• Go Web——http标准库

    文章目录

    简介

    Golang http标准库提供了HTTP客户端和服务端的实现。

    注意了，客户端实现可以发出http请求，并解析响应。服务器可以实现http server功能。市面上的所有golang web框架都是基于http标准库实现的。

    Get、Head、Post和PostForm函数发出HTTP/ HTTPS请求。

    resp, err := http.Get("http://example.com/")
...
resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)
...
resp, err := http.PostForm("http://example.com/form",
	url.Values{"key": {"Value"}, "id": {"123"}})

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6

    程序在使用完回复后必须关闭回复的主体。

    resp, err := http.Get("http://example.com/")
if err != nil {
	// handle error
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
// ...

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7

    一 HTTP Client

    1.1 发送GET请求

    func Get(url string) (resp *Response, err error)

    • 1

    Get向指定的URL发出一个GET请求，如果回应的状态码如下，Get会在调用c.CheckRedirect后执行重定向：

    • 301 (Moved Permanently)
    • 302 (Found)
    • 303 (See Other)
    • 307 (Temporary Redirect)

    如果c.CheckRedirect执行失败或存在HTTP协议错误时，本方法将返回该错误；如果回应的状态码不是2xx，本方法并不会返回错误。如果返回值err为nil，resp.Body总是非nil的，调用者应该在读取完resp.Body后关闭它。

    Get是对包变量DefaultClient的Get方法的包装。

    实例演示：

    package main

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

func main() {
	url := "http://apis.juhe.cn/simpleWeather/query?city=成都&key=904d15a2893c4d81c5c5a1fd0a7a7ed6"
	r, err := http.Get(url)
	if err != nil {
		log.Fatal(err)
	}
	b, err := ioutil.ReadAll(r.Body)
	r.Body.Close()	// 程序在使用完response后必须关闭回复的主体。
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("b: %v\n", string(b))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
b: {"reason":"查询成功!","result":{"city":"成都","realtime":{"temperature":"39","humidity":"30","info":"多云","wid":"01","direct":"西南风","power":"3级","aqi":"78"},"future":[{"date":"2022-08-21","temperature":"27\/39℃","weather":"多云转阴","wid":{"day":"01","night":"02"},"direct":"持续无风向"},{"date":"2022-08-22","temperature":"27\/39℃","weather":"阴转晴","wid":{"day":"02","night":"00"},"direct":"持续无风向"},{"date":"2022-08-23","temperature":"29\/38℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"持续无风向"},{"date":"2022-08-24","temperature":"27\/37℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"持续无风向"},{"date":"2022-08-25","temperature":"23\/35℃","weather":"小雨转中雨","wid":{"day":"07","night":"08"},"direct":"持续无风向"}]},"error_code":0}

[Done] exited with code=0 in 1.636 seconds

    • 1
    • 2
    • 3
    • 4

    还可以把一些参数做成变量而不是直接放到URL里：

    package main

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

func main() {
	params := url.Values{}
	u, err := url.Parse("http://apis.juhe.cn/simpleWeather/query")
	if err != nil {
		log.Fatal(err)
	}
	params.Set("city", "成都")
	params.Set("key", "904d15a2893c4d81c5c5a1fd0a7a7ed6")

	// 如果参数中有中文，则堆params进行encode
	u.RawQuery = params.Encode()
	urlPath := u.String()
	fmt.Printf("urlPath: %v\n", urlPath)

	r, err := http.Get(urlPath)
	if err != nil {
		log.Fatal(err)
	}
	b, err := ioutil.ReadAll(r.Body)
	r.Body.Close()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("b: %v\n", string(b))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34
    • 35

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
urlPath: http://apis.juhe.cn/simpleWeather/query?city=%E6%88%90%E9%83%BD&key=904d15a2893c4d81c5c5a1fd0a7a7ed6
b: {"reason":"查询成功!","result":{"city":"成都","realtime":{"temperature":"39","humidity":"34","info":"多云","wid":"01","direct":"西南风","power":"3级","aqi":"78"},"future":[{"date":"2022-08-21","temperature":"27\/39℃","weather":"多云转阴","wid":{"day":"01","night":"02"},"direct":"持续无风向"},{"date":"2022-08-22","temperature":"27\/39℃","weather":"阴转晴","wid":{"day":"02","night":"00"},"direct":"持续无风向"},{"date":"2022-08-23","temperature":"29\/38℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"持续无风向"},{"date":"2022-08-24","temperature":"27\/37℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"持续无风向"},{"date":"2022-08-25","temperature":"23\/35℃","weather":"小雨转中雨","wid":{"day":"07","night":"08"},"direct":"持续无风向"}]},"error_code":0}

