[PATCH V3 0/4] git-remote-mediawiki: new tool to preview local changes without pushing

@@ -0,0 +1,24 @@
+package GitMediawiki;
+
+use 5.008;
+use strict;
+use Git;
+
+BEGIN {
+
+our ($VERSION, @ISA, @EXPORT, @EXPORT_OK);
+
+# Totally unstable API.
+$VERSION = '0.01';
+
+require Exporter;
+
+@ISA = qw(Exporter);
+
+@EXPORT = ();
+
+# Methods which can be called as standalone functions as well:
+@EXPORT_OK = ();
+}
+
+1; # Famous last words

@@ -4,16 +4,36 @@
 #
 ## Build git-remote-mediawiki
 
+GIT_MEDIAWIKI_PM=GitMediawiki.pm
 SCRIPT_PERL=git-remote-mediawiki.perl
 GIT_ROOT_DIR=../..
 HERE=contrib/mw-to-git/
 
 SCRIPT_PERL_FULL=$(patsubst %,$(HERE)/%,$(SCRIPT_PERL))
+INSTLIBDIR=$(shell $(MAKE) -C $(GIT_ROOT_DIR)/perl \
+                -s --no-print-directory instlibdir)
 
 all: build
 
-build install clean:
+copy_pm:
+	cp $(GIT_MEDIAWIKI_PM) $(GIT_ROOT_DIR)/perl/blib/lib/
+
+install_pm:
+	cp $(GIT_MEDIAWIKI_PM) $(INSTLIBDIR)
+
+build: copy_pm
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
+                build-perl-script
+
+install: install_pm
 	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
-                $@-perl-script
+                install-perl-script
+
+clean:
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
+                clean-perl-script
+	rm $(INSTLIBDIR)/$(GIT_MEDIAWIKI_PM) \
+       $(GIT_ROOT_DIR)/perl/blib/lib/$(GIT_MEDIAWIKI_PM)
+
 perlcritic:
-	perlcritic -2 *.perl
+	perlcritic -2 *.perl

@@ -6,6 +6,7 @@
 
 GIT_MEDIAWIKI_PM=GitMediawiki.pm
 SCRIPT_PERL=git-remote-mediawiki.perl
+SCRIPT_PERL+=git-mw.perl
 GIT_ROOT_DIR=../..
 HERE=contrib/mw-to-git/
 

@@ -22,15 +23,15 @@ install_pm:
 	cp $(GIT_MEDIAWIKI_PM) $(INSTLIBDIR)
 
 build: copy_pm
-	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
                 build-perl-script
 
 install: install_pm
-	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
                 install-perl-script
 
 clean:
-	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL=$(SCRIPT_PERL_FULL) \
+	$(MAKE) -C $(GIT_ROOT_DIR) SCRIPT_PERL="$(SCRIPT_PERL_FULL)" \
                 clean-perl-script
 	rm $(INSTLIBDIR)/$(GIT_MEDIAWIKI_PM) \
        $(GIT_ROOT_DIR)/perl/blib/lib/$(GIT_MEDIAWIKI_PM)

@@ -0,0 +1,46 @@
+#!/usr/bin/perl
+
+# Copyright (C) 2013
+#     Benoit Person <benoit.person@ensimag.imag.fr>
+#     Celestin Matte <celestin.matte@ensimag.imag.fr>
+# License: GPL v2 or later
+
+# Set of tools for git repo with a mediawiki remote.
+# Documentation & bugtracker: https://github.com/moy/Git-Mediawiki/
+
+use strict;
+use warnings;
+
+use Getopt::Long;
+
+my %commands = (
+	'help' =>
+		[\&help, {}, \&help]
+);
+
+# Search for sub-command
+my $cmd = $commands{'help'};
+for (0..@ARGV) {
+	if (defined $commands{$ARGV[$_]}) {
+		$cmd = $commands{$ARGV[$_]};
+		splice @ARGV, $_, 1;
+		last;
+	}
+};
+GetOptions( %{$cmd->[1]},
+	'help|h' => \&{$cmd->[2]});
+
+# Launch command
+&{$cmd->[0]};
+
+############################## Help Functions ##################################
+
+sub help {
+	print {*STDOUT} <<'END';
+usage: git mw <command> <args>
+
+git mw commands are:
+    help        Display help information about git mw
+END
+	exit;
+}

@@ -18,7 +18,82 @@ require Exporter;
 @EXPORT = ();
 
