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//usr/lib/python2.4/site-packages/urlgrabber/grabber.py
# This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the # Free Software Foundation, Inc., # 59 Temple Place, Suite 330, # Boston, MA 02111-1307 USA # This file is part of urlgrabber, a high-level cross-protocol url-grabber # Copyright 2002-2004 Michael D. Stenner, Ryan Tomayko """A high-level cross-protocol url-grabber. GENERAL ARGUMENTS (kwargs) Where possible, the module-level default is indicated, and legal values are provided. copy_local = 0 [0|1] ignored except for file:// urls, in which case it specifies whether urlgrab should still make a copy of the file, or simply point to the existing copy. The module level default for this option is 0. close_connection = 0 [0|1] tells URLGrabber to close the connection after a file has been transfered. This is ignored unless the download happens with the http keepalive handler (keepalive=1). Otherwise, the connection is left open for further use. The module level default for this option is 0 (keepalive connections will not be closed). keepalive = 1 [0|1] specifies whether keepalive should be used for HTTP/1.1 servers that support it. The module level default for this option is 1 (keepalive is enabled). progress_obj = None a class instance that supports the following methods: po.start(filename, url, basename, length, text) # length will be None if unknown po.update(read) # read == bytes read so far po.end() text = None specifies an alternativ text item in the beginning of the progress bar line. If not given, the basename of the file is used. throttle = 1.0 a number - if it's an int, it's the bytes/second throttle limit. If it's a float, it is first multiplied by bandwidth. If throttle == 0, throttling is disabled. If None, the module-level default (which can be set on default_grabber.throttle) is used. See BANDWIDTH THROTTLING for more information. timeout = None a positive float expressing the number of seconds to wait for socket operations. If the value is None or 0.0, socket operations will block forever. Setting this option causes urlgrabber to call the settimeout method on the Socket object used for the request. See the Python documentation on settimeout for more information. http://www.python.org/doc/current/lib/socket-objects.html bandwidth = 0 the nominal max bandwidth in bytes/second. If throttle is a float and bandwidth == 0, throttling is disabled. If None, the module-level default (which can be set on default_grabber.bandwidth) is used. See BANDWIDTH THROTTLING for more information. range = None a tuple of the form (first_byte, last_byte) describing a byte range to retrieve. Either or both of the values may set to None. If first_byte is None, byte offset 0 is assumed. If last_byte is None, the last byte available is assumed. Note that the range specification is python-like in that (0,10) will yeild the first 10 bytes of the file. If set to None, no range will be used. reget = None [None|'simple'|'check_timestamp'] whether to attempt to reget a partially-downloaded file. Reget only applies to .urlgrab and (obviously) only if there is a partially downloaded file. Reget has two modes: 'simple' -- the local file will always be trusted. If there are 100 bytes in the local file, then the download will always begin 100 bytes into the requested file. 'check_timestamp' -- the timestamp of the server file will be compared to the timestamp of the local file. ONLY if the local file is newer than or the same age as the server file will reget be used. If the server file is newer, or the timestamp is not returned, the entire file will be fetched. NOTE: urlgrabber can do very little to verify that the partial file on disk is identical to the beginning of the remote file. You may want to either employ a custom "checkfunc" or simply avoid using reget in situations where corruption is a concern. user_agent = 'urlgrabber/VERSION' a string, usually of the form 'AGENT/VERSION' that is provided to HTTP servers in the User-agent header. The module level default for this option is "urlgrabber/VERSION". http_headers = None a tuple of 2-tuples, each containing a header and value. These will be used for http and https requests only. For example, you can do http_headers = (('Pragma', 'no-cache'),) ftp_headers = None this is just like http_headers, but will be used for ftp requests. proxies = None a dictionary that maps protocol schemes to proxy hosts. For