqlx.Open("mysql", "root:0000@tcp(127.0.0.1:3306)/test")
    if err != nil {
        fmt.Println("open mysql failed,", err)
        return
    }

    Db = database
}

func main() {

    _, err := Db.Exec("update person set username=? where user_id=?", "stu0003", 1)
    if err != nil {
        fmt.Println("exec failed, ", err)
        return
    }

}

mysql_update

5. delete操作

_, err := Db.Exec("delete from person where user_id=?", 1)

package main

import (
    "fmt"

    _ "github.com/go-sql-driver/mysql"
    "github.com/jmoiron/sqlx"
)

type Person struct {
    UserId   int    `db:"user_id"`
    Username string `db:"username"`
    Sex      string `db:"sex"`
    Email    string `db:"email"`
}

type Place struct {
    Country string `db:"country"`
    City    string `db:"city"`
    TelCode int    `db:"telcode"`
}

var Db *sqlx.DB

func init() {

    database, err := sqlx.Open("mysql", "root:0000@tcp(127.0.0.1:3306)/test")
    if err != nil {
        fmt.Println("open mysql failed,", err)
        return
    }

    Db = database
}

func main() {

    _, err := Db.Exec("delete from person where user_id=?", 1)
    if err != nil {
        fmt.Println("exec failed, ", err)
        return
    }

    fmt.Println("delete succ")
}

mysql_delete

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原文地址：https://www.cnblogs.com/zhangyafei/p/10993315.html