 # Methods which can be called as standalone functions as well:
-@EXPORT_OK = ();
+@EXPORT_OK = qw(clean_filename smudge_filename connect_maybe
+				EMPTY HTTP_CODE_OK);
+}
+
+# Mediawiki filenames can contain forward slashes. This variable decides by which pattern they should be replaced
+use constant SLASH_REPLACEMENT => '%2F';
+
+# Used to test for empty strings
+use constant EMPTY => q{};
+
+# HTTP codes
+use constant HTTP_CODE_OK => 200;
+
+sub clean_filename {
+	my $filename = shift;
+	$filename =~ s{@{[SLASH_REPLACEMENT]}}{/}g;
+	# [, ], |, {, and } are forbidden by MediaWiki, even URL-encoded.
+	# Do a variant of URL-encoding, i.e. looks like URL-encoding,
+	# but with _ added to prevent MediaWiki from thinking this is
+	# an actual special character.
+	$filename =~ s/[\[\]\{\}\|]/sprintf("_%%_%x", ord($&))/ge;
+	# If we use the uri escape before
+	# we should unescape here, before anything
+
+	return $filename;
+}
+
+sub smudge_filename {
+	my $filename = shift;
+	$filename =~ s{/}{@{[SLASH_REPLACEMENT]}}g;
+	$filename =~ s/ /_/g;
+	# Decode forbidden characters encoded in clean_filename
+	$filename =~ s/_%_([0-9a-fA-F][0-9a-fA-F])/sprintf('%c', hex($1))/ge;
+	return $filename;
+}
+
+sub connect_maybe {
+	my $wiki = shift;
+	if ($wiki) {
+		return $wiki;
+	}
+
+	my $remote_name = shift;
+	my $remote_url = shift;
+	my ($wiki_login, $wiki_password, $wiki_domain);
+
+	$wiki_login = Git::config("remote.${remote_name}.mwLogin");
+	$wiki_password = Git::config("remote.${remote_name}.mwPassword");
+	$wiki_domain = Git::config("remote.${remote_name}.mwDomain");
+
+	$wiki = MediaWiki::API->new;
+	$wiki->{config}->{api_url} = "${remote_url}/api.php";
+	if ($wiki_login) {
+		my %credential = (
+			'url' => $remote_url,
+			'username' => $wiki_login,
+			'password' => $wiki_password
+		);
+		Git::credential(\%credential);
+		my $request = {lgname => $credential{username},
+			       lgpassword => $credential{password},
+			       lgdomain => $wiki_domain};
+		if ($wiki->login($request)) {
+			Git::credential(\%credential, 'approve');
+			print {*STDERR} qq(Logged in mediawiki user "$credential{username}".\n);
+		} else {
+			print {*STDERR} qq(Failed to log in mediawiki user "$credential{username}" on ${remote_url}\n);
+			print {*STDERR} '  (error ' .
+				$wiki->{error}->{code} . ': ' .
+				$wiki->{error}->{details} . ")\n";
+			Git::credential(\%credential, 'reject');
+			exit 1;
+		}
+	}
+
+	return $wiki;
 }
 
 1; # Famous last words

@@ -14,6 +14,8 @@
 use strict;
 use MediaWiki::API;
 use Git;
+use GitMediawiki qw(clean_filename smudge_filename connect_maybe
+					EMPTY HTTP_CODE_OK);
 use DateTime::Format::ISO8601;
 use warnings;
 

@@ -23,9 +25,6 @@ binmode STDOUT, ':encoding(UTF-8)';
 
 use URI::Escape;
 
-# Mediawiki filenames can contain forward slashes. This variable decides by which pattern they should be replaced
-use constant SLASH_REPLACEMENT => '%2F';
-
 # It's not always possible to delete pages (may require some
 # privileges). Deleted pages are replaced with this content.
 use constant DELETED_CONTENT => "[[Category:Deleted]]\n";

@@ -40,8 +39,6 @@ use constant NULL_SHA1 => '0000000000000000000000000000000000000000';
 # Used on Git's side to reflect empty edit messages on the wiki
 use constant EMPTY_MESSAGE => '*Empty MediaWiki Message*';
 
-use constant EMPTY => q{};
-
 # Number of pages taken into account at once in submodule get_mw_page_list
 use constant SLICE_SIZE => 50;
 

@@ -50,8 +47,6 @@ use constant SLICE_SIZE => 50;
 # the number of links to be returned (500 links max).
 use constant BATCH_SIZE => 10;
 
-use constant HTTP_CODE_OK => 200;
-
 my $remotename = $ARGV[0];
 my $url = $ARGV[1];
 

@@ -184,37 +179,6 @@ sub parse_command {
 # MediaWiki API instance, created lazily.
 my $mediawiki;
 
-sub mw_connect_maybe {
-	if ($mediawiki) {
-		return;
-	}
-	$mediawiki = MediaWiki::API->new;
-	$mediawiki->{config}->{api_url} = "${url}/api.php";
-	if ($wiki_login) {
-		my %credential = (
-			'url' => $url,
-			'username' => $wiki_login,
-			'password' => $wiki_passwd
-		);
-		Git::credential(\%credential);
-		my $request = {lgname => $credential{username},
-			       lgpassword => $credential{password},
-			       lgdomain => $wiki_domain};
-		if ($mediawiki->login($request)) {
-			Git::credential(\%credential, 'approve');
-			print {*STDERR} qq(Logged in mediawiki user "$credential{username}".\n);
-		} else {
-			print {*STDERR} qq(Failed to log in mediawiki user "$credential{username}" on ${url}\n);
-			print {*STDERR} '  (error ' .
-				$mediawiki->{error}->{code} . ': ' .
-				$mediawiki->{error}->{details} . ")\n";
-			Git::credential(\%credential, 'reject');
-			exit 1;
-		}
-	}
-	return;
-}
-
 sub fatal_mw_error {
 	my $action = shift;
 	print STDERR "fatal: could not $action.\n";

@@ -324,7 +288,7 @@ sub get_mw_first_pages {
 
 # Get the list of pages to be fetched according to configuration.
 sub get_mw_pages {
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 	print {*STDERR} "Listing pages on remote wiki...\n";
 

@@ -514,7 +478,7 @@ sub get_last_local_revision {
 # avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
 # option.
 sub get_last_global_remote_rev {
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 	my $query = {
 		action => 'query',

@@ -530,7 +494,7 @@ sub get_last_global_remote_rev {
 # Get the last remote revision concerning the tracked pages and the tracked
 # categories.
 sub get_last_remote_revision {
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 	my %pages_hash = get_mw_pages();
 	my @pages = values(%pages_hash);

@@ -586,29 +550,6 @@ sub mediawiki_smudge {
 	return "${string}\n";
 }
 
-sub mediawiki_clean_filename {
-	my $filename = shift;
-	$filename =~ s{@{[SLASH_REPLACEMENT]}}{/}g;
-	# [, ], |, {, and } are forbidden by MediaWiki, even URL-encoded.
-	# Do a variant of URL-encoding, i.e. looks like URL-encoding,
-	# but with _ added to prevent MediaWiki from thinking this is
-	# an actual special character.
-	$filename =~ s/[\[\]\{\}\|]/sprintf("_%%_%x", ord($&))/ge;
-	# If we use the uri escape before
-	# we should unescape here, before anything
-
-	return $filename;
-}
-
-sub mediawiki_smudge_filename {
-	my $filename = shift;
-	$filename =~ s{/}{@{[SLASH_REPLACEMENT]}}g;
-	$filename =~ s/ /_/g;
-	# Decode forbidden characters encoded in mediawiki_clean_filename
-	$filename =~ s/_%_([0-9a-fA-F][0-9a-fA-F])/sprintf('%c', hex($1))/ge;
-	return $filename;
-}
-
 sub literal_data {
 	my ($content) = @_;
 	print {*STDOUT} 'data ', bytes::length($content), "\n", $content;

@@ -816,7 +757,7 @@ sub mw_import_ref {
 		return;
 	}
 
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 	print {*STDERR} "Searching revisions...\n";
 	my $last_local = get_last_local_revision();

@@ -930,7 +871,7 @@ sub mw_import_revids {
 		my %commit;
 		$commit{author} = $rev->{user} || 'Anonymous';
 		$commit{comment} = $rev->{comment} || EMPTY_MESSAGE;
-		$commit{title} = mediawiki_smudge_filename($page_title);
+		$commit{title} = smudge_filename($page_title);
 		$commit{mw_revision} = $rev->{revid};
 		$commit{content} = mediawiki_smudge($rev->{'*'});
 

@@ -991,7 +932,7 @@ sub mw_upload_file {
 	}
 	# Deleting and uploading a file requires a priviledged user
 	if ($file_deleted) {
-		mw_connect_maybe();
+		$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 		my $query = {
 			action => 'delete',
 			title => $path,

