Golang HTTP编程及源码解析-请求/响应处理

1. HTTP协议

HTTP 协议是 Hyper Text Transfer Protocol（超文本传输协议）的缩写，基于TCP/IP通信协议来传递数据（HTML 文件、图片文件、查询结果等）。

HTTP 是无连接的：无连接的含义是限制每次连接只处理一个请求，服务器处理完客户的请求，并收到客户的应答后，即断开连接，采用这种方式可以节省传输时间。
HTTP是独立于媒体的：只要客户端和服务器都知道如何处理数据内容，任何类型的数据都可以通过HTTP发送。客户端和服务器都需要使用适当的 MIME 类型指定内容类型。
HTTP是无状态的：HTTP 协议是无状态协议，无状态是指协议对于事务处理没有记忆能力，缺少状态意味着如果后续处理需要前面的信息，则它必须重传，这样可能导致每次连接传送的数据量增大，另一方面，在服务器不需要先前信息时它的应答就较快。

2. HTTP请求报文格式

HTTP请求报文包含以下三个部分。

请求行
请求头
请求体

基本结构如下图所示

3. HTTP响应报文格式

与请求报文结构类型，HTTP响应报文包含以下三个部分

状态行
响应头
响应体

基本结构如下图所示。

下面通过代码结合实例来看Golang的HTTP的请求处理和响应处理。

4. Golang HTTP请求处理

4.1 请求行

 func requestLineHandler(w http.ResponseWriter, r *http.Request) {
    // 请求行
    fmt.Fprintf(w, "\nresp method:%v url:%v Proto:%v\n", r.Method, r.URL, r.Proto)
    // URL参数获取
    fmt.Fprintf(w, "resp URL查询参数:%v\n", r.URL.Query())
    w.WriteHeader(http.StatusOK)
}
 
func main() {
    // 1. 新建路由解码器
    h := http.NewServeMux()
    // 2. 路由注册
    h.HandleFunc("/reqline", requestLineHandler)
    // 3. 服务启动 阻塞监听
    http.ListenAndServe(":8000", h)
}

通过curl发起POST请求，通过-v打印请求报文和响应报文。

 $ curl -v -X POST  http://localhost:8000/reqline?name=jack
*   Trying 127.0.0.1:8000...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /reqline?name=jack HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.86.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Sat, 04 Mar 2023 12:13:25 GMT
< Content-Length: 94
< Content-Type: text/plain; charset=utf-8
<
 
resp method:POST url:/reqline?name=jack Proto:HTTP/1.1
resp URL查询参数:map[name:[jack]]

4.2 请求头

 func requestHeaderHandler(w http.ResponseWriter, r *http.Request) {
    // 头部
    fmt.Fprintf(w, "header:\n")
    for key, val := range r.Header {
        fmt.Fprintf(w, "%v:%v\n", key, val)
    }
    fmt.Fprintf(w, "Get(\"Content-Type\"):%v\n", r.Header.Get("Content-Type"))
}
func main() {
    // 1. 新建路由解码器
    h := http.NewServeMux()
    // 2. 路由注册
    h.HandleFunc("/reqheader", requestHeaderHandler)
    // 3. 服务启动 阻塞监听
    http.ListenAndServe(":8000", h)
}

通过curl发起POST请求

可以看出curl的请求报文和HTTP服务端获取到的请求Header都包含version:1.1.1

 $ curl -v -d "age=18" -H "Accept-Language:en-US" -H "version:1.1.1" http://localhost:8000/reqheader
*   Trying 127.0.0.1:8000...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /reqheader HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.86.0
> Accept: */*
> Accept-Language:en-US
> version:1.1.1
> Content-Length: 6
> Content-Type: application/x-www-form-urlencoded
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Sat, 04 Mar 2023 12:21:13 GMT
< Content-Length: 208
< Content-Type: text/plain; charset=utf-8
<
header:
Version:[1.1.1]
Content-Length:[6]
Content-Type:[application/x-www-form-urlencoded]
User-Agent:[curl/7.86.0]
Accept:[*/*]
Accept-Language:[en-US]
Get("Content-Type"):application/x-www-form-urlencoded

