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author | R. Tyler Ballance <tyler@slide.com> | 2009-04-16 22:32:41 -0700 |
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committer | R. Tyler Ballance <tyler@slide.com> | 2009-04-16 22:32:41 -0700 |
commit | 45f570f03abfbe929a14a7c23e2aa2a39ce152c5 (patch) | |
tree | 992e83fd05db4ab0231ec1a2257ba45b744376c5 /src/contrib/markdown/inlinepatterns.py | |
parent | 2fc2c598e3ab45631739fe0f582fbfc18573b417 (diff) | |
parent | 1c42c232c419001116a099e4a49032231fff38fe (diff) | |
download | python-cheetah-45f570f03abfbe929a14a7c23e2aa2a39ce152c5.tar.gz |
Merge branch 'next' of git@github.com:rtyler/cheetahv2.1.1
Diffstat (limited to 'src/contrib/markdown/inlinepatterns.py')
-rw-r--r-- | src/contrib/markdown/inlinepatterns.py | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/src/contrib/markdown/inlinepatterns.py b/src/contrib/markdown/inlinepatterns.py new file mode 100644 index 0000000..89fa3b2 --- /dev/null +++ b/src/contrib/markdown/inlinepatterns.py @@ -0,0 +1,371 @@ +""" +INLINE PATTERNS +============================================================================= + +Inline patterns such as *emphasis* are handled by means of auxiliary +objects, one per pattern. Pattern objects must be instances of classes +that extend markdown.Pattern. Each pattern object uses a single regular +expression and needs support the following methods: + + pattern.getCompiledRegExp() # returns a regular expression + + pattern.handleMatch(m) # takes a match object and returns + # an ElementTree element or just plain text + +All of python markdown's built-in patterns subclass from Pattern, +but you can add additional patterns that don't. + +Also note that all the regular expressions used by inline must +capture the whole block. For this reason, they all start with +'^(.*)' and end with '(.*)!'. In case with built-in expression +Pattern takes care of adding the "^(.*)" and "(.*)!". + +Finally, the order in which regular expressions are applied is very +important - e.g. if we first replace http://.../ links with <a> tags +and _then_ try to replace inline html, we would end up with a mess. +So, we apply the expressions in the following order: + +* escape and backticks have to go before everything else, so + that we can preempt any markdown patterns by escaping them. + +* then we handle auto-links (must be done before inline html) + +* then we handle inline HTML. At this point we will simply + replace all inline HTML strings with a placeholder and add + the actual HTML to a hash. + +* then inline images (must be done before links) + +* then bracketed links, first regular then reference-style + +* finally we apply strong and emphasis +""" + +import markdown +import re +from urlparse import urlparse, urlunparse +import sys +if sys.version >= "3.0": + from html import entities as htmlentitydefs +else: + import htmlentitydefs + +""" +The actual regular expressions for patterns +----------------------------------------------------------------------------- +""" + +NOBRACKET = r'[^\]\[]*' +BRK = ( r'\[(' + + (NOBRACKET + r'(\[')*6 + + (NOBRACKET+ r'\])*')*6 + + NOBRACKET + r')\]' ) +NOIMG = r'(?<!\!)' + +BACKTICK_RE = r'(?<!\\)(`+)(.+?)(?<!`)\2(?!`)' # `e=f()` or ``e=f("`")`` +ESCAPE_RE = r'\\(.)' # \< +EMPHASIS_RE = r'(\*)([^\*]*)\2' # *emphasis* +STRONG_RE = r'(\*{2}|_{2})(.*?)\2' # **strong** +STRONG_EM_RE = r'(\*{3}|_{3})(.*?)\2' # ***strong*** + +if markdown.SMART_EMPHASIS: + EMPHASIS_2_RE = r'(?<!\S)(_)(\S.*?)\2' # _emphasis_ +else: + EMPHASIS_2_RE = r'(_)(.*?)\2' # _emphasis_ + +LINK_RE = NOIMG + BRK + \ +r'''\(\s*(<.*?>|((?:(?:\(.*?\))|[^\(\)]))*?)\s*((['"])(.*)\12)?\)''' +# [text](url) or [text](<url>) + +IMAGE_LINK_RE = r'\!' + BRK + r'\s*\((<.*?>|([^\)]*))\)' +# ![alttxt](http://x.com/) or ![alttxt](<http://x.com/>) +REFERENCE_RE = NOIMG + BRK+ r'\s*\[([^\]]*)\]' # [Google][3] +IMAGE_REFERENCE_RE = r'\!' + BRK + '\s*\[([^\]]*)\]' # ![alt text][2] +NOT_STRONG_RE = r'( \* )' # stand-alone * or _ +AUTOLINK_RE = r'<((?:f|ht)tps?://[^>]*)>' # <http://www.123.com> +AUTOMAIL_RE = r'<([^> \!]