@@ -1007,7 +948,7 @@ sub mw_upload_file {
 		# Don't let perl try to interpret file content as UTF-8 => use "raw"
 		my $content = run_git("cat-file blob ${new_sha1}", 'raw');
 		if ($content ne EMPTY) {
-			mw_connect_maybe();
+			$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 			$mediawiki->{config}->{upload_url} =
 				"${url}/index.php/Special:Upload";
 			$mediawiki->edit({

@@ -1055,7 +996,7 @@ sub mw_push_file {
 	my $old_sha1 = $diff_info_split[2];
 	my $page_created = ($old_sha1 eq NULL_SHA1);
 	my $page_deleted = ($new_sha1 eq NULL_SHA1);
-	$complete_file_name = mediawiki_clean_filename($complete_file_name);
+	$complete_file_name = clean_filename($complete_file_name);
 
 	my ($title, $extension) = $complete_file_name =~ /^(.*)\.([^\.]*)$/;
 	if (!defined($extension)) {

@@ -1078,7 +1019,7 @@ sub mw_push_file {
 			$file_content = run_git("cat-file blob ${new_sha1}");
 		}
 
-		mw_connect_maybe();
+		$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 		my $result = $mediawiki->edit( {
 			action => 'edit',

@@ -1264,7 +1205,7 @@ sub mw_push_revision {
 }
 
 sub get_allowed_file_extensions {
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 
 	my $query = {
 		action => 'query',

@@ -1288,7 +1229,7 @@ my %cached_mw_namespace_id;
 # Return MediaWiki id for a canonical namespace name.
 # Ex.: "File", "Project".
 sub get_mw_namespace_id {
-	mw_connect_maybe();
+	$mediawiki = connect_maybe($mediawiki, $remotename, $url);
 	my $name = shift;
 
 	if (!exists $namespace_id{$name}) {

@@ -19,7 +19,7 @@ require Exporter;
 
 # Methods which can be called as standalone functions as well:
 @EXPORT_OK = qw(clean_filename smudge_filename connect_maybe
-				EMPTY HTTP_CODE_OK);
+				EMPTY HTTP_CODE_OK HTTP_CODE_PAGE_NOT_FOUND);
 }
 
 # Mediawiki filenames can contain forward slashes. This variable decides by which pattern they should be replaced

@@ -30,6 +30,7 @@ use constant EMPTY => q{};
 
 # HTTP codes
 use constant HTTP_CODE_OK => 200;
+use constant HTTP_CODE_PAGE_NOT_FOUND => 404;
 
 sub clean_filename {
 	my $filename = shift;

@@ -12,10 +12,41 @@ use strict;
 use warnings;
 
 use Getopt::Long;
+use URI::URL qw(url);
+use LWP::UserAgent;
+use HTML::TreeBuilder;
+
+use Git;
+use MediaWiki::API;
+use GitMediawiki qw(smudge_filename connect_maybe
+					EMPTY HTTP_CODE_PAGE_NOT_FOUND);
+
+# By default, use UTF-8 to communicate with Git and the user
+binmode STDERR, ':encoding(UTF-8)';
+binmode STDOUT, ':encoding(UTF-8)';
+
+#preview parameters
+my $file_name = EMPTY;
+my $remote_name = EMPTY;
+my $preview_file_name = EMPTY;
+my $autoload = 0;
+my $verbose = 0;
+sub file {
+	$file_name = shift;
+	return $file_name;
+}
 
 my %commands = (
 	'help' =>
-		[\&help, {}, \&help]
+		[\&help, {}, \&help],
+	'preview' =>
+		[\&preview, {
+			'<>' => \&file,
+			'output|o=s' => \$preview_file_name,
+			'remote|r=s' => \$remote_name,
+			'autoload|a' => \$autoload,
+			'verbose|v'  => \$verbose
+		}, \&preview_help]
 );
 
 # Search for sub-command

@@ -33,6 +64,275 @@ GetOptions( %{$cmd->[1]},
 # Launch command
 &{$cmd->[0]};
 