[Done] exited with code=0 in 2.198 seconds

    • 1
    • 2
    • 3
    • 4
    • 5

    1.2 解析JSON类型返回结果

    package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
)

func main() {
	type result struct {
		Args    string            `json:"args"`
		Headers map[string]string `json:"headers"`
		Origin  string            `json:"origin"`
		Url     string            `json:"url"`
	}

	r, err := http.Get("http://httpbin.org/get")
	if err != nil {
		log.Fatal(err)
	}
	b, err := ioutil.ReadAll(r.Body)
	defer r.Body.Close()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("b: %v\n", string(b))

	var res result
	_ = json.Unmarshal(b, &res)
	fmt.Printf("res: %#v\n", res)
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31
    • 32
    • 33
    • 34

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
b: {
  "args": {}, 
  "headers": {
    "Accept-Encoding": "gzip", 
    "Host": "httpbin.org", 
    "User-Agent": "Go-http-client/1.1", 
    "X-Amzn-Trace-Id": "Root=1-6301e9e7-6a3a381f2ae14307082b524b"
  }, 
  "origin": "171.223.97.152", 
  "url": "http://httpbin.org/get"
}

res: main.result{Args:"", Headers:map[string]string{"Accept-Encoding":"gzip", "Host":"httpbin.org", "User-Agent":"Go-http-client/1.1", "X-Amzn-Trace-Id":"Root=1-6301e9e7-6a3a381f2ae14307082b524b"}, Origin:"171.223.97.152", Url:"http://httpbin.org/get"}

[Done] exited with code=0 in 2.287 seconds

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16

    1.3 GET请求添加请求头

    package main

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

func main() {
	client := &http.Client{}
	request, err := http.NewRequest("GET", "http://httpbin.org/get", nil)
	if err != nil {
		log.Fatal(err)
	}
	request.Header.Add("name", "Psych")
	request.Header.Add("age", "18")

	response, err := client.Do(request)
	if err != nil {
		log.Fatal(err)
	}

	body, err := ioutil.ReadAll(response.Body)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("body: %v\n", string(body))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
body: {
  "args": {}, 
  "headers": {
    "Accept-Encoding": "gzip", 
    "Age": "18", 
    "Host": "httpbin.org", 
    "Name": "Psych", 
    "User-Agent": "Go-http-client/1.1", 
    "X-Amzn-Trace-Id": "Root=1-6301eb7f-0d585b7d5877f5f51ea2cc21"
  }, 
  "origin": "171.223.97.152", 
  "url": "http://httpbin.org/get"
}


[Done] exited with code=0 in 2.818 seconds

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17

    1.4 发送POST请求

    func Post(url string, bodyType string, body io.Reader) (resp *Response, err error)

    • 1

    Post向指定的URL发出一个POST请求。bodyType为POST数据的类型， body为POST数据，作为请求的主体。如果参数body实现了io.Closer接口，它会在发送请求后被关闭。调用者有责任在读取完返回值resp的主体后关闭它。

    func PostForm(url string, data url.Values) (resp *Response, err error)

    • 1

    PostForm向指定的URL发出一个POST请求，url.Values类型的data会被编码为请求的主体。如果返回值err为nil，resp.Body总是非nil的，调用者应该在读取完resp.Body后关闭它。

    实例演示：

    package main

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

func main() {
	path := "http://apis.juhe.cn/simpleWeather/query"
	urlValues := url.Values{}
	urlValues.Add("city", "成都")
	urlValues.Add("key", "904d15a2893c4d81c5c5a1fd0a7a7ed6")

	r, err := http.PostForm(path, urlValues)
	if err != nil {
		log.Fatal(err)
	}
	defer r.Body.Close()

	b, err := ioutil.ReadAll(r.Body)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("天气信息: %v\n", string(b))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
body: {
  "args": {}, 
  "headers": {
    "Accept-Encoding": "gzip", 
    "Age": "18", 
    "Host": "httpbin.org", 
    "Name": "Psych", 
    "User-Agent": "Go-http-client/1.1", 
    "X-Amzn-Trace-Id": "Root=1-6301eb7f-0d585b7d5877f5f51ea2cc21"
  }, 
  "origin": "171.223.97.152", 
  "url": "http://httpbin.org/get"
}


