The u32 page is excellent, but I wonder if documenting the procedure here
would be worthwhile. Who knows, the remote site might disappear. But also
there are some variations on the approach that might be useful:

 * using a python script and the dom library to extract the page names from
   Special:Allpages (such as
   <http://www.staff.ncl.ac.uk/jon.dowland/unix/docs/get_pagenames.py>)
 * Or, querying the mysql back-end to get the names
 * using WWW::MediaWiki for importing/exporting pages from the wiki, instead
   of Special::Export

Also, some detail on converting mediawiki transclusion to ikiwiki inlines...

-- [[users/Jon]]

> "Who knows, the remote site might disappear.". Right now, it appears to
> have done just that. -- [[users/Jon]]


The iki-fast-load ruby script from the u32 page is given below:

        #!/usr/bin/env ruby

        # This script is called on the final sorted, de-spammed revision
        # XML file.
        #
        # It doesn't currently check for no-op revisions...  I believe
        # that git-fast-load will dutifully load them even though nothing
        # happened.  I don't care to solve this by adding a file cache
        # to this script.  You can run iki-diff-next.rb to highlight any
        # empty revisions that need to be removed.
        #
        # This turns each node into an equivalent file.
        #    It does not convert spaces to underscores in file names.
        #       This would break wikilinks.
        #       I suppose you could fix this with mod_speling or mod_rewrite.
        #
        # It replaces nodes in the Image: namespace with the files themselves.


        require 'rubygems'
        require 'node-callback'
        require 'time'
        require 'ostruct'


        # pipe is the stream to receive the git-fast-import commands
        # putfrom is true if this branch has existing commits on it, false if not.
        def format_git_commit(pipe, f)
           # Need to escape backslashes and double-quotes for git?
           # No, git breaks when I do this. 
           # For the filename "path with \\", git sez: bad default revision 'HEAD'
           # filename = '"' + filename.gsub('\\', '\\\\\\\\').gsub('"', '\\"') + '"'

           # In the calls below, length must be the size in bytes!!
           # TODO: I haven't figured out how this works in the land of UTF8 and Ruby 1.9.
           pipe.puts "commit #{f.branch}"
           pipe.puts "committer #{f.username} <#{f.email}> #{f.timestamp.rfc2822}"
           pipe.puts "data #{f.message.length}\n#{f.message}\n"
           pipe.puts "from #{f.branch}^0" if f.putfrom
           pipe.puts "M 644 inline #{f.filename}"
           pipe.puts "data #{f.content.length}\n#{f.content}\n"
           pipe.puts
        end

> Would be nice to know where you could get "node-callbacks"... this thing is useless without it. --[[users/simonraven]]


Mediawiki.pm - A plugin which supports mediawiki format.

	#!/usr/bin/perl
	# By Scott Bronson.  Licensed under the GPLv2+ License.
	# Extends Ikiwiki to be able to handle Mediawiki markup.
	#
	# To use the Mediawiki Plugin:
	# - Install Text::MediawikiFormat
	# - Turn of prefix_directives in your setup file.
	#     (TODO: we probably don't need to do this anymore?)
	#        prefix_directives => 1,
	# - Add this plugin on Ikiwiki's path (perl -V, look for @INC)
	#       cp mediawiki.pm something/IkiWiki/Plugin
	# - And enable it in your setup file
	#        add_plugins => [qw{mediawiki}],
	# - Finally, turn off the link plugin in setup (this is important)
	#        disable_plugins => [qw{link}],
	# - Rebuild everything (actually, this should be automatic right?)
	# - Now all files with a .mediawiki extension should be rendered properly.
	
	
	package IkiWiki::Plugin::mediawiki;
	
	use warnings;
	use strict;
	use IkiWiki 2.00;
	use URI;
	
	
	# This is a gross hack...  We disable the link plugin so that our
	# linkify routine is always called.  Then we call the link plugin
	# directly for all non-mediawiki pages.  Ouch...  Hopefully Ikiwiki
	# will be updated soon to support multiple link plugins.
	require IkiWiki::Plugin::link;
	
	# Even if T:MwF is not installed, we can still handle all the linking.
	# The user will just see Mediawiki markup rather than formatted markup.
	eval q{use Text::MediawikiFormat ()};
	my $markup_disabled = $@;
	
