Added new module for constructing URLs

1 files changed, 279 insertions, 0 deletions

diff --git a/paste/url.py b/paste/url.py
new file mode 100644
index 0000000..3e92186
--- /dev/null
+++ b/paste/url.py
@@ -0,0 +1,279 @@
+"""
+This module implements a class for handling URLs.
+"""
+import urllib
+import cgi
+
+__all__ = ["URL"]
+
+def html_quote(v):
+    if v is None:
+        return ''
+    return cgi.escape(str(v), 1)
+
+def url_quote(v):
+    if v is None:
+        return ''
+    return urllib.quote(str(v))
+
+url_unquote = urllib.unquote
+
+def js_repr(v):
+    if v is None:
+        return 'null'
+    elif v is False:
+        return 'false'
+    elif v is True:
+        return 'true'
+    elif isinstance(v, list):
+        return '[%s]' % ', '.join(map(js_repr, v))
+    elif isinstance(v, dict):
+        return '{%s}' % ', '.join(
+            ['%s: %s' % (js_repr(key), js_repr(value))
+             for key, value in v])
+    elif isinstance(v, str):
+        return repr(v)
+    elif isinstance(v, unicode):
+        # @@: how do you do Unicode literals in Javascript?
+        return repr(v.encode('UTF-8'))
+    elif isinstance(v, (float, int)):
+        return repr(v)
+    elif isinstance(v, long):
+        return repr(v).lstrip('L')
+    elif hasattr(v, '__js_repr__'):
+        return v.__js_repr__()
+    else:
+        raise ValueError(
+            "I don't know how to turn %r into a Javascript representation"
+            % v)
+
+class URLResource(object):
+
+    """
+    This is an abstract superclass for different kinds of URLs
+    """
+
+    default_params = {}
+
+    def __init__(self, url, vars=None, attrs=None,
+                 params=None):
+        self.url = url
+        self.vars = vars or []
+        self.attrs = attrs or {}
+        self.params = self.default_params.copy()
+        self.original_params = params or {}
+        if params:
+            self.params.update(params)
+
+    def __call__(self, *args, **kw):
+        res = self._add_positional(args)
+        res = res._add_vars(kw)
+        return res
+
+    def __getitem__(self, item):
+        if '=' in item:
+            name, value = item.split('=', 1)
+            return self._add_vars({url_unquote(name): url_unquote(value)})
+        return self._add_positional((item,))
+
+    def attr(self, **kw):
+        for key in kw.keys():
+            if key.endswith('_'):
+                kw[key[:-1]] = kw[key]
+                del kw[key]
+        new_attrs = self.attrs.copy()
+        new_attrs.update(kw)
+        return self.__class__(self.url, vars=self.vars,
+                              attrs=new_attrs,
+                              params=self.original_params)
+
+    def param(self, **kw):
+        new_params = self.original_params.copy()
+        new_params.update(kw)
+        return self.__class__(self.url, vars=self.vars,
+                              attrs=self.attrs,
+                              params=new_params)
+
+    def var(self, **kw):
+        for key in kw.keys():
+            if key.endswith('_'):
+                kw[key[:-1]] = kw[key]
+                del kw[key]
+        new_vars = self.vars + kw.items()
+        return self.__class__(self.url, vars=new_vars,
+                              attrs=self.attrs,
+                              params=self.original_params)
+
+    def addpath(self, *paths):
+        u = self
+        for path in paths:
+            path = path.lstrip('/')
+            new_url = u.url
+            if not new_url.endswith('/'):
+                new_url += '/'
+            u = u.__class__(new_url+path, vars=u.vars,
+                            attrs=u.attrs,
+                            params=u.original_params)
+        return u
+            
+    __div__ = addpath
+    
+    def href__get(self):
+        s = self.url
+        if self.vars:
+            s += '?'