4.3 请求体

以下代码大致说明了Content-Type为application/x-www-form-urlencoded和application/json的处理方法

 func requestBodyHandler(w http.ResponseWriter, r *http.Request) {
    contentType := r.Header.Get("Content-Type")
    fmt.Fprintf(w, "Content-Type:%v\n", contentType)
    // URL参数获取
    fmt.Fprintf(w, "URL查询参数:%v\n", r.URL.Query())
    // 解析 Content-Type为multipart/form-data的请求体
    switch contentType {
    case "application/x-www-form-urlencoded": // 表单默认的提交数据的格式
        // 解析 URL查询参数 和 POST、PUT、PATCH的请求体参数
        // 并将结果放入r.Form, 且POST、PUT、PATCH的请求体参数的优先级比URL查询参数高
        // r.PostForm只存放POST、PUT、PATCH的请求体参数
        r.ParseForm()
        fmt.Fprintf(w, "PostForm:%v\n", r.PostForm)
        fmt.Fprintf(w, "Form:%v\n", r.Form)
    case "application/json": // json数据格式
        json, _ := ioutil.ReadAll(r.Body)
        fmt.Fprintf(w, "Json:%v", string(json))
    default:
        fmt.Fprintf(w, "unkown Content-Type")
    }
}

通过curl发起Content-Type为application/x-www-form-urlencoded的POST请求，

URL查询参数和请求体都包含name=，从Form:map[age:[18] name:[juli jack]]可以看出POST的请求体参数优先级更高。

 $ curl -v http://localhost:8000/reqbody?name=jack -d "age=18" -d "name=juli"
*   Trying 127.0.0.1:8000...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /reqbody?name=jack HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.86.0
> Accept: */*
> Content-Length: 16
> Content-Type: application/x-www-form-urlencoded
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Sat, 04 Mar 2023 12:35:15 GMT
< Content-Length: 151
< Content-Type: text/plain; charset=utf-8
<
Content-Type:application/x-www-form-urlencoded
URL查询参数:map[name:[jack]]
PostForm:map[age:[18] name:[juli]]
Form:map[age:[18] name:[juli jack]]

通过curl发起Content-Type为application/json的请求。

 $ curl -v http://localhost:8000/reqbody -H "Content-Type: application/json" -d "{"name":"jack","age":"18"}"
*   Trying 127.0.0.1:8000...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /reqbody HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.86.0
> Accept: */*
> Content-Type: application/json
> Content-Length: 18
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Sat, 04 Mar 2023 12:38:34 GMT
< Content-Length: 75
< Content-Type: text/plain; charset=utf-8
<
Content-Type:application/json
URL查询参数:map[]
Json:{name:jack,age:18}

5. Golang HTTP响应处理

 func respHandler(w http.ResponseWriter, r *http.Request) {
	// 设置响应头
	w.Header().Set("name", "jack")
	// 设置cookie
	ck := &http.Cookie{
		Name:     "testCookie",
		Value:    "cookieval",
		Path:     "/",
		HttpOnly: true,
	}
	http.SetCookie(w, ck)
	// 设置响应体
	w.Write([]byte("hello i'm jack"))
	// 设置响应状态码
	w.WriteHeader(http.StatusOK)
}
 
func main() {
	// 1. 新建路由解码器
	h := http.NewServeMux()
	// 2. 路由注册
	h.HandleFunc("/resp", respHandler)
	// 3. 服务启动 阻塞监听
	http.ListenAndServe(":8000", h)
}

值得注意的是，设置Header、设置Cookie必须先于设置响应体，否则不会生效

 $ curl -v http://localhost:8000/resp
*   Trying 127.0.0.1:8000...
* Connected to localhost (127.0.0.1) port 8000 (#0)
> GET /resp HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.86.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Name: jack
< Set-Cookie: testCookie=cookieval; Path=/; HttpOnly
< Date: Sat, 04 Mar 2023 13:15:15 GMT
< Content-Length: 14
< Content-Type: text/plain; charset=utf-8
<
hello i'm jack

