git: Make git server supports i18n

Make Yobi as a git server says in user's preferred language. Git
2.4.0-rc0 or more is required.

app/controllers/GitApp.java

@@ -27,13 +27,17 @@
 import models.Project;
 import models.enumeration.Operation;
 
+import com.github.zafarkhaja.semver.Version;
+import play.api.i18n.Lang;
+import play.i18n.Messages;
 import play.mvc.Controller;
 import play.mvc.Result;
 import play.mvc.With;
 import playRepository.PlayRepository;
 import playRepository.RepositoryService;
 import utils.AccessControl;
 import utils.BasicAuthAction;
+import utils.Config;
 
 public class GitApp extends Controller {
 
@@ -55,6 +59,26 @@ private static boolean isAllowed(Project project, String service) throws
 
     }
 
+    /**
+     * Checks whether the Git client allows Content-Type has a charset.
+     *
+     * Charset is allowed since Git 2.1.0.
+     *
+     * @param userAgent
+     * @return
+     */
+    private static boolean isCharsetAllowed(String userAgent) {
+        try {
+            String version = Config.semverize(userAgent.substring(userAgent.indexOf('/') + 1));
+            if (Version.valueOf(version).greaterThanOrEqualTo(Version.forIntegers(2, 1, 0))) {
+                return true;
+            }
+        } catch (Exception e) {
+            return false;
+        }
+        return false;
+    }
+
     public static Result service(String ownerName, String projectName, String service,
             boolean isAdvertise) throws IOException, UnsupportedOperationException,
             ServletException {
@@ -78,14 +102,17 @@ public static Result service(String ownerName, String projectName, String servic
             if (user.isAnonymous()) {
                 return BasicAuthAction.unauthorized(response());
             } else {
-                // If you want the Git client showing your custom message to
-                // the user, the Content-Type should be exact "text/plain"
-                // without any parameter. For more details, see the code at
-                // https://github.com/git/git/commit/426e70d4a11ce3b4f70636d57c6a0ab16ae08a00#diff-eea0ad565ec5903a11b6023755d491cfR154
-                response().setHeader("Content-Type", "text/plain");
-                return forbidden(
-                        String.format("'%s' has no permission to '%s/%s'.",
-                            user.loginId, ownerName, projectName));
+                String contentType = "text/plain", message;
+                if (isCharsetAllowed(request().getHeader("User-Agent"))) {
+                    contentType += ";charset=" + Config.getCharset();
+                    message = Messages.get(
+                            "git.error.permission", user.loginId, ownerName, projectName);
+                } else {
+                    message = Messages.get(Lang.defaultLang(),
+                            "git.error.permission", user.loginId, ownerName, projectName);
+                }
+                response().setHeader("Content-Type", contentType);
+                return forbidden(message);
             }
         }
 

conf/messages

@@ -225,6 +225,7 @@ fork.help.message.2 = Once you fork a project, you can contribute your code to t
 fork.help.title = Fork this project''s repository.
 fork.original = Forked from
 fork.redirect.exist = Move to the forked project
+git.error.permission = ''{0}'' has no permission to ''{1}/{2}''.
 issue.assignToAuthor = Assign to author
 issue.assignToMe = Assign to me
 issue.assignee = Assignee

conf/messages.ko-KR

@@ -225,6 +225,7 @@ fork.help.message.2 = 코드 보내기 기능을 사용하여 복사한 프로
 fork.help.title = 프로젝트의 코드 저장소를 복사합니다.
 fork.original = 원본 프로젝트
 fork.redirect.exist = 이전에 만들어둔 포크 프로젝트로 이동합니다.
+git.error.permission = ''{0}''님은 ''{1}/{2}'' 프로젝트에 대한 권한이 없습니다.
 issue.assignToAuthor = 등록자에게 할당하기
 issue.assignToMe = 나에게 할당하기
 issue.assignee = 담당자