FM / urllib

/snap/core24/1587/usr/lib/python3.12/urllib/

/snap/core24/1587/usr/lib/python3.12/urllib

Name	Size	Mode	Actions
__pycache__/	-	0755	rm
error.py	2415	0644	edit dl rm
parse.py	45591	0644	edit dl rm
request.py	103013	0644	edit dl rm
response.py	2361	0644	edit dl rm
robotparser.py	9424	0644	edit dl rm
__init__.py	0	0644	edit dl rm

Edit: /snap/core24/1587/usr/lib/python3.12/urllib/robotparser.py (9424B)

""" robotparser.py

You can choose between two licenses when using this package:
    1) GNU GPLv2
    2) PSF license for Python 2.2

The robots.txt Exclusion Protocol is implemented as specified in
    http://www.robotstxt.org/norobots-rfc.txt
"""

import collections
import urllib.parse
import urllib.request

__all__ = ["RobotFileParser"]

RequestRate = collections.namedtuple("RequestRate", "requests seconds")

class RobotFileParser:
    """ This class provides a set of methods to read, parse and answer
    questions about a single robots.txt file.

"""

def __init__(self, url=''):
        self.entries = []
        self.sitemaps = []
        self.default_entry = None
        self.disallow_all = False
        self.allow_all = False
        self.set_url(url)
        self.last_checked = 0

def mtime(self):
        """Returns the time the robots.txt file was last fetched.

This is useful for long-running web spiders that need to
        check for new robots.txt files periodically.

"""
        return self.last_checked

def modified(self):
        """Sets the time the robots.txt file was last fetched to the
        current time.

"""
        import time
        self.last_checked = time.time()

def set_url(self, url):
        """Sets the URL referring to a robots.txt file."""
        self.url = url
        self.host, self.path = urllib.parse.urlparse(url)[1:3]

def read(self):
        """Reads the robots.txt URL and feeds it to the parser."""
        try:
            f = urllib.request.urlopen(self.url)
        except urllib.error.HTTPError as err:
            if err.code in (401, 403):
                self.disallow_all = True
            elif err.code >= 400 and err.code < 500:
                self.allow_all = True
        else:
            raw = f.read()
            self.parse(raw.decode("utf-8").splitlines())

def _add_entry(self, entry):
        if "*" in entry.useragents:
            # the default entry is considered last
            if self.default_entry is None:
                # the first default entry wins
                self.default_entry = entry
        else:
            self.entries.append(entry)

def parse(self, lines):
        """Parse the input lines from a robots.txt file.

We allow that a user-agent: line is not preceded by
        one or more blank lines.
        """
        # states:
        #   0: start state
        #   1: saw user-agent line
        #   2: saw an allow or disallow line
        state = 0
        entry = Entry()

self.modified()
        for line in lines:
            if not line:
                if state == 1:
                    entry = Entry()
                    state = 0
                elif state == 2:
                    self._add_entry(entry)
                    entry = Entry()
                    state = 0
            # remove optional comment and strip line
            i = line.find('#')
            if i >= 0:
                line = line[:i]
            line = line.strip()
            if not line:
                continue
            line = line.split(':', 1)
            if len(line) == 2:
                line[0] = line[0].strip().lower()
                line[1] = urllib.parse.unquote(line[1].strip())
                if line[0] == "user-agent":
                    if state == 2:
                        self._add_entry(entry)
                        entry = Entry()
                    entry.useragents.append(line[1])
                    state = 1
                elif line[0] == "disallow":
                    if state != 0:
                        entry.rulelines.append(RuleLine(line[1], False))
                        state = 2
                elif line[0] == "allow":
                    if state != 0:
                        entry.rulelines.append(RuleLine(line[1], True))
                        state = 2
                elif line[0] == "crawl-delay":
                    if state != 0:
                        # before trying to convert to int we need to make
                        # sure that robots.txt has valid syntax otherwise
                        # it will crash
                        if line[1].strip().isdigit():
                            entry.delay = int(line[1])
                        state = 2
                elif line[0] == "request-rate":
                    if state != 0:
                        numbers = line[1].split('/')
                        # check if all values are sane
                        if (len(numbers) == 2 and numbers[0].strip().isdigit()
                            and numbers[1].strip().isdigit()):
                            entry.req_rate = RequestRate(int(numbers[0]), int(numbers[1]))
                        state = 2
                elif line[0] == "sitemap":
                    # According to http://www.sitemaps.org/protocol.html
                    # "This directive is independent of the user-agent line,
                    #  so it doesn't matter where you place it in your file."
                    # Therefore we do not change the state of the parser.
                    self.sitemaps.append(line[1])
        if state == 2:
            self._add_entry(entry)

def can_fetch(self, useragent, url):
        """using the parsed robots.txt decide if useragent can fetch url"""
        if self.disallow_all:
            return False
        if self.allow_all:
            return True
        # Until the robots.txt file has been read or found not
        # to exist, we must assume that no url is allowable.
        # This prevents false positives when a user erroneously
        # calls can_fetch() before calling read().
        if not self.last_checked:
            return False
        # search for given user agent matches
        # the first match counts
        parsed_url = urllib.parse.urlparse(urllib.parse.unquote(url))
        url = urllib.parse.urlunparse(('','',parsed_url.path,
            parsed_url.params,parsed_url.query, parsed_url.fragment))
        url = urllib.parse.quote(url)
        if not url:
            url = "/"
        for entry in self.entries:
            if entry.applies_to(useragent):
                return entry.allowance(url)
        # try the default entry last
        if self.default_entry:
            return self.default_entry.allowance(url)
        # agent not found ==> access granted
        return True

def crawl_delay(self, useragent):
        if not self.mtime():
            return None
        for entry in self.entries:
            if entry.applies_to(useragent):
                return entry.delay
        if self.default_entry:
            return self.default_entry.delay
        return None

def request_rate(self, useragent):
        if not self.mtime():
            return None
        for entry in self.entries:
            if entry.applies_to(useragent):
                return entry.req_rate
        if self.default_entry:
            return self.default_entry.req_rate
        return None

def site_maps(self):
        if not self.sitemaps:
            return None
        return self.sitemaps

def __str__(self):
        entries = self.entries
        if self.default_entry is not None:
            entries = entries + [self.default_entry]
        return '\n\n'.join(map(str, entries))

class RuleLine:
    """A rule line is a single "Allow:" (allowance==True) or "Disallow:"
       (allowance==False) followed by a path."""
    def __init__(self, path, allowance):
        if path == '' and not allowance:
            # an empty value means allow all
            allowance = True
        path = urllib.parse.urlunparse(urllib.parse.urlparse(path))
        self.path = urllib.parse.quote(path)
        self.allowance = allowance

def applies_to(self, filename):
        return self.path == "*" or filename.startswith(self.path)

def __str__(self):
        return ("Allow" if self.allowance else "Disallow") + ": " + self.path

class Entry:
    """An entry has one or more user-agents and zero or more rulelines"""
    def __init__(self):
        self.useragents = []
        self.rulelines = []
        self.delay = None
        self.req_rate = None

def __str__(self):
        ret = []
        for agent in self.useragents:
            ret.append(f"User-agent: {agent}")
        if self.delay is not None:
            ret.append(f"Crawl-delay: {self.delay}")
        if self.req_rate is not None:
            rate = self.req_rate
            ret.append(f"Request-rate: {rate.requests}/{rate.seconds}")
        ret.extend(map(str, self.rulelines))
        return '\n'.join(ret)

def applies_to(self, useragent):
        """check if this entry applies to the specified agent"""
        # split the name token and make it lower case
        useragent = useragent.split("/")[0].lower()
        for agent in self.useragents:
            if agent == '*':
                # we have the catch-all agent
                return True
            agent = agent.lower()
            if agent in useragent:
                return True
        return False

def allowance(self, filename):
        """Preconditions:
        - our agent applies to this entry
        - filename is URL decoded"""
        for line in self.rulelines:
            if line.applies_to(filename):
                return line.allowance
        return True

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