+            s += '&'.join(['%s=%s' % (url_quote(n), url_quote(v))
+                           for n, v in self.vars])
+        return s
+
+    href = property(href__get)
+
+    def __repr__(self):
+        base = '<%s %s' % (self.__class__.__name__,
+                           self.href or "''")
+        if self.attrs:
+            base += ' attrs(%s)' % (
+                ' '.join(['%s="%s"' % (html_quote(n), html_quote(v))
+                          for n, v in self.attrs.items()]))
+        if self.original_params:
+            base += ' params(%s)' % (
+                ', '.join(['%s=%r' % (n, v)
+                           for n, v in self.attrs.items()]))
+        return base + '>'
+    
+    def html__get(self):
+        if not self.params.get('tag'):
+            raise ValueError(
+                "You cannot get the HTML of %r until you set the "
+                "'tag' param'" % self)
+        content = self._get_content()
+        tag = '<%s' % self.params.get('tag')
+        attrs = ' '.join([
+            '%s="%s"' % (html_quote(n), html_quote(v))
+            for n, v in self._html_attrs()])
+        if attrs:
+            tag += ' ' + attrs
+        tag += self._html_extra()
+        if content is None:
+            return tag + ' />'
+        else:
+            return '%s>%s</%s>' % (tag, content, self.params.get('tag'))
+
+    html = property(html__get)
+
+    def _html_attrs(self):
+        return self.attrs.items()
+
+    def _html_extra(self):
+        return ''
+
+    def _get_content(self):
+        """
+        Return the content for a tag (for self.html); return None
+        for an empty tag (like ``<img />``)
+        """
+        raise NotImplementedError
+    
+    def _add_vars(self, vars):
+        raise NotImplementedError
+
+    def _add_positional(self, args):
+        raise NotImplementedError
+
+class URL(URLResource):
+
+    r"""
+    >>> u = URL('http://localhost')
+    >>> u
+    <URL http://localhost>
+    >>> u = u['view']
+    >>> str(u)
+    'http://localhost/view'
+    >>> u['//foo'].param(content='view').html
+    '<a href="http://localhost/view/foo">view</a>'
+    >>> u.param(confirm='Really?', content='goto').html
+    '<a href="http://localhost/view" onclick="return prompt(&quot;\'Really?\'&quot;)">goto</a>'
+    >>> u(title='See "it"', content='goto').html
+    '<a href="http://localhost/view?title=See%20%22it%22">goto</a>'
+    >>> u('another', var='fuggetaboutit', content='goto').html
+    '<a href="http://localhost/view/another?var=fuggetaboutit">goto</a>'
+    >>> u.attr(content='goto').html
+    Traceback (most recent call last):
+        ....
+    ValueError: You must give a content param to <URL http://localhost/view attrs(content="goto")> generate anchor tags
+    >>> str(u['foo=bar%20stuff'])
+    'http://localhost/view?foo=bar%20stuff'
+    """
+
+    default_params = {'tag': 'a'}
+
+    def __str__(self):
+        return self.href
+
+    def _get_content(self):
+        if not self.params.get('content'):
+            raise ValueError(
+                "You must give a content param to %r generate anchor tags"
+                % self)
+        return self.params['content']
+
+    def _add_vars(self, vars):
+        url = self
+        if 'confirm' in vars:
+            url = url.param(confirm=vars.pop('confirm'))
+        if 'content' in vars:
+            url = url.param(content=vars.pop('content'))
+        return url.var(**vars)
+
+    def _add_positional(self, args):
+        return self.addpath(*args)
+
+    def _html_attrs(self):
+        attrs = self.attrs.items()
+        attrs.insert(0, ('href', self.href))
+        if self.params.get('confirm'):
+            attrs.append(('onclick', 'return prompt(%r)'
+                          % js_repr(self.params['confirm'])))
+        return attrs
+
+    def onclick_goto__get(self):
+        return 'location.href=%r; return false' % js_repr(self.href)
+    
+    onclick_goto = property(onclick_goto__get)
+            
+class Image(URLResource):
+
+    r"""
+    >>> i = Image('/images')
+    >>> i = i / '/foo.png'
+    >>> i.html
+    '<img src="/images/foo.png" />'
+    >>> str(i['alt=foo'])
+    '<img src="/images/foo.png" alt="foo" />'
+    >>> i.href
+    '/images/foo.png'
+    """
+    
+    default_params = {'tag': 'img'}
+
+    def __str__(self):
+        return self.html
+
+    def _get_content(self):
+        return None
+
+    def _add_vars(self, vars):
+        return self.attr(**vars)
+
+    def _add_positional(self, args):
+        return self.addpath(*args)
+
+    def _html_attrs(self):
+        attrs = self.attrs.items()
+        attrs.insert(0, ('src', self.href))
+        return attrs
+    
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+