path: root/sandbox/cliechti/html2rst/html2rst.py

"""html2rst: Turn HTML into reStructured text.

based on Aaron Swartz <me@aaronsw.com> html2text V 2.23
http://www.aaronsw.com/2002/html2text/

| GNU GPL 2.
| (C) 2004 Aaron Swartz.
| (C) 2005 Chris Liechti.

Changes to the original:

- generate reST comaptible output
- don't number links, use named references
- redo wrap function so that it keeps indents in lists


There a re a number of problems with this approach and implementation, see
README.txt
"""


# TODO:
#   Support decoded entities with unifiable.
#    Relative URL resolution

if not hasattr(__builtins__, 'True'): True, False = 1, 0
import re, sys, urllib, htmlentitydefs, codecs, StringIO, types
import sgmllib
sgmllib.charref = re.compile('&#([xX]?[0-9a-fA-F]+)[^0-9a-fA-F]')

try: from textwrap import wrap
except: pass

# Use Unicode characters instead of their ascii psuedo-replacements
UNICODE_SNOB = 0

# Put the links after each paragraph instead of at the end.
LINKS_EACH_PARAGRAPH = 0

# Wrap long lines at position. 0 for no wrapping. (Requires Python 2.3.)
BODY_WIDTH = 0

### Entity Nonsense ###

def name2cp(k):
    if k == 'apos': return ord("'")
    if hasattr(htmlentitydefs, "name2codepoint"): # requires Python 2.3
        return htmlentitydefs.name2codepoint[k]
    else:
        k = htmlentitydefs.entitydefs[k]
        if k.startswith("&#") and k.endswith(";"): return int(k[2:-1]) # not in latin-1
        return ord(codecs.latin_1_decode(k)[0])

unifiable = {'rsquo':"'", 'lsquo':"'", 'rdquo':'"', 'ldquo':'"', 
'copy':'(C)', 'mdash':'--', 'nbsp':' ', 'rarr':'->', 'larr':'<-', 'middot':'*',
'ndash':'-', 'oelig':'oe', 'aelig':'ae',
'agrave':'a', 'aacute':'a', 'acirc':'a', 'atilde':'a', 'auml':'a', 'aring':'a', 
'egrave':'e', 'eacute':'e', 'ecirc':'e', 'euml':'e', 
'igrave':'i', 'iacute':'i', 'icirc':'i', 'iuml':'i',
'ograve':'o', 'oacute':'o', 'ocirc':'o', 'otilde':'o', 'ouml':'o', 
'ugrave':'u', 'uacute':'u', 'ucirc':'u', 'uuml':'u'}

unifiable_n = {}

for k in unifiable.keys():
    unifiable_n[name2cp(k)] = unifiable[k]

def charref(name):
    if name[0] in ['x','X']:
        c = int(name[1:], 16)
    else:
        c = int(name)
    
    if not UNICODE_SNOB and c in unifiable_n.keys():
        return unifiable_n[c]
    else:
        return unichr(c)

def entityref(c):
    if not UNICODE_SNOB and c in unifiable.keys():
        return unifiable[c]
    else:
        try: name2cp(c)
        except KeyError: return "&" + c
        else: return unichr(name2cp(c))

def replaceEntities(s):
    s = s.group(1)
    if s[0] == "#": 
        return charref(s[1:])
    else: return entityref(s)

r_unescape = re.compile(r"&(#?[xX]?(?:[0-9a-fA-F]+|\w{1,8}));")
def unescape(s):
    return r_unescape.sub(replaceEntities, s)
    
def fixattrs(attrs):
    # Fix bug in sgmllib.py
    if not attrs: return attrs
    newattrs = []
    for attr in attrs:
        newattrs.append((attr[0], unescape(attr[1])))
    return newattrs

### End Entity Nonsense ###

def onlywhite(line):
    """Return true if the line does only consist of whitespace characters."""
    for c in line:
        if c is not ' ' and c is not '    ':
            return c is ' '
    return line

def optwrap(text):
    """Wrap all paragraphs in the provided text."""
    if not BODY_WIDTH:
        return text
    
    assert wrap # Requires Python 2.3.
    result = ''
    newlines = 0
    for para in text.split("\n"):
        if len(para) > 0:
            if para[0] is not ' ' and para[0] is not '-' and para[0] is not '*':
                for line in wrap(para, BODY_WIDTH):
                    result += line + "\n"
                result += "\n"
                newlines = 2
            else:
                if not onlywhite(para):
                    result += para + "\n"
                    newlines = 1
        else:
            if newlines < 2:
                result += "\n"
                newlines += 1
    return result

