Go语言实现一个Http Server框架(一) http库的使用

func readBodyOnce(w http.ResponseWriter, r *http.Request)  {
	body, err := io.ReadAll(r.Body)
	if err != nil {
		fmt.Fprintf(w, "read body failed: %v", err)
		// 记住要返回，不然就还会执行后面的代码
		return
	}
	// 类型转换，将 []byte 转换为 string
	fmt.Fprintf(w, "read the data: %s \n", string(body))

	// 尝试再次读取，啥也读不到，但是也不会报错
	body, err = io.ReadAll(r.Body)
	if err != nil {
		// 不会进来这里
		fmt.Fprintf(w, "read the data one more time got error: %v", err)
		return
	}
	fmt.Fprintf(w, "read the data one more time: [%s] and read data length %d \n", string(body), len(body))
}

func getBodyIsNil(w http.ResponseWriter, r *http.Request) {
	if r.GetBody == nil {
		fmt.Fprint(w, "GetBody is nil \n")
	} else {
		fmt.Fprintf(w, "GetBody not nil \n")
	}
}

func queryParams(w http.ResponseWriter, r *http.Request) {
	values := r.URL.Query()
	fmt.Fprintf(w, "query is %v\n", values)
}

func header(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "header is %v\n", r.Header)
}

func method(w http.ResponseWriter, r *http.Request) {  
    fmt.Fprintf(w, "Method is %v\n", r.Method)  
}