	# Work around a UTF8 bug in Text::MediawikiFormat
	# http://rt.cpan.org/Public/Bug/Display.html?id=26880
	unless($markup_disabled) {
	   no strict 'refs';
	   no warnings;
	   *{'Text::MediawikiFormat::uri_escape'} = \&URI::Escape::uri_escape_utf8;
	}
	
	my %metaheaders;    # keeps track of redirects for pagetemplate.
	my %tags;      # keeps track of tags for pagetemplate.
	
	
	sub import { #{{{
	   hook(type => "checkconfig", id => "mediawiki", call => \&checkconfig);
	   hook(type => "scan", id => "mediawiki", call => \&scan);
	   hook(type => "linkify", id => "mediawiki", call => \&linkify);
	   hook(type => "htmlize", id => "mediawiki", call => \&htmlize);
	   hook(type => "pagetemplate", id => "mediawiki", call => \&pagetemplate);
	} # }}}
	
	
	sub checkconfig
	{
	   return IkiWiki::Plugin::link::checkconfig(@_);
	}
	
	
	my $link_regexp = qr{
	    \[\[(?=[^!])        # beginning of link
	    ([^\n\r\]#|<>]+)      # 1: page to link to
	    (?:
	        \#              # '#', beginning of anchor
	        ([^|\]]+)       # 2: anchor text
	    )?                  # optional
	
	    (?:
	        \|              # followed by '|'
	        ([^\]\|]*)      # 3: link text
	    )?                  # optional
	    \]\]                # end of link
	        ([a-zA-Z]*)   # optional trailing alphas
	}x;
	
	
	# Convert spaces in the passed-in string into underscores.
	# If passed in undef, returns undef without throwing errors.
	sub underscorize
	{
	   my $var = shift;
	   $var =~ tr{ }{_} if $var;
	   return $var;
	}
	
	
	# Underscorize, strip leading and trailing space, and scrunch
	# multiple runs of spaces into one underscore.
	sub scrunch
	{
	   my $var = shift;
	   if($var) {
	      $var =~ s/^\s+|\s+$//g;      # strip leading and trailing space
	      $var =~ s/\s+/ /g;      # squash multiple spaces to one
	   }
	   return $var;
	}
	
	
	# Translates Mediawiki paths into Ikiwiki paths.
	# It needs to be pretty careful because Mediawiki and Ikiwiki handle
	# relative vs. absolute exactly opposite from each other.
	sub translate_path
	{
	   my $page = shift;
	   my $path = scrunch(shift);
	
	   # always start from root unless we're doing relative shenanigans.
	   $page = "/" unless $path =~ /^(?:\/|\.\.)/;
	
	   my @result = ();
	   for(split(/\//, "$page/$path")) {
	      if($_ eq '..') {
	         pop @result;
	      } else {
	         push @result, $_ if $_ ne "";
	      }
	   }
	
	   # temporary hack working around http://ikiwiki.info/bugs/Can__39__t_create_root_page/index.html?updated
	   # put this back the way it was once this bug is fixed upstream.
	   # This is actually a major problem because now Mediawiki pages can't link from /Git/git-svn to /git-svn.  And upstream appears to be uninterested in fixing this bug.  :(
	   # return "/" . join("/", @result);
	   return join("/", @result);
	}
	
	
	# Figures out the human-readable text for a wikilink
	sub linktext
	{
	   my($page, $inlink, $anchor, $title, $trailing) = @_;
	   my $link = translate_path($page,$inlink);
	
	   # translate_path always produces an absolute link.
	   # get rid of the leading slash before we display this link.
	   $link =~ s#^/##;
	
	   my $out = "";
	   if($title) {
	       $out = IkiWiki::pagetitle($title);
	   } else {
	      $link = $inlink if $inlink =~ /^\s*\//;
	       $out = $anchor ? "$link#$anchor" : $link;
	      if(defined $title && $title eq "") {
	         # a bare pipe appeared in the link...
	         # user wants to strip namespace and trailing parens.
	         $out =~ s/^[A-Za-z0-9_-]*://;
	         $out =~ s/\s*\(.*\)\s*$//;
	      }
	      # A trailing slash suppresses the leading slash
	      $out =~ s#^/(.*)/$#$1#;
	   }
	   $out .= $trailing if defined $trailing;
	   return $out;
	}
	
	
	sub tagpage ($)
	{
	   my $tag=shift;
	
	   if (exists $config{tagbase} && defined $config{tagbase}) {
	      $tag=$config{tagbase}."/".$tag;
	   }
	
	   return $tag;
	}
	
	
	# Pass a URL and optional text associated with it.  This call turns
	# it into fully-formatted HTML the same way Mediawiki would.
	# Counter is used to number untitled links sequentially on the page.
	# It should be set to 1 when you start parsing a new page.  This call
	# increments it automatically.
	sub generate_external_link
	{
	   my $url = shift;
	   my $text = shift;
	   my $counter = shift;
	
	   # Mediawiki trims off trailing commas.
	   # And apparently it does entity substitution first.
	   # Since we can't, we'll fake it.
	