*@[^> ]*)>' # <me@example.com> + +HTML_RE = r'(\<([a-zA-Z/][^\>]*?|\!--.*?--)\>)' # <...> +ENTITY_RE = r'(&[\#a-zA-Z0-9]*;)' # & +LINE_BREAK_RE = r' \n' # two spaces at end of line +LINE_BREAK_2_RE = r' $' # two spaces at end of text + + +def dequote(string): + """Remove quotes from around a string.""" + if ( ( string.startswith('"') and string.endswith('"')) + or (string.startswith("'") and string.endswith("'")) ): + return string[1:-1] + else: + return string + +ATTR_RE = re.compile("\{@([^\}]*)=([^\}]*)}") # {@id=123} + +def handleAttributes(text, parent): + """Set values of an element based on attribute definitions ({@id=123}).""" + def attributeCallback(match): + parent.set(match.group(1), match.group(2).replace('\n', ' ')) + return ATTR_RE.sub(attributeCallback, text) + + +""" +The pattern classes +----------------------------------------------------------------------------- +""" + +class Pattern: + """Base class that inline patterns subclass. """ + + def __init__ (self, pattern, markdown_instance=None): + """ + Create an instant of an inline pattern. + + Keyword arguments: + + * pattern: A regular expression that matches a pattern + + """ + self.pattern = pattern + self.compiled_re = re.compile("^(.*?)%s(.*?)$" % pattern, re.DOTALL) + + # Api for Markdown to pass safe_mode into instance + self.safe_mode = False + if markdown_instance: + self.markdown = markdown_instance + + def getCompiledRegExp (self): + """ Return a compiled regular expression. """ + return self.compiled_re + + def handleMatch(self, m): + """Return a ElementTree element from the given match. + + Subclasses should override this method. + + Keyword arguments: + + * m: A re match object containing a match of the pattern. + + """ + pass + + def type(self): + """ Return class name, to define pattern type """ + return self.__class__.__name__ + +BasePattern = Pattern # for backward compatibility + +class SimpleTextPattern (Pattern): + """ Return a simple text of group(2) of a Pattern. """ + def handleMatch(self, m): + text = m.group(2) + if text == markdown.INLINE_PLACEHOLDER_PREFIX: + return None + return text + +class SimpleTagPattern (Pattern): + """ + Return element of type `tag` with a text attribute of group(3) + of a Pattern. + + """ + def __init__ (self, pattern, tag): + Pattern.__init__(self, pattern) + self.tag = tag + + def handleMatch(self, m): + el = markdown.etree.Element(self.tag) + el.text = m.group(3) + return el + + +class SubstituteTagPattern (SimpleTagPattern): + """ Return a eLement of type `tag` with no children. """ + def handleMatch (self, m): + return markdown.etree.Element(self.tag) + + +class BacktickPattern (Pattern): + """ Return a `<code>` element containing the matching text. """ + def __init__ (self, pattern): + Pattern.__init__(self, pattern) + self.tag = "code" + + def handleMatch(self, m): + el = markdown.etree.Element(self.tag) + el.text = markdown.AtomicString(m.group(3).strip()) + return el + + +class DoubleTagPattern (SimpleTagPattern): + """Return a ElementTree element nested in tag2 nested in tag1. + + Useful for strong emphasis etc. + + """ + def handleMatch(self, m): + tag1, tag2 = self.tag.split(",") + el1 = markdown.etree.Element(tag1) + el2 = markdown.etree.SubElement(el1, tag2) + el2.text = m.group(3) + return el1 + + +class HtmlPattern (Pattern): + """ Store raw inline html and return a placeholder. """ + def handleMatch (self, m): + rawhtml = m.group(2) + inline = True + place_holder = self.markdown.htmlStash.store(rawhtml) + return place_holder + + +class LinkPattern (Pattern): + """ Return a link element from the given match. """ + def handleMatch(self, m): + el = markdown.etree.Element("a") + el.text = m.group(2) + title = m.group(11) + href = m.group(9) + + if href: + if href[0] == "<": + href = href[1:-1] + el.set("href", self.sanitize_url(href.strip())) + else: + el.set("href", "") + + if title: + title = dequote(title) #.replace('"', """) + el.set("title", title) + return el + + def sanitize_url(self, url): + """ + Sanitize a url against xss attacks in "safe_mode". + + Rather than specifically blacklisting `javascript:alert("XSS")` and all + its aliases (see <http://ha.ckers.org/xss.html>), we whitelist known + safe url formats. Most urls contain a network location, however some + are known not to (i.e.: mailto links). Script urls do not contain a + location. Additionally, for `javascript:...