posted @ 2023-03-04 22:13 bulldozer 阅读(1080) 评论(0) 编辑收藏举报

刷新页面返回顶部

登录后才能查看或发表评论，立即登录或者逛逛博客园首页

相关博文：

· Golang HTTP编程及源码解析-路由分发

· Gin使用及源码简析

· Golang基础库之net/http

· http简介

· HTTP协议

公告

昵称： bulldozer
园龄： 4年
粉丝： 2
关注： 3

+加关注

2025年3月

日

一

二

三

四

五

六

推土机

Golang HTTP编程及源码解析-请求/响应处理

1. HTTP协议

2. HTTP请求报文格式

3. HTTP响应报文格式

4. Golang HTTP请求处理

4.1 请求行

4.2 请求头

4.3 请求体

5. Golang HTTP响应处理

公告

常用链接

最新随笔

积分与排名

随笔分类 (21)

随笔档案 (29)

阅读排行榜

评论排行榜

推荐排行榜

最新评论

	func requestLineHandler(w http.ResponseWriter, r *http.Request) {
	// 请求行
	fmt.Fprintf(w, "\nresp method:%v url:%v Proto:%v\n", r.Method, r.URL, r.Proto)
	// URL参数获取
	fmt.Fprintf(w, "resp URL查询参数:%v\n", r.URL.Query())
	w.WriteHeader(http.StatusOK)
	}

	func main() {
	// 1. 新建路由解码器
	h := http.NewServeMux()
	// 2. 路由注册
	h.HandleFunc("/reqline", requestLineHandler)
	// 3. 服务启动阻塞监听
	http.ListenAndServe(":8000", h)
	}

	$ curl -v -X POST http://localhost:8000/reqline?name=jack
	* Trying 127.0.0.1:8000...
	* Connected to localhost (127.0.0.1) port 8000 (#0)
	> POST /reqline?name=jack HTTP/1.1
	> Host: localhost:8000
	> User-Agent: curl/7.86.0
	> Accept: /
	>
	* Mark bundle as not supporting multiuse
	< HTTP/1.1 200 OK
	< Date: Sat, 04 Mar 2023 12:13:25 GMT
	< Content-Length: 94
	< Content-Type: text/plain; charset=utf-8
	<

	resp method:POST url:/reqline?name=jack Proto:HTTP/1.1
	resp URL查询参数:map[name:[jack]]

	func requestHeaderHandler(w http.ResponseWriter, r *http.Request) {
	// 头部
	fmt.Fprintf(w, "header:\n")
	for key, val := range r.Header {
	fmt.Fprintf(w, "%v:%v\n", key, val)
	}
	fmt.Fprintf(w, "Get(\"Content-Type\"):%v\n", r.Header.Get("Content-Type"))
	}
	func main() {
	// 1. 新建路由解码器
	h := http.NewServeMux()
	// 2. 路由注册
	h.HandleFunc("/reqheader", requestHeaderHandler)
	// 3. 服务启动阻塞监听
	http.ListenAndServe(":8000", h)
	}

	$ curl -v -d "age=18" -H "Accept-Language:en-US" -H "version:1.1.1" http://localhost:8000/reqheader
	* Trying 127.0.0.1:8000...
	* Connected to localhost (127.0.0.1) port 8000 (#0)
	> POST /reqheader HTTP/1.1
	> Host: localhost:8000
	> User-Agent: curl/7.86.0
	> Accept: /
	> Accept-Language:en-US
	> version:1.1.1
	> Content-Length: 6
	> Content-Type: application/x-www-form-urlencoded
	>
	* Mark bundle as not supporting multiuse
	< HTTP/1.1 200 OK
	< Date: Sat, 04 Mar 2023 12:21:13 GMT
	< Content-Length: 208
	< Content-Type: text/plain; charset=utf-8
	<
	header:
	Version:[1.1.1]
	Content-Length:[6]
	Content-Type:[application/x-www-form-urlencoded]
	User-Agent:[curl/7.86.0]
	Accept:[/]
	Accept-Language:[en-US]
	Get("Content-Type"):application/x-www-form-urlencoded

