Implement FZ download

app/Main.hs

@@ -1,21 +1,12 @@
-{-# LANGUAGE OverloadedStrings #-}
-
 module Main (main) where
 
-import Control.Exception (bracket)
+import qualified Data.Text.IO as TextIO
 
-import qualified Database.PostgreSQL.Opium as Opium
-
-import qualified Yore.DB
+import Yore.Repl (getToday)
 
 main :: IO ()
-main = bracket unsafeConnect Opium.close $ \conn -> do
-  result <- Yore.DB.getTables conn
-
-  case result of
-    Left e ->
-      putStrLn $ "Got error: " ++ show e
-    Right rows ->
-      mapM_ print rows
-  where
-    unsafeConnect = either (error . show) id <$> Opium.connect "host=localhost port=5432 user=yore-test dbname=yore-test"
+main = do
+  putStrLn "* Getting URLs for today..."
+  urls <- getToday
+  putStrLn "* Done:"
+  mapM_ TextIO.putStrLn urls

src/Yore/DB.hs

@@ -1,10 +1,16 @@
 {-# LANGUAGE OverloadedStrings #-}
 
 module Yore.DB
-  ( Table (..)
+  ( DayIndex (..)
+  , createDayFile
+  , createDayIndex
+  , readDayIndex
+  , Table (..)
   , getTables
 ) where
 
+import Data.Functor.Identity (Identity (..))
+import Data.Time (Day)
 import GHC.Generics (Generic)
 
 import qualified Database.PostgreSQL.Opium as Opium
@@ -18,3 +24,30 @@ instance Opium.FromRow Table
 
 getTables :: Opium.Connection -> IO (Either Opium.Error [Table])
 getTables = Opium.fetch_ "SELECT table_schema AS schema, table_name AS name FROM information_schema.tables"
+
+data DayIndex = DayIndex
+  { id  :: Int
+  , day :: Day
+  } deriving (Show, Generic)
+
+instance Opium.FromRow DayIndex
+
+createDayIndex :: Day -> Opium.Connection -> IO (Either Opium.Error DayIndex)
+createDayIndex date = ex runIdentity .
+  Opium.fetch
+    "INSERT INTO yore.day_index (day) VALUES ($1) RETURNING *"
+    (Identity date)
+
+createDayFile :: Int -> FilePath -> Opium.Connection -> IO (Either Opium.Error ())
+createDayFile dayId path =
+  Opium.execute
+    "INSERT INTO yore.day_file (day_id, relative_path) VALUES ($1, $2)" (dayId, path)
+
+readDayIndex :: Day -> Opium.Connection -> IO (Either Opium.Error (Maybe DayIndex))
+readDayIndex date =
+  Opium.fetch
+    "SELECT * FROM yore.day_index WHERE day = $1"
+    (Identity date)
+
+ex :: (a -> b) -> IO (Either e a) -> IO (Either e b)
+ex = fmap . fmap

src/Yore/Download.hs

@@ -1,21 +1,28 @@
+{-# LANGUAGE DataKinds #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE QuasiQuotes #-}
 
-module Yore.Download where
+module Yore.Download (downloadInto, getUrls) where
 
+import Control.Lens hiding ((<.>))
 import Control.Monad (guard)
 import Data.Char
-import Data.List (find)
-import Data.Maybe (fromMaybe, listToMaybe, mapMaybe)
+import Data.Maybe (fromJust, fromMaybe, listToMaybe, mapMaybe, catMaybes)
 import Data.Text (Text)
 import Data.Time (Day, MonthOfYear, Year, fromGregorian, toGregorian)
-import Network.HTTP.Req
+import Network.HTTP.Req hiding (queryParam)
+import System.Directory (createDirectoryIfMissing)
+import System.FilePath (makeRelative, takeExtension, (</>), (<.>))
 import Text.HTML.Parser
 import Text.Printf (printf)
 import Text.URI (URI)
+import Text.URI.Lens
+import Text.URI.QQ hiding (uri)
 
-import qualified Data.List.NonEmpty as NonEmpty
+import qualified Data.ByteString.Lazy as LBS
 import qualified Data.Text as Text
 import qualified Data.Text.Encoding as Encoding
+import qualified Data.UUID.V4 as UUID
 import qualified Text.URI as URI
 
 data TargetSpec = TargetSpec
@@ -25,12 +32,36 @@ data TargetSpec = TargetSpec
   }
   deriving (Show)
 
