Change internal links rendering using python-creole

Question

My goal is to create a locally-browsable clone of the bitbucket's wiki browser. Pages are written using creole syntax.

I'm using python-creole to render the files into html. It works relatively fine, but there is a difference between the way python-creole and bitbucket render internal links.

On the Bitbucket site, an internal link with spaces like [[system programming]] will render to something like <a href="/wiki/system_programming">system programming</a> (spaces are replaced by _ ) while using python-creole this will render to <a href="system programming">system programming</a>.

Can I tweak python-creole into replacing spaces by _ and how?

Answer 1

I think I have found a quite dirty way to do this. Looking to creole source-code, the code which turns links to html is here:

def link_emit(self, node):
    target = node.content
    if node.children:
        inside = self.emit_children(node)
    else:
        inside = self.html_escape(target)

    return '<a href="%s">%s</a>' % (
        self.attr_escape(target), inside)

In a python shell I have tried the following code:

>>> import creole
>>> from creole.creole2html import emitter
>>> def new_emitter(self, node):
...    return 'blah'
>>> emitter.HtmlEmitter.link_emit = new_emitter
>>> creole.creole2html(u"[[link]]")
u'<p>blah</p>'

The exact code to replace spaces by '_' is left as an exercice to the reader...

I'm still looking for a more correct way to do this in "the official way".

Answer 2

Ascobol's answer works, but it is cleaner to use class inheritance.

This is an (slightly changed) extract from a wiki-application I am making. It changes the output from links and tables. If you want to see which methods you can override, you can look at the source-code of python-creole.

class WikiLinkHtmlEmitter(HtmlEmitter):
    def link_emit(self, node):
        target = node.content
        if node.children:
            inside = self.emit_children(node)
        else:
            inside = self.html_escape(target)
        m = self.link_rules.addr_re.match(target)
        if m:
            if m.group('extern_addr'):
                return u'<a href="%s">%s</a>' % (
                    self.attr_escape(target), inside)
            elif m.group('inter_wiki'):
                raise NotImplementedError
        if re.match(r'^\S+@\S+$', target):
            target = 'mailto:%s' % target
            return u'<a href="%s">%s</a>' % (
                self.attr_escape(target), inside)

        target = target.lower()
        target = slugify(target)

        target = '/wiki/' + target

        return u'<a href="%s" class="%s">%s</a>' % (
            self.attr_escape(target), classes, inside)

    def table_emit(self, node):
        return u'''
        <table class="table table-bordered table-striped">
            \n%s
        </table>\n''' % self.emit_children(node)

def creole_markup(value):
    document = Parser(value).parse()
    return mark_safe(WikiLinkHtmlEmitter(document).emit())