`, the scheme would be + "javascript" but some aliases will appear to `urlparse()` to have no + scheme. On top of that relative links (i.e.: "foo/bar.html") have no + scheme. Therefore we must check "path", "parameters", "query" and + "fragment" for any literal colons. We don't check "scheme" for colons + because it *should* never have any and "netloc" must allow the form: + `username:password@host:port`. + + """ + locless_schemes = ['', 'mailto', 'news'] + scheme, netloc, path, params, query, fragment = url = urlparse(url) + safe_url = False + if netloc != '' or scheme in locless_schemes: + safe_url = True + + for part in url[2:]: + if ":" in part: + safe_url = False + + if self.markdown.safeMode and not safe_url: + return '' + else: + return urlunparse(url) + +class ImagePattern(LinkPattern): + """ Return a img element from the given match. """ + def handleMatch(self, m): + el = markdown.etree.Element("img") + src_parts = m.group(9).split() + if src_parts: + src = src_parts[0] + if src[0] == "<" and src[-1] == ">": + src = src[1:-1] + el.set('src', self.sanitize_url(src)) + else: + el.set('src', "") + if len(src_parts) > 1: + el.set('title', dequote(" ".join(src_parts[1:]))) + + if markdown.ENABLE_ATTRIBUTES: + truealt = handleAttributes(m.group(2), el) + else: + truealt = m.group(2) + + el.set('alt', truealt) + return el + +class ReferencePattern(LinkPattern): + """ Match to a stored reference and return link element. """ + def handleMatch(self, m): + if m.group(9): + id = m.group(9).lower() + else: + # if we got something like "[Google][]" + # we'll use "google" as the id + id = m.group(2).lower() + + if not id in self.markdown.references: # ignore undefined refs + return None + href, title = self.markdown.references[id] + + text = m.group(2) + return self.makeTag(href, title, text) + + def makeTag(self, href, title, text): + el = markdown.etree.Element('a') + + el.set('href', self.sanitize_url(href)) + if title: + el.set('title', title) + + el.text = text + return el + + +class ImageReferencePattern (ReferencePattern): + """ Match to a stored reference and return img element. """ + def makeTag(self, href, title, text): + el = markdown.etree.Element("img") + el.set("src", self.sanitize_url(href)) + if title: + el.set("title", title) + el.set("alt", text) + return el + + +class AutolinkPattern (Pattern): + """ Return a link Element given an autolink (`<http://example/com>`). """ + def handleMatch(self, m): + el = markdown.etree.Element("a") + el.set('href', m.group(2)) + el.text = markdown.AtomicString(m.group(2)) + return el + +class AutomailPattern (Pattern): + """ + Return a mailto link Element given an automail link (`<foo@example.com>`). + """ + def handleMatch(self, m): + el = markdown.etree.Element('a') + email = m.group(2) + if email.startswith("mailto:"): + email = email[len("mailto:"):] + + def codepoint2name(code): + """Return entity definition by code, or the code if not defined.""" + entity = htmlentitydefs.codepoint2name.get(code) + if entity: + return "%s%s;" % (markdown.AMP_SUBSTITUTE, entity) + else: + return "%s#%d;" % (markdown.AMP_SUBSTITUTE, code) + + letters = [codepoint2name(ord(letter)) for letter in email] + el.text = markdown.AtomicString(''.join(letters)) + + mailto = "mailto:" + email + mailto = "".join([markdown.AMP_SUBSTITUTE + '#%d;' % + ord(letter) for letter in mailto]) + el.set('href', mailto) + return el + |