	func requestBodyHandler(w http.ResponseWriter, r *http.Request) {
	contentType := r.Header.Get("Content-Type")
	fmt.Fprintf(w, "Content-Type:%v\n", contentType)
	// URL参数获取
	fmt.Fprintf(w, "URL查询参数:%v\n", r.URL.Query())
	// 解析 Content-Type为multipart/form-data的请求体
	switch contentType {
	case "application/x-www-form-urlencoded": // 表单默认的提交数据的格式
	// 解析 URL查询参数和 POST、PUT、PATCH的请求体参数
	// 并将结果放入r.Form, 且POST、PUT、PATCH的请求体参数的优先级比URL查询参数高
	// r.PostForm只存放POST、PUT、PATCH的请求体参数
	r.ParseForm()
	fmt.Fprintf(w, "PostForm:%v\n", r.PostForm)
	fmt.Fprintf(w, "Form:%v\n", r.Form)
	case "application/json": // json数据格式
	json, _ := ioutil.ReadAll(r.Body)
	fmt.Fprintf(w, "Json:%v", string(json))
	default:
	fmt.Fprintf(w, "unkown Content-Type")
	}
	}

	$ curl -v http://localhost:8000/reqbody?name=jack -d "age=18" -d "name=juli"
	* Trying 127.0.0.1:8000...
	* Connected to localhost (127.0.0.1) port 8000 (#0)
	> POST /reqbody?name=jack HTTP/1.1
	> Host: localhost:8000
	> User-Agent: curl/7.86.0
	> Accept: /
	> Content-Length: 16
	> Content-Type: application/x-www-form-urlencoded
	>
	* Mark bundle as not supporting multiuse
	< HTTP/1.1 200 OK
	< Date: Sat, 04 Mar 2023 12:35:15 GMT
	< Content-Length: 151
	< Content-Type: text/plain; charset=utf-8
	<
	Content-Type:application/x-www-form-urlencoded
	URL查询参数:map[name:[jack]]
	PostForm:map[age:[18] name:[juli]]
	Form:map[age:[18] name:[juli jack]]

	$ curl -v http://localhost:8000/reqbody -H "Content-Type: application/json" -d "{"name":"jack","age":"18"}"
	* Trying 127.0.0.1:8000...
	* Connected to localhost (127.0.0.1) port 8000 (#0)
	> POST /reqbody HTTP/1.1
	> Host: localhost:8000
	> User-Agent: curl/7.86.0
	> Accept: /
	> Content-Type: application/json
	> Content-Length: 18
	>
	* Mark bundle as not supporting multiuse
	< HTTP/1.1 200 OK
	< Date: Sat, 04 Mar 2023 12:38:34 GMT
	< Content-Length: 75
	< Content-Type: text/plain; charset=utf-8
	<
	Content-Type:application/json
	URL查询参数:map[]
	Json:{name:jack,age:18}

	func respHandler(w http.ResponseWriter, r *http.Request) {
	// 设置响应头
	w.Header().Set("name", "jack")
	// 设置cookie
	ck := &http.Cookie{
	Name: "testCookie",
	Value: "cookieval",
	Path: "/",
	HttpOnly: true,
	}
	http.SetCookie(w, ck)
	// 设置响应体
	w.Write([]byte("hello i'm jack"))
	// 设置响应状态码
	w.WriteHeader(http.StatusOK)
	}

	func main() {
	// 1. 新建路由解码器
	h := http.NewServeMux()
	// 2. 路由注册
	h.HandleFunc("/resp", respHandler)
	// 3. 服务启动阻塞监听
	http.ListenAndServe(":8000", h)
	}

	$ curl -v http://localhost:8000/resp
	* Trying 127.0.0.1:8000...
	* Connected to localhost (127.0.0.1) port 8000 (#0)
	> GET /resp HTTP/1.1
	> Host: localhost:8000
	> User-Agent: curl/7.86.0
	> Accept: /
	>
	* Mark bundle as not supporting multiuse
	< HTTP/1.1 200 OK
	< Name: jack
	< Set-Cookie: testCookie=cookieval; Path=/; HttpOnly
	< Date: Sat, 04 Mar 2023 13:15:15 GMT
	< Content-Length: 14
	< Content-Type: text/plain; charset=utf-8
	<
	hello i'm jack