	   # trim any leading and trailing whitespace
	   $url =~ s/^\s+|\s+$//g;
	
	   # url properly terminates on > but must special-case &gt;
	   my $trailer = "";
	   $url =~ s{(\&(?:gt|lt)\;.*)$}{ $trailer = $1, ''; }eg;
	
	   # Trim some potential trailing chars, put them outside the link.
	   my $tmptrail = "";
	   $url =~ s{([,)]+)$}{ $tmptrail .= $1, ''; }eg;
	   $trailer = $tmptrail . $trailer;
	
	   my $title = $url;
	   if(defined $text) {
	      if($text eq "") {
	         $text = "[$$counter]";
	         $$counter += 1;
	      }
	      $text =~ s/^\s+|\s+$//g;
	      $text =~ s/^\|//;
	   } else {
	      $text = $url;
	   }
	
	   return "<a href='$url' title='$title'>$text</a>$trailer";
	}
	
	
	# Called to handle bookmarks like \[[#heading]] or <span class="createlink"><a href="http://u32.net/cgi-bin/ikiwiki.cgi?page=%20text%20&amp;from=Mediawiki_Plugin%2Fmediawiki&amp;do=create" rel="nofollow">?</a>#a</span>
	sub generate_fragment_link
	{
	   my $url = shift;
	   my $text = shift;
	
	   my $inurl = $url;
	   my $intext = $text;
	   $url = scrunch($url);
	
	   if(defined($text) && $text ne "") {
	      $text = scrunch($text);
	   } else {
	      $text = $url;
	   }
	
	   $url = underscorize($url);
	
	   # For some reason Mediawiki puts blank titles on all its fragment links.
	   # I don't see why we would duplicate that behavior here.
	   return "<a href='$url'>$text</a>";
	}
	
	
	sub generate_internal_link
	{
	   my($page, $inlink, $anchor, $title, $trailing, $proc) = @_;
	
	   # Ikiwiki's link link plugin wrecks this line when displaying on the site.
	   # Until the code highlighter plugin can turn off link finding,
	   # always escape double brackets in double quotes: \[[
	   if($inlink eq '..') {
	      # Mediawiki doesn't touch links like \[[..#hi|ho]].
	      return "\[[" . $inlink . ($anchor?"#$anchor":"") .
	         ($title?"|$title":"") . "]]" . $trailing;
	   }
	
	   my($linkpage, $linktext);
	   if($inlink =~ /^ (:?) \s* Category (\s* \: \s*) ([^\]]*) $/x) {
	      # Handle category links
	      my $sep = $2;
	      $inlink = $3;
	      $linkpage = IkiWiki::linkpage(translate_path($page, $inlink));
	      if($1) {
	         # Produce a link but don't add this page to the given category.
	         $linkpage = tagpage($linkpage);
	         $linktext = ($title ? '' : "Category$sep") .
	            linktext($page, $inlink, $anchor, $title, $trailing);
	         $tags{$page}{$linkpage} = 1;
	      } else {
	         # Add this page to the given category but don't produce a link.
	         $tags{$page}{$linkpage} = 1;
	         &$proc(tagpage($linkpage), $linktext, $anchor);
	         return "";
	      }
	   } else {
	      # It's just a regular link
	      $linkpage = IkiWiki::linkpage(translate_path($page, $inlink));
	      $linktext = linktext($page, $inlink, $anchor, $title, $trailing);
	   }
	
	   return &$proc($linkpage, $linktext, $anchor);
	}
	
	
	sub check_redirect
	{
	   my %params=@_;
	
	   my $page=$params{page};
	   my $destpage=$params{destpage};
	   my $content=$params{content};
	
	   return "" if $page ne $destpage;
	
	   if($content !~ /^ \s* \#REDIRECT \s* \[\[ ( [^\]]+ ) \]\]/x) {
	      # this page isn't a redirect, render it normally.
	      return undef;
	   }
	
