Refactored Database files to MVC architecture (#1604)

* created Program file in models folder
* created Meeting file in models folder
* removed CourseQueries.hs and CourseInsertion.hs
* renamed post -> program across the codebase, excluding database tables and route names

Author: akarki2005

CHANGELOG.md

@@ -26,6 +26,8 @@
 - Upgraded `jest-environment-jsdom` to v30
 - Refactored navigation bar into a React component (for the graph, grid and generate pages only - the about page navigation bar is still rendered using Blaze)
 - Refactored backend tests to use `tasty` and `tasty-hunit` instead of `HUnit`
+- Refactored course insertion and query functions to align with MVC architectural principles
+- Renamed functions that query the database for post/program information from post -> program
 - Modified CircleCI configuration so that Jest tests now emit coverage reports which are then uploaded to Coveralls
 - Refactored export modal behaviour such that it is handled entirely through React state, rather than through DOM manipulation with vanilla JS
 - Added test cases for the `ExportModal` component in `js/components/common`

app/Controllers/Course.hs

@@ -4,12 +4,11 @@ module Controllers.Course
 import Config (runDb)
 import Control.Monad.IO.Class (liftIO)
 import qualified Data.Text as T (Text, unlines)
-import qualified Database.CourseQueries as CourseHelpers (getDeptCourses)
 import Database.Persist (Entity)
 import Database.Persist.Sqlite (SqlPersistM, entityVal, selectList)
 import Database.Tables as Tables (Courses, coursesCode)
 import Happstack.Server (Response, ServerPart, lookText', toResponse)
-import Models.Course (returnCourse)
+import Models.Course (getDeptCourses, returnCourse)
 import Util.Happstack (createJSONResponse)
 
 -- | Takes a course code (e.g. \"CSC108H1\") and sends a JSON representation
@@ -33,4 +32,4 @@ index = do
 courseInfo :: ServerPart Response
 courseInfo = do
     dept <- lookText' "dept"
-    fmap createJSONResponse (CourseHelpers.getDeptCourses dept)
+    fmap createJSONResponse (getDeptCourses dept)

app/Controllers/Generate.hs

@@ -7,11 +7,11 @@ import Data.Aeson (decode, object, (.=))
 import Data.List (nub)
 import Data.Maybe (fromJust, isNothing, mapMaybe)
 import qualified Data.Text.Lazy as TL
-import Database.CourseQueries (reqsForPost, returnPost)
 import DynamicGraphs.GraphOptions (CourseGraphOptions (..), GraphOptions (..))
 import DynamicGraphs.WriteRunDot (generateAndSavePrereqResponse, getBody)
 import Happstack.Server
 import MasterTemplate
+import Models.Program (reqsForProgram, returnProgram)
 import Scripts
 import Text.Blaze ((!))
 import qualified Text.Blaze.Html5 as H
@@ -43,7 +43,7 @@ findAndSavePrereqsResponse = do
     let coursesOptions :: CourseGraphOptions = fromJust $ decode requestBody
 
     postResults <- liftIO $ mapM (\code -> do
-                        post <- returnPost (TL.toStrict code)
+                        post <- returnProgram (TL.toStrict code)
                         return (TL.toStrict code, post))
                    (programs coursesOptions)
 
@@ -52,7 +52,7 @@ findAndSavePrereqsResponse = do
 
     allCourses <- liftIO $ nub <$>
         if all (== TL.empty) (courses coursesOptions)
-            then return $ map TL.pack (concatMap reqsForPost validPrograms)
+            then return $ map TL.pack (concatMap reqsForProgram validPrograms)
             else return $ courses coursesOptions
 
     let updatedCoursesOptions = coursesOptions

app/Controllers/Program.hs

@@ -1,12 +1,15 @@
-module Controllers.Program(index) where
+module Controllers.Program(index, retrieveProgram) where
 
 import Config (runDb)
 import Control.Monad.IO.Class (liftIO)
 import qualified Data.Text as T (Text, unlines)
 import Database.Persist (Entity)
 import Database.Persist.Sqlite (SqlPersistM, entityVal, selectList)
-import Database.Tables as Tables (Post, postCode)
-import Happstack.Server (Response, ServerPart, toResponse)
+import Database.Tables as Tables (Post, postCode, postModified)
+import Happstack.Server (Request, Response, ServerPart, askRq, ifModifiedSince, lookText',
+                         toResponse)
+import Models.Program (returnProgram)
+import Util.Happstack (createJSONResponse)
 
 -- | Builds a list of all program codes in the database
 index :: ServerPart Response
@@ -16,3 +19,22 @@ index = do
         let codes = map (postCode . entityVal) programsList
         return $ T.unlines codes :: SqlPersistM T.Text
     return $ toResponse response
+
+-- | Takes a http request with a program code and sends a JSON response containing the program data
+-- | if the program data has been modified since the timestamp in the request,
+-- | or a 304 "Not Modified" response otherwise
+retrieveProgram :: ServerPart Response
+retrieveProgram = do
+    req <- askRq
+    code <- lookText' "code"
+    liftIO $ queryProgram req code
+
+-- | Queries the database for the program data then returns a JSON response of it
+-- | if the program data has been modified since the timestamp in the request,
+-- | or a 304 "Not Modified" response otherwise
+queryProgram :: Request -> T.Text -> IO Response
+queryProgram req code = do
+    programMaybe <- returnProgram code
+    case programMaybe of
+        Nothing -> return $ createJSONResponse (Nothing :: Maybe Post)
+        Just program -> return $ ifModifiedSince (postModified program) req (createJSONResponse program)

app/Controllers/Timetable.hs

@@ -12,14 +12,14 @@ import Data.List.Split (splitOn)
 import qualified Data.Text as T
 import Data.Time (Day, defaultTimeLocale, formatTime, getCurrentTime, toGregorian)
 import Data.Time.Calendar.OrdinalDate (fromMondayStartWeek, mondayStartWeek)
-import Database.CourseQueries (returnMeeting)
 import Database.Persist.Sqlite (entityKey, entityVal, selectList, (==.))
 import Database.Tables
 import Export.GetImages
 import Export.LatexGenerator
 import Export.PdfGenerator
 import Happstack.Server
 import MasterTemplate
+import Models.Meeting (returnMeeting)
 import Response.Image (returnImageData)
 import Scripts
 import System.Directory (removeFile)

app/Database/CourseInsertion.hs

@@ -12,9 +12,9 @@ import Control.Monad.Trans.State (StateT, execStateT, modify)
 import qualified Data.Map.Strict as Map
 import qualified Data.Set as Set
 import qualified Data.Text.Lazy as T
-import Database.CourseQueries (prereqsForCourse)
 import Database.Requirement (Modifier (..), Req (..))
 import DynamicGraphs.GraphOptions (GraphOptions (..))
+import Models.Course (prereqsForCourse)
 import WebParsing.ReqParser (parseReqs)
 
 lookupCourses :: GraphOptions -> [T.Text] -> IO (Map.Map T.Text Req)

app/Database/CourseQueries.hs

@@ -17,10 +17,10 @@ import Data.Fixed (mod')
 import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
 import qualified Data.Text as T
-import Database.CourseQueries (getMeetingTime)
 import Database.Tables as Tables
 import Export.ImageConversion
 import Export.TimetableImageCreator (renderTable, renderTableHelper, times)
+import Models.Meeting (getMeetingTime)
 import Svg.Generator
 import System.Random (genWord32, newStdGen)