extra metadata loading from a yaml file

1 files changed, 28 insertions, 0 deletions

diff --git a/reploy.hs b/reploy.hs
index dbdb091..cf4de56 100644
--- a/reploy.hs
+++ b/reploy.hs
@@ -26,6 +26,7 @@ import qualified Data.Aeson as AE
 import qualified Data.Aeson.Key as K
 import qualified Data.Aeson.KeyMap as KM
 import qualified Data.ByteString.Lazy as B
+import qualified Data.ByteString.UTF8
 import Data.Digest.Pure.SHA (sha256, showDigest)
 import Data.Foldable (traverse_)
 import Data.List (inits, nub, sort)
@@ -511,10 +512,37 @@ renderSearchData = use searchDataOut >>= traverse_ go
         putStrLn $ "S -> " ++ out
         AE.encodeFile out $ Y.array (concat ps)
 
+-- | Souce extra metadata accordingly to the metadata specifications
+sourceExtraMetadata :: Site ()
+sourceExtraMetadata = do
+  use extraMetaSpec
+    >>= fmap (foldl objMerge Y.Null) . traverse loadSpec
+    >>= assign extraMeta
+  where
+    loadSpec :: MetaSpec -> Site Y.Value
+    loadSpec (MetaSpecInline yaml) =
+      case Y.decodeEither' $ Data.ByteString.UTF8.fromString yaml of
+        Right v -> pure v
+        Left err ->
+          error
+            $ "cannot parse extra metadata from inline YAML: "
+                ++ Y.prettyPrintParseException err
+    loadSpec (MetaSpecFile path) = do
+      res <- io $ Y.decodeFileEither path
+      case res of
+        Right v -> pure v
+        Left err ->
+          error
+            $ "cannot load YAML metadata from "
+                ++ path
+                ++ ": "
+                ++ Y.prettyPrintParseException err
+
 -- | Build the whole site.
 main = do
   init <- Options.Applicative.execParser siteOptions
   flip runStateT init $ do
+    sourceExtraMetadata
     installAssets
     use sourceDirs >>= traverse sourcePages
     use sourceDirs >>= traverse sourceTagMeta