reprogl

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package avatar
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import (
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	"errors"
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	"fmt"
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	"image"
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	"log"
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	"net/http"
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	"runtime"
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	"strings"
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	"time"
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	"xelbot.com/reprogl/container"
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)
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var (
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	GravatarNotFound = errors.New("gravatar: not found")
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	chanBuf          chan struct{}
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)
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func init() {
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	chanBuf = make(chan struct{}, (runtime.NumCPU()/2)+1)
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}
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type MaybeGravatar interface {
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	NeedToCheckGravatar() bool
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	GetEmail() string
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}
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func tryGravatar(object MaybeGravatar, size int, logger *log.Logger) (image.Image, error) {
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	if !object.NeedToCheckGravatar() {
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		return nil, GravatarNotFound
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	}
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	hash := gravatarHash(object.GetEmail())
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	request, err := http.NewRequest(
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		http.MethodGet,
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		fmt.Sprintf(
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			"https://www.gravatar.com/avatar/%s?s=%d&d=404",
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			hash,
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			size,
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		),
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		nil)
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	if err != nil {
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		return nil, err
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	}
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	logger.Printf("[IMG] check gravatar hash %s on gravatar.com\n", hash)
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	resp, err := sendRequest(request)
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	if err != nil {
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		return nil, err
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	}
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	if resp.StatusCode != http.StatusOK {
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		return nil, GravatarNotFound
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	}
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	contentType, ok := resp.Header["Content-Type"]
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	if !ok || !strings.HasPrefix(contentType[0], "image") {
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		return nil, GravatarNotFound
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	}
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	defer resp.Body.Close()
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	img, _, err := image.Decode(resp.Body)
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	if err != nil {
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		return nil, err
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	}
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	return img, nil
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}
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func gravatarHash(s string) string {
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	return container.MD5(strings.ToLower(strings.TrimSpace(s)))
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}
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func sendRequest(req *http.Request) (*http.Response, error) {
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	chanBuf <- struct{}{}
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	defer func() { <-chanBuf }()
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	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11")
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	client := http.Client{
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		Timeout: 5 * time.Second,
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	}
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	return client.Do(req)
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}
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