	   # The rest of this function is copied from the redir clause
	   # in meta::preprocess and actually handles the redirect.
	
	   my $value = $1;
	   $value =~ s/^\s+|\s+$//g;
	
	   my $safe=0;
	   if ($value !~ /^\w+:\/\//) {
	      # it's a local link
	      my ($redir_page, $redir_anchor) = split /\#/, $value;
	
	      add_depends($page, $redir_page);
	      my $link=bestlink($page, underscorize(translate_path($page,$redir_page)));
	      if (! length $link) {
	         return "<b>Redirect Error:</b> <nowiki>\[[$redir_page]] not found.</nowiki>";
	      }
	
	      $value=urlto($link, $page);
	      $value.='#'.$redir_anchor if defined $redir_anchor;
	      $safe=1;
	
	      # redir cycle detection
	      $pagestate{$page}{mediawiki}{redir}=$link;
	      my $at=$page;
	      my %seen;
	      while (exists $pagestate{$at}{mediawiki}{redir}) {
	         if ($seen{$at}) {
	            return "<b>Redirect Error:</b> cycle found on <nowiki>\[[$at]]</nowiki>";
	         }
	         $seen{$at}=1;
	         $at=$pagestate{$at}{mediawiki}{redir};
	      }
	   } else {
	      # it's an external link
	      $value = encode_entities($value);
	   }
	
	   my $redir="<meta http-equiv=\"refresh\" content=\"0; URL=$value\" />";
	   $redir=scrub($redir) if !$safe;
	   push @{$metaheaders{$page}}, $redir;
	
	   return "Redirecting to $value ...";
	}
	
	
	# Feed this routine a string containing <nowiki>...</nowiki> sections,
	# this routine calls your callback for every section not within nowikis,
	# collecting its return values and returning the rewritten string.
	sub skip_nowiki
	{
	   my $content = shift;
	   my $proc = shift;
	
	   my $result = "";
	   my $state = 0;
	
	   for(split(/(<nowiki[^>]*>.*?<\/nowiki\s*>)/s, $content)) {
	      $result .= ($state ? $_ : &$proc($_));
	      $state = !$state;
	   }
	
	   return $result;
	}
	
	
	# Converts all links in the page, wiki and otherwise.
	sub linkify (@)
	{
	   my %params=@_;
	
	   my $page=$params{page};
	   my $destpage=$params{destpage};
	   my $content=$params{content};
	
	   my $file=$pagesources{$page};
	   my $type=pagetype($file);
	   my $counter = 1;
	
	   if($type ne 'mediawiki') {
	      return IkiWiki::Plugin::link::linkify(@_);
	   }
	
	   my $redir = check_redirect(%params);
	   return $redir if defined $redir;
	
	   # this code was copied from MediawikiFormat.pm.
	   # Heavily changed because MF.pm screws up escaping when it does
	   # this awful hack: $uricCheat =~ tr/://d;
	   my $schemas = [qw(http https ftp mailto gopher)];
	   my $re = join "|", map {qr/\Q$_\E/} @$schemas;
	   my $schemes = qr/(?:$re)/;
	   # And this is copied from URI:
	   my $reserved   = q(;/?@&=+$,);   # NOTE: no colon or [] !
	   my $uric       = quotemeta($reserved) . $URI::unreserved . "%#";
	
	   my $result = skip_nowiki($content, sub {
	      $_ = shift;
	
	      # Escape any anchors
	      #s/<(a[\s>\/])/&lt;$1/ig;
	      # Disabled because this appears to screw up the aggregate plugin.
	      # I guess we'll rely on Iki to post-sanitize this sort of stuff.
	
	      # Replace external links, http://blah or [http://blah]
	      s{\b($schemes:[$uric][:$uric]+)|\[($schemes:[$uric][:$uric]+)([^\]]*?)\]}{
	         generate_external_link($1||$2, $3, \$counter)
	      }eg;
	
	      # Handle links that only contain fragments.
	      s{ \[\[ \s* (\#[^|\]'"<>&;]+) (?:\| ([^\]'"<>&;]*))? \]\] }{
	         generate_fragment_link($1, $2)
	      }xeg;
	
