WIP Allow to automatically open attachments

This adds a proof of concept mailcap declaration. If we can lookup a command,
use it as a preference otherwise show an input editor. Keep the possibility to
open the attachment with a different command by binding the input editor to a
different keystroke tho. This patch would also fix #174 since it is now possible
to automatically invoke a program to see HTML output.

Fixes #182 and
      #174

Author: romanofski

src/Config/Main.hs

@@ -12,6 +12,7 @@ import qualified Graphics.Vty as V
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Lazy as LB
 import qualified Data.Text as T
+import qualified Data.Map as Map
 import System.Environment (lookupEnv)
 import System.Directory (getHomeDirectory)
 import Data.Maybe (fromMaybe)
@@ -178,6 +179,7 @@ defaultConfig =
       , _mvMailListOfAttachmentsKeybindings = mailAttachmentsKeybindings
       , _mvOpenWithKeybindings = openWithKeybindings
       , _mvPipeToKeybindings = pipeToKeybindings
+      , _mvMailcap = Map.fromList [(("text", "html"), "elinks -force-html")]
       }
     , _confIndexView = IndexViewSettings
       { _ivBrowseThreadsKeybindings = browseThreadsKeybindings

src/Types.hs

@@ -342,6 +342,7 @@ data MailViewSettings = MailViewSettings
     , _mvMailListOfAttachmentsKeybindings :: [Keybinding 'ViewMail 'MailListOfAttachments]
     , _mvOpenWithKeybindings :: [Keybinding 'ViewMail 'MailAttachmentOpenWithEditor]
     , _mvPipeToKeybindings :: [Keybinding 'ViewMail 'MailAttachmentPipeToEditor]
+    , _mvMailcap :: Map.Map (CI.CI B.ByteString, CI.CI B.ByteString) String
     }
     deriving (Generic, NFData)
 
@@ -369,6 +370,9 @@ mvOpenWithKeybindings = lens _mvOpenWithKeybindings (\s x -> s { _mvOpenWithKeyb
 mvPipeToKeybindings :: Lens' MailViewSettings [Keybinding 'ViewMail 'MailAttachmentPipeToEditor]
 mvPipeToKeybindings = lens _mvPipeToKeybindings (\s x -> s { _mvPipeToKeybindings = x })
 
+mvMailcap :: Lens' MailViewSettings (Map.Map (CI.CI B.ByteString, CI.CI B.ByteString) String)
+mvMailcap = lens _mvMailcap (\s x -> s { _mvMailcap = x })
+
 data ViewName
     = Threads
     | Mails

src/UI/Actions.hs

@@ -28,6 +28,7 @@ module UI.Actions (
   Scrollable(..)
   , quit
   , focus
+  , foo
   , done
   , abort
   , noop
@@ -112,8 +113,9 @@ import Data.MIME
         contentDisposition, dispositionType, headers, filename,
         parseContentType, attachments, isAttachment, entities,
         matchContentType, contentType, mailboxList, renderMailboxes,
-        addressList, renderAddresses, renderRFC5422Date, MIMEMessage,
-        WireEntity, DispositionType(..), ContentType(..), Mailbox(..))
+        addressList, renderAddresses, renderRFC5422Date, ctType, ctSubtype,
+        MIMEMessage, WireEntity, DispositionType(..), ContentType(..),
+        Mailbox(..))
 import qualified Storage.Notmuch as Notmuch
 import Storage.ParsedMail
        (parseMail, getTo, getFrom, getSubject, toQuotedMail, entityToBytes)
@@ -516,6 +518,22 @@ invokeEditor = Action ["invoke external editor"] (Brick.suspendAndResume . liftI
 edit :: Action 'ComposeView 'ComposeListOfAttachments (T.Next AppState)
 edit = Action ["edit file"] (Brick.suspendAndResume . liftIO . editAttachment)
 
+foo :: Action 'ViewMail ctx (T.Next AppState)
+foo =
+  Action
+  { _aDescription = ["pass to external command"]
+  , _aAction = \s -> let
+      contenttype = preview (asMailView . mvAttachments . to L.listSelectedElement . _Just . _2 . headers . contentType) s
+      in case contenttype of
+           Nothing -> Brick.continue $ setError (GenericError "Couldn't determine content type") s
+           (Just ct) -> let maybeCommand = preview (asConfig . confMailView . mvMailcap . ix (view ctType ct, view ctSubtype ct)) s
+                        in case maybeCommand of
+                             (Just cmd) -> Brick.suspendAndResume $ liftIO $ openCommand' s cmd
+                             Nothing -> Brick.continue
+                               $ s & set (asViews . vsViews . at ViewMail . _Just . vFocus) MailAttachmentOpenWithEditor
+                               . set (asViews . vsViews . at ViewMail . _Just . vWidgets . ix MailAttachmentOpenWithEditor . veState) Visible
+  }
+
 openWithCommand :: Action 'ViewMail 'MailAttachmentOpenWithEditor (T.Next AppState)
 openWithCommand =
   Action

src/UI/Mail/Keybindings.hs

@@ -41,7 +41,8 @@ mailAttachmentsKeybindings =
     [ Keybinding (V.EvKey (V.KChar 'j') []) (listDown `chain` continue)
     , Keybinding (V.EvKey (V.KChar 'k') []) (listUp `chain` continue)
     , Keybinding (V.EvKey (V.KChar 'q') []) (abort `chain'` (focus :: Action 'ViewMail 'ScrollingMailView AppState) `chain` continue)
-    , Keybinding (V.EvKey V.KEnter []) (noop `chain'` (focus :: Action 'ViewMail 'MailAttachmentOpenWithEditor AppState) `chain` continue)
+    , Keybinding (V.EvKey V.KEnter []) foo
+    , Keybinding (V.EvKey (V.KChar 'o') []) (noop `chain'` (focus :: Action 'ViewMail 'MailAttachmentOpenWithEditor AppState) `chain` continue)
     , Keybinding (V.EvKey (V.KChar '|') []) (noop `chain'` (focus :: Action 'ViewMail 'MailAttachmentPipeToEditor AppState) `chain` continue)
     ]