Golang.net/http包学习记录 - 铃仙的个人博客

1430 字

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Golang.net/http包学习记录

2025-04-07

Golang

/

net/http

/

HTTP

请求该网站，可以将请求的内容以json的形式返回 http://httpbin.org/

如何打印请求内容？

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// 打印请求
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dump, _ := httputil.DumpRequest(req, true)
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fmt.Println(string(dump))

Example#

流程：发送请求——>接收返回内容

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func get() {
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    r, err := http.Get("http://httpbin.org/get")
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    if err != nil {
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       panic(err)
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    }
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    //记得关闭
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    defer r.Body.Close()
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    content, err := io.ReadAll(r.Body)
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    if err != nil {
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       panic(err)
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    }
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    //回应内容
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    fmt.Println(string(content))
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}

net/http默认只封装了get和post方法，put和delete需要自己根据实现

实现方法:

NewRequest

设置Content-type

选择Client执行Do方法发送请求

接收返回内容

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// put sends an HTTP PUT request to http://httpbin.org/put and prints the response.
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// The function demonstrates how to make a PUT request with custom headers.
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// It sets the Content-Type header but sends no body in this example.
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func put() {
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 // Create a new PUT request with nil body
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 request, err := http.NewRequest(http.MethodPut, "http://httpbin.org/put", nil)
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 if err != nil {
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  panic(err) // Handle error if request creation fails
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 }
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 // Set the Content-Type header (though we're not sending any content in this example)
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 request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
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 // Send the request using the default HTTP client
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 r, err := http.DefaultClient.Do(request)
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 if err != nil {
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  panic(err) // Handle error if request fails
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 }
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 defer r.Body.Close() // Ensure the response body is closed when we're done
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 // Read the entire response body
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 content, err := io.ReadAll(r.Body)
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 if err != nil {
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  panic(err) // Handle error if reading response fails
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 }
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 // Print the response content as string
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 fmt.Println(string(content))
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}

Request#

1. 带查询参数请求#

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func requestByParams() {
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    req, err := http.NewRequest("GET", "http://httpbin.org/get", nil)
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    if err != nil {
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       panic(err)
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    }
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    //设置url参数
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    params := make(url.Values)
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    params.Set("param1", "value1")
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    params.Set("param2", "value2")
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    params.Add("param1", "value3")
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    fmt.Println(req.Method, params)
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    //编码成param1=value1&param1=value3格式
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    fmt.Println(params.Encode())
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    req.URL.RawQuery = params.Encode()
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    r, err := http.DefaultClient.Do(req)
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    if err != nil {
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       panic(err)
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    }
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    printBody(r)
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}
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//请求内容 ： param1=value1&param1=value3&param2=value2

2. 定制请求头#

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func requestByHeaders() {
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    req, err := http.NewRequest("GET", "http://httpbin.org/get", nil)
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    if err != nil {
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       panic(err)
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    }
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    //可以通过修改User-Agent简单绕过反爬
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    req.Header.Set("User-Agent", "Safari")
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    req.Header.Add("header1", "value1")
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    req.Header.Add("header2", "value2")
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    r, err := http.DefaultClient.Do(req)
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    if err != nil {
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       panic(err)
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    }
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    printBody(r)
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}

Response#

状态#

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func getStat(r *http.Response) {
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    fmt.Println(r.StatusCode) //状态码  200
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    fmt.Println(r.Status)     //状态信息  ok 200
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}

头#

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func header(r *http.Response) {
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    //Header是一个map，通过get的方式比通过at的方式好处:大小写忽略
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    fmt.Println(r.Header.Get("content-type"))
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}

编码#

需要解码的主要场景

响应内容使用非UTF-8编码时
- 网页常用编码如 GBK、ISO-8859-1(西欧)、EUC-JP(日文)等
- 若不正确解码，中文字符等会显示为乱码
Content-Type头部指定了字符集
- 如 Content-Type: text/html; charset=gbk

