220 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			220 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""Diagnostic functions, mainly for use when doing tech support."""
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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__license__ = "MIT"
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import cProfile
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from StringIO import StringIO
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from HTMLParser import HTMLParser
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import bs4
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from bs4 import BeautifulSoup, __version__
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from bs4.builder import builder_registry
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import os
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import pstats
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import random
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import tempfile
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import time
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import traceback
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import sys
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import cProfile
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def diagnose(data):
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    """Diagnostic suite for isolating common problems."""
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    print "Diagnostic running on Beautiful Soup %s" % __version__
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    print "Python version %s" % sys.version
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    basic_parsers = ["html.parser", "html5lib", "lxml"]
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    for name in basic_parsers:
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        for builder in builder_registry.builders:
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            if name in builder.features:
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                break
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        else:
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            basic_parsers.remove(name)
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            print (
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                "I noticed that %s is not installed. Installing it may help." %
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                name)
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    if 'lxml' in basic_parsers:
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        basic_parsers.append(["lxml", "xml"])
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        try:
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            from lxml import etree
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            print "Found lxml version %s" % ".".join(map(str,etree.LXML_VERSION))
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        except ImportError, e:
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            print (
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                "lxml is not installed or couldn't be imported.")
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    if 'html5lib' in basic_parsers:
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        try:
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            import html5lib
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            print "Found html5lib version %s" % html5lib.__version__
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        except ImportError, e:
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            print (
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                "html5lib is not installed or couldn't be imported.")
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    if hasattr(data, 'read'):
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        data = data.read()
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    elif os.path.exists(data):
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        print '"%s" looks like a filename. Reading data from the file.' % data
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        with open(data) as fp:
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            data = fp.read()
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    elif data.startswith("http:") or data.startswith("https:"):
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        print '"%s" looks like a URL. Beautiful Soup is not an HTTP client.' % data
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        print "You need to use some other library to get the document behind the URL, and feed that document to Beautiful Soup."
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        return
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    print
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    for parser in basic_parsers:
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        print "Trying to parse your markup with %s" % parser
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        success = False
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        try:
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            soup = BeautifulSoup(data, parser)
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            success = True
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        except Exception, e:
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            print "%s could not parse the markup." % parser
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            traceback.print_exc()
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        if success:
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            print "Here's what %s did with the markup:" % parser
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            print soup.prettify()
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        print "-" * 80
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def lxml_trace(data, html=True, **kwargs):
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    """Print out the lxml events that occur during parsing.
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    This lets you see how lxml parses a document when no Beautiful
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    Soup code is running.
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    """
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    from lxml import etree
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    for event, element in etree.iterparse(StringIO(data), html=html, **kwargs):
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        print("%s, %4s, %s" % (event, element.tag, element.text))
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class AnnouncingParser(HTMLParser):
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    """Announces HTMLParser parse events, without doing anything else."""
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    def _p(self, s):
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        print(s)
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    def handle_starttag(self, name, attrs):
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        self._p("%s START" % name)
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    def handle_endtag(self, name):
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        self._p("%s END" % name)
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    def handle_data(self, data):
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        self._p("%s DATA" % data)
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    def handle_charref(self, name):
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        self._p("%s CHARREF" % name)
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    def handle_entityref(self, name):
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        self._p("%s ENTITYREF" % name)
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    def handle_comment(self, data):
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        self._p("%s COMMENT" % data)
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    def handle_decl(self, data):
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        self._p("%s DECL" % data)
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    def unknown_decl(self, data):
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        self._p("%s UNKNOWN-DECL" % data)
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    def handle_pi(self, data):
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        self._p("%s PI" % data)
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def htmlparser_trace(data):
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    """Print out the HTMLParser events that occur during parsing.
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    This lets you see how HTMLParser parses a document when no
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    Beautiful Soup code is running.
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    """
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    parser = AnnouncingParser()
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    parser.feed(data)
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_vowels = "aeiou"
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_consonants = "bcdfghjklmnpqrstvwxyz"
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def rword(length=5):
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    "Generate a random word-like string."
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    s = ''
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    for i in range(length):
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        if i % 2 == 0:
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            t = _consonants
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        else:
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            t = _vowels
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        s += random.choice(t)
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    return s
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def rsentence(length=4):
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    "Generate a random sentence-like string."
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    return " ".join(rword(random.randint(4,9)) for i in range(length))
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def rdoc(num_elements=1000):
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    """Randomly generate an invalid HTML document."""
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    tag_names = ['p', 'div', 'span', 'i', 'b', 'script', 'table']
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    elements = []
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    for i in range(num_elements):
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        choice = random.randint(0,3)
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        if choice == 0:
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            # New tag.
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            tag_name = random.choice(tag_names)
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            elements.append("<%s>" % tag_name)
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        elif choice == 1:
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            elements.append(rsentence(random.randint(1,4)))
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        elif choice == 2:
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            # Close a tag.
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            tag_name = random.choice(tag_names)
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            elements.append("</%s>" % tag_name)
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    return "<html>" + "\n".join(elements) + "</html>"
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def benchmark_parsers(num_elements=100000):
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    """Very basic head-to-head performance benchmark."""
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    print "Comparative parser benchmark on Beautiful Soup %s" % __version__
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    data = rdoc(num_elements)
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    print "Generated a large invalid HTML document (%d bytes)." % len(data)
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    for parser in ["lxml", ["lxml", "html"], "html5lib", "html.parser"]:
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        success = False
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        try:
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            a = time.time()
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            soup = BeautifulSoup(data, parser)
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            b = time.time()
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            success = True
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        except Exception, e:
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            print "%s could not parse the markup." % parser
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            traceback.print_exc()
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        if success:
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            print "BS4+%s parsed the markup in %.2fs." % (parser, b-a)
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    from lxml import etree
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    a = time.time()
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    etree.HTML(data)
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    b = time.time()
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    print "Raw lxml parsed the markup in %.2fs." % (b-a)
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    import html5lib
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    parser = html5lib.HTMLParser()
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    a = time.time()
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    parser.parse(data)
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    b = time.time()
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    print "Raw html5lib parsed the markup in %.2fs." % (b-a)
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def profile(num_elements=100000, parser="lxml"):
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    filehandle = tempfile.NamedTemporaryFile()
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    filename = filehandle.name
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    data = rdoc(num_elements)
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    vars = dict(bs4=bs4, data=data, parser=parser)
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    cProfile.runctx('bs4.BeautifulSoup(data, parser)' , vars, vars, filename)
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    stats = pstats.Stats(filename)
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    # stats.strip_dirs()
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    stats.sort_stats("cumulative")
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    stats.print_stats('_html5lib|bs4', 50)
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if __name__ == '__main__':
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    diagnose(sys.stdin.read())
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