145 lines
5.4 KiB
Python
145 lines
5.4 KiB
Python
"""Subclass of HTMLParser.HTMLParser for MessageView widget"""
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import inspect
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import re
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from HTMLParser import HTMLParser
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from urllib import quote_plus
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from urlparse import urlparse
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class SafeHTMLParser(HTMLParser):
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"""HTML parser with sanitisation"""
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# from html5lib.sanitiser
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acceptable_elements = (
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'a', 'abbr', 'acronym', 'address', 'area',
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'article', 'aside', 'audio', 'b', 'big', 'blockquote', 'br', 'button',
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'canvas', 'caption', 'center', 'cite', 'code', 'col', 'colgroup',
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'command', 'datagrid', 'datalist', 'dd', 'del', 'details', 'dfn',
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'dialog', 'dir', 'div', 'dl', 'dt', 'em', 'event-source', 'fieldset',
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'figcaption', 'figure', 'footer', 'font', 'header', 'h1',
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'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'img', 'ins',
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'keygen', 'kbd', 'label', 'legend', 'li', 'm', 'map', 'menu', 'meter',
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'multicol', 'nav', 'nextid', 'ol', 'output', 'optgroup', 'option',
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'p', 'pre', 'progress', 'q', 's', 'samp', 'section', 'select',
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'small', 'sound', 'source', 'spacer', 'span', 'strike', 'strong',
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'sub', 'sup', 'table', 'tbody', 'td', 'textarea', 'time', 'tfoot',
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'th', 'thead', 'tr', 'tt', 'u', 'ul', 'var', 'video'
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)
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replaces_pre = (
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("&", "&"), ("\"", """), ("<", "<"), (">", ">"))
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replaces_post = (
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("\n", "<br/>"), ("\t", " "),
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(" ", " "), (" ", " "), ("<br/> ", "<br/> "))
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src_schemes = ["data"]
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# uriregex1 = re.compile(
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# r'(?i)\b((?:(https?|ftp|bitcoin):(?:/{1,3}|[a-z0-9%])'
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# r'|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)'
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# r'(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))'
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# r'+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:\'".,<>?]))')
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uriregex1 = re.compile(
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r'((https?|ftp|bitcoin):(?:/{1,3}|[a-z0-9%])'
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r'(?:[a-zA-Z]|[0-9]|[$-_@.&+#]|[!*\(\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+)'
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)
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uriregex2 = re.compile(r'<a href="([^"]+)&')
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emailregex = re.compile(
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r'\b([A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,})\b')
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@staticmethod
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def replace_pre(text):
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"""Perform substring replacement before regex replacements"""
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for a in SafeHTMLParser.replaces_pre:
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text = text.replace(*a)
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return text
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@staticmethod
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def replace_post(text):
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"""Perform substring replacement after regex replacements"""
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for a in SafeHTMLParser.replaces_post:
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text = text.replace(*a)
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if len(text) > 1 and text[0] == " ":
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text = " " + text[1:]
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return text
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def __init__(self, *args, **kwargs):
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HTMLParser.__init__(self, *args, **kwargs)
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self.reset()
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self.reset_safe()
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def reset_safe(self):
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"""Reset runtime variables specific to this class"""
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self.elements = set()
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self.raw = u""
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self.sanitised = u""
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self.has_html = False
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self.allow_picture = False
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self.allow_external_src = False
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def add_if_acceptable(self, tag, attrs=None):
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"""Add tag if it passes sanitisation"""
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if tag not in self.acceptable_elements:
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return
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self.sanitised += "<"
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if inspect.stack()[1][3] == "handle_endtag":
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self.sanitised += "/"
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self.sanitised += tag
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if attrs is not None:
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for attr, val in attrs:
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if tag == "img" and attr == "src" and not self.allow_picture:
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val = ""
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elif attr == "src" and not self.allow_external_src:
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url = urlparse(val)
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if url.scheme not in self.src_schemes:
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val = ""
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self.sanitised += " " + quote_plus(attr)
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if not (val is None):
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self.sanitised += "=\"" + val + "\""
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if inspect.stack()[1][3] == "handle_startendtag":
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self.sanitised += "/"
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self.sanitised += ">"
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def handle_starttag(self, tag, attrs):
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if tag in self.acceptable_elements:
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self.has_html = True
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self.add_if_acceptable(tag, attrs)
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def handle_endtag(self, tag):
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self.add_if_acceptable(tag)
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def handle_startendtag(self, tag, attrs):
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if tag in self.acceptable_elements:
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self.has_html = True
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self.add_if_acceptable(tag, attrs)
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def handle_data(self, data):
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self.sanitised += data
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def handle_charref(self, name):
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self.sanitised += "&#" + name + ";"
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def handle_entityref(self, name):
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self.sanitised += "&" + name + ";"
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def feed(self, data):
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try:
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data = unicode(data, 'utf-8')
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except UnicodeDecodeError:
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data = unicode(data, 'utf-8', errors='replace')
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HTMLParser.feed(self, data)
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tmp = SafeHTMLParser.replace_pre(data)
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tmp = self.uriregex1.sub(r'<a href="\1">\1</a>', tmp)
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tmp = self.uriregex2.sub(r'<a href="\1&', tmp)
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tmp = self.emailregex.sub(r'<a href="mailto:\1">\1</a>', tmp)
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tmp = SafeHTMLParser.replace_post(tmp)
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self.raw += tmp
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def is_html(self, text=None, allow_picture=False):
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"""Detect if string contains HTML tags"""
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if text:
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self.reset()
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self.reset_safe()
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self.allow_picture = allow_picture
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self.feed(text)
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self.close()
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return self.has_html
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