diff --git a/src/main/scala/app/AccountController.scala b/src/main/scala/app/AccountController.scala
index 3304480..1db5882 100644
--- a/src/main/scala/app/AccountController.scala
+++ b/src/main/scala/app/AccountController.scala
@@ -5,6 +5,7 @@
 import util.StringUtil._
 import util.Directory._
 import util.ControlUtil._
+import util.Implicits._
 import ssh.SshUtil
 import jp.sf.amateras.scalatra.forms._
 import org.apache.commons.io.FileUtils
diff --git a/src/main/scala/app/ControllerBase.scala b/src/main/scala/app/ControllerBase.scala
index 2bdc417..b36d53c 100644
--- a/src/main/scala/app/ControllerBase.scala
+++ b/src/main/scala/app/ControllerBase.scala
@@ -9,8 +9,7 @@
 import org.json4s._
 import jp.sf.amateras.scalatra.forms._
 import org.apache.commons.io.FileUtils
-import slick.jdbc.JdbcBackend
-import model.Account
+import model._
 import service.{SystemSettingsService, AccountService}
 import javax.servlet.http.{HttpServletResponse, HttpServletRequest}
 import javax.servlet.{FilterChain, ServletResponse, ServletRequest}
@@ -25,10 +24,6 @@
 
   implicit val jsonFormats = DefaultFormats
 
-  // Convert to slick session.
-  implicit def request2Session(implicit request: HttpServletRequest): JdbcBackend#Session =
-    request.getAttribute(Keys.Request.DBSession).asInstanceOf[JdbcBackend#Session]
-
   // Don't set content type via Accept header.
   override def format(implicit request: HttpServletRequest) = ""
 
diff --git a/src/main/scala/app/IndexController.scala b/src/main/scala/app/IndexController.scala
index 802b9b1..84270b8 100644
--- a/src/main/scala/app/IndexController.scala
+++ b/src/main/scala/app/IndexController.scala
@@ -1,6 +1,7 @@
 package app
 
 import util._
+import util.Implicits._
 import service._
 import jp.sf.amateras.scalatra.forms._
 
diff --git a/src/main/scala/app/LabelsController.scala b/src/main/scala/app/LabelsController.scala
index acbfef8..2ac47fc 100644
--- a/src/main/scala/app/LabelsController.scala
+++ b/src/main/scala/app/LabelsController.scala
@@ -3,6 +3,7 @@
 import jp.sf.amateras.scalatra.forms._
 import service._
 import util.CollaboratorsAuthenticator
+import util.Implicits._
 import org.scalatra.i18n.Messages
 
 class LabelsController extends LabelsControllerBase
diff --git a/src/main/scala/app/RepositorySettingsController.scala b/src/main/scala/app/RepositorySettingsController.scala
index 92b4360..1f2c35e 100644
--- a/src/main/scala/app/RepositorySettingsController.scala
+++ b/src/main/scala/app/RepositorySettingsController.scala
@@ -2,13 +2,14 @@
 
 import service._
 import util.Directory._
+import util.ControlUtil._
+import util.Implicits._
 import util.{UsersAuthenticator, OwnerAuthenticator}
+import util.JGitUtil.CommitInfo
 import jp.sf.amateras.scalatra.forms._
 import org.apache.commons.io.FileUtils
 import org.scalatra.i18n.Messages
 import service.WebHookService.WebHookPayload
-import util.JGitUtil.CommitInfo
-import util.ControlUtil._
 import org.eclipse.jgit.api.Git
 
 class RepositorySettingsController extends RepositorySettingsControllerBase
diff --git a/src/main/scala/app/UserManagementController.scala b/src/main/scala/app/UserManagementController.scala
index dc3543c..ee568f3 100644
--- a/src/main/scala/app/UserManagementController.scala
+++ b/src/main/scala/app/UserManagementController.scala
@@ -4,10 +4,11 @@
 import util.AdminAuthenticator
 import util.StringUtil._
 import util.ControlUtil._
+import util.Directory._
+import util.Implicits._
 import jp.sf.amateras.scalatra.forms._
 import org.scalatra.i18n.Messages
 import org.apache.commons.io.FileUtils
-import util.Directory._
 
 class UserManagementController extends UserManagementControllerBase
   with AccountService with RepositoryService with AdminAuthenticator
diff --git a/src/main/scala/app/WikiController.scala b/src/main/scala/app/WikiController.scala
index d7399ed..5270d03 100644
--- a/src/main/scala/app/WikiController.scala
+++ b/src/main/scala/app/WikiController.scala
@@ -4,10 +4,10 @@
 import util._
 import util.Directory._
 import util.ControlUtil._
+import util.Implicits._
 import jp.sf.amateras.scalatra.forms._
 import org.eclipse.jgit.api.Git
 import org.scalatra.i18n.Messages
-import scala.Some
 import java.util.ResourceBundle
 
 class WikiController extends WikiControllerBase 
diff --git a/src/main/scala/service/RequestCache.scala b/src/main/scala/service/RequestCache.scala
index b53cc28..34c5ef3 100644
--- a/src/main/scala/service/RequestCache.scala
+++ b/src/main/scala/service/RequestCache.scala
@@ -2,6 +2,7 @@
 
 import model._
 import slick.jdbc.JdbcBackend
+import util.Implicits.request2Session
 
