http client

http client.md

func client() *http.Client {
	//判断url是否有效
	//没有http://开头，就加上http://
	if !strings.HasPrefix(feed, "http") {
		feed = "http://" + feed
	}

	//判断url是否合理
	host, err := url.ParseRequestURI(feed)
		if err != nil {
	}

	//判断是否能解析到对应的host记录
	_, err = net.LookupIP(host.Host)
		if err != nil {
	}

	//向主机请求数据
	client := &http.Client{
		Transport: &http.Transport{
			Dial: func(netw, addr string) (net.Conn, error) {
				deadline := time.Now().Add(10 * time.Second)
				c, err := net.DialTimeout(netw, addr, 5*time.Second) //连接超时时间
				if err != nil {
					return nil, err
				}

				c.SetDeadline(deadline)
				return c, nil
			},
		},
	}

	req, err := http.NewRequest("GET", feed, nil)
	if err != nil {
	}

	//数据传输压缩
	//告诉主机 支持gzip 数据请求回来后 ungzip
	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; UJCspider/0.1; +http://ujiecao.com/help)")
	req.Header.Set("Accept-Encoding", "gzip")

	resp, err := client.Do(req)
	if err != nil {
	}

	defer resp.Body.Close()

	var reader io.ReadCloser
	switch resp.Header.Get("Content-Encoding") {
	case "gzip":
		reader, _ = gzip.NewReader(resp.Body)
		defer reader.Close()
	default:
		reader = resp.Body
	}
	
}