example, to use a proxy server on host "foo" port 3128 for http and https URLs: proxies={ 'http' : 'http://foo:3128', 'https' : 'http://foo:3128' } note that proxy authentication information may be provided using normal URL constructs: proxies={ 'http' : 'http://user:host@foo:3128' } Lastly, if proxies is None, the default environment settings will be used. prefix = None a url prefix that will be prepended to all requested urls. For example: g = URLGrabber(prefix='http://foo.com/mirror/') g.urlgrab('some/file.txt') ## this will fetch 'http://foo.com/mirror/some/file.txt' This option exists primarily to allow identical behavior to MirrorGroup (and derived) instances. Note: a '/' will be inserted if necessary, so you cannot specify a prefix that ends with a partial file or directory name. opener = None Overrides the default urllib2.OpenerDirector provided to urllib2 when making requests. This option exists so that the urllib2 handler chain may be customized. Note that the range, reget, proxy, and keepalive features require that custom handlers be provided to urllib2 in order to function properly. If an opener option is provided, no attempt is made by urlgrabber to ensure chain integrity. You are responsible for ensuring that any extension handlers are present if said features are required. data = None Only relevant for the HTTP family (and ignored for other protocols), this allows HTTP POSTs. When the data kwarg is present (and not None), an HTTP request will automatically become a POST rather than GET. This is done by direct passthrough to urllib2. If you use this, you may also want to set the 'Content-length' and 'Content-type' headers with the http_headers option. Note that python 2.2 handles the case of these badly and if you do not use the proper case (shown here), your values will be overridden with the defaults. RETRY RELATED ARGUMENTS retry = None the number of times to retry the grab before bailing. If this is zero, it will retry forever. This was intentional... really, it was :). If this value is not supplied or is supplied but is None retrying does not occur. retrycodes = [-1,2,4,5,6,7] a sequence of errorcodes (values of e.errno) for which it should retry. See the doc on URLGrabError for more details on this. You might consider modifying a copy of the default codes rather than building yours from scratch so that if the list is extended in the future (or one code is split into two) you can still enjoy the benefits of the default list. You can do that with something like this: retrycodes = urlgrabber.grabber.URLGrabberOptions().retrycodes if 12 not in retrycodes: retrycodes.append(12) checkfunc = None a function to do additional checks. This defaults to None, which means no additional checking. The function should simply return on a successful check. It should raise URLGrabError on an unsuccessful check. Raising of any other exception will be considered immediate failure and no retries will occur. If it raises URLGrabError, the error code will determine the retry behavior. Negative error numbers are reserved for use by these passed in functions, so you can use many negative numbers for different types of failure. By default, -1 results in a retry, but this can be customized with retrycodes. If you simply pass in a function, it will be given exactly one argument: a CallbackObject instance with the .url attribute defined and either .filename (for urlgrab) or .data (for urlread). For urlgrab, .filename is the name of the local file. For urlread, .data is the actual string data. If you need other arguments passed to the callback (program state of some sort), you can do so like this: checkfunc=(function, ('arg1', 2), {'kwarg': 3}) if the downloaded file has filename /tmp/stuff, then this will result in this call (for urlgrab): function(obj, 'arg1', 2, kwarg=3) # obj.filename = '/tmp/stuff' # obj.url = 'http://foo.com/stuff' NOTE: both the "args" tuple and "kwargs" dict must be present if you use this syntax, but either (or both) can be empty. failure_callback = None The callback that gets called during retries when an attempt to fetch a file fails. The syntax for specifying the callback is identical to checkfunc, except for the attributes defined in the CallbackObject instance. The attributes for failure_callback are: exception = the raised exception url = the url we're trying to fetch tries = the number of tries so far (including this one) retry = the value of the retry option The callback