markup.py

#!/usr/bin/env python
# coding: utf8

# This code is in the public domain, it comes
# with absolutely no warranty and you can do
# absolutely whatever you want with it.
"""
simple HTML/XML generation (forked from `markup <http://pypi.python.org/pypi/markup/>`_)
"""

import sys, six
    
#from http://www.voidspace.org.uk/python/cgiutils.html
def cgiprint(line='', unbuff=True, line_end='\r\n'):
    """
    Print to the stdout.
    :param line: string to print, followed by line_end
    :param unbuff: boolean, True to flush the buffer after every write.
    :param line_end: string to print after each line. By default this is \r\n , which is the standard specified by the RFC for http headers.
    """
    # print(line,line_end)
    # return
    sys.stdout.write(line)
    sys.stdout.write(line_end)
    if unbuff:
        sys.stdout.flush()
        
def style_dict2str(style):
    return ' '.join('%s:%s;'%(k,v) for k,v in six.iteritems(style))

def style_str2dict(style):
    res={}
    for s in style.split(';'):
        try:
            k,v=s.split(':')
            k=k.lstrip().rstrip()
            v=v.lstrip().rstrip()
            res[k]=v
        except: #pro
            pass
    return res
        
def tag( tag, between, **kwargs ):
    """generate full tag."""
    single=kwargs.pop('single',False)
    out = "<%s" % tag
    for key, value in list(kwargs.items()):
        if value is None:               # when value is None that means stuff like <... checked>
            out = "%s %s" % ( out, key )
        else:
            key = key.strip('_')            # strip this so class_ will mean class, etc.
            if key == 'http_equiv':         # special cases, maybe change _ to - overall?
                key = 'http-equiv'
            elif key == 'accept_charset':
                key = 'accept-charset'
            elif key == 'style' and isinstance(value,dict):
                value=style_dict2str(value)
            out = '%s %s="%s"' % ( out, key, escape( value ) )
           
    if between is not None:
        if isinstance(between,six.text_type): #unicode
            between=between.encode('ascii', 'xmlcharrefreplace').decode('unicode_escape')
        out = "%s>%s</%s>" % ( out, between, tag )
    else:
        if single:
            out = "%s />" % out
        else:
            out = "%s>" % out
    return out

# tags which are reserved python keywords will be referred 
# to by a leading underscore otherwise we end up with a syntax error
import keyword

class element:
    """This class handles the addition of a new element."""

    def __init__( self, tag, case='lower', parent=None ):
        self.parent = parent

        if case == 'upper':
            self.tag = tag.upper( )
        elif case == 'lower':
            self.tag = tag.lower( )
        elif case =='given':
            self.tag = tag
        else:
            self.tag = tag
    
    def __call__( self, *args, **kwargs ):

        # if class_ was defined in parent it should be added to every element
        if self.parent is not None and self.parent.class_ is not None:
            if 'class_' not in kwargs:
                kwargs['class_'] = self.parent.class_
            
        if self.parent is None and len( args ) == 1:
            x = [ self.render( self.tag, False, myarg, **mydict ) for myarg, mydict in _argsdicts( args, kwargs ) ]
            return '\n'.join( x )
        elif self.parent is None and len( args ) == 0:
            x = [ self.render( self.tag, True, myarg, **mydict ) for myarg, mydict in _argsdicts( args, kwargs ) ]
            return '\n'.join( x )
            
        if self.tag in self.parent.twotags:
            for myarg, mydict in _argsdicts( args, kwargs ):
                self.render( self.tag, False, myarg, **mydict )
        elif self.tag in self.parent.onetags:
            if len( args ) == 0:
                for myarg, mydict in _argsdicts( args, kwargs ):
                    self.render( self.tag, True, myarg, **mydict )    # here myarg is always None, because len( args ) = 0
            else:
                raise ClosingError( self.tag )
        elif self.parent.mode == 'strict_html' and self.tag in self.parent.deptags:
            raise DeprecationError( self.tag )
        else:
            raise InvalidElementError( self.tag, self.parent.mode )
    
    def render( self, t, single, args, **kwargs ):
        """Append the actual tags to content."""
        if single:
            kwargs['single']=True
        out=tag(t, args, **kwargs)
        cgiprint(out)
        return
        if self.parent is not None:
            self.parent.content.append( out )
        else:
            return out
    
    def close( self ):
        """Append a closing tag unless element has only opening tag."""

        if self.tag in self.parent.twotags:
            cgiprint("</%s>" % self.tag)
            # self.parent.content.append( "</%s>" % self.tag )
        elif self.tag in self.parent.onetags:
            raise ClosingError( self.tag )
        elif self.parent.mode == 'strict_html' and self.tag in self.parent.deptags:
            raise DeprecationError( self.tag )

    def open( self, **kwargs ):
        """Append an opening tag."""

        if self.tag in self.parent.twotags or self.tag in self.parent.onetags:
            self.render( self.tag, False, None, **kwargs )
        elif self.mode == 'strict_html' and self.tag in self.parent.deptags:
            raise DeprecationError( self.tag )

class page:
    """
    This is our main class representing a document. Elements are added
    as attributes of an instance of this class.
    """

    def __init__( self, mode='strict_html', case='lower', onetags=None, twotags=None, separator='\n', class_=None ):
        """Stuff that effects the whole document.