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func encoding(r *http.Response) {
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    //可以通过网页的头部猜测网页的编码信息
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    //引入包:golang.org/x/net/html
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    bufReader := bufio.NewReader(r.Body)
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    bytes, _ := bufReader.Peek(1024) //预读,不会移动reader的读取位置
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    //提供content-type的原因：Content-Type 提供的上下文（如语言区域）能显著提高准确性，检测优先级高
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    res, _, _ := charset.DetermineEncoding(bytes, r.Header.Get("content-type"))
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    fmt.Println(res)
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    //不解码结果
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    //rawBody, _ := io.ReadAll(bufReader)
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    //fmt.Println(string(rawBody))
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    // 当编码不是UTF-8时需要解码转换
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    //引入包:golang.org/x/text/transform，解码
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    bodyReader := transform.NewReader(bufReader, res.NewDecoder())
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    content, _ := io.ReadAll(bodyReader)
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    fmt.Println(string(content))
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}

Post#

提交表单#

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func postForm() {
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    //http.Post()
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    data := make(url.Values)
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    data.Add("name", "John Doe")
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    data.Add("email", "johndoe@gmail.com")
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    u := "http://httpbin.org/post"
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    //相当于http.Post(u,content-type,data)里让content-type="application/x-www-form-urlencoded"的封装
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    r, _ := http.PostForm(u, data)
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    defer r.Body.Close()
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    content, _ := io.ReadAll(r.Body)
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    fmt.Println(string(content))
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}

提交JSON格式内容#

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func postJson() {
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    //http.Post()
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    sourceData := struct {
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       Name  string `json:"name"`
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       Email string `json:"email"`
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    }{"John Doe", "johndoe@gmail.com"}
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    data, _ := json.Marshal(sourceData)
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    u := "http://httpbin.org/post"
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    r, _ := http.Post(u, "application/json", bytes.NewReader(data))
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    defer r.Body.Close()
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    content, _ := io.ReadAll(r.Body)
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    fmt.Println(string(content))
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}

提交文件#

muiltipart实现拼接请求
multipart会随机创建一个boundary

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func postFile() {
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    //数据缓冲区
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    body := &bytes.Buffer{}
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    //创建拼接类
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    writer := multipart.NewWriter(body)
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    //增加字段
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    _ = writer.WriteField("name", "John Doe")
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    _ = writer.WriteField("email", "johndoe@gmail.com")
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    //上传文件 表单名 + 文件名
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    uploadFile_1, _ := writer.CreateFormFile("uploadfile_1", "test.jpg")
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    file, _ := os.Open("./request.go")
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    defer file.Close()
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    _, err := io.Copy(uploadFile_1, file)
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    if err != nil {
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       return
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    }
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    //关闭拼接
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    _ = writer.Close()
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    fmt.Println(writer.FormDataContentType())
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    fmt.Println(body)
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    r, _ := http.Post("http://httpbin.org/post", writer.FormDataContentType(), body)
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    defer r.Body.Close()
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    content, _ := io.ReadAll(r.Body)
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    fmt.Println(string(content))
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}

Download#

实现带进度条的下载

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func downloadWithProcess(url, filename string) {
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    r, err := http.Get(url)
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    if err != nil {
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       fmt.Println(err)
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       return
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    }
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    defer func(Body io.ReadCloser) {
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       err := Body.Close()
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       if err != nil {
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          fmt.Println(err)
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       }
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    }(r.Body)
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    out, err := os.Create(filename)
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    if err != nil {
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       fmt.Println(err)
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       return
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    }
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    defer func(out *os.File) {
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       err := out.Close()
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       if err != nil {
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          fmt.Println(err)
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       }
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    }(out)
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    newReader := &Reader{
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       Reader: r.Body,
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       Total:  r.ContentLength,
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    }
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    _, err = io.Copy(out, newReader)
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    if err != nil {
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       fmt.Println(err)
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    }
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    fmt.Println("\nDone")
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}
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// Reader 重写Reader实现进度条功能
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// 本质是io.copy内部有循环调用Read，而我们重写了Read，才能实现进度条刷新
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type Reader struct {
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    io.Reader
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    Total   int64
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    Current int64
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}
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func (r *Reader) Read(p []byte) (n int, err error) {
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    n, err = r.Reader.Read(p)
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    r.Current += int64(n)
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    // \r实现每次打印都回到行首
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    fmt.Printf("\rDownloading: %.2f of %%100", float64(r.Current*10000/r.Total)/100)
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    return
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}

