How to implement limit on number of request attempts using Go and http.Transport?

How to use Go and http.Transport to limit the number of request attempts?

When writing network requests in Go language, sometimes we need to retry the request multiple times to increase the success rate of the request. Using http.Transport and some simple code, we can easily implement a limit on the number of request attempts.

First, we need to import the net/http and net/url packages. Then, we create a custom http.Transport object and set its maximum number of attempts. The code is as follows:

package main

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

// 自定义Transport
type RetryTransport struct {
    Transport http.Transport
    Retries   int
}

// 实现RoundTrip方法
func (rt *RetryTransport) RoundTrip(request *http.Request) (*http.Response, error) {
    var (
        resp *http.Response
        err  error
    )
    for i := 0; i < rt.Retries; i++ {
        resp, err = rt.Transport.RoundTrip(request)
        if err == nil {
            // 请求成功，直接返回
            return resp, nil
        }
    }
    return nil, fmt.Errorf("maximum retries reached")
}

func main() {
    // 创建自定义Transport，并设置最大尝试次数为3次
    rt := &RetryTransport{
        Transport: http.Transport{},
        Retries:   3,
    }

    client := http.Client{
        Transport: rt,
    }

    // 构造请求
    url := "https://example.com"
    request, _ := http.NewRequest(http.MethodGet, url, nil)

    // 发送请求，并获取响应
    response, err := client.Do(request)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }
    defer response.Body.Close()

    // 输出响应的内容
    body, _ := ioutil.ReadAll(response.Body)
    fmt.Println(string(body))
}

In the above code, we define a RetryTransport structure, which contains a http.Transport object and a Retries field, used to record the maximum number of attempts. We also implement the RoundTrip method, which will be called when the request is initiated. In this method, we use a loop to try multiple requests until the maximum number of attempts is reached or the request succeeds.

In the main function, we create a custom RetryTransport object and assign it to http.Client #Transport field. Then, we use http.NewRequest to construct a request, and use client.Do to initiate the request and get the response. Finally, we print the contents of the response.

Through the above code example, we can easily implement the limit on the number of request attempts. In actual development, we can customize the maximum number of attempts of the

RetryTransport object according to our needs and configure it as needed.

To summarize, using http.Transport in the Go language and some simple code, we can easily implement a limit on the number of request attempts. This method can improve the success rate of network requests and also increase the reliability of the program. I hope this article can be helpful to you when handling network requests in Go language development.

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