Use an Esqueleto query to efficiently fetch and render the user profiles on h-cards, rather than several queries and lots of fussing around

src/Site.hs

@@ -1,21 +0,0 @@
-module Site ( fetch ) where
-
-import Foundation ( Handler )
-import Model
-import Util ( compileMustache, entityToTuple )
-
-import Text.Mustache ( Template )
-import Yesod ( Key, runDB, selectList, (<-.) )
-
-import qualified Data.Map as M
-import qualified Data.Text as T
-
-compileTemplates :: M.Map (Key Site) Site -> M.Map (Key Site) (Site, Template)
-compileTemplates = fmap $ \site -> (site, compile site)
-    where compile site = T.unpack (siteIcon site) `compileMustache` siteTemplate site
-
-fetch :: [Key Site] -> Handler (M.Map (Key Site) (Site, Template))
-fetch = fmap compileTemplates . fetchSites
-
-fetchSites :: [SiteId] -> Handler (M.Map (Key Site) Site)
-fetchSites siteIds = runDB $ M.fromList . map entityToTuple <$> selectList [SiteId <-. siteIds] []

src/Widget/Card.hs

@@ -5,31 +5,30 @@ module Widget.Card ( hCard ) where
 
 import Import
 
-import qualified Site
+import Database.Esqueleto ( (^.) )
+import qualified Database.Esqueleto as E
+
+import Text.Mustache ( substitute )
+import Util ( compileMustache )
 
-import Data.Maybe (fromJust)
-import Text.Mustache ( Template, substitute )
-import qualified Data.Map as M
 import qualified Data.Text as T
 
-arrangeProfiles :: [Profile] -> M.Map (Key Site) (Site, Template) -> [((Site, Template), Profile)]
-arrangeProfiles profiles sites = sortBy icon $ zip profileSites profiles
-    where findSite = fromJust . flip M.lookup sites . profileSiteId
-          profileSites = findSite <$> profiles
-          icon = comparing $ siteName . fst . fst
-
 prettyPgp :: PgpKey -> Text
 prettyPgp = T.unwords . T.chunksOf 4 . pgpKeyFingerprint
 
 routeFromPgp :: PgpKey -> Route App
 routeFromPgp PgpKey { pgpKeyFingerprint = f } = staticR ["pgp", T.takeEnd 8 f ++ ".asc"]
 
+profileUrl :: Site -> Profile -> Text
+profileUrl site = substitute $ T.unpack (siteName site) `compileMustache` siteTemplate site
+
 hCard :: Entity User -> Widget
 hCard (Entity userId user) = do
     mcurrentRoute <- getCurrentRoute
-    userProfiles <- handlerToWidget $ do
-        profiles <- runDB $ map entityVal <$> selectList [ProfileUserId ==. userId] []
-        sites <- Site.fetch $ profileSiteId <$> profiles
-        return . arrangeProfiles profiles $ sites
+    userProfiles <- handlerToWidget . runDB . E.select . E.from $ \(profile `E.InnerJoin` site) -> do
+        E.on $ profile ^. ProfileSiteId E.==. site ^. SiteId
+        E.where_ $ profile ^. ProfileUserId E.==. E.val userId
+        E.orderBy [E.asc $ site ^. SiteName]
+        return (site, profile)
     pgpKeys <- handlerToWidget . runDB $ map entityVal <$> selectList [PgpKeyUserId ==. userId] []
     $(widgetFile "mf2/h-card")

templates/mf2/h-card.hamlet

@@ -18,9 +18,9 @@
         <a .u-email itemprop="email" rel="me" href="mailto:#{userEmail user}">
           <i .fa.fa-envelope>
           #{userEmail user}
-      $forall ((site, template), profile) <- userProfiles
+      $forall (Entity _ site, Entity _ profile) <- userProfiles
         <li>
-          <a .u-url itemprop="sameAs" rel="me" href="#{substitute template profile}">
+          <a .u-url itemprop="sameAs" rel="me" href="#{profileUrl site profile}">
             <i .#{siteIcon site}>
             $maybe name <- profileDisplayName profile
               #{name}