is present primarily to inform the calling program of the failure, but if it raises an exception (including the one it's passed) that exception will NOT be caught and will therefore cause future retries to be aborted. The callback is called for EVERY failure, including the last one. On the last try, the callback can raise an alternate exception, but it cannot (without severe trickiness) prevent the exception from being raised. interrupt_callback = None This callback is called if KeyboardInterrupt is received at any point in the transfer. Basically, this callback can have three impacts on the fetch process based on the way it exits: 1) raise no exception: the current fetch will be aborted, but any further retries will still take place 2) raise a URLGrabError: if you're using a MirrorGroup, then this will prompt a failover to the next mirror according to the behavior of the MirrorGroup subclass. It is recommended that you raise URLGrabError with code 15, 'user abort'. If you are NOT using a MirrorGroup subclass, then this is the same as (3). 3) raise some other exception (such as KeyboardInterrupt), which will not be caught at either the grabber or mirror levels. That is, it will be raised up all the way to the caller. This callback is very similar to failure_callback. They are passed the same arguments, so you could use the same function for both. urlparser = URLParser() The URLParser class handles pre-processing of URLs, including auth-handling for user/pass encoded in http urls, file handing (that is, filenames not sent as a URL), and URL quoting. If you want to override any of this behavior, you can pass in a replacement instance. See also the 'quote' option. quote = None Whether or not to quote the path portion of a url. quote = 1 -> quote the URLs (they're not quoted yet) quote = 0 -> do not quote them (they're already quoted) quote = None -> guess what to do This option only affects proper urls like 'file:///etc/passwd'; it does not affect 'raw' filenames like '/etc/passwd'. The latter will always be quoted as they are converted to URLs. Also, only the path part of a url is quoted. If you need more fine-grained control, you should probably subclass URLParser and pass it in via the 'urlparser' option. BANDWIDTH THROTTLING urlgrabber supports throttling via two values: throttle and bandwidth Between the two, you can either specify and absolute throttle threshold or specify a theshold as a fraction of maximum available bandwidth. throttle is a number - if it's an int, it's the bytes/second throttle limit. If it's a float, it is first multiplied by bandwidth. If throttle == 0, throttling is disabled. If None, the module-level default (which can be set with set_throttle) is used. bandwidth is the nominal max bandwidth in bytes/second. If throttle is a float and bandwidth == 0, throttling is disabled. If None, the module-level default (which can be set with set_bandwidth) is used. THROTTLING EXAMPLES: Lets say you have a 100 Mbps connection. This is (about) 10^8 bits per second, or 12,500,000 Bytes per second. You have a number of throttling options: *) set_bandwidth(12500000); set_throttle(0.5) # throttle is a float This will limit urlgrab to use half of your available bandwidth. *) set_throttle(6250000) # throttle is an int This will also limit urlgrab to use half of your available bandwidth, regardless of what bandwidth is set to. *) set_throttle(6250000); set_throttle(1.0) # float Use half your bandwidth *) set_throttle(6250000); set_throttle(2.0) # float Use up to 12,500,000 Bytes per second (your nominal max bandwidth) *) set_throttle(6250000); set_throttle(0) # throttle = 0 Disable throttling - this is more efficient than a very large throttle setting. *) set_throttle(0); set_throttle(1.0) # throttle is float, bandwidth = 0 Disable throttling - this is the default when the module is loaded. SUGGESTED AUTHOR IMPLEMENTATION (THROTTLING) While this is flexible, it's not extremely obvious to the user. I suggest you implement a float throttle as a percent to make the distinction between absolute and relative throttling very explicit. Also, you may want to convert the units to something more convenient than bytes/second, such as kbps or kB/s, etc. """ # $Id: grabber.py,v 1.48 2006/09/22 00:58:05 mstenner Exp $ import os import os.path import sys import urlparse import rfc822 import time import types import string import urllib import urllib2 from stat import * # S_* and ST_* ######################################################################## # MODULE INITIALIZATION ######################################################################## try: exec('from ' + (__name__.split('.'))