如何修复 proxyconnect tcp: tls: 第一条记录看起来不像 TLS 握手

error getting cat fact: 
      Get "https://catfact.ninja/fact": 
      proxyconnect tcp: tls: first record does not look like a TLS handshake

<code>
For control over proxies, TLS configuration, keep-alives, compression, and other settings, create a Transport:
</code>

<code>    // DialContext specifies the dial function for creating unencrypted TCP connections.
    // If DialContext is nil (and the deprecated Dial below is also nil),
    // then the transport dials using package net.
    //
    // DialContext runs concurrently with calls to RoundTrip.
    // A RoundTrip call that initiates a dial may end up using
    // a connection dialed previously when the earlier connection
    // becomes idle before the later DialContext completes.
    DialContext func(ctx context.Context, network, addr string) (net.Conn, error)
</code>

<code>
This is because the proxy answers with an plain HTTP error to the strange HTTP request (which is actually the start of the TLS handshake).
</code>

<code>    tr := &http.Transport{
        TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
    }
    client := &http.Client{Transport: tr}
</code>

<code>var tr = &http.Transport{ TLSClientConfig: 
                           &tls.Config{InsecureSkipVerify: true}, } 
                           // lacks DialContext config
var client*  http.Client = &http.Client{Transport: tr} // modified * added
// var client *http.Client // code from tutorial

type CatFact struct {
    Fact   string `json:"fact"`
    Length int    `json:"length"`
}

func GetCatFact() {
    url := "http://catfact.ninja/fact" // changed from https to http
    var catFact CatFact

    err := GetJson(url, &catFact)
    if err != nil {
        fmt.Printf("error getting cat fact: %s\n", err.Error())
    } else {
        fmt.Printf("A super interesting Cat Fact: %s\n", catFact.Fact)
    }
}

func main() {
    client = &http.Client{Timeout: 10 * time.Second}
    GetCatFact()
    // same error 
    // proxyconnect tcp: tls: first record does 
    //                   not look like a TLS handshake
    // still uses https 
    // for GET catfact.ninja
}
</code>

package main

import (
    "context"
    "crypto/tls"
    "encoding/json"
    "fmt"
    "net"
    "net/http"
    "time"
)

type CatFact struct {
    Fact   string `json:"fact"`
    Length int    `json:"length"`
}

// Custom dialing function to handle connections
func customDialContext(ctx context.Context, network, addr string) (net.Conn, error) {
    conn, err := net.Dial(network, addr)
    return conn, err
}

// Function to get a cat fact
func GetCatFact(client *http.Client) {
    url := "https://catfact.ninja/fact"  // Reverted back to https
    var catFact CatFact

    err := GetJson(url, &catFact, client)
    if err != nil {
        fmt.Printf("error getting cat fact: %s\n", err.Error())
    } else {
        fmt.Printf("A super interesting Cat Fact: %s\n", catFact.Fact)
    }
}

// Function to send a GET request and decode the JSON response
func GetJson(url string, target interface{}, client *http.Client) error {
    resp, err := client.Get(url)
    if err != nil {
        return fmt.Errorf("error sending GET request: %w", err)
    }
    defer resp.Body.Close()

    if resp.StatusCode != http.StatusOK {
        return fmt.Errorf("received non-OK HTTP status: %d", resp.StatusCode)
    }

    err = json.NewDecoder(resp.Body).Decode(target)
    if err != nil {
        return fmt.Errorf("error decoding JSON response: %w", err)
    }

    return nil
}

func main() {
    // Create a custom Transport with the desired settings
    tr := &http.Transport{
        Proxy: http.ProxyFromEnvironment,  // Use the proxy settings from the environment
        DialContext: customDialContext,    // Use the custom dialing function
        TLSClientConfig: &tls.Config{
            InsecureSkipVerify: true,  // Skip certificate verification (not recommended in production)
        },
    }

    // Create a new HTTP client using the custom Transport
    client := &http.Client{
        Transport: tr,
        Timeout:   10 * time.Second,
    }

    // Call the function to get a cat fact
    GetCatFact(client)
}

tr := &http.Transport{
    TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
}
client := &http.Client{Transport: tr}