TITLE_UNDERLININGS = "$=-~:."

def hn(tag):
    if tag[0] == 'h' and len(tag) == 2:
        try:
            n = int(tag[1])
            if n in range(1, 10): return n
        except ValueError: return 0

class _html2text(sgmllib.SGMLParser):
    def __init__(self, out=sys.stdout.write):
        sgmllib.SGMLParser.__init__(self)
        
        if out is None: self.out = self.outtextf
        else: self.out = out
        self.outtext = u''
        self.quiet = 0
        self.p_p = 0
        self.outcount = 0
        self.start = 1
        self.space = 0
        self.a = []
        self.astack = []
        self.acount = 0
        self.list = []
        self.blockquote = 0
        self.pre = 0
        self.startpre = 0
        self.lastWasNL = 0
        self.indentation = 0
        self.indentation_stack = []
        """required to keep indent after unbalanced <li>s"""
    
    def outtextf(self, s): 
        if type(s) is type(''): s = codecs.utf_8_decode(s)[0]
        self.outtext += s
    
    def close(self):
        sgmllib.SGMLParser.close(self)
        
        self.pbr()
        self.o('', 0, 'end')
        
        return self.outtext
        
    def handle_charref(self, c):
        self.o(charref(c))

    def handle_entityref(self, c):
        self.o(entityref(c))
            
    def unknown_starttag(self, tag, attrs):
        self.handle_tag(tag, attrs, 1)
    
    def unknown_endtag(self, tag):
        self.handle_tag(tag, None, 0)
        
    def previousIndex(self, attrs):
         """ returns the index of certain set of attributes (of a link) in the
             self.a list
 
             If the set of attributes is not found, returns None
         """
         if not attrs.has_key('href'): return None
         
         i = -1
         for a in self.a:
             i += 1
             match = 0
             
             if a.has_key('href') and a['href'] == attrs['href']:
                 if a.has_key('title') or attrs.has_key('title'):
                         if (a.has_key('title') and attrs.has_key('title') and
                            a['title'] == attrs['title']):
                             match = True
                 else:
                     match = True

             if match: return i

    def handle_tag(self, tag, attrs, start):
        attrs = fixattrs(attrs)
    
        if hn(tag):
            #~ if start: self.o(hn(tag)*"#" + ' ')
            if start:
                self.o('\n')
            else:
                self.o('\n' + TITLE_UNDERLININGS[hn(tag)]*len(self.last_output))
                self.p()

        if tag in ['p', 'div']: self.p()
        
        if tag == "br" and start: self.o("  \n")

        if tag == "hr" and start:
            self.p()
            self.o("--------")
            self.p()

        if tag in ["head", "style", 'script']: 
            if start:
                self.quiet += 1
            else:
                self.quiet -= 1
        
        if tag == "blockquote":
            if start: 
                self.p(); self.o('> ', 0, 1); self.start = 1
                self.blockquote += 1
            else:
                self.blockquote -= 1
                self.p()
        
        if tag in ['em', 'i', 'u']:
            self.o("*")
        if tag in ['strong', 'b']:
            self.o("**")
        if tag in ['code', 'tt'] and not self.pre:
            self.o('``') #TODO: `` `this` ``
        
        if tag == "a":
            if start:
                attrsD = {}
                for (x, y) in attrs: attrsD[x] = y
                attrs = attrsD
                if attrs.has_key('href'):
                    self.astack.append(attrs)
                    self.o("`")
                else:
                    self.astack.append(None)
            else:
                if self.astack:
                    a = self.astack.pop()
                    if a:
                        i = self.previousIndex(a)
                        if i is not None:
                            a = self.a[i]
                        else:
                            self.acount += 1
                            a['count'] = self.acount
                            a['outcount'] = self.outcount
                            a['data'] = self.last_output.replace('\n', ' ')
                            self.a.append(a)
                        self.o("`_")
        
        if tag == "img" and start:
            attrsD = {}
            for (x, y) in attrs: attrsD[x] = y
            attrs = attrsD
            if attrs.has_key('src'):
                #~ attrs['href'] = attrs['src']
                alt = attrs.get('alt', '')
                #~ i = self.previousIndex(attrs)
                #~ if i is not None:
                    #~ attrs = self.a[i]
                #~ else:
                    #~ self.acount += 1
                    #~ attrs['count'] = self.acount
                    #~ attrs['outcount'] = self.outcount
                    #~ attrs['data'] = attrs['src']
                    #~ self.a.append(attrs)
                self.o(".. image:: %s\n" % attrs['src'])
                if alt:
                    self.o("    :alt: %s\n" % alt)
                #~ self.o("["+ repr(attrs['count']) +"]")
        