[0] + ' import __version__') except: __version__ = '???' import sslfactory auth_handler = urllib2.HTTPBasicAuthHandler( \ urllib2.HTTPPasswordMgrWithDefaultRealm()) try: from i18n import _ except ImportError, msg: def _(st): return st try: from httplib import HTTPException except ImportError, msg: HTTPException = None try: from httplib import HTTPResponse except ImportError, msg: HTTPResponse = None try: # This is a convenient way to make keepalive optional. # Just rename the module so it can't be imported. import keepalive from keepalive import HTTPHandler, HTTPSHandler keepalive_http_handler = HTTPHandler() have_keepalive = True except ImportError, msg: have_keepalive = False try: # add in range support conditionally too import byterange from byterange import HTTPRangeHandler, HTTPSRangeHandler, \ FileRangeHandler, FTPRangeHandler, range_tuple_normalize, \ range_tuple_to_header, RangeError except ImportError, msg: range_handlers = () RangeError = None have_range = 0 else: range_handlers = (HTTPRangeHandler(), HTTPSRangeHandler(), FileRangeHandler(), FTPRangeHandler()) have_range = 1 # check whether socket timeout support is available (Python >= 2.3) import socket try: TimeoutError = socket.timeout have_socket_timeout = True except AttributeError: TimeoutError = None have_socket_timeout = False ######################################################################## # functions for debugging output. These functions are here because they # are also part of the module initialization. DEBUG = None def set_logger(DBOBJ): """Set the DEBUG object. This is called by _init_default_logger when the environment variable URLGRABBER_DEBUG is set, but can also be called by a calling program. Basically, if the calling program uses the logging module and would like to incorporate urlgrabber logging, then it can do so this way. It's probably not necessary as most internal logging is only for debugging purposes. The passed-in object should be a logging.Logger instance. It will be pushed into the keepalive and byterange modules if they're being used. The mirror module pulls this object in on import, so you will need to manually push into it. In fact, you may find it tidier to simply push your logging object (or objects) into each of these modules independently. """ global DEBUG DEBUG = DBOBJ if have_keepalive and keepalive.DEBUG is None: keepalive.DEBUG = DBOBJ if have_range and byterange.DEBUG is None: byterange.DEBUG = DBOBJ if sslfactory.DEBUG is None: sslfactory.DEBUG = DBOBJ def _init_default_logger(): '''Examines the environment variable URLGRABBER_DEBUG and creates a logging object (logging.logger) based on the contents. It takes the form URLGRABBER_DEBUG=level,filename where "level" can be either an integer or a log level from the logging module (DEBUG, INFO, etc). If the integer is zero or less, logging will be disabled. Filename is the filename where logs will be sent. If it is "-", then stdout will be used. If the filename is empty or missing, stderr will be used. If the variable cannot be processed or the logging module cannot be imported (python < 2.3) then logging will be disabled. Here are some examples: URLGRABBER_DEBUG=1,debug.txt # log everything to debug.txt URLGRABBER_DEBUG=WARNING,- # log warning and higher to stdout URLGRABBER_DEBUG=INFO # log info and higher to stderr This funtion is called during module initialization. It is not intended to be called from outside. The only reason it is a function at all is to keep the module-level namespace tidy and to collect the code into a nice block.''' try: dbinfo = os.environ['URLGRABBER_DEBUG'].split(',') import logging level = logging._levelNames.get(dbinfo[0], int(dbinfo[0])) if level < 1: raise ValueError() formatter = logging.Formatter('%(asctime)s %(message)s') if len(dbinfo) > 1: filename = dbinfo[1] else: filename = '' if filename == '': handler = logging.StreamHandler(sys.stderr) elif filename == '-': handler = logging.StreamHandler(sys.stdout) else: handler = logging.FileHandler(filename) handler.setFormatter(formatter) DBOBJ = logging.getLogger('urlgrabber') DBOBJ.addHandler(handler) DBOBJ.setLevel(level) except (KeyError, ImportError, ValueError): DBOBJ = None set_logger(DBOBJ) _init_default_logger() ######################################################################## # END MODULE INITIALIZATION ######################################################################## class URLGrabError(IOError): """ URLGrabError error codes: URLGrabber error codes (0 -- 255) 0 - everything looks good (you should never see this) 1 - malformed url 2 - local file doesn't exist 3 - request for non-file local file (dir, etc) 4 - IOError on fetch 5 - OSError on fetch 6 - no content length header when we expected one 7 - HTTPException 8 - Exceeded read limit (for urlread) 9 - Requested byte range not satisfiable. 