        :param mode: string. can be either:
        
        - 'strict_html'   for HTML 4.01 (default)
        - 'html'          alias for 'strict_html'
        - 'loose_html'    to allow some deprecated elements
        - 'xml'           to allow arbitrary elements

        :param case:  string. can be either:
        
        - 'lower'         element names will be printed in lower case (default)
        - 'upper'         they will be printed in upper case
        - 'given'         element names will be printed as they are given

        :param onetags:  list or tuple of valid elements with opening tags only
        :param twotags:  list or tuple of valid elements with both opening and closing tags
        
        these two keyword arguments may be used to select the set of valid elements in 'xml' mode
        invalid elements will raise appropriate exceptions
        
        :param separator: string to place between added elements, defaults to newline
        
        :param class_:    a class that will be added to every element if defined
        
        """
        
        valid_onetags = [ "AREA", "BASE", "BR", "COL", "FRAME", "HR", "IMG", "INPUT", "LINK", "META", "PARAM" ]
        valid_twotags = [ "A", "ABBR", "ACRONYM", "ADDRESS", "B", "BDO", "BIG", "BLOCKQUOTE", "BODY", "BUTTON",
                "CAPTION", "CITE", "CODE", "COLGROUP", "DD", "DEL", "DFN", "DIV", "DL", "DT", "EM", "FIELDSET",
                "FORM", "FRAMESET", "H1", "H2", "H3", "H4", "H5", "H6", "HEAD", "HTML", "I", "IFRAME", "INS",
                "KBD", "LABEL", "LEGEND", "LI", "MAP", "NOFRAMES", "NOSCRIPT", "OBJECT", "OL", "OPTGROUP",
                "OPTION", "P", "PRE", "Q", "SAMP", "SCRIPT", "SELECT", "SMALL", "SPAN", "STRONG", "STYLE",
                "SUB", "SUP", "TABLE", "TBODY", "TD", "TEXTAREA", "TFOOT", "TH", "THEAD", "TITLE", "TR",
                "TT", "UL", "VAR" ]
        dont_wait = ["HTML","BODY"]
        deprecated_onetags = [ "BASEFONT", "ISINDEX" ]
        deprecated_twotags = [ "APPLET", "CENTER", "DIR", "FONT", "MENU", "S", "STRIKE", "U" ]

        self.header = [ ]
        self.content = [ ]
        self.footer = [ ]
        self.case = case
        self.separator = separator

        # init( ) sets it to True so we know that </body></html> has to be printed at the end
        self._full = False
        self.class_= class_

        if mode == 'strict_html' or mode == 'html':
            self.onetags = valid_onetags
            self.onetags += [x.lower() for x in self.onetags]
            self.twotags = valid_twotags
            self.twotags += [x.lower() for x in self.twotags]
            self.deptags = deprecated_onetags + deprecated_twotags
            self.deptags += [x.lower() for x in self.deptags]
            self.mode = 'strict_html'
        elif mode == 'loose_html':
            self.onetags = valid_onetags + deprecated_onetags 
            self.onetags += [x.lower() for x in self.onetags]
            self.twotags = valid_twotags + deprecated_twotags
            self.twotags += [x.lower() for x in self.twotags]
            self.mode = mode
        elif mode == 'xml':
            if onetags and twotags:
                self.onetags = onetags
                self.twotags = twotags
            elif ( onetags and not twotags ) or ( twotags and not onetags ):
                raise CustomizationError( )
            else:
                self.onetags = russell( )
                self.twotags = russell( )
            self.mode = mode
        else:
            raise ModeError( mode )

    def __getattr__( self, attr ):

        # tags should start with double underscore
        if attr.startswith("__") and attr.endswith("__"):
            raise AttributeError( attr )
        # tag with single underscore should be a reserved keyword
        if attr.startswith( '_' ):
            attr = attr.lstrip( '_' ) 
            if attr not in keyword.kwlist:
                raise AttributeError( attr )

        return element( attr, case=self.case, parent=self )

    def __str__( self ):
        
        if self._full and ( self.mode == 'strict_html' or self.mode == 'loose_html' ):
            end = [ '</body>', '</html>' ]
        else:
            end = [ ]

        return self.separator.join( self.footer + end )
        return self.separator.join( self.header + self.content + self.footer + end )

    def __call__( self, escape=False ):
        """Return the document as a string.

