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()
}