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"""
module for generating and serializing xml and html structures
by using simple python objects.
(c) holger krekel, holger at merlinux eu. 2009
"""
import sys, re
if sys.version_info >= (3,0):
def u(s):
return s
def unicode(x, errors=None):
if hasattr(x, '__unicode__'):
return x.__unicode__()
return str(x)
else:
def u(s):
return unicode(s)
unicode = unicode
class NamespaceMetaclass(type):
def __getattr__(self, name):
if name[:1] == '_':
raise AttributeError(name)
if self == Namespace:
raise ValueError("Namespace class is abstract")
tagspec = self.__tagspec__
if tagspec is not None and name not in tagspec:
raise AttributeError(name)
classattr = {}
if self.__stickyname__:
classattr['xmlname'] = name
cls = type(name, (self.__tagclass__,), classattr)
setattr(self, name, cls)
return cls
class Tag(list):
class Attr(object):
def __init__(self, **kwargs):
self.__dict__.update(kwargs)
def __init__(self, *args, **kwargs):
super(Tag, self).__init__(args)
self.attr = self.Attr(**kwargs)
def __unicode__(self):
return self.unicode(indent=0)
__str__ = __unicode__
def unicode(self, indent=2):
l = []
SimpleUnicodeVisitor(l.append, indent).visit(self)
return u("").join(l)
def __repr__(self):
name = self.__class__.__name__
return "<%r tag object %d>" % (name, id(self))
Namespace = NamespaceMetaclass('Namespace', (object, ), {
'__tagspec__': None,
'__tagclass__': Tag,
'__stickyname__': False,
})
class HtmlTag(Tag):
def unicode(self, indent=2):
l = []
HtmlVisitor(l.append, indent, shortempty=False).visit(self)
return u("").join(l)
# exported plain html namespace
class html(Namespace):
__tagclass__ = HtmlTag
__stickyname__ = True
__tagspec__ = dict([(x,1) for x in (
'a,abbr,acronym,address,applet,area,article,aside,audio,b,'
'base,basefont,bdi,bdo,big,blink,blockquote,body,br,button,'
'canvas,caption,center,cite,code,col,colgroup,command,comment,'
'datalist,dd,del,details,dfn,dir,div,dl,dt,em,embed,'
'fieldset,figcaption,figure,footer,font,form,frame,frameset,h1,'
'h2,h3,h4,h5,h6,head,header,hgroup,hr,html,i,iframe,img,input,'
'ins,isindex,kbd,keygen,label,legend,li,link,listing,map,mark,'
'marquee,menu,meta,meter,multicol,nav,nobr,noembed,noframes,'
'noscript,object,ol,optgroup,option,output,p,param,pre,progress,'
'q,rp,rt,ruby,s,samp,script,section,select,small,source,span,'
'strike,strong,style,sub,summary,sup,table,tbody,td,textarea,'
'tfoot,th,thead,time,title,tr,track,tt,u,ul,xmp,var,video,wbr'
).split(',') if x])
class Style(object):
def __init__(self, **kw):
for x, y in kw.items():
x = x.replace('_', '-')
setattr(self, x, y)
class raw(object):
"""just a box that can contain a unicode string that will be
included directly in the output"""
def __init__(self, uniobj):
self.uniobj = uniobj
class SimpleUnicodeVisitor(object):
""" recursive visitor to write unicode. """
def __init__(self, write, indent=0, curindent=0, shortempty=True):
self.write = write
self.cache = {}
self.visited = {} # for detection of recursion
self.indent = indent
self.curindent = curindent
self.parents = []
self.shortempty = shortempty # short empty tags or not
def visit(self, node):
""" dispatcher on node's class/bases name. """
cls = node.__class__
try:
visitmethod = self.cache[cls]
except KeyError:
for subclass in cls.__mro__:
visitmethod = getattr(self, subclass.__name__, None)
if visitmethod is not None:
break
else:
visitmethod = self.__object
self.cache[cls] = visitmethod
visitmethod(node)
# the default fallback handler is marked private
# to avoid clashes with the tag name object
def __object(self, obj):
#self.write(obj)
self.write(escape(unicode(obj)))
def raw(self, obj):
self.write(obj.uniobj)
def list(self, obj):
assert id(obj) not in self.visited
self.visited[id(obj)] = 1
for elem in obj:
self.visit(elem)
def Tag(self, tag):
assert id(tag) not in self.visited
try:
tag.parent = self.parents[-1]
except IndexError:
tag.parent = None
self.visited[id(tag)] = 1
tagname = getattr(tag, 'xmlname', tag.__class__.__name__)
if self.curindent and not self._isinline(tagname):
self.write("\n" + u(' ') * self.curindent)
if tag:
self.curindent += self.indent
self.write(u('<%s%s>') % (tagname, self.attributes(tag)))
self.parents.append(tag)
for x in tag:
self.visit(x)
self.parents.pop()
self.write(u('</%s>') % tagname)
self.curindent -= self.indent
else:
nameattr = tagname+self.attributes(tag)
if self._issingleton(tagname):
self.write(u('<%s/>') % (nameattr,))
else:
self.write(u('<%s></%s>') % (nameattr, tagname))
def attributes(self, tag):
# serialize attributes
attrlist = dir(tag.attr)
attrlist.sort()
l = []
for name in attrlist:
res = self.repr_attribute(tag.attr, name)
if res is not None:
l.append(res)
l.extend(self.getstyle(tag))
return u("").join(l)
def repr_attribute(self, attrs, name):
if name[:2] != '__':
value = getattr(attrs, name)
if name.endswith('_'):
name = name[:-1]
if isinstance(value, raw):
insert = value.uniobj
else:
insert = escape(unicode(value))
return ' %s="%s"' % (name, insert)
def getstyle(self, tag):
""" return attribute list suitable for styling. """
try:
styledict = tag.style.__dict__
except AttributeError:
return []
else:
stylelist = [x+': ' + y for x,y in styledict.items()]
return [u(' style="%s"') % u('; ').join(stylelist)]
def _issingleton(self, tagname):
"""can (and will) be overridden in subclasses"""
return self.shortempty
def _isinline(self, tagname):
"""can (and will) be overridden in subclasses"""
return False
class HtmlVisitor(SimpleUnicodeVisitor):
single = dict([(x, 1) for x in
('br,img,area,param,col,hr,meta,link,base,'
'input,frame').split(',')])
inline = dict([(x, 1) for x in
('a abbr acronym b basefont bdo big br cite code dfn em font '
'i img input kbd label q s samp select small span strike '
'strong sub sup textarea tt u var'.split(' '))])
def repr_attribute(self, attrs, name):
if name == 'class_':
value = getattr(attrs, name)
if value is None:
return
return super(HtmlVisitor, self).repr_attribute(attrs, name)
def _issingleton(self, tagname):
return tagname in self.single
def _isinline(self, tagname):
return tagname in self.inline
class _escape:
def __init__(self):
self.escape = {
u('"') : u('&quot;'), u('<') : u('&lt;'), u('>') : u('&gt;'),
u('&') : u('&amp;'), u("'") : u('&apos;'),
}
self.charef_rex = re.compile(u("|").join(self.escape.keys()))
def _replacer(self, match):
return self.escape[match.group(0)]
def __call__(self, ustring):
""" xml-escape the given unicode string. """
try:
ustring = unicode(ustring)
except UnicodeDecodeError:
ustring = unicode(ustring, 'utf-8', errors='replace')
return self.charef_rex.sub(self._replacer, ustring)
escape = _escape()