	      # Match all internal links
	      s{$link_regexp}{
	         generate_internal_link($page, $1, $2, $3, $4, sub {
	            my($linkpage, $linktext, $anchor) = @_;
	            return htmllink($page, $destpage, $linkpage,
	               linktext => $linktext,
	               anchor => underscorize(scrunch($anchor)));
	         });
	      }eg;
	   
	      return $_;
	   });
	
	   return $result;
	}
	
	
	# Find all WikiLinks in the page.
	sub scan (@)
	{
	   my %params = @_;
	   my $page=$params{page};
	   my $content=$params{content};
	
	   my $file=$pagesources{$page};
	   my $type=pagetype($file);
	
	   if($type ne 'mediawiki') {
	      return IkiWiki::Plugin::link::scan(@_);
	   }
	
	   skip_nowiki($content, sub {
	      $_ = shift;
	      while(/$link_regexp/g) {
	         generate_internal_link($page, $1, '', '', '', sub {
	            my($linkpage, $linktext, $anchor) = @_;
	            push @{$links{$page}}, $linkpage;
	            return undef;
	         });
	      }
	      return '';
	   });
	}
	
	
	# Convert the page to HTML.
	sub htmlize (@)
	{
	   my %params=@_;
	   my $page = $params{page};
	   my $content = $params{content};
	
	
	   return $content if $markup_disabled;
	
	   # Do a little preprocessing to babysit Text::MediawikiFormat
	   # If a line begins with tabs, T:MwF won't convert it into preformatted blocks.
	   $content =~ s/^\t/    /mg;
	
	   my $ret = Text::MediawikiFormat::format($content, {
	
	       allowed_tags    => [#HTML
	                # MediawikiFormat default
	                qw(b big blockquote br caption center cite code dd
	                   div dl dt em font h1 h2 h3 h4 h5 h6 hr i li ol p
	                   pre rb rp rt ruby s samp small strike strong sub
	                   sup table td th tr tt u ul var),
	                 # Mediawiki Specific
	                 qw(nowiki),
	                 # Our additions
	                 qw(del ins),   # These should have been added all along.
	                 qw(span),   # Mediawiki allows span but that's rather scary...?
	                 qw(a),      # this is unfortunate; should handle links after rendering the page.
	               ],
	
	       allowed_attrs   => [
	                qw(title align lang dir width height bgcolor),
	                qw(clear), # BR
	                qw(noshade), # HR
	                qw(cite), # BLOCKQUOTE, Q
	                qw(size face color), # FONT
	                # For various lists, mostly deprecated but safe
	                qw(type start value compact),
	                # Tables
	                qw(summary width border frame rules cellspacing
	                   cellpadding valign char charoff colgroup col
	                   span abbr axis headers scope rowspan colspan),
	                qw(id class name style), # For CSS
	                # Our additions
	                qw(href),
	               ],
	
	      }, {
	      extended => 0,
	      absolute_links => 0,
	      implicit_links => 0
	      });
	
	   return $ret;
	}
	
	
	# This is only needed to support the check_redirect call.
	sub pagetemplate (@)
	{
	   my %params = @_;
	   my $page = $params{page};
	   my $destpage = $params{destpage};
	   my $template = $params{template};
	
	   # handle metaheaders for redirects
	   if (exists $metaheaders{$page} && $template->query(name => "meta")) {
	   # avoid duplicate meta lines
	      my %seen;
	      $template->param(meta => join("\n", grep { (! $seen{$_}) && ($seen{$_}=1) } @{$metaheaders{$page}}));
	   }
	
	   $template->param(tags => [
	      map {
	         link => htmllink($page, $destpage, tagpage($_), rel => "tag")
	      }, sort keys %{$tags{$page}}
	   ]) if exists $tags{$page} && %{$tags{$page}} && $template->query(name => "tags");
	
	   # It's an rss/atom template. Add any categories.
	   if ($template->query(name => "categories")) {
	      if (exists $tags{$page} && %{$tags{$page}}) {
	         $template->param(categories => [map { category => $_ },
	            sort keys %{$tags{$page}}]);
	      }
	   }
	}
	
	1

Hello. Got ikiwiki running and I'm planning to convert my personal
Mediawiki wiki to ikiwiki so I can take offline copies around. If anyone
has an old copy of the instructions, or any advice on where to start I'd be
glad to hear it. Otherwise I'm just going to chronicle my journey on the
page.--[[users/Chadius]]

> Today I saw that someone is working to import wikipedia into git.
> <http://www.gossamer-threads.com/lists/wiki/foundation/181163>
> Since wikipedia uses mediawiki, perhaps his importer will work
> on mediawiki in general. It seems to produce output that could be
> used by the [[plugins/contrib/mediawiki]] plugin, if the filenames
> were fixed to use the right extension.  --[[Joey]]