working with tags

Application.hs

@@ -45,6 +45,7 @@ import Handler.Admin
 import Handler.AdminProfileSettings
 import Handler.AdminAlbumSettings
 import Handler.AdminMediumSettings
+import Handler.Tag
 
 -- This line actually creates our YesodDispatch instance. It is the second half
 -- of the call to mkYesodData which occurs in Foundation.hs. Please see the

Handler/Tag.hs

@@ -0,0 +1,16 @@
+module Handler.Tag where
+
+import Import
+import Data.Maybe
+
+getTagR :: Text -> Handler Html
+getTagR tag = do
+  tempMedia <- runDB $ selectList [] [Desc MediumTitle]
+  almostMedia <- mapM (\a -> do
+    case tag `elem` (mediumTags $ entityVal a) of
+      True -> return (Just a)
+      False -> return Nothing
+      ) tempMedia
+  media <- return $ removeItem Nothing almostMedia
+  defaultLayout $ do
+    $(widgetFile "tagMedia")

config/routes

@@ -36,3 +36,4 @@
 /admin/medium			AdminMediaR		GET
 /admin/medium/#MediumId		AdminMediumSettingsR	GET POST
 /admin/meidum/#MediumId/delete	AdminMediumDeleteR	GET
+/tag/#Text TagR GET

eidolon.cabal

@@ -38,6 +38,7 @@ library
                      Handler.AdminProfileSettings
                      Handler.AdminAlbumSettings
                      Handler.AdminMediumSettings
+                     Handler.Tag
 
     if flag(dev) || flag(library-only)
         cpp-options:   -DDEVELOPMENT

templates/medium.hamlet

@@ -13,5 +13,14 @@ by <a href=@{UserR ownerName}>#{ownerName}</a> from album <a href=@{AlbumR album
   Description:<br>
   #{mediumDescription medium}
 <br>
+<div class="tags">
+  Tags:
+  <ul>
+    $if null (mediumTags medium)
+      none
+    $else
+      $forall tag <- mediumTags medium
+        <li>
+          <a href=@{TagR tag}>#{tag}
 $if presence == True
   <a href=@{MediumSettingsR mediumId}>Change medium settings

templates/tagMedia.hamlet

@@ -0,0 +1,13 @@
+$newline always
+
+<h3>#{tag}
+
+$if null media
+  There are no media tagged with #{tag}
+$else
+  <ul>
+  $forall Just (Entity mId m) <- media
+    <li>
+      <a href=@{MediumR mId}>
+        <img src=#{mediumPath m}>
+        #{mediumTitle m}