第三章-HTTP

了解net/http包

• 有以下几个常用的函数

  • Get(url string) (resp *Response, err error)
  • Head(url string) (resp *Response, err error)
  • Post(url string, bodyType string, body io.Reader) (resp *Response, err error)
  • PostForm(url string, data url.Values) (resp *Response, err error)

• 简单地发送GET/POST请求

  package main
  
  import (
      "fmt"
      "io/ioutil"
      "log"
      "net/http"
      "net/url"
      "strings"
  )
  
  func main() {
      r1, err := http.Get("http://httpbin.org/get?a=1")
      if err != nil {
          log.Fatalln("Error: ", err)
      }
      defer r1.Body.Close()
      body, err := ioutil.ReadAll(r1.Body)
      if err != nil {
          log.Fatalln("Error: ", err)
      }
      fmt.Println(string(body))
      form := url.Values{}
      form.Add("foo", "bar")
      r2, err := http.Post(
          "http://httpbin.org/post",
          "application/x-www-form-urlencoded",
          strings.NewReader(form.Encode()),
      )
      if err != nil {
          log.Fatalln("Error: ", err)
      }
      defer r2.Body.Close()
      r3, err := http.PostForm(
          "http://httpbin.org/post",
          form,
      )
      if err != nil {
          log.Fatalln("Error: ", err)
      }
      defer r3.Body.Close()
  }
  

通过NewReuqest/Client拓展请求

• NewRequest定义为: NewRequest(umethod, vurl string, wbody io.Reader) (req *Request, err error)

  • 通过NewRequest自定义请求头,示例如下:

      package main
  
      import (
          "encoding/json"
          "fmt"
          "log"
          "net/http"
      )
  
      type Result struct {
          Slideshow map[string]interface{} json:"slideshow"
      }
  
      func main() {
          req, err := http.NewRequest("GET", "https://httpbin.org/json", nil)
          var client http.Client = http.Client{}
          req.Header.Add("Accept", "application/json")
          resp, err := client.Do(req)
          if err != nil {
              log.Fatalln("error:", err)
          }
          defer resp.Body.Close()
          var result Result
          if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
              log.Fatalln("error:", err)
          }
          fmt.Printf("%#v\n", result)
      }

  • 通过NewReuqest发送其他请求方法, 示例如下:

  package main
  
  import (
      "log"
      "net/http"
  )
  
  func main() {
      req, err := http.NewRequest("DELETE", "https://www.google.com/robots.txt", nil)
      var client http.Client
      resp, err := client.Do(req)
      if err != nil {
          log.Fatalln("error:", err)
      }
      defer resp.Body.Close()
  }
  

  • Client可以控制重定向, 超时时间等,示例如下:

  package main
  
  import (
      "log"
      "net/http"
      "time"
  )
  
  func main() {
      req, err := http.NewRequest("GET", "https://www.google.com/robots.txt", nil)
      var client http.Client = http.Client{
          CheckRedirect: func(req *http.Request, via []*http.Request) error {  // 禁止重定向
              return http.ErrUseLastResponse
          },
          Timeout: time.Duration(90 * time.Second),  // 90秒超时时间
      }
      resp, err := client.Do(req)
      if err != nil {
          log.Fatalln("error:", err)
      }
      defer resp.Body.Close()
  }