Changes between Version 1 and Version 2 of WikiMacros

Timestamp:

10/20/08 09:40:49 (16 years ago)

Author:

trac

Comment:

--

WikiMacros

@@ -1 @@
-=  Wiki Macros =
+= Trac Macros =
+
+[[PageOutline]]
+
 Trac macros are plugins to extend the Trac engine with custom 'functions' written in Python. A macro inserts dynamic HTML data in any context supporting WikiFormatting.
 
-Another kind of macros are WikiProcessors. They typically deal with alternate markup formats and representation of larger blocks of information (like source code highlighting). See also: WikiProcessors.
+Another kind of macros are WikiProcessors. They typically deal with alternate markup formats and representation of larger blocks of information (like source code highlighting).
 
 == Using Macros ==
-Macro calls are enclosed in two ''square brackets''. Like python functions, macros can also have arguments, a comma separated list within parenthesis. 
+Macro calls are enclosed in two ''square brackets''. Like Python functions, macros can also have arguments, a comma separated list within parentheses. 
 
-=== Examples ===
+Trac macros can also be written as TracPlugins. This gives them some capabilities that macros do not have, such as being able to directly access the HTTP request.
+
+=== Example ===
+
+A list of 3 most recently changed wiki pages starting with 'Trac':
 
 {{{
- [[Timestamp]]
+ [[RecentChanges(Trac,3)]]
 }}}
+
 Display:
- [[Timestamp]]
+ [[RecentChanges(Trac,3)]]
+
+== Available Macros ==
+
+''Note that the following list will only contain the macro documentation if you've not enabled `-OO` optimizations, or not set the `PythonOptimize` option for [wiki:TracModPython mod_python].''
+
+[[MacroList]]
+
+== Macros from around the world ==
+
+The [http://trac-hacks.org/ Trac Hacks] site provides a wide collection of macros and other Trac [TracPlugins plugins] contributed by the Trac community. If you're looking for new macros, or have written one that you'd like to share with the world, please don't hesitate to visit that site.
+
+== Developing Custom Macros ==
+Macros, like Trac itself, are written in the [http://python.org/ Python programming language].
+
+For more information about developing macros, see the [wiki:TracDev development resources] on the main project site.
+
+
+== Implementation ==
+
+Here are 2 simple examples on how to create a Macro with [wiki:0.11 Trac 0.11] have a look at source:trunk/sample-plugins/Timestamp.py for an example that shows the difference between old style and new style macros and also source:trunk/wiki-macros/README which provides a little more insight about the transition.
+
+=== Macro without arguments ===
+It should be saved as `TimeStamp.py` as Trac will use the module name as the Macro name
+{{{
+#!python
+from datetime import datetime
+# Note: since Trac 0.11, datetime objects are used internally
+
+from genshi.builder import tag
+
+from trac.util.datefmt import format_datetime, utc
+from trac.wiki.macros import WikiMacroBase
+
+class TimestampMacro(WikiMacroBase):
+    """Inserts the current time (in seconds) into the wiki page."""
+
+    revision = "$Rev$"
+    url = "$URL$"
+
+    def expand_macro(self, formatter, name, args):
+        t = datetime.now(utc)
+        return tag.b(format_datetime(t, '%c'))
+}}}
+
+=== Macro with arguments ===
+It should be saved as `HelloWorld.py` (in the plugins/ directory) as Trac will use the module name as the Macro name
+{{{
+#!python
+from trac.wiki.macros import WikiMacroBase
+
+class HelloWorldMacro(WikiMacroBase):
+    """Simple HelloWorld macro.
+
+    Note that the name of the class is meaningful:
+     - it must end with "Macro"
+     - what comes before "Macro" ends up being the macro name
+
+    The documentation of the class (i.e. what you're reading)
+    will become the documentation of the macro, as shown by
+    the !MacroList macro (usually used in the WikiMacros page).
+    """
+
+    revision = "$Rev$"
+    url = "$URL$"
+
+    def expand_macro(self, formatter, name, args):
+        """Return some output that will be displayed in the Wiki content.
+
+        `name` is the actual name of the macro (no surprise, here it'll be
+        `'HelloWorld'`),
+        `args` is the text enclosed in parenthesis at the call of the macro.
+          Note that if there are ''no'' parenthesis (like in, e.g.
+          [[HelloWorld]]), then `args` is `None`.
+        """
+        return 'Hello World, args = ' + unicode(args)
+    
+    # Note that there's no need to HTML escape the returned data,
+    # as the template engine (Genshi) will do it for us.
+}}}
+
+
+=== {{{expand_macro}}} details ===
+{{{expand_macro}}} should return either a simple Python string which will be interpreted as HTML, or preferably a Markup object (use {{{from trac.util.html import Markup}}}).  {{{Markup(string)}}} just annotates the string so the renderer will render the HTML string as-is with no escaping. You will also need to import Formatter using {{{from trac.wiki import Formatter}}}.
+
+If your macro creates wiki markup instead of HTML, you can convert it to HTML like this:
 
 {{{
- [[HelloWorld(Testing)]]
+#!python
+  text = "whatever wiki markup you want, even containing other macros"
+  # Convert Wiki markup to HTML, new style
+  out = StringIO()
+  Formatter(self.env, formatter.context).format(text, out)
+  return Markup(out.getvalue())
 }}}
-Display:
- [[HelloWorld(Testing)]]
-
-
-== Available Macros ==
-Macros are still a new feature, and the list of available (and distributed) macros is 
-admittedly not very impressive. In future Trac releases, we hope to build a library of useful macros, and will of course happily include contributed macros (see below). 
-
- * '''!HelloWorld''' -- An example macro, useful for learning how to write macros.
- * '''Timestamp''' -- Insert the current date and time.
-
-
-----
-
-
-== Macros from around the world ==
-The [http://projects.edgewall.com/trac/ Trac Project] has a section dedicated to user-contributed macros, [http://projects.edgewall.com/trac/wiki/MacroBazaar MacroBazaar]. If you're looking for new macros, or have written new ones to share with the world, don't hesitate adding it to the [http://projects.edgewall.com/trac/wiki/MacroBazaar MacroBazaar] wiki page.
-
-  http://projects.edgewall.com/trac/wiki/MacroBazaar
-
-
-----
-
-
-== Developing New Macros ==
-Macros, like Trac itself, are written in the [http://www.python.org/ Python programming language]. They are very simple modules, identified by the filename and should contain a single ''entry point'' function. Trac will display the returned data inserted into the HTML where the macro was called.
-
-It's easiest to learn from an example:
-{{{
-# MyMacro.py -- The world's simplest macro
-
-def execute(hdf, args, env):
-    return "Hello World called with args: %s" % args
-}}}
-
-=== Advanced Topics: Template-enabled Macros ===
-For advanced uses, macros can also render structured output in HDF, to be rendered to HTML using clearsilver templates - like most Trac output. In short, this allows more generic and well-designed advanced macros.
-
-Macros gain direct access to the main HDF tree, and are free to manipulate it. 
-
-Example:
-{{{
-def execute(hdf, args, env):
-    # Currently hdf is set only when the macro is called
-    # From a wiki page
-    if hdf:
-        hdf.setValue('wiki.macro.greeting', 'Hello World')
-        
-    # args will be null if the macro is called without parentesis.
-    args = args or 'No arguments'
-    return 'Hello World, args = ' + args
-}}}
-
-You can also use the environment (env) object to access configuration data.
-
-Example.
-{{{
-def execute(hdf, txt, env):
-    return env.get_config('trac', 'repository_dir')
-}}}
-----
-See also:  WikiProcessors, WikiFormatting, TracGuide