        if tag in ["ol", "ul"]:
            if start:
                self.list.append({'name':tag, 'num':0})
                self.indentation_stack.append(self.indentation)
            else:
                if self.list: self.list.pop()
                self.indentation = self.indentation_stack.pop()
            self.p()
        
        if tag == 'li':
            if start:
                if self.indentation_stack:
                    self.indentation = self.indentation_stack[-1]
                self.pbr()
                if self.list: li = self.list[-1]
                else: li = {'name':'ul', 'num':0}
                #~ self.o("  "*len(self.list)) #TODO: line up <ol><li>s > 9 correctly.
                if li['name'] == "ul": self.o("-   ")
                elif li['name'] == "ol":
                    li['num'] += 1
                    self.o('%-4s' % ('%d.' % li['num']))
                self.start = 1
                self.indentation += 1
            else:
                self.indentation -= 1
                self.pbr()
        
        if tag in ['tr']: self.pbr()
        
        if tag == "pre":
            if start:
                self.o('::')
                self.startpre = 1
                self.pre = 1
            else:
                self.pre = 0
            #~ self.p()
            
    def pbr(self):
        if self.p_p == 0: self.p_p = 1

    def p(self): self.p_p = 2
    
    def o(self, data, puredata=0, force=0):
        if not self.quiet: 
            if puredata and not self.pre:
                data = re.sub(r'\s+', ' ', data)
                if data and data[0] == ' ':
                    self.space = 1
                    data = data[1:]
            if not data and not force: return
            
            if self.startpre:
                #self.out(" :") #TODO: not output when already one there
                self.startpre = 0
            
            bq = (">" * self.blockquote)
            if not (force and data and data[0] == ">") and self.blockquote: bq += " "
            bq += '    '*self.indentation
            
            if self.pre:
                bq += "    "
                data = data.replace("\n", "\n"+bq)
            
            if self.start:
                self.space = 0
                self.p_p = 0
                self.start = 0

            if force == 'end':
                # It's the end.
                self.p_p = 0
                self.out("\n")
                self.space = 0

            if self.p_p:
                self.out(('\n'+bq)*self.p_p)
                self.space = 0
                
            if self.space:
                if not self.lastWasNL: self.out(' ')
                self.space = 0

            if self.a and ((self.p_p == 2 and LINKS_EACH_PARAGRAPH) or force == "end"):
                if force == "end": self.out("\n")

                newa = []
                for link in self.a:
                    if self.outcount > link['outcount']:
                        self.out(".. _"+link['data']+": " + link['href']) #TODO: base href
                        if link.has_key('title'): self.out(" ("+link['title']+")")
                        self.out("\n")
                    else:
                        newa.append(link)

                if self.a != newa: self.out("\n") # Don't need an extra line when nothing was done.

                self.a = newa

            self.p_p = 0
            self.out(data)
            self.lastWasNL = data and data[-1] == '\n'
            self.outcount += 1

    def handle_data(self, data):
        self.last_output = data
        self.o(data, 1)
    
    def unknown_decl(self, data): pass

def html2text_file(html, out=sys.stdout.write):
    h = _html2text(out)
    h.feed(html)
    h.feed("")
    return h.close()

def html2text(html):
    return optwrap(html2text_file(html, None))

import textwrap
def optwrap(text):
    """smart wrapping, keeping indents"""
    output = []
    iii = re.compile(r'(\.\. )|(\d+.)|(-   )')
    for p in text.splitlines():
        indent = 0
        while indent < len(p) and p[indent] == ' ':
            indent += 1
        j = '\n'
        un = p[indent:]
        if iii.match(p):
            j += '    '
        j += ' '*indent
        output.append(j.join(textwrap.wrap(p, width=78-len(j))))
    return '\n'.join(output)

if __name__ == "__main__":
    if sys.argv[1:]:
        arg = sys.argv[1]
        if arg.startswith('http://'):
            data = urllib.urlopen(arg).read()
        else:
            data = open(arg, 'r').read()
    else:
        data = sys.stdin.read()
    #~ html2text_file(data)
    rest = optwrap(html2text_file(data, None))
    sys.stdout.write(rest.encode('ascii', 'replace'))