-getUrl :: Day -> IO Text
-getUrl date = do
+-- | Download a URL and save it to a directory.
+-- Returns the path of the downloaded file relative to the directory.
+downloadInto
+  :: FilePath -- ^ Directory where to store the file.
+  -> Text -- ^ The URL to download.
+  -> IO FilePath
+downloadInto downloadDir textUrl = download >>= save
+  where
+    download :: IO LBS.ByteString
+    download = do
+      uri <- URI.mkURI textUrl
+      let (url, opts) = fromJust $ useHttpsURI uri
+      res <- runReq defaultHttpConfig $ req GET url NoReqBody lbsResponse opts
+      guard $ responseStatusCode res == 200
+      pure $ responseBody res
+
+    save :: LBS.ByteString -> IO FilePath
+    save contents = do
+      let suffix = takeExtension $ Text.unpack textUrl
+      uuid <- UUID.nextRandom
+      let fullPath = downloadDir </> show uuid <.> suffix
+      createDirectoryIfMissing True downloadDir
+      LBS.writeFile fullPath contents
+      pure $ makeRelative downloadDir fullPath
+
+getUrls :: Day -> IO [Text]
+getUrls date = do
   let (y, m, _) = toGregorian date
-  candidates <- getMonthOverview y m
-  let (_, ts) = fromMaybe (error "no candidates") $ find ((date ==) . fst) candidates
-  fromMaybe (error "could not get showpdf url") <$> getShowpdf ts
+  candidates <- filter ((date ==) . fst) <$> getMonthOverview y m
+  catMaybes <$> mapM (getShowpdf . snd) candidates
 
 getShowpdf :: TargetSpec -> IO (Maybe Text)
 getShowpdf (TargetSpec y m d) = do
@@ -59,12 +90,14 @@ getShowpdf (TargetSpec y m d) = do
       httpEquiv <- getAttr "http-equiv" attrs
       guard $ httpEquiv == "refresh"
       content <- getAttr "content" attrs
-      Just $ snd $ Text.breakOnEnd "URL=" content
+      Just $ escapeBrackets $ snd $ Text.breakOnEnd "URL=" content
     getRefreshTarget _ =
       Nothing
 
     getAttr k = lookup k . map (\(Attr k' v) -> (k', v))
 
+    escapeBrackets = Text.replace "[" "%5B" . Text.replace "]" "%5D"
+
 getMonthOverview :: Year -> MonthOfYear -> IO [(Day, TargetSpec)]
 getMonthOverview year month = do
   res <- runReq defaultHttpConfig $ req
@@ -93,16 +126,16 @@ getMonthOverview year month = do
     extractDay uri =
       fromGregorian y m d
       where
-        y = read $ maybe "0" Text.unpack $ getParam "year" uri
-        m = read $ maybe "0" Text.unpack $ getParam "month" uri
-        d = read $ maybe "0" (takeWhile isDigit . Text.unpack) $ getParam "day" uri
+        y = read $ Text.unpack $ getParam [queryKey|year|] "0" uri
+        m = read $ Text.unpack $ getParam [queryKey|month|] "0" uri
+        d = read $ Text.unpack $ Text.takeWhile isDigit $ getParam [queryKey|day|] "0" uri
 
     extractTarget uri =
       TargetSpec y m d
       where
-        y = fromMaybe "" $ getParam "year" uri
-        m = fromMaybe "" $ getParam "month" uri
-        d = fromMaybe "" $ getParam "day" uri
+        y = fromMaybe "" (uri ^? uriQuery . queryParam [queryKey|year|] . unRText)
+        m = fromMaybe "" (uri ^? uriQuery . queryParam [queryKey|month|] . unRText)
+        d = fromMaybe "" (uri ^? uriQuery . queryParam [queryKey|day|] . unRText)
 
     decodeHtmlEntities = Text.pack . q0 . Text.unpack
       where
@@ -118,16 +151,14 @@ getMonthOverview year month = do
           -- Or if they end unexpectedly.
           | otherwise = c : q0 r
 
-    isShowpdf uri =
-      getPath uri == ["show", "fz.cgi"] && getParam "cmd" uri == Just "showpdf"
 