        escape --   False   print normally
                    True    replace < and > by &lt; and &gt;
                            the default escape sequences in most browsers"""

        if escape:
            return _escape( self.__str__( ) )
        else:
            return self.__str__( )

    def add( self, text ):
        """This is an alias to addcontent."""
        self.addcontent(str(text))

    def addfooter( self, text ):
        """Add some text to the bottom of the document"""
        self.footer.append( text )

    def addheader( self, text ):
        """Add some text to the top of the document"""
        cgiprint(text)
        return
        self.header.append( text )

    def addcontent( self, text ):
        """Add some text to the main part of the document"""
        cgiprint(text)
        return
        self.content.append( text )


    def init( self, lang='en', css=None, metainfo=None, title=None, header=None,
              footer=None, charset=None, encoding=None, doctype=None, bodyattrs=None, script=None, base=None ):
        """This method is used for complete documents with appropriate
        doctype, encoding, title, etc information. For an /XML snippet
        omit this method.

        lang --     language, usually a two character string, will appear
                    as <html lang='en'> in html mode (ignored in xml mode)
        
        css --      Cascading Style Sheet filename as a string or a list of
                    strings for multiple css files (ignored in xml mode)

        metainfo -- a dictionary in the form { 'name':'content' } to be inserted
                    into meta element(s) as <meta name='name' content='content'>
                    (ignored in xml mode)
        
        base     -- set the <base href="..."> tag in <head>
        
        bodyattrs --a dictionary in the form { 'key':'value', ... } which will be added
                    as attributes of the <body> element as <body key='value' ... >
                    (ignored in xml mode)

        script --   dictionary containing src:type pairs, <script type='text/type' src=src></script>
                    or a list of [ 'src1', 'src2', ... ] in which case 'javascript' is assumed for all

        title --    the title of the document as a string to be inserted into
                    a title element as <title>my title</title> (ignored in xml mode)

        header --   some text to be inserted right after the <body> element
                    (ignored in xml mode)

        footer --   some text to be inserted right before the </body> element
                    (ignored in xml mode)

        charset --  a string defining the character set, will be inserted into a
                    <meta http-equiv='Content-Type' content='text/html; charset=myset'>
                    element (ignored in xml mode)

        encoding -- a string defining the encoding, will be put into to first line of
                    the document as <?xml version='1.0' encoding='myencoding' ?> in
                    xml mode (ignored in html mode)

        doctype --  the document type string, defaults to
                    <!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN'>
                    in html mode (ignored in xml mode)"""

        self._full = True

        if self.mode == 'strict_html' or self.mode == 'loose_html':
            if doctype is None:
                doctype = "<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN'>"
            self.header.append( doctype )
            cgiprint(self.separator.join(self.header))
            self.html( lang=lang )
            self.head( )
            if charset is not None:
                self.meta( http_equiv='Content-Type', content="text/html; charset=%s" % charset )
            if metainfo is not None:
                self.metainfo( metainfo )
            if css is not None:
                self.css( css )
            if title is not None:
                self.title( title )
            if script is not None:
                self.scripts( script )
            if base is not None:
                self.base( href='%s' % base )
            self.head.close()
            if bodyattrs is not None:
                self.body( **bodyattrs )
            else:
                self.body( )
            if header is not None:
                self.content.append( header )
            if footer is not None:
                self.footer.append( footer )

        elif self.mode == 'xml':
            if doctype is None:
                if encoding is not None:
                    doctype = "<?xml version='1.0' encoding='%s' ?>" % encoding
                else:
                    doctype = "<?xml version='1.0' ?>"
            self.header.append( doctype )

    def css( self, filelist ):
        """This convenience function is only useful for html.
        It adds css stylesheet(s) to the document via the <link> element."""
      
        if isinstance( filelist, str ):
            self.link( href=filelist, rel='stylesheet', type='text/css', media='all' )
        else:
            for file in filelist:
                self.link( href=file, rel='stylesheet', type='text/css', media='all' )

    def metainfo( self, mydict ):
        """This convenience function is only useful for html.
        It adds meta information via the <meta> element, the argument is
        a dictionary of the form { 'name':'content' }."""

        if isinstance( mydict, dict ):
            for name, content in list( mydict.items( ) ):
                self.meta( name=name, content=content )
        else:
            raise TypeError( "Metainfo should be called with a dictionary argument of name:content pairs." )

    def scripts( self, mydict ):
        """Only useful in html, mydict is dictionary of src:type pairs or a list
        of script sources [ 'src1', 'src2', ... ] in which case 'javascript' is assumed for type.
        Will be rendered as <script type='text/type' src=src></script>"""

        if isinstance( mydict, dict ):
            for src, type in list( mydict.items( ) ):
                self.script( '', src=src, type='text/%s' % type )
        else:
            try:
                for src in mydict:
                    self.script( '', src=src, type='text/javascript' )
            except:
                raise TypeError( "Script should be given a dictionary of src:type pairs or a list of javascript src's." )


class _oneliner:
    """An instance of oneliner returns a string corresponding to one element.
    This class can be used to write 'oneliners' that return a string
    immediately so there is no need to instantiate the page class."""
    
