add avatar inorder to view code on github

modules/avatar/avatar.go

@@ -0,0 +1,136 @@
+package avatar
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+)
+
+var gravatar = "http://www.gravatar.com/avatar"
+
+// hash email to md5 string
+func HashEmail(email string) string {
+	h := md5.New()
+	h.Write([]byte(strings.ToLower(email)))
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+type Avatar struct {
+	Hash      string
+	cacheDir  string // image save dir
+	reqParams string
+	imagePath string
+}
+
+func New(hash string, cacheDir string) *Avatar {
+	return &Avatar{
+		Hash:     hash,
+		cacheDir: cacheDir,
+		reqParams: url.Values{
+			"d":    {"retro"},
+			"size": {"200"},
+			"r":    {"pg"}}.Encode(),
+		imagePath: filepath.Join(cacheDir, hash+".jpg"),
+	}
+}
+
+// get image from gravatar.com
+func (this *Avatar) Update() {
+	thunder.Fetch(gravatar+"/"+this.Hash+"?"+this.reqParams,
+		this.Hash+".jpg")
+}
+
+func (this *Avatar) UpdateTimeout(timeout time.Duration) {
+	select {
+	case <-time.After(timeout):
+		log.Println("timeout")
+	case <-thunder.GoFetch(gravatar+"/"+this.Hash+"?"+this.reqParams,
+		this.Hash+".jpg"):
+	}
+}
+
+var thunder = &Thunder{QueueSize: 10}
+
+type Thunder struct {
+	QueueSize int // download queue size
+	q         chan *thunderTask
+	once      sync.Once
+}
+
+func (t *Thunder) init() {
+	if t.QueueSize < 1 {
+		t.QueueSize = 1
+	}
+	t.q = make(chan *thunderTask, t.QueueSize)
+	for i := 0; i < t.QueueSize; i++ {
+		go func() {
+			for {
+				task := <-t.q
+				task.Fetch()
+			}
+		}()
+	}
+}
+
+func (t *Thunder) Fetch(url string, saveFile string) error {
+	t.once.Do(t.init)
+	task := &thunderTask{
+		Url:      url,
+		SaveFile: saveFile,
+	}
+	task.Add(1)
+	t.q <- task
+	task.Wait()
+	return task.err
+}
+
+func (t *Thunder) GoFetch(url, saveFile string) chan error {
+	c := make(chan error)
+	go func() {
+		c <- t.Fetch(url, saveFile)
+	}()
+	return c
+}
+
+// thunder download
+type thunderTask struct {
+	Url      string
+	SaveFile string
+	sync.WaitGroup
+	err error
+}
+
+func (this *thunderTask) Fetch() {
+	this.err = this.fetch()
+	this.Done()
+}
+
+func (this *thunderTask) fetch() error {
+	resp, err := http.Get(this.Url)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("status code: %d", resp.StatusCode)
+	}
+	fd, err := os.Create(this.SaveFile)
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+	_, err = io.Copy(fd, resp.Body)
+	if err != nil {
+		return err
+	}
+	return nil
+}

modules/avatar/avatar_test.go

@@ -0,0 +1,35 @@
+package avatar
+
+import (
+	"log"
+	"strconv"
+	"testing"
+	"time"
+)
+
+func TestFetch(t *testing.T) {
+	hash := HashEmail("ssx205@gmail.com")
+	avatar := New(hash, "./")
+	//avatar.Update()
+	avatar.UpdateTimeout(time.Millisecond * 200)
+	time.Sleep(5 * time.Second)
+}
+
+func TestFetchMany(t *testing.T) {
+	log.Println("start")
+	var n = 50
+	ch := make(chan bool, n)
+	for i := 0; i < n; i++ {
+		go func(i int) {
+			hash := HashEmail(strconv.Itoa(i) + "ssx205@gmail.com")
+			avatar := New(hash, "./")
+			avatar.Update()
+			log.Println("finish", hash)
+			ch <- true
+		}(i)
+	}
+	for i := 0; i < n; i++ {
+		<-ch
+	}
+	log.Println("end")
+}