 /**
  * This service is used for a view helper mainly.
@@ -11,22 +12,25 @@
  */
 trait RequestCache extends SystemSettingsService with AccountService with IssuesService {
 
+  private implicit def context2Session(implicit context: app.Context): JdbcBackend#Session =
+    request2Session(context.request)
+
   def getIssue(userName: String, repositoryName: String, issueId: String)
-              (implicit context: app.Context, session: JdbcBackend#Session): Option[Issue] = {
+              (implicit context: app.Context): Option[Issue] = {
     context.cache(s"issue.${userName}/${repositoryName}#${issueId}"){
       super.getIssue(userName, repositoryName, issueId)
     }
   }
 
   def getAccountByUserName(userName: String)
-                          (implicit context: app.Context, session: JdbcBackend#Session): Option[Account] = {
+                          (implicit context: app.Context): Option[Account] = {
     context.cache(s"account.${userName}"){
       super.getAccountByUserName(userName)
     }
   }
 
   def getAccountByMailAddress(mailAddress: String)
-                             (implicit context: app.Context, session: JdbcBackend#Session): Option[Account] = {
+                             (implicit context: app.Context): Option[Account] = {
     context.cache(s"account.${mailAddress}"){
       super.getAccountByMailAddress(mailAddress)
     }
diff --git a/src/main/scala/servlet/BasicAuthenticationFilter.scala b/src/main/scala/servlet/BasicAuthenticationFilter.scala
index aab6e21..64d85ad 100644
--- a/src/main/scala/servlet/BasicAuthenticationFilter.scala
+++ b/src/main/scala/servlet/BasicAuthenticationFilter.scala
@@ -3,7 +3,7 @@
 import javax.servlet._
 import javax.servlet.http._
 import service.{SystemSettingsService, AccountService, RepositoryService}
-import model.Account
+import model._
 import org.slf4j.LoggerFactory
 import slick.jdbc.JdbcBackend
 import util.Implicits._
@@ -22,9 +22,8 @@
   def destroy(): Unit = {}
   
   def doFilter(req: ServletRequest, res: ServletResponse, chain: FilterChain): Unit = {
-    val request  = req.asInstanceOf[HttpServletRequest]
+    implicit val request  = req.asInstanceOf[HttpServletRequest]
     val response = res.asInstanceOf[HttpServletResponse]
-    implicit val session = req.getAttribute(Keys.Request.DBSession).asInstanceOf[JdbcBackend#Session]
 
     val wrappedResponse = new HttpServletResponseWrapper(response){
       override def setCharacterEncoding(encoding: String) = {}
diff --git a/src/main/scala/servlet/GitRepositoryServlet.scala b/src/main/scala/servlet/GitRepositoryServlet.scala
index bb357ad..0b19858 100644
--- a/src/main/scala/servlet/GitRepositoryServlet.scala
+++ b/src/main/scala/servlet/GitRepositoryServlet.scala
@@ -17,6 +17,7 @@
 import org.eclipse.jgit.api.Git
 import util.JGitUtil.CommitInfo
 import service.IssuesService.IssueSearchCondition
+import slick.jdbc.JdbcBackend
 
 /**
  * Provides Git repository via HTTP.
@@ -64,7 +65,7 @@
 }
 
 class GitBucketReceivePackFactory extends ReceivePackFactory[HttpServletRequest] with SystemSettingsService {
-  
+
   private val logger = LoggerFactory.getLogger(classOf[GitBucketReceivePackFactory])
 
   override def create(request: HttpServletRequest, db: Repository): ReceivePack = {
@@ -81,9 +82,11 @@
       logger.debug("repository:" + owner + "/" + repository)
 
       if(!repository.endsWith(".wiki")){
-        val hook = new CommitLogHook(owner, repository, pusher, baseUrl(request))
-        receivePack.setPreReceiveHook(hook)
-        receivePack.setPostReceiveHook(hook)
+        defining(request) { implicit r =>
+          val hook = new CommitLogHook(owner, repository, pusher, baseUrl)
+          receivePack.setPreReceiveHook(hook)
+          receivePack.setPostReceiveHook(hook)
+        }
       }
       receivePack
     }
@@ -92,7 +95,8 @@
 
 import scala.collection.JavaConverters._
 
-class CommitLogHook(owner: String, repository: String, pusher: String, baseUrl: String) extends PostReceiveHook with PreReceiveHook
+class CommitLogHook(owner: String, repository: String, pusher: String, baseUrl: String)(implicit session: JdbcBackend#Session)
+  extends PostReceiveHook with PreReceiveHook
   with RepositoryService with AccountService with IssuesService with ActivityService with PullRequestService with WebHookService {
   
   private val logger = LoggerFactory.getLogger(classOf[CommitLogHook])