Proxy configuration method and practice of http.Transport in Go language

Proxy configuration method and practice of http.Transport in Go language

In Go language, we can use http.Transport to send HTTP requests. http.Transport provides a simple and efficient way to configure and manage the transport of HTTP requests.

A proxy is a common method of network communication used to relay between the client and the target server. By configuring a proxy, we can access blocked sites, bypass network restrictions, and even perform some network debugging and testing work. In Go language, we can use http.Transport to configure and use the proxy.

Below we will introduce how to configure the http.Transport proxy in the Go language and provide some practical examples.

1. Simple proxy

First, we need to import the "net/http" and "net/url" packages:

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

Next, we can use http.ProxyURL Function to create a proxy URL. The format of the proxy URL is "protocol://hostname:port", where protocol can be "http" or "https", hostname is the domain name or IP address of the proxy server, and port is the port number of the proxy server.

proxyStr := "http://localhost:8888"
proxyURL, err := url.Parse(proxyStr)
if err != nil {
    fmt.Println("Error parsing proxy URL:", err)
    return
}

Then, we can create a http.Transport and pass the proxy URL to its Proxy field:

transport := &http.Transport{
    Proxy: http.ProxyURL(proxyURL),
}

Next, we can create a http.Client and use the just created http.Transport:

client := &http.Client{
    Transport: transport,
}

Now, we can use the created http.Client to send HTTP requests:

resp, err := client.Get("http://example.com")
if err != nil {
    fmt.Println("Error sending request:", err)
    return
}
defer resp.Body.Close()

// 处理响应

The above is a simple proxy method to configure http.Transport.

2. Proxy Authentication

Some proxy servers require authentication before they can be used. In this case, we can set the type of the Proxy field of http.Transport to "proxy.Func" and provide a function to implement the proxy authentication logic.

The following is an example:

proxyAuth := &proxy.Auth{
    User:     "username",
    Password: "password",
}

transport := &http.Transport{
    Proxy: http.ProxyURL(proxyURL),
}

proxyTransport := &proxy.Transport{
    Proxy:         transport.Proxy,
    Dial:          transport.Dial,
    DialTLS:       transport.DialTLS,
    TLSClientConfig: transport.TLSClientConfig,
    ProxyConnectHeader: http.Header{},
}

proxyTransport.ProxyConnectHeader.Add("Proxy-Authorization", proxyAuth.ProxyAuthentication())

client := &http.Client{
    Transport: proxyTransport,
}

resp, err := client.Get("http://example.com")
if err != nil {
    fmt.Println("Error sending request:", err)
    return
}
defer resp.Body.Close()

// 处理响应

In the above example, we use proxy.Auth to provide the username and password for proxy authentication. Then, we created a proxy.Transport, specified the various fields of http.Transport, and added the Proxy-Authorization header to the ProxyConnectHeader. Next, we use the created proxy.Transport as the Transport of http.Client and continue to send HTTP requests.

3. Proxy connection pool

In actual development, we usually need to maintain multiple connections to the proxy server to improve performance.

In the Go language, we can configure the size of the proxy connection pool and the maximum number of idle connections for each proxy server by setting the MaxIdleConns and MaxIdleConnsPerHost fields of http.Transport.

The following is an example:

transport := &http.Transport{
    Proxy: http.ProxyURL(proxyURL),
    MaxIdleConns:        100,
    MaxIdleConnsPerHost: 10,
}

client := &http.Client{
    Transport: transport,
}

resp, err := client.Get("http://example.com")
if err != nil {
    fmt.Println("Error sending request:", err)
    return
}
defer resp.Body.Close()

// 处理响应

In the above example, we set MaxIdleConns to 100, which means that the connection pool maintains a maximum of 100 idle connections. At the same time, we also set MaxIdleConnsPerHost to 10, which means that each proxy server can maintain up to 10 idle connections.

In actual applications, adjust these two values ​​appropriately as needed to achieve the best performance.

Summary:

By using the proxy configuration of http.Transport, we can easily implement the proxy function in the Go language. We can simply configure the proxy URL, or perform proxy authentication, and perform performance optimization through connection pooling.

I hope this article will help you configure and use the http.Transport proxy in the Go language. I wish you good results in your development process!

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