(refs #34)Link conversion checks existence of accounts and issues.

src/main/scala/service/RequestCache.scala

@@ -0,0 +1,26 @@
+package service
+
+import model._
+
+/**
+ * This service is used for a view helper mainly.
+ *
+ * It may be called many times in one request, so each method stores
+ * its result into the cache which available during a request.
+ */
+trait RequestCache {
+
+  def getIssue(userName: String, repositoryName: String, issueId: String)(implicit context: app.Context): Option[Issue] = {
+    context.cache(s"issue.${userName}/${repositoryName}#${issueId}"){
+      new IssuesService {}.getIssue(userName, repositoryName, issueId)
+    }
+  }
+
+  def getAccountByUserName(userName: String)(implicit context: app.Context): Option[Account] = {
+    context.cache(s"account.${userName}"){
+      new AccountService {}.getAccountByUserName(userName)
+    }
+  }
+
+}
+