    def __init__( self, case='lower' ):
        self.case = case
    
    def __getattr__( self, attr ):
        
        # tags should start with double underscore
        if attr.startswith("__") and attr.endswith("__"):
            raise AttributeError( attr )
        # tag with single underscore should be a reserved keyword
        if attr.startswith( '_' ):
            attr = attr.lstrip( '_' ) 
            if attr not in keyword.kwlist:
                raise AttributeError( attr )
        
        return element( attr, case=self.case, parent=None )

oneliner = _oneliner( case='lower' )
upper_oneliner = _oneliner( case='upper' )
given_oneliner = _oneliner( case='given' )

def _argsdicts( args, mydict ):
    """A utility generator that pads argument list and dictionary values, will only be called with len( args ) = 0, 1."""
    
    if len( args ) == 0:
        args = None, 
    elif len( args ) == 1:
        args = _totuple( args[0] )
    else:
        raise Exception( "We should have never gotten here." )

    mykeys = list( mydict.keys( ) )
    myvalues = list( map( _totuple, list( mydict.values( ) ) ) )

    maxlength = max( list( map( len, [ args ] + myvalues ) ) )

    for i in range( maxlength ):
        thisdict = { }
        for key, value in zip( mykeys, myvalues ):
            try:
                thisdict[ key ] = value[i]
            except IndexError:
                thisdict[ key ] = value[-1]
        try:
            thisarg = args[i]
        except IndexError:
            thisarg = args[-1]

        yield thisarg, thisdict

def _totuple( x ):
    """Utility stuff to convert string, int, long, float, None or anything to a usable tuple."""

    if isinstance( x, six.string_types ):
        out = x,
    elif isinstance( x, ( int, float ) ):
        out = str( x ),
    elif x is None:
        out = None,
    else:
        out = tuple( x )

    return out

def escape( text, newline=False ):
    """Escape special html characters."""

    if isinstance( text, str ):
        if '&' in text:
            text = text.replace( '&', '&amp;' )
        if '>' in text:
            text = text.replace( '>', '&gt;' )
        if '<' in text:
            text = text.replace( '<', '&lt;' )
        if '\"' in text:
            text = text.replace( '\"', '&quot;' )
        if '\'' in text:
            text = text.replace( '\'', '&quot;' )
        if newline:
            if '\n' in text:
                text = text.replace( '\n', '<br>' )

    return text

_escape = escape

def unescape( text ):
    """Inverse of escape."""
    
    if isinstance( text, str ):
        if '&amp;' in text:
            text = text.replace( '&amp;', '&' )
        if '&gt;' in text:
            text = text.replace( '&gt;', '>' )
        if '&lt;' in text:
            text = text.replace( '&lt;', '<' )
        if '&quot;' in text:
            text = text.replace( '&quot;', '\"' )

    return text

class dummy:
    """A dummy class for attaching attributes."""
    pass

doctype = dummy( )
doctype.frameset = """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd">"""
doctype.strict = """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">"""
doctype.loose = """<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">"""

class russell:
    """A dummy class that contains anything."""

    def __contains__( self, item ):
        return True


class MarkupError( Exception ):
    """All our exceptions subclass this."""
    def __str__( self ):
        return self.message

class ClosingError( MarkupError ):
    def __init__( self, tag ):
        self.message = "The element '%s' does not accept non-keyword arguments (has no closing tag)." % tag

class OpeningError( MarkupError ):
    def __init__( self, tag ):
        self.message = "The element '%s' can not be opened." % tag

class ArgumentError( MarkupError ):
    def __init__( self, tag ):
        self.message = "The element '%s' was called with more than one non-keyword argument." % tag

class InvalidElementError( MarkupError ):
    def __init__( self, tag, mode ):
        self.message = "The element '%s' is not valid for your mode '%s'." % ( tag, mode )

class DeprecationError( MarkupError ):
    def __init__( self, tag ):
        self.message = "The element '%s' is deprecated, instantiate markup.page with mode='loose_html' to allow it." % tag

class ModeError( MarkupError ):
    def __init__( self, mode ):
        self.message = "Mode '%s' is invalid, possible values: strict_html, html (alias for strict_html), loose_html, xml." % mode

class CustomizationError( MarkupError ):
    def __init__( self ):
        self.message = "If you customize the allowed elements, you must define both types 'onetags' and 'twotags'."

if __name__ == '__main__':
    import sys
    sys.stdout.write( __doc__ )