10 - Byte range requested, but range support unavailable 11 - Illegal reget mode 12 - Socket timeout 13 - malformed proxy url 14 - HTTPError (includes .code and .exception attributes) 15 - user abort MirrorGroup error codes (256 -- 511) 256 - No more mirrors left to try Custom (non-builtin) classes derived from MirrorGroup (512 -- 767) [ this range reserved for application-specific error codes ] Retry codes (< 0) -1 - retry the download, unknown reason Note: to test which group a code is in, you can simply do integer division by 256: e.errno / 256 Negative codes are reserved for use by functions passed in to retrygrab with checkfunc. The value -1 is built in as a generic retry code and is already included in the retrycodes list. Therefore, you can create a custom check function that simply returns -1 and the fetch will be re-tried. For more customized retries, you can use other negative number and include them in retry-codes. This is nice for outputting useful messages about what failed. You can use these error codes like so: try: urlgrab(url) except URLGrabError, e: if e.errno == 3: ... # or print e.strerror # or simply print e #### print '[Errno %i] %s' % (e.errno, e.strerror) """ pass class CallbackObject: """Container for returned callback data. This is currently a dummy class into which urlgrabber can stuff information for passing to callbacks. This way, the prototype for all callbacks is the same, regardless of the data that will be passed back. Any function that accepts a callback function as an argument SHOULD document what it will define in this object. It is possible that this class will have some greater functionality in the future. """ def __init__(self, **kwargs): self.__dict__.update(kwargs) def urlgrab(url, filename=None, **kwargs): """grab the file at <url> and make a local copy at <filename> If filename is none, the basename of the url is used. urlgrab returns the filename of the local file, which may be different from the passed-in filename if the copy_local kwarg == 0. See module documentation for a description of possible kwargs. """ return default_grabber.urlgrab(url, filename, **kwargs) def urlopen(url, **kwargs): """open the url and return a file object If a progress object or throttle specifications exist, then a special file object will be returned that supports them. The file object can be treated like any other file object. See module documentation for a description of possible kwargs. """ return default_grabber.urlopen(url, **kwargs) def urlread(url, limit=None, **kwargs): """read the url into a string, up to 'limit' bytes If the limit is exceeded, an exception will be thrown. Note that urlread is NOT intended to be used as a way of saying "I want the first N bytes" but rather 'read the whole file into memory, but don't use too much' See module documentation for a description of possible kwargs. """ return default_grabber.urlread(url, limit, **kwargs) class URLParser: """Process the URLs before passing them to urllib2. This class does several things: * add any prefix * translate a "raw" file to a proper file: url * handle any http or https auth that's encoded within the url * quote the url Only the "parse" method is called directly, and it calls sub-methods. An instance of this class is held in the options object, which means that it's easy to change the behavior by sub-classing and passing the replacement in. It need only have a method like: url, parts = urlparser.parse(url, opts) """ def parse(self, url, opts): """parse the url and return the (modified) url and its parts Note: a raw file WILL be quoted when it's converted to a URL. However, other urls (ones which come with a proper scheme) may or may not be quoted according to opts.quote opts.quote = 1 --> quote it opts.quote = 0 --> do not quote it opts.quote = None --> guess """ quote = opts.quote if opts.prefix: url = self.add_prefix(url, opts.prefix) parts = urