|
"""Diagnostic functions, mainly for use when doing tech support.""" |
|
|
|
|
|
__license__ = "MIT" |
|
|
|
import cProfile |
|
from io import BytesIO |
|
from html.parser import HTMLParser |
|
import bs4 |
|
from bs4 import BeautifulSoup, __version__ |
|
from bs4.builder import builder_registry |
|
|
|
import os |
|
import pstats |
|
import random |
|
import tempfile |
|
import time |
|
import traceback |
|
import sys |
|
import cProfile |
|
|
|
def diagnose(data): |
|
"""Diagnostic suite for isolating common problems. |
|
|
|
:param data: A string containing markup that needs to be explained. |
|
:return: None; diagnostics are printed to standard output. |
|
""" |
|
print(("Diagnostic running on Beautiful Soup %s" % __version__)) |
|
print(("Python version %s" % sys.version)) |
|
|
|
basic_parsers = ["html.parser", "html5lib", "lxml"] |
|
for name in basic_parsers: |
|
for builder in builder_registry.builders: |
|
if name in builder.features: |
|
break |
|
else: |
|
basic_parsers.remove(name) |
|
print(( |
|
"I noticed that %s is not installed. Installing it may help." % |
|
name)) |
|
|
|
if 'lxml' in basic_parsers: |
|
basic_parsers.append("lxml-xml") |
|
try: |
|
from lxml import etree |
|
print(("Found lxml version %s" % ".".join(map(str,etree.LXML_VERSION)))) |
|
except ImportError as e: |
|
print( |
|
"lxml is not installed or couldn't be imported.") |
|
|
|
|
|
if 'html5lib' in basic_parsers: |
|
try: |
|
import html5lib |
|
print(("Found html5lib version %s" % html5lib.__version__)) |
|
except ImportError as e: |
|
print( |
|
"html5lib is not installed or couldn't be imported.") |
|
|
|
if hasattr(data, 'read'): |
|
data = data.read() |
|
|
|
for parser in basic_parsers: |
|
print(("Trying to parse your markup with %s" % parser)) |
|
success = False |
|
try: |
|
soup = BeautifulSoup(data, features=parser) |
|
success = True |
|
except Exception as e: |
|
print(("%s could not parse the markup." % parser)) |
|
traceback.print_exc() |
|
if success: |
|
print(("Here's what %s did with the markup:" % parser)) |
|
print((soup.prettify())) |
|
|
|
print(("-" * 80)) |
|
|
|
def lxml_trace(data, html=True, **kwargs): |
|
"""Print out the lxml events that occur during parsing. |
|
|
|
This lets you see how lxml parses a document when no Beautiful |
|
Soup code is running. You can use this to determine whether |
|
an lxml-specific problem is in Beautiful Soup's lxml tree builders |
|
or in lxml itself. |
|
|
|
:param data: Some markup. |
|
:param html: If True, markup will be parsed with lxml's HTML parser. |
|
if False, lxml's XML parser will be used. |
|
""" |
|
from lxml import etree |
|
recover = kwargs.pop('recover', True) |
|
if isinstance(data, str): |
|
data = data.encode("utf8") |
|
reader = BytesIO(data) |
|
for event, element in etree.iterparse( |
|
reader, html=html, recover=recover, **kwargs |
|
): |
|
print(("%s, %4s, %s" % (event, element.tag, element.text))) |
|
|
|
class AnnouncingParser(HTMLParser): |
|
"""Subclass of HTMLParser that announces parse events, without doing |
|
anything else. |
|
|
|
You can use this to get a picture of how html.parser sees a given |
|
document. The easiest way to do this is to call `htmlparser_trace`. |
|
""" |
|
|
|
def _p(self, s): |
|
print(s) |
|
|
|
def handle_starttag(self, name, attrs): |
|
self._p("%s START" % name) |
|
|
|
def handle_endtag(self, name): |
|
self._p("%s END" % name) |
