Lua: make lua.mediabag.fetch return filename and mime type.

This is necessary because you may need to insert the filename
into an image or link element.

2 files changed, 7 insertions, 1 deletions

diff --git a/doc/lua-filters.md b/doc/lua-filters.md
index d17c44adf..e1007f452 100644
--- a/doc/lua-filters.md
+++ b/doc/lua-filters.md
@@ -1133,7 +1133,9 @@ storage. The "media bag" is used when pandoc is called with the
 [`fetch (source, base_url)`]{#mediabag-fetch}
 
 :   Fetches the given source and inserts it into the media bag
-    using a SHA1 hash of the content as filename.
+    using a SHA1 hash of the content as filename.  Returns two
+    values:  the filename (based on SHA1 hash) and the mime
+    type (or an empty string).
 
     Usage:
 
diff --git a/src/Text/Pandoc/Lua/PandocModule.hs b/src/Text/Pandoc/Lua/PandocModule.hs
index bf45cab17..a110905e5 100644
--- a/src/Text/Pandoc/Lua/PandocModule.hs
+++ b/src/Text/Pandoc/Lua/PandocModule.hs
@@ -38,6 +38,7 @@ import Control.Monad (unless, zipWithM_)
 import Data.ByteString.Char8 (unpack)
 import Data.Default (Default (..))
 import Data.IORef
+import Data.Maybe (fromMaybe)
 import Data.Text (pack)
 import Foreign.Lua (Lua, FromLuaStack, ToLuaStack, NumResults, liftIO)
 import Text.Pandoc.Class (fetchMediaResource, readDataFile, runIO,
@@ -146,6 +147,9 @@ insertResource commonState mbRef src = do
     fetchMediaResource src
   liftIO $ print (fp, mimeType) -- TODO DEBUG
   insertMediaFn mbRef fp (OrNil mimeType) bs
+  Lua.push fp
+  Lua.push $ fromMaybe "" mimeType
+  return 2 -- returns 2 values: name in mediabag, mimetype
 
 --
 -- Helper types and orphan instances