client.go

package dingtalk

import (
	"bytes"
	"context"
	"io/ioutil"
	"net"
	"net/http"
	"time"
)

var httpClient *http.Client

func init() {
	httpClient = &http.Client{
		Transport: &http.Transport{
			Proxy: http.ProxyFromEnvironment,
			DialContext: (&net.Dialer{
				Timeout:   30 * time.Second,
				KeepAlive: 30 * time.Second,
			}).DialContext,
			MaxIdleConns:        100,
			MaxIdleConnsPerHost: 100,
			IdleConnTimeout:     90 * time.Second,
		},
	}
}

func request(url string, body []byte) (data []byte, err error) {

	// timeout context
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(body))
	if err != nil {
		return
	}
	req.Header.Set("Content-type", "application/json")
	resp, err := httpClient.Do(req)
	if err != nil {
		return
	}

	defer resp.Body.Close()

	data, err = ioutil.ReadAll(resp.Body)
	if err != nil {
		return
	}

	return
}