X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FTSN%2FDbImport.hs;h=7a420d380afc38bbc2903b9f334fc4b253ae577e;hb=f9a9d6fdcdd2ee0e6bb1882ed2eba936535a52ac;hp=e0dd1349a1469cc7ead734923a2a5d027aea9007;hpb=ce9fabd584f2e8844b8b1ede9b29bb573e2033f7;p=dead%2Fhtsn-import.git

diff --git a/src/TSN/DbImport.hs b/src/TSN/DbImport.hs
index e0dd134..7a420d3 100644
--- a/src/TSN/DbImport.hs
+++ b/src/TSN/DbImport.hs
@@ -1,34 +1,79 @@
 -- | Definition of the DbImport typeclass.
-module TSN.DbImport
+--
+--   When we parse an XML tree, there are two functions that we would
+--   like to call on the result independent of its type. First, we
+--   would like to be able to run the database migrations for that
+--   type. The migrations are kept separate from insertion because, at
+--   some later point, it make make sense to disable automatic
+--   migrations.
+--
+--   Next we want to import the thing.
+--
+--   Neither of these should depend on the type -- we should just be
+--   able to call 'dbmigrate' followed by 'dbimport' on the
+--   datastructure and have the right thing happen. That is the
+--   purpose of the 'DbImport' typeclass. It allows the XML types to
+--   define their own \"migrate me\" and \"insert me\" functions that
+--   the rest of the application doesn't have to care about.
+--
+module TSN.DbImport (
+  DbImport(..),
+  ImportResult(..),
+  run_dbmigrate )
 where
 
-import Control.Monad.IO.Class ( MonadIO )
-import Database.Groundhog.Core ( PersistBackend )
+-- System imports
+import Control.Monad ( forM_ )
+import Control.Monad.IO.Class ( MonadIO( liftIO ) )
+import qualified Data.Map as Map ( elems )
+import Database.Groundhog ( executeRaw )
+import Database.Groundhog.Generic (
+  createMigration,
+  getQueries,
+  mergeMigrations )
+import Database.Groundhog.Core ( Migration, NamedMigrations, PersistBackend )
+import Network.Services.TSN.Report ( report_info )
 
-import TSN.XmlImport ( XmlImport(..) )
 
 -- | The type that will be returned from every file import attempt.
 --
 data ImportResult =
   ImportFailed String -- ^ Failure with an error message.
-    | ImportSkipped String -- ^ We processed the file, but didn't import it.
-                           --   The reason is contained in the second field.
-    | ImportSucceeded      -- ^ We did import records.
-    | ImportUnsupported String -- ^ We didn't know how to process this file.
-                               --   The second field should contain info.
-
--- | Instances of this type know how to insert themselves into a
---   Groundhog database.
+
+  | ImportSkipped String -- ^ We processed the file, but didn't import it.
+                         --   The reason is contained in the second field.
+
+  | ImportSucceeded      -- ^ We did import records.
+
+  | ImportUnsupported String -- ^ We didn't know how to process this file.
+                             --   The second field should contain info.
+
+
+-- | Instances of this type know how to run their own database
+--   migrations and insert themselves into a database.
 --
 class DbImport a where
   -- | Import an instance of type @a@.
   dbimport :: (PersistBackend m) => a -> m ImportResult
 
   -- | This must migrate *all* stuffs that can potentially be
-  -- created/used by the type @a@.
+  --   created/used by the type @a@.
   dbmigrate :: (MonadIO m, PersistBackend m) => a -> m ()
 
-dbimport_generic :: (XmlImport a, MonadIO m, PersistBackend m)
-                 => a
-                 -> m ImportResult
-dbimport_generic x = insert_xml x >> return ImportSucceeded
+
+-- | A migration runner that will use our normal info reporting
+--   mechanism. The top-level code was stolen from 'runMigration' in
+--   "Data.Groundhog.Generic" and the 'execute_pretty' code was stolen
+--   from 'executeMigration'' in the same module.
+--
+run_dbmigrate :: (MonadIO m, PersistBackend m) => Migration m -> m ()
+run_dbmigrate migration = createMigration migration >>= execute_pretty
+  where
+    execute_pretty :: (PersistBackend m, MonadIO m) => NamedMigrations -> m ()
+    execute_pretty m = do
+      let migs = getQueries False $ mergeMigrations $ Map.elems m
+      case migs of
+        Left errs -> fail $ unlines errs
+        Right qs -> forM_ qs $ \q -> do
+                         liftIO $ report_info ("Migration: " ++ q ++ ";")
+                         executeRaw False q []