wechat_hitxy/download.go

package main

import (
	"encoding/json"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"
	"strconv"
	"time"
)

func saveURL(url string) (tmpFile string, contentType string, err error) {
	var myClient = &http.Client{Timeout: 20 * time.Second}
	r, err := myClient.Get(url)
	if err != nil {
		log.Fatal("Fail to get URL:" + url)
		log.Fatal(err)
		return "", "", err
	}
	defer r.Body.Close()

	contentType = r.Header.Get("Content-Type")
	contentLen := r.Header.Get("Content-Length")
	len, _ := strconv.Atoi(contentLen)

	file, err := ioutil.TempFile(os.TempDir(), "wechat_hitxy_")
	// Use io.Copy to just dump the response body to the file. This supports huge files
	_, err = io.Copy(file, r.Body)
	if err != nil {
		return "", contentType, err
	}
	tmpFile = file.Name()
	file.Close()

	//see if its a video url
	if len < 4096 && contentType == "text/plain" {
		u := readVideoURL(tmpFile)
		if u != "" {
			os.Remove(tmpFile) //remove json file
			tmpFile, contentType, err = saveVideo(u)
		}
	}

	return
}

func contentType2MediaType(contentType string) (mediaType string) {
	switch contentType {
	case "image/jpeg":
		mediaType = "image"
	case "text/plain":
		mediaType = "json"
	}
	return
}

//{"video_url":"http://153.37.232.145/vweixinp.tc.qq.com/1007_6475d21fb443453b8adeac7e59cc0e1c.f10.mp4?vkey=E79C6B0DA06E7A434D15E24774F91412386D1956768C400AC93ECA5320ACAAAF050E1E1BA5C22DFD81B5EE3FBA97E928E0FC2DC597CF611B3E6641BC1AEE2892736FFE29E993F200AA4A0811FEB4E234C48516131207DDE4&sha=0&save=1"}
type videoURL struct {
	VideoURL string `json:"video_url"`
}

//readVideoURL try to read a file into json structure
//containing video_url
//
func readVideoURL(path string) (u string) {
	body, err := ioutil.ReadFile(path)
	if err == nil {
		var v = videoURL{}
		err = json.Unmarshal([]byte(body), &v)
		if err == nil {
			_, err = url.ParseRequestURI(v.VideoURL)
			if err == nil {

				return v.VideoURL
			}
		}
	}
	return ""
}

func saveVideo(path string) (tmpFile string, contentType string, err error) {
	u := readVideoURL(path)
	if u != "" {
		tmpFile, contentType, err = saveURL(u)
	}
	return
}