[Done] exited with code=0 in 2.818 seconds

[Running] go run "e:\golang开发学习\go_pro\test.go"
天气信息: {"reason":"查询成功!","result":{"city":"成都","realtime":{"temperature":"39","humidity":"30","info":"多云","wid":"01","direct":"南风","power":"3级","aqi":"84"},"future":[{"date":"2022-08-21","temperature":"27\/39℃","weather":"多云转阴","wid":{"day":"01","night":"02"},"direct":"持续无风向"},{"date":"2022-08-22","temperature":"27\/39℃","weather":"阴转晴","wid":{"day":"02","night":"00"},"direct":"持续无风向"},{"date":"2022-08-23","temperature":"29\/38℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"持续无风向"},{"date":"2022-08-24","temperature":"27\/37℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"持续无风向"},{"date":"2022-08-25","temperature":"23\/35℃","weather":"小雨转中雨","wid":{"day":"07","night":"08"},"direct":"持续无风向"}]},"error_code":0}

[Done] exited with code=0 in 1.666 seconds

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22

    另一种方法：

    package main

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

func main() {
	urlValues := url.Values{
		"name": {"Psych"},
		"age":  {"18"},
	}
	requestBody := urlValues.Encode()
	response, _ := http.Post("http://httpbin.org/post", "text/html", strings.NewReader(requestBody))
	body, _ := ioutil.ReadAll(response.Body)
	fmt.Printf("信息: %v\n", string(body))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
信息: {
  "args": {}, 
  "data": "age=18&name=Psych", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Accept-Encoding": "gzip", 
    "Content-Length": "17", 
    "Content-Type": "text/html", 
    "Host": "httpbin.org", 
    "User-Agent": "Go-http-client/1.1", 
    "X-Amzn-Trace-Id": "Root=1-6301f289-16bb6b7364feb63441b6a3c2"
  }, 
  "json": null, 
  "origin": "171.223.97.152", 
  "url": "http://httpbin.org/post"
}


[Done] exited with code=0 in 2.616 seconds

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21

    1.5 发送JSON数据的POST请求

    package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
)

func main() {
	data := make(map[string]interface{})
	data["site"] = "www.baidu.com"
	data["name"] = "百度"

	bytesData, _ := json.Marshal(data)
	response, _ := http.Post("http://httpbin.org/post", "application/json", bytes.NewReader(bytesData))

	body, _ := ioutil.ReadAll(response.Body)
	fmt.Printf("信息: %v\n", string(body))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
信息: {
  "args": {}, 
  "data": "{\"name\":\"\u767e\u5ea6\",\"site\":\"www.baidu.com\"}", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Accept-Encoding": "gzip", 
    "Content-Length": "40", 
    "Content-Type": "application/json", 
    "Host": "httpbin.org", 
    "User-Agent": "Go-http-client/1.1", 
    "X-Amzn-Trace-Id": "Root=1-6301f466-03c547cb3c1424ae5e9439ca"
  }, 
  "json": {
    "name": "\u767e\u5ea6", 
    "site": "www.baidu.com"
  }, 
  "origin": "171.223.97.152", 
  "url": "http://httpbin.org/post"
}


[Done] exited with code=0 in 2.056 seconds

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24

    1.6 使用Client自定义请求

    要管理HTTP客户端的头域、重定向策略和其他设置，创建一个Client：

    client := &http.Client{
	CheckRedirect: redirectPolicyFunc,
}
resp, err := client.Get("http://example.com")
// ...
req, err := http.NewRequest("GET", "http://example.com", nil)
// ...
req.Header.Add("If-None-Match", `W/"wyzzy"`)
resp, err := client.Do(req)
// ...

