Update when no cached version is available

package.yaml

@@ -38,6 +38,7 @@ library:
   - containers
   - http-conduit
   - zip-archive
+  - time
 
 ghc-options:
   - -Wall

src/Tldr/App/Handler.hs

@@ -18,6 +18,9 @@ import Data.List (intercalate)
 import Data.Semigroup ((<>))
 import qualified Data.Set as Set
 import Data.Version (showVersion)
+import Data.Time.Clock
+
+import Control.Monad (when)
 
 import Options.Applicative
 import Paths_tldr (version)
@@ -26,6 +29,8 @@ import System.Directory
   , createDirectory
   , removePathForcibly
   , doesFileExist
+  , doesDirectoryExist
+  , getModificationTime
   , getXdgDirectory
   )
 import System.Environment (lookupEnv, getExecutablePath)
@@ -68,6 +73,8 @@ handleTldrOpts opts@TldrOpts {..} =
     UpdateIndex -> updateTldrPages
     About -> handleAboutFlag
     ViewPage voptions pages -> do
+      performUpdate <- updateNecessary
+      when performUpdate updateTldrPages 
       let npage = intercalate "-" pages
       locale <-
         case languageOption voptions of
@@ -87,6 +94,21 @@ handleTldrOpts opts@TldrOpts {..} =
                           ViewPage (englishViewOptions voptions) pages
                       })
 
+-- We update if the data directory does not exist.
+-- We also update if the cached pages version is older than 7 days.
+-- TODO: Make the auto-update interval configurable.
+-- TODO: Add command line option to skip auto update.
+updateNecessary :: IO Bool
+updateNecessary = do
+  dataDir <- getXdgDirectory XdgData tldrDirName
+  dataDirExists <- doesDirectoryExist dataDir
+  if not dataDirExists 
+    then return True
+    else do
+      lastCachedTime <- getModificationTime dataDir
+      currentTime <- getCurrentTime
+      return $ currentTime `diffUTCTime` lastCachedTime > 7 * nominalDay
+
 updateTldrPages :: IO ()
 updateTldrPages = do
   dataDir <- getXdgDirectory XdgData tldrDirName

tldr.cabal

@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 21691ba2cc19cdb8ae6d8a3bd0e84803e28b8866530a0da9fe44e6187df4fec1
+-- hash: 15cea8fa6220a4fef978ba47b6907236174a550cef396d6b25755d1549b6a5a5
 
 name:           tldr
 version:        0.8.1
@@ -50,7 +50,7 @@ library
       Paths_tldr
   hs-source-dirs:
       src
-  ghc-options: -Wall
+  ghc-options: -Wall -O2
   build-depends:
       ansi-terminal
     , base >=4.7 && <5
@@ -63,6 +63,7 @@ library
     , optparse-applicative
     , semigroups
     , text
+    , time
     , zip-archive
   default-language: Haskell2010
 
@@ -72,7 +73,7 @@ executable tldr
       Paths_tldr
   hs-source-dirs:
       app
-  ghc-options: -Wall
+  ghc-options: -Wall -O2
   build-depends:
       base
     , tldr
@@ -90,7 +91,7 @@ test-suite tldr-test
       Paths_tldr
   hs-source-dirs:
       test
-  ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
+  ghc-options: -Wall -O2 -threaded -rtsopts -with-rtsopts=-N
   build-depends:
       base
     , tasty