Implement URL filename parsing (with tests) and the save_image function.

[dead/lwn-epub.git] / src / LWN / HTTP.hs

diff --git a/src/LWN/HTTP.hs b/src/LWN/HTTP.hs
index 8b4c14d0cc04a09badc271f15bd0ea628ca24390..c74248ba9dca05bdcc54c2417758906ecd021212 100644 (file)
--- a/src/LWN/HTTP.hs
+++ b/src/LWN/HTTP.hs
@@ -1,6 +1,7 @@
 module LWN.HTTP
 where
 
+import qualified Data.ByteString as B (hPut)
 import Network.Curl (
   CurlCode(..),
   CurlOption(..),
@@ -12,7 +13,12 @@ import Network.Curl (
   respCurlCode,
   withCurlDo               
   )
+import Network.Curl.Download (openURI)
+import System.Directory (getTemporaryDirectory)
 import System.IO (hPutStrLn, stderr)
+import System.IO.Temp (openBinaryTempFile)
+
+import LWN.URI (filename)
 
 login_url :: URLString
 login_url = "https://lwn.net/login"
@@ -118,3 +124,28 @@ log_in cookie_jar username password =
         
     curl_opts :: [CurlOption]
     curl_opts = default_curl_opts ++ post_opts
+
+
+-- | Save the image at 'url'. Saves to a temporary file, and
+--   returns the path to that file if successful. Otherwise,
+--   returns 'Nothing'.
+--
+--   We need to be able to parse the filename out of the URL
+--   so that when we stick our image in the document, the reader
+--   knows that type (jpg, png, etc.) it is.
+save_image :: URLString -> IO (Maybe FilePath)
+save_image url = do
+  let fn = filename url
+  case fn of
+    Nothing -> return Nothing
+    Just file -> do
+      temp_dir <- getTemporaryDirectory
+      (out_path, out_handle) <- openBinaryTempFile temp_dir file
+      result <- openURI url
+      case result of
+        Left err -> do
+          hPutStrLn stderr ("HTTP Error: " ++ err)
+          return Nothing
+        Right bs -> do
+          B.hPut out_handle bs
+          return $ Just out_path