Redirect#

DefaultClient是包内提供的一个已经设置了一些默认属性和Client变量可以如下根据需求自定义client

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//默认的检查重定向实现
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func defaultCheckRedirect(req *Request, via []*Request) error {
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  if len(via) >= 10 {
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   return errors.New("stopped after 10 redirects")
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  }
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  return nil
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}

设置重定向上限#

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func redirectLimits() {
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    client := &http.Client{
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       CheckRedirect: func(r *http.Request, via []*http.Request) error {
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          if len(via) >= 10 {
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             //如果重定向次数过多
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             return errors.New("stopped after 10 redirects")
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          }
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          return nil
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       },
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    }
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    //重定向11次，报错
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    resp, err := client.Get("https://httpbin.org/absolute-redirect/11")
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    if err != nil {
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       fmt.Println(err)
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       return
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    }
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    defer resp.Body.Close()
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    content, _ := io.ReadAll(resp.Body)
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    fmt.Println(string(content))
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}

禁止重定向#

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client := &http.Client{
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    CheckRedirect: func(r *http.Request, via []*http.Request) error {
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        return http.ErrUseLastResponse
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    },
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}

![cookie示意图](截屏2025-04-19 16.28.32.png)

cookie 的分类有两种，一种是会话期 cookie，一种是持久性 cookie

手动附加Cookie#

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// 不用jar手动附加cookie
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func redirWithCookieManual() {
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    client := &http.Client{
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       CheckRedirect: func(r *http.Request, via []*http.Request) error {
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          //禁止重定向
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          return http.ErrUseLastResponse
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       },
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    }
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    firstReq, _ := http.NewRequest(http.MethodGet, "https://httpbin.org/cookies/set?freeform=sada&name=tie", nil)
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    firstRes, _ := client.Do(firstReq)
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    defer firstRes.Body.Close()
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    //获得服务端返回的cookies
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    //手动重定向地址
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    secondReq, _ := http.NewRequest(http.MethodGet, "https://httpbin.org/cookies", nil)
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    for _, cookie := range firstRes.Cookies() {
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       //将cookie附加到重定向的请求中
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       secondReq.AddCookie(cookie)
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    }
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    secondRes, _ := client.Do(secondReq)
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    defer secondRes.Body.Close()
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    content, _ := io.ReadAll(secondRes.Body)
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    fmt.Println(string(content))
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}

使用Jar自动附加Cookie#

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// 使用Jar附加cookie
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func jarCookie() {
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    jar, _ := cookiejar.New(nil)
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    client := &http.Client{
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       Jar: jar,
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    }
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    r, _ := client.Get("https://httpbin.org/cookies/set?freeform=sada&name=tie")
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    defer r.Body.Close()
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    _, _ = io.Copy(os.Stdout, r.Body)
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}

标准库只提供了会话期cookie

Proxy#

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proxyUrl, _ := url.Parse("http://127.0.0.1:7897")  //代理启动的端口
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t := http.Transport{
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    Proxy: http.ProxyURL(proxyUrl),
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}
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//代理一般分两种，http代理和shadowsocks的代理,socks5
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client := &http.Client{Transport: &t}
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r, _ := client.Get("https://google.com")
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defer r.Body.Close()
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_, _ = io.Copy(os.Stdout, r.Body)

Golang.net/http包学习记录

https://fuwari.vercel.app/posts/httpnet包笔记/

作者

Lorem Ipsum

发布于

2025-04-07

许可协议

CC BY-NC-SA 4.0

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