SiteHierarchy.py

# $Id: SiteHierarchy.py,v 1.1 2001/10/11 03:25:54 tavis_rudd Exp $
"""Create menus and crumbs from a site hierarchy.

You define the site hierarchy as lists/tuples.  Each location in the hierarchy
is a (url, description) tuple.  Each list has the base URL/text in the 0
position, and all the children coming after it.  Any child can be a list,
representing further depth to the hierarchy.  See the end of the file for an
example hierarchy.

Use Hierarchy(contents, currentURL), where contents is this hierarchy, and
currentURL is the position you are currently in.  The menubar and crumbs methods
give you the HTML output.

There are methods you can override to customize the HTML output.
"""

##################################################
## DEPENDENCIES
import string
try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO

##################################################
## CLASSES

class Hierarchy:
    def __init__(self, hierarchy, currentURL, prefix='', menuCSSClass=None,
                 crumbCSSClass=None):
        """
        hierarchy is described above, currentURL should be somewhere in
        the hierarchy.  prefix will be added before all of the URLs (to
        help mitigate the problems with absolute URLs), and if given,
        cssClass will be used for both links *and* nonlinks.
        """

        self._contents = hierarchy
        self._currentURL = currentURL
        if menuCSSClass:
            self._menuCSSClass = ' class="%s"' % menuCSSClass
        else:
            self._menuCSSClass = ''
        if crumbCSSClass:
            self._crumbCSSClass = ' class="%s"' % crumbCSSClass
        else:
            self._crumbCSSClass = ''
        self._prefix=prefix

    
    ## Main output methods
    
    def menuList(self, menuCSSClass=None):
        """An indented menu list"""
        if menuCSSClass:
            self._menuCSSClass = ' class="%s"' % menuCSSClass
        
        stream = StringIO()
        for item in self._contents[1:]:
            self._menubarRecurse(item, 0, stream)
        return stream.getvalue()

    def crumbs(self, crumbCSSClass=None):
        """The home>where>you>are crumbs"""
        if crumbCSSClass:
            self._crumbCSSClass = ' class="%s"' % crumbCSSClass
        
        path = []
        pos = self._contents
        while True:
            ## This is not the fastest algorithm, I'm afraid.
            ## But it probably won't be for a huge hierarchy anyway.
            foundAny = False
            path.append(pos[0])
            for item in pos[1:]:
                if self._inContents(item):
                    if isinstance(item, tuple):
                        path.append(item)
                        break
                    else:
                        pos = item
                        foundAny = True
                        break
            if not foundAny:
                break
        if len(path) == 1:
            return self.emptyCrumb()
        return string.join(map(lambda x, self=self: self.crumbLink(x[0], x[1]),
                               path), self.crumbSeperator()) + \
                               self.crumbTerminator()

    ## Methods to control the Aesthetics
    #  - override these methods for your own look
        
    def menuLink(self, url, text, indent):
        if url == self._currentURL or self._prefix + url == self._currentURL:
            return '%s<B%s>%s</B> <BR>\n' % ('&nbsp;'*2*indent,
                             self._menuCSSClass, text)
        else:
            return '%s<A HREF="%s%s"%s>%s</A> <BR>\n' % \
                   ('&nbsp;'*2*indent, self._prefix, url,
                    self._menuCSSClass, text)
        
    def crumbLink(self, url, text):
        if url == self._currentURL or self._prefix + url == self._currentURL:
            return '<B%s>%s</B>' % (text, self._crumbCSSClass)
        else:
            return '<A HREF="%s%s"%s>%s</A>' % \
                   (self._prefix, url, self._crumbCSSClass, text)
        
    def crumbSeperator(self):
        return '&nbsp;&gt;&nbsp;'
    
    def crumbTerminator(self):
        return ''
    
    def emptyCrumb(self):
        """When you are at the homepage"""
        return ''
                
    ## internal methods
    
    def _menubarRecurse(self, contents, indent, stream):
        if isinstance(contents, tuple):
            url, text = contents
            rest = []
        else:
            url, text = contents[0]
            rest = contents[1:]
        stream.write(self.menuLink(url, text, indent))
        if self._inContents(contents):
            for item in rest:
                self._menubarRecurse(item, indent+1, stream)

    def _inContents(self, contents):
        if isinstance(contents, tuple):
            return self._currentURL == contents[0]
        for item in contents:
            if self._inContents(item):
                return True
        return False
##################################################
## from the command line

if __name__ == '__main__':
    hierarchy = [('/', 'home'),
            ('/about', 'About Us'),
            [('/services', 'Services'),
             [('/services/products', 'Products'),
              ('/services/products/widget', 'The Widget'),
              ('/services/products/wedge', 'The Wedge'),
              ('/services/products/thimble', 'The Thimble'),
              ],
             ('/services/prices', 'Prices'),
             ],
            ('/contact', 'Contact Us'),
            ]

    for url in ['/', '/services', '/services/products/widget', '/contact']:
        print('<p>', '='*50)
        print('<br> %s: <br>\n' % url)
        n = Hierarchy(hierarchy, url, menuCSSClass='menu', crumbCSSClass='crumb',
                  prefix='/here')
        print(n.menuList())
        print('<p>', '-'*50)
        print(n.crumbs())