Added script for pandoc_reader users

Added a script to allow pandoc_reader users to include PlantUML diagrams
in their documents.
See Readme.rst and comments in pandoc-plantuml for usage details.

plantuml/Readme.rst

@@ -78,6 +78,44 @@ order ``format``, ``classes`` anmd ``alt``. The general syntax for option is
 Option can be enclosed with single or double quotes, as you like.
 Options defaults are the same as for the rst plugin.
 
+For pandoc_reader plugin users
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The plugin ``pandoc_reader`` sends the Markdown body to the pandoc_ tool which has it's own Markdown parser, written
+in Haskell_ language: Python_ plugins manipulating Markdown posts (such this) are not used because the entire body
+id passed to pandoc_ without any iteraction by Pelican_.
+
+For those who are using the ``pandoc_reader`` plugin and wants to include PlantUML_ diagrams, use the
+``pandoc-plantuml`` script (only *nix, sorry): it is a wrapper for filtering the code blocks parsed by pandoc_ before
+writing out the converted file.
+It is an adaption of the great work by Kurt Bonne for his
+`pandoc-plantuml-filter <https://github.com/kbonne/pandoc-plantuml-filter.git>`_.
+
+To use it, copy the ``pandoc-plantuml`` file in a subdirectory of your pelican project (for example `pandoc_extensions`)
+and make sure it is executable (``chmod +x pandoc-plantuml``).
+
+In the ``pelicanconf.py`` configure the needed plugins:
+
+.. code-block:: python
+
+    PLUGINS = ['pandoc_reader'] // Yes, plantuml plugin non necessary
+    PANDOC_ARGS = ['--filter=pandoc_extensions/pandoc-plantuml']
+
+In Markdown posts use the following syntax to include PlantUML_ diagrams:
+
+.. code-block:: markdown
+
+    ```plantuml
+    @startuml
+      Alice -> Bob: Authentication Request
+      Bob --> Alice: Authentication Response
+
+      Alice -> Bob: Another authentication Request
+      Alice <-- Bob: another authentication Response
+    @enduml
+    ```
+
+Rendered images will bu put in the output/images folder.
+
 Debugging
 ---------
 The plugin can produce debugging informations to help to locate errors. To enable debugging
@@ -196,3 +234,7 @@ Generated image:
 .. _layman: http://wiki.gentoo.org/wiki/Layman
 .. _Graphviz: http://www.graphviz.org
 .. _Pyhton-Markdown: http://pythonhosted.org/Markdown
+.. _pandoc: http://johnmacfarlane.net/pandoc
+.. _Haskell: http://www.haskell.org/haskellwiki/Haskell
+.. _Python:: http://www.python.org
+.. _Pelican: http://docs.getpelican.com/en

plantuml/pandoc-plantuml

@@ -0,0 +1,86 @@
+#!/usr/bin/runhaskell
+{-|
+
+  Script adapted from pandoc-plantuml-filter by Kurt Bonne
+  Original source at https://github.com/kbonne/pandoc-plantuml-filter.git
+
+  This script is meant to be run by pandoc executed by the pandoc_reader pelican plugin.
+  I've changed output paths to be compatibile with pelican output structure.
+
+  If using the pandoc_reader pelican plugin with this script, the plantuml plugin is not necessary.
+
+  Installation:
+  -------------
+    This script requires Haskell, but if you are using pandoc, it's already installed :-)
+    Copy this file in your pelican project, in the same directory of pelicanconf.py, and make sure it is executable.
+
+    In the pelicanconf.py configure the need plugins:
+
+      PLUGINS = ['pandoc_reader']
+      PANDOC_ARGS = ['--filter=pandoc-plantuml']
+
+    If this script will be putted in a different location, adapt the PANDOC_ARGS value.
+
+  Usage:
+  ------
+    In Markdown posts use the following syntax to include PlantUML diagrams:
+
+    ```plantuml
+    @startuml
+       Alice -> Bob: Authentication Request
+       Bob --> Alice: Authentication Response
+
+       Alice -> Bob: Another authentication Request
+       Alice <-- Bob: another authentication Response
+    @enduml
+    ```
+
+    Rendered images will bu put in the output/images folder.
+-}
+
+import Text.Pandoc.JSON
+import Data.ByteString.Lazy (hGetContents, hPut)
+import Data.ByteString.Lazy.UTF8 (fromString)
+import Data.Digest.Pure.SHA (sha1, showDigest)
+import System.IO (hClose, hPutStr, IOMode(..), openBinaryFile)
+import System.Process
+import System.Directory
+
+processBlocks :: Block -> IO Block
+processBlocks b =
+  case b of
+    CodeBlock (_ , ["plantuml"], _) content -> plantUMLToImg content
+    _ -> return b
+
+plantUMLToImg :: String -> IO Block
+plantUMLToImg content =  do
+  path <- renderImage content
+  return $ Para [Image [] (path, "")]
+
+renderImage :: String -> IO String
+renderImage content = do
+  createDirectoryIfMissing (True) "output/images"
+  let path = uniqueName content ++ ".png"
+  (Just hIn, Just hOut, _, _) <-
+    createProcess (proc "plantuml" ["-pipe", "-tepg"]){ std_in = CreatePipe,
+                                                        std_out = CreatePipe }
+  hPutStr hIn content
+  hClose hIn
+
+  let outPath = "output/images/" ++ path
+  hFile <- openBinaryFile outPath WriteMode
+  img <- hGetContents hOut
+  hPut hFile img
+
+  hClose hFile
+  hClose hOut
+
+  let imgPath = "images/" ++ path
+
+  return imgPath
+
+uniqueName :: String -> String
+uniqueName = showDigest . sha1 . fromString
+
+main :: IO ()
+main = toJSONFilter processBlocks