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10

    实例演示：

    package main

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

func main() {
	client := http.Client{
		Timeout: time.Second * 5,
	}
	url := "http://apis.juhe.cn/simpleWeather/query?city=成都&key=904d15a2893c4d81c5c5a1fd0a7a7ed6"
	request, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		log.Fatal(err)
	}

	request.Header.Add("referer", "http://apis.juhe.cn/")
	res, err := client.Do(request)
	if err != nil {
		log.Fatal(err)
	}

	defer res.Body.Close()

	b, _ := ioutil.ReadAll(res.Body)
	fmt.Printf("信息: %v\n", string(b))
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24
    • 25
    • 26
    • 27
    • 28
    • 29
    • 30
    • 31

    运行结果：

    [Running] go run "e:\golang开发学习\go_pro\test.go"
信息: {"reason":"查询成功!","result":{"city":"成都","realtime":{"temperature":"39","humidity":"31","info":"多云","wid":"01","direct":"南风","power":"3级","aqi":"83"},"future":[{"date":"2022-08-21","temperature":"27\/39℃","weather":"多云转阴","wid":{"day":"01","night":"02"},"direct":"持续无风向"},{"date":"2022-08-22","temperature":"27\/39℃","weather":"阴转晴","wid":{"day":"02","night":"00"},"direct":"持续无风向"},{"date":"2022-08-23","temperature":"29\/38℃","weather":"多云","wid":{"day":"01","night":"01"},"direct":"持续无风向"},{"date":"2022-08-24","temperature":"27\/37℃","weather":"多云转小雨","wid":{"day":"01","night":"07"},"direct":"持续无风向"},{"date":"2022-08-25","temperature":"23\/35℃","weather":"小雨转中雨","wid":{"day":"07","night":"08"},"direct":"持续无风向"}]},"error_code":0}

[Done] exited with code=0 in 1.846 seconds

    • 1
    • 2
    • 3
    • 4

    Client可以安全的被多个go程同时使用。出于效率考虑，应该一次建立、尽量重用。

    二 HTTP Server

    2.1 默认的Server

    ListenAndServe使用指定的监听地址和处理器启动一个HTTP服务端。处理器参数通常是nil，这表示采用包变量DefaultServeMux作为处理器。

    Handle和HandleFunc函数可以向DefaultServeMux添加处理器。

    http.Handle("/foo", fooHandler)
http.HandleFunc("/bar", func(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))
})
log.Fatal(http.ListenAndServe(":8080", nil))

    • 1
    • 2
    • 3
    • 4
    • 5

    实例演示：

    package main

import (
	"fmt"
	"net/http"
)

// http server
// 请求处理函数
func sayHello(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintln(w, "Hello world！")
}

func main() {
	// 响应路径，注意前面要有斜杠/
	http.HandleFunc("/hello", sayHello)

	// 设置监听窗口并监听，注意前面要有冒号：
	err := http.ListenAndServe(":9090", nil)
	if err != nil {
		fmt.Printf("http server failed, err:%v\n", err)
		return
	}
}

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
    • 9
    • 10
    • 11
    • 12
    • 13
    • 14
    • 15
    • 16
    • 17
    • 18
    • 19
    • 20
    • 21
    • 22
    • 23
    • 24

    将上面的代码编译之后执行，打开浏览器在地址栏输入http://127.0.0.1:9090/hello回车，此时就能够看到 Hello world！

    2.2 自定义Server

    要管理服务端的行为，可以创建一个自定义的Server：

    s := &http.Server{
	Addr:           ":8080",
	Handler:        myHandler,
	ReadTimeout:    10 * time.Second,
	WriteTimeout:   10 * time.Second,
	MaxHeaderBytes: 1 << 20,
}
log.Fatal(s.ListenAndServe())

    • 1
    • 2
    • 3
    • 4
    • 5
    • 6
    • 7
    • 8
  • 相关阅读:
    java-php-python-ssm一起组局校园交友平台计算机毕业设计
    Cobbler
    ChatGpt 反向代理
    九. Linux网络命令
    浅谈java单元测试框架junit4/5
    阿里云——OpenAPI使用——短信服务
    Flask基础学习笔记
    尚硅谷Webpack实战教程基础配置
    分治法、动态规划、贪心算法区别
    对象、数组深拷贝与浅拷贝
  • 原文地址：https://blog.csdn.net/qq_39280718/article/details/126468998