chore(lpr): call lpr in qualfication renewal message

src/Handler/Course/Users.hs

@@ -513,7 +513,7 @@ makeCourseUserTable cid acts restrict colChoices psValidator csvColumns = do
           , dbParamsFormResult   = id
           , dbParamsFormIdent    = def
           }
-        dbtCsvName = MsgCourseUserCsvName courseTerm courseSchool courseShorthand
+        dbtCsvName      = MsgCourseUserCsvName courseTerm courseSchool courseShorthand
         dbtCsvSheetName = MsgCourseUserCsvSheetName courseTerm courseSchool courseShorthand
         dbtCsvEncode = do
           csvColumns' <- csvColumns

src/Jobs/Handler/SendNotification/Qualification.hs

@@ -52,7 +52,10 @@ dispatchNotificationQualificationRenewal nQualification jRecipient = do
       -- content = $(i18nWidgetFile "qualification/renewal")
   $logDebugS "LMS" $ "Notify " <> tshow jRecipient <> " for renewal of qualifiaction " <> qname
 
-  let pdfMeta = applyMetas [("recipient", userDisplayName)] mempty -- TODO: add more info to interpolate here!
+  let pdfMeta = applyMetas 
+                  [ ("recipient", userDisplayName)                  
+                  -- TODO: add more info to interpolate here!
+                  ] mempty
   pdfRenewal pdfMeta >>= \case
     Left err -> do
       let msg = "Notify " <> tshow jRecipient <> " PDF generation failed with error: " <> err
@@ -81,7 +84,12 @@ dispatchNotificationQualificationRenewal nQualification jRecipient = do
             -- TODO: this is just a dummy to continue while i18nHamletFile usage is unclear
             addHtmlMarkdownAlternatives $(ihamletFile "templates/mail/qualificationRenewal.hamlet")
 
-    Right _pdf | otherwise -> do
-        let _letterHead = error "TODO"
-        -- makePDF "pdflatex" [] writer woptions pandoc
-        error "TODO"
+    Right pdf | otherwise -> do
+        let printJobName = mempty --TODO
+        lprPDF printJobName pdf >>= \case
+          Left err -> do
+            let msg = "Notify " <> tshow jRecipient <> "  PDF printing to send letter failed with error: " <> err
+            $logErrorS "LMS" msg
+            error $ unpack msg
+          Right msg | null msg  -> return ()
+                    | otherwise -> $logWarnS "LMS" $ "PDF printing to send letter with lpr returned ExitSucces and the following message: " <> msg

src/Utils/Print.hs

@@ -272,6 +272,19 @@ sendLetter' printJobName pdf printJobRecipient printJobSender printJobCourse pri
                 }
 
 
+-----------------------------
+-- Typed Process Utilities --
+-----------------------------
+
+-- | Converts Triple consisting of @ExitCode@, Success- and Failure-Value to Either Failue- or Success-Value.
+--   Returns @Right@  if the @ExitCode@ is @ExitsSuccess, entirely ignoring the Failure-Value, which ususally might contain warning messages.
+--   To be used with 'System.Process.Typed.readProcess'
+exit2either :: (ExitCode, a, b) -> Either b a
+exit2either (ExitSuccess   , ok,   _) = Right ok   -- warnings are ignored here!
+exit2either (ExitFailure _ ,  _, err) = Left err
+
+
+
 -----------
 -- pdftk --
 -----------
@@ -295,6 +308,26 @@ encryptPDF pw bs = over _Left (decodeUtf8 . LBS.toStrict) . exit2either <$> read
     -- Note that pdftk will issue a warning, which will be ignored:
     --    Warning: Using a password on the command line interface can be insecure.
     --    Use the keyword PROMPT to supply a password via standard input instead.
-    exit2either :: (ExitCode, a, b) -> Either b a
-    exit2either (ExitSuccess   , ok,   _) = Right ok   -- warnings are ignored here!
-    exit2either (ExitFailure _ ,  _, err) = Left err 
+
+
+
+---------
+-- lpr --
+---------
+--
+-- We use the external tool lpr in the variant supplied by busybox
+-- to print pdfs like so:
+--  > lpr -P fradrive@fravm017173.fra.fraport.de -J printJobName -
+--
+
+lprPDF :: MonadIO m => String -> LBS.ByteString -> m (Either Text Text)
+lprPDF jb bs = over _Left  (decodeUtf8 . LBS.toStrict) .
+               over _Right (decodeUtf8 . LBS.toStrict) . exit2either <$> readProcess pc
+  where
+    pc =  setStdin (byteStringInput bs) $
+          proc "lpr" $ [ "-P fradrive@fravm017173.fra.fraport.de:515"  -- queue@hostname:port TODO: turn this into a setting
+                       ] ++ jobname ++                                 -- a name for job identification at printing site
+                       [ "-"                                           -- read from stdin
+                       ]
+    jobname | null jb   = []
+            | otherwise = ["-J", jb]