-getPath :: URI -> [Text]
-getPath uri = case URI.uriPath uri of
-  Nothing -> []
-  Just (_, rts) -> map URI.unRText $ NonEmpty.toList rts
-
-getParam :: Text -> URI ->  Maybe Text
-getParam param uri = listToMaybe [value | (key, value) <- map go (URI.uriQuery uri), key == param]
+isShowpdf :: URI -> Bool
+isShowpdf uri =
+  path == ["show", "fz.cgi"] && cmd == Just "showpdf"
   where
-    go (URI.QueryFlag k) = (URI.unRText k, "")
-    go (URI.QueryParam k v) = (URI.unRText k, URI.unRText v)
+    path = uri ^.. uriPath . each . unRText
+    cmd  = uri ^? uriQuery . queryParam [queryKey|cmd|] . unRText
+
+getParam :: URI.RText URI.QueryKey -> Text -> URI -> Text
+getParam param fallback uri =
+  fromMaybe fallback (uri ^? uriQuery . queryParam param . unRText)

src/Yore/Index.hs

@@ -0,0 +1,22 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE OverloadedRecordDot #-}
+
+module Yore.Index (createEntries) where
+
+import Control.Exception (Exception, throwIO)
+import Control.Monad (forM_)
+import Data.Time (Day)
+
+import qualified Database.PostgreSQL.Opium as Opium
+
+import qualified Yore.DB as DB
+
+createEntries :: Day -> [FilePath] -> Opium.Connection -> IO ()
+createEntries date urls conn = do
+  confidently $ Opium.execute_ "BEGIN" conn
+  dayIndex <- confidently $ DB.createDayIndex date conn
+  forM_ urls $ \url -> confidently $ DB.createDayFile dayIndex.id url conn
+  confidently $ Opium.execute_ "COMMIT" conn
+
+confidently :: Exception e => IO (Either e a) -> IO a
+confidently action = action >>= either throwIO pure

src/Yore/Repl.hs

@@ -1,15 +1,58 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
 
-module Yore.Repl (connect, exec) where
+module Yore.Repl (connect, exec, getToday, indexDay, addYears) where
+
+import Control.Exception (bracket, throwIO)
+import Control.Monad (forM)
+import Data.Text (Text)
+import Data.Time (Day)
+import Data.Time.LocalTime (getZonedTime, localDay, zonedTimeToLocalTime)
+import Text.Printf (printf)
 
 import qualified Database.PostgreSQL.Opium as Opium
 
+import Yore.DB (DayIndex)
+import Yore.Download (downloadInto, getUrls)
+import Yore.Index (createEntries)
+import Yore.Time (addYears)
+
+import qualified Yore.DB as DB
+
 connect :: IO Opium.Connection
 connect =
-  Opium.connect "host=localhost" >>= \case
+  Opium.connect "host=localhost port=5433 user=yore-test" >>= \case
     Left e -> error $ show e
     Right c -> pure c
 
 exec :: (Opium.Connection -> IO a) -> IO a
-exec f = f =<< connect
+exec = bracket connect Opium.close
+
+getToday :: IO [Text]
+getToday = do
+  now <- getZonedTime
+  print now
+  let currentDay = localDay $ zonedTimeToLocalTime now
+  case addYears (-100) currentDay of
+    Just then_ ->
+      getUrls then_
+    Nothing ->
+      pure []
+
+indexDay :: Day -> IO ()
+indexDay date = exec $ \conn -> do
+  either throwIO pure =<< Opium.execute_ "SELECT pg_advisory_lock(42);" conn
+  printf "Checking whether %s already exists...\n" (show date)
+  mbDi <- either throwIO pure =<< DB.readDayIndex date conn
+  case mbDi of
+    Just (_ :: DayIndex) ->
+      putStrLn "Nothing to do."
+    Nothing -> do
+      putStrLn "Retrieving URLs..."
+      urls <- getUrls date
+      paths <- forM urls $ \url -> do
+        printf "Downloading %s...\n" url
+        downloadInto "./download" url
+      putStrLn "Creating DB entries..."
+      createEntries date paths conn
+      putStrLn "Done."

src/Yore/Time.hs

@@ -0,0 +1,16 @@
+module Yore.Time (addYears) where
+
+import Data.Time (Day, addGregorianYearsClip, isLeapYear, toGregorian)
+
+addYears :: Integer -> Day -> Maybe Day
+addYears yearOffset date
+  | isFebruary29th && not (isLeapYear year') =
+    Nothing
+  | otherwise =
+    Just $ addGregorianYearsClip yearOffset date
+    
+  where
+    (year, month, day) = toGregorian date
+    year' = year + yearOffset
+
+    isFebruary29th = month == 2 && day == 29

yore.cabal

@@ -32,19 +32,25 @@ library
   import: shared-options
   exposed-modules:
       Yore.DB
-    , Yore.Repl
     , Yore.Download
+    , Yore.Index
+    , Yore.Repl
+    , Yore.Time
   hs-source-dirs:
       src
   build-depends:
       base >=4.18 && <5
     , bytestring
+    , directory
+    , filepath
     , html-parse
+    , lens
     , modern-uri
     , opium
     , req
     , text
     , time
+    , uuid
 
 executable yore
   import: shared-options