By default http.Client follows redirects so it tries to query "long" link after it receives 302 and gets remote error: tls: internal error.

You may disable redirect following like so:

	client := &http.Client{
		Timeout:   3 * time.Second,
		Transport: DefaultTransports,
		CheckRedirect: func(*http.Request, []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}

Then the part to get Location header value looks weird, it should be just (after redirects are disabled):

	defer resp.Body.Close()

	return resp.Header.Get("Location"), nil

I am not sure what is going on here but this client:

package main

import (
	"log"
	"net/http"
)

func main() {
	client := &http.Client{
		Transport: &http.Transport{
			//TLSClientConfig: &tls.Config{},
		},
	}

	_, err := client.Get("https://mobile.yangkeduo.com/")
	if err != nil {
		log.Fatalf("error: %v", err)
	}
}

fails with error: Get "https://mobile.yangkeduo.com/": remote error: tls: internal error
and works if //TLSClientConfig: &tls.Config{}, is uncommented.

The actual error comes from here

Looks like server returns alert record with internal error code:

@golang/security @neild
Not 100% sure if this is "crypto" or some http/s handshake problem.

By default http.Client follows redirects so it tries to query "long" link after it receives 302 and gets remote error: tls: internal error.

You may disable redirect following like so:

	client := &http.Client{
		Timeout:   3 * time.Second,
		Transport: DefaultTransports,
		CheckRedirect: func(*http.Request, []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}

Then the part to get Location header value looks weird, it should be just (after redirects are disabled):

	defer resp.Body.Close()

	return resp.Header.Get("Location"), nil

I am not sure what is going on here but this client:

package main

import (
	"log"
	"net/http"
)

func main() {
	client := &http.Client{
		Transport: &http.Transport{
			//TLSClientConfig: &tls.Config{},
		},
	}

	_, err := client.Get("https://mobile.yangkeduo.com/")
	if err != nil {
		log.Fatalf("error: %v", err)
	}
}

fails with error: Get "https://mobile.yangkeduo.com/": remote error: tls: internal error and works if //TLSClientConfig: &tls.Config{}, is uncommented.

The actual error comes from here

go/src/crypto/tls/conn.go

Lines 712 to 713 in aa5b225

	case alertLevelError:
	return c.in.setErrorLocked(&net.OpError{Op: "remote error", Err: alert(data[1])})

Looks like server returns alert record with internal error code:

go/src/crypto/tls/common.go

Line 53 in aa5b225

recordTypeAlert recordType = 21

go/src/crypto/tls/alert.go

Line 38 in aa5b225

alertInternalError alert = 80

But I want to know why this kind of error, will lead to Ctrip number of millions of instant surge, resulting in memory leakage

But I want to know why this kind of error

The difference between transport with nil tls.Config and empty tls.Config{} is that empty tls config disables ALPN so the problem is that mobile.yangkeduo.com does not like default set of TLS extensions default go client uses.