+############################# Preview Functions ################################
+
+# @TODO : add documentation for verbose option
+sub preview_help {
+	print {*STDOUT} <<'END';
+USAGE: git mw preview [--remote|-r <remote name>] [--autoload|-a]
+                      [--output|-o <output filename>] [--verbose|-v]
+                      <blob> | <filename>
+
+DESCRIPTION:
+Preview is an utiliy to preview local content of a mediawiki repo as if it was
+pushed on the remote.
+
+For that, preview searches for the remote name of the current branch's upstream
+if --remote is not set. If that remote is not found or if it is not a mediawiki,
+it lists all mediawiki remotes configured and asks you to replay your command
+with the --remote option set properly.
+
+Then, it searches for a file named 'filename'. If it's not found in the current
+dir, it will assume it's a blob.
+
+The content retrieved in the file (or in the blob) will then be parsed by the
+distant mediawiki and combined with a template retrieved from the mediawiki.
+
+Finally, preview will save the HTML result in a file. and autoload it in your
+default web browser if the option --autoload is present.
+
+OPTIONS:
+	-r <remote name>, --remote <remote name>
+		If the remote is a mediawiki, the template and the parse engine used for
+		the preview will be those of that remote.
+		If not, a list of valid remotes will be shown.
+
+	-a, --autoload
+		Try to load the HTML output in a new tab (or new window) of your default
+		web browser.
+
+	-o <output filename>, --output <output filename>
+		Change the HTML output filename. Default filename is based on the input
+		filename with its extension replaced by '.html'.
+
+	-v, --verbose
+		Show more information on what's going on under the hood.
+END
+	exit;
+}
+
+sub preview {
+	my $wiki;
+	my ($remote_url, $wiki_page_name);
+	my ($content, $content_tree, $template, $html_tree, $mw_content_text);
+	my $file_content;
+	my $template_content_id = 'bodyContent';
+
+	# file_name argumeent is mandatory
+	if (!defined $file_name) {
+		die "File not set, see `git mw help` \n";
+	}
+
+	v_print("### SELECTING REMOTE ###\n");
+
+	if ($remote_name eq EMPTY) {
+		# Search current branch upstream branch remote
+		my $current_branch = git_cmd_try {
+			Git::command_oneline('symbolic-ref', '--short', 'HEAD') }
+			"%s failed w/ code %d";
+		$remote_name = Git::config("branch.${current_branch}.remote");
+
+		if ($remote_name) {
+			$remote_url = mediawiki_remote_url_maybe($remote_name);
+		}
+
+		# Search all possibles mediawiki remotes
+		if (! $remote_url) {
+			my @remotes = git_cmd_try {
+				Git::command('remote'); }
+				"%s failed w/ code %d";
+
+			my @valid_remotes = ();
+			foreach my $remote (@remotes) {
+				$remote_url = mediawiki_remote_url_maybe($remote);
+				if ($remote_url) {
+					push(@valid_remotes, $remote);
+				}
+			}
+
+			if ($#valid_remotes == 0) {
+				print {*STDERR} "Can not find any mediawiki remote in this repo. \n";
+				exit 1;
+			} else {
+				print {*STDERR} "There are multiple mediawiki remotes, which of:\n";
+				foreach my $remote (@remotes) {
+					print {*STDERR} "\t${remote}\n";
+				}
+				print {*STDERR} "do you want ? Use the -r option to specify the remote\n";
+			}
+
+			exit 0;
+		}
+	} else {
+		# Check remote name
+		my @remotes = git_cmd_try {
+			Git::command('remote') }
+			"%s failed w/ code %d";
+		my $found_remote = 0;
+		foreach my $remote (@remotes) {
+			if ($remote eq $remote_name) {
+				$found_remote = 1;
+				last;
+			}
+		}
+		if (!$found_remote) {
+			die "${remote_name} is not a remote\n";
+		}
+
+		# Find remote url
+		$remote_url = mediawiki_remote_url_maybe($remote_name);
+		if (! $remote_url) {
+			die "the remote you selected is not a mediawiki remote\n";
+		}
+	}
+	v_print("selected remote:\n\tname: ${remote_name}\n\turl: ${remote_url}\n");
+
+	# Create and connect to the wiki if necessary
+	$wiki = connect_maybe($wiki, $remote_name, $remote_url);
+
+	# Read file content
+	if (! -e $file_name) {
+		$file_content = git_cmd_try {
+			Git::command('cat-file', 'blob', $file_name); }
+			"%s failed w/ code %d";
+
+		if ($file_name =~ /(.+):(.+)/) {
+			$file_name = $2;
+		}
+	} else {
+		open my $read_fh, "<", $file_name
+			or die "could not open ${file_name}: $!\n";
+		$file_content = do { local $/ = undef; <$read_fh> };
+		close $read_fh
+			or die "unable to close: $!\n";
+	}
+
+	# Transform file_name into a mediawiki page name
+	$wiki_page_name = smudge_filename($file_name);
+	$wiki_page_name =~ s/\.[^.]+$//;
+
+	# Default preview_file_name is file_name with .html ext
+	if ($preview_file_name eq EMPTY) {
+		$preview_file_name = $file_name;
+		$preview_file_name =~ s/\.[^.]+$/.html/;
+	}
+
+	v_print("### Retrieving template\n");
+	$template = get_template($remote_url, $wiki_page_name);
+
+	v_print("### Parsing & merging contents\n");
+	# Parsing template page
+	$html_tree = HTML::TreeBuilder->new;
+	$html_tree->parse($template);
+
+	# Load new content
+	$content = $wiki->api({
+		action => 'parse',
+		text => $file_content,
+		title => $wiki_page_name
+	}, {
+		skip_encoding => 1
+	}) or die "No response from distant mediawiki\n";
+	$content = $content->{'parse'}->{'text'}->{'*'};
+	$content_tree = HTML::TreeBuilder->new;
+	$content_tree->parse($content);
+
+	# Replace old content with new one
+	$template_content_id = Git::config('mediawiki.IDContent')
+		|| $template_content_id;
+	v_print("Using '${template_content_id}' as the content ID\n");
+	$mw_content_text = $html_tree->look_down('id', $template_content_id);
+	if (!defined $mw_content_text) {
+		print {*STDERR} <<"CONFIG";
+Could not combine the new parsed content with the template. You might want to
+configure `mediawiki.IDContent` in your config:
+	git config --add mediawiki.IDContent <your_template_content_element_id>
+CONFIG
+	}
+	$mw_content_text->delete_content();
+	$mw_content_text->push_content($content_tree);
+
+	# Transform relative links into absolute ones
+	for (@{ $html_tree->extract_links() }) {
+		my ($link, $element, $attr) = @{ $_ };
+		my $url = url($link)->canonical;
+		$element->attr($attr, URI->new_abs($url, $remote_url));
+	}
+
+	# Save the preview file
+	open(my $save_fh, '>:encoding(UTF-8)', $preview_file_name)
+		or die "Could not open: $!\n";
+	print {$save_fh} $html_tree->as_HTML;
+	close($save_fh)
+		or die "Could not close: $!\n";
+
+	# Auto-loading in browser
+	v_print("### Results\n");
+	if ($autoload) {
+		v_print("Launching browser w/ file: ${preview_file_name}");
+		system('git', 'web--browse', $preview_file_name);
+	} else {
+		print {*STDERR} "Preview file saved as: ${preview_file_name}\n";
+	}
+
+	exit;
+}
+
+sub mediawiki_remote_url_maybe {
+	my $remote = shift;
+
+	# Find remote url
+	my $remote_url = Git::config("remote.${remote}.url");
+	if ($remote_url =~ s/mediawiki::(.*)/$1/) {
+		return url($remote_url)->canonical;
+	}
+
+	return;
+}
+
+sub get_template {
+	my $url = shift;
+	my $page_name = shift;
+	my ($req, $res, $code, $url_after);
+
+	$req = LWP::UserAgent->new;
+	if ($verbose) {
+		$req->show_progress(1);
+	}
+
+	$res = $req->get("${url}/index.php?title=${page_name}");
+	if (!$res->is_success) {
+		$code = $res->code;
+		$url_after = $res->request()->uri(); # resolve all redirections
+		if ($code == HTTP_CODE_PAGE_NOT_FOUND) {
+			if ($verbose) {
+				print {*STDERR} <<"WARNING";
+Warning: Failed to retrieve '$page_name'. Create it on the mediawiki if you want
+all the links to work properly.
+Trying to use the mediawiki homepage as a fallback template ...
+WARNING
+			}
+
+			# LWP automatically redirects GET request
+			$res = $req->get("${url}/index.php");
+			if (!$res->is_success) {
+				$url_after = $res->request()->uri(); # resolve all redirections
+				die "Failed to get homepage @ ${url_after} w/ code ${code}\n";
+			}
+		} else {
+			die "Failed to get '${page_name}' @ ${url_after} w/ code ${code}\n";
+		}
+	}
+
+	return $res->decoded_content;
+}
+
+sub v_print {
+	if ($verbose) {
+		print {*STDERR} @_;
+	}
+}
+
 ############################## Help Functions ##################################
 
 sub help {

@@ -41,6 +341,7 @@ usage: git mw <command> <args>
 
 git mw commands are:
     help        Display help information about git mw
+    preview 	Parse and render local file into HTML
 END
 	exit;
 }