Direct avatar rendering (#13649)

* Direct avatar rendering

This adds new template helpers for avatar rendering which output image
elements with direct links to avatars which makes them cacheable by the
browsers.

This should be a major performance improvment for pages with many avatars.

* fix avatars of other user's profile pages

* fix top border on user avatar name

* uncircle avatars

* remove old incomplete avatar selector

* use title attribute for name and add it back on blame

* minor refactor

* tweak comments

* fix url path join and adjust test to new result

* dedupe functions

models/avatar.go

@@ -8,9 +8,13 @@ import (
 	"crypto/md5"
 	"fmt"
 	"net/url"
+	"path"
+	"strconv"
 	"strings"
 
+	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/cache"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 )
 
@@ -20,6 +24,28 @@ type EmailHash struct {
 	Email string `xorm:"UNIQUE NOT NULL"`
 }
 
+// DefaultAvatarLink the default avatar link
+func DefaultAvatarLink() string {
+	u, err := url.Parse(setting.AppSubURL)
+	if err != nil {
+		log.Error("GetUserByEmail: %v", err)
+		return ""
+	}
+
+	u.Path = path.Join(u.Path, "/img/avatar_default.png")
+	return u.String()
+}
+
+// DefaultAvatarSize is a sentinel value for the default avatar size, as
+// determined by the avatar-hosting service.
+const DefaultAvatarSize = -1
+
+// HashEmail hashes email address to MD5 string.
+// https://en.gravatar.com/site/implement/hash/
+func HashEmail(email string) string {
+	return base.EncodeMD5(strings.ToLower(strings.TrimSpace(email)))
+}
+
 // GetEmailForHash converts a provided md5sum to the email
 func GetEmailForHash(md5Sum string) (string, error) {
 	return cache.GetString("Avatar:"+md5Sum, func() (string, error) {
@@ -32,8 +58,24 @@ func GetEmailForHash(md5Sum string) (string, error) {
 	})
 }
 
-// AvatarLink returns an avatar link for a provided email
-func AvatarLink(email string) string {
+// LibravatarURL returns the URL for the given email. This function should only
+// be called if a federated avatar service is enabled.
+func LibravatarURL(email string) (*url.URL, error) {
+	urlStr, err := setting.LibravatarService.FromEmail(email)
+	if err != nil {
+		log.Error("LibravatarService.FromEmail(email=%s): error %v", email, err)
+		return nil, err
+	}
+	u, err := url.Parse(urlStr)
+	if err != nil {
+		log.Error("Failed to parse libravatar url(%s): error %v", urlStr, err)
+		return nil, err
+	}
+	return u, nil
+}
+
+// HashedAvatarLink returns an avatar link for a provided email
+func HashedAvatarLink(email string) string {
 	lowerEmail := strings.ToLower(strings.TrimSpace(email))
 	sum := fmt.Sprintf("%x", md5.Sum([]byte(lowerEmail)))
 	_, _ = cache.GetString("Avatar:"+sum, func() (string, error) {
@@ -57,3 +99,34 @@ func AvatarLink(email string) string {
 	})
 	return setting.AppSubURL + "/avatar/" + url.PathEscape(sum)
 }
+
+// MakeFinalAvatarURL constructs the final avatar URL string
+func MakeFinalAvatarURL(u *url.URL, size int) string {
+	vals := u.Query()
+	vals.Set("d", "identicon")
+	if size != DefaultAvatarSize {
+		vals.Set("s", strconv.Itoa(size))
+	}
+	u.RawQuery = vals.Encode()
+	return u.String()
+}
+
+// SizedAvatarLink returns a sized link to the avatar for the given email address.
+func SizedAvatarLink(email string, size int) string {
+	var avatarURL *url.URL
+	if setting.EnableFederatedAvatar && setting.LibravatarService != nil {
+		// This is the slow path that would need to call LibravatarURL() which
+		// does DNS lookups. Avoid it by issuing a redirect so we don't block
+		// the template render with network requests.
+		return HashedAvatarLink(email)
+	} else if !setting.DisableGravatar {
+		// copy GravatarSourceURL, because we will modify its Path.
+		copyOfGravatarSourceURL := *setting.GravatarSourceURL
+		avatarURL = &copyOfGravatarSourceURL
+		avatarURL.Path = path.Join(avatarURL.Path, HashEmail(email))
+	} else {
+		return DefaultAvatarLink()
+	}
+
+	return MakeFinalAvatarURL(avatarURL, size)
+}