|
|
|
def handle_data(self, data): |
|
self._p("%s DATA" % data) |
|
|
|
def handle_charref(self, name): |
|
self._p("%s CHARREF" % name) |
|
|
|
def handle_entityref(self, name): |
|
self._p("%s ENTITYREF" % name) |
|
|
|
def handle_comment(self, data): |
|
self._p("%s COMMENT" % data) |
|
|
|
def handle_decl(self, data): |
|
self._p("%s DECL" % data) |
|
|
|
def unknown_decl(self, data): |
|
self._p("%s UNKNOWN-DECL" % data) |
|
|
|
def handle_pi(self, data): |
|
self._p("%s PI" % data) |
|
|
|
def htmlparser_trace(data): |
|
"""Print out the HTMLParser events that occur during parsing. |
|
|
|
This lets you see how HTMLParser parses a document when no |
|
Beautiful Soup code is running. |
|
|
|
:param data: Some markup. |
|
""" |
|
parser = AnnouncingParser() |
|
parser.feed(data) |
|
|
|
_vowels = "aeiou" |
|
_consonants = "bcdfghjklmnpqrstvwxyz" |
|
|
|
def rword(length=5): |
|
"Generate a random word-like string." |
|
s = '' |
|
for i in range(length): |
|
if i % 2 == 0: |
|
t = _consonants |
|
else: |
|
t = _vowels |
|
s += random.choice(t) |
|
return s |
|
|
|
def rsentence(length=4): |
|
"Generate a random sentence-like string." |
|
return " ".join(rword(random.randint(4,9)) for i in range(length)) |
|
|
|
def rdoc(num_elements=1000): |
|
"""Randomly generate an invalid HTML document.""" |
|
tag_names = ['p', 'div', 'span', 'i', 'b', 'script', 'table'] |
|
elements = [] |
|
for i in range(num_elements): |
|
choice = random.randint(0,3) |
|
if choice == 0: |
|
|
|
tag_name = random.choice(tag_names) |
|
elements.append("<%s>" % tag_name) |
|
elif choice == 1: |
|
elements.append(rsentence(random.randint(1,4))) |
|
elif choice == 2: |
|
|
|
tag_name = random.choice(tag_names) |
|
elements.append("</%s>" % tag_name) |
|
return "<html>" + "\n".join(elements) + "</html>" |
|
|
|
def benchmark_parsers(num_elements=100000): |
|
"""Very basic head-to-head performance benchmark.""" |
|
print(("Comparative parser benchmark on Beautiful Soup %s" % __version__)) |
|
data = rdoc(num_elements) |
|
print(("Generated a large invalid HTML document (%d bytes)." % len(data))) |
|
|
|
for parser in ["lxml", ["lxml", "html"], "html5lib", "html.parser"]: |
|
success = False |
|
try: |
|
a = time.time() |
|
soup = BeautifulSoup(data, parser) |
|
b = time.time() |
|
success = True |
|
except Exception as e: |
|
print(("%s could not parse the markup." % parser)) |
|
traceback.print_exc() |
|
if success: |
|
print(("BS4+%s parsed the markup in %.2fs." % (parser, b-a))) |
|
|
|
from lxml import etree |
|
a = time.time() |
|
etree.HTML(data) |
|
b = time.time() |
|
print(("Raw lxml parsed the markup in %.2fs." % (b-a))) |
|
|
|
import html5lib |
|
parser = html5lib.HTMLParser() |
|
a = time.time() |
|
parser.parse(data) |
|
b = time.time() |
|
print(("Raw html5lib parsed the markup in %.2fs." % (b-a))) |
|
|
|
def profile(num_elements=100000, parser="lxml"): |
|
"""Use Python's profiler on a randomly generated document.""" |
|
filehandle = tempfile.NamedTemporaryFile() |
|
filename = filehandle.name |
|
|
|
data = rdoc(num_elements) |
|
vars = dict(bs4=bs4, data=data, parser=parser) |
|
cProfile.runctx('bs4.BeautifulSoup(data, parser)' , vars, vars, filename) |
|
|
|
stats = pstats.Stats(filename) |
|
|
|
stats.sort_stats("cumulative") |
|
stats.print_stats('_html5lib|bs4', 50) |
|
|
|
|
|
if __name__ == '__main__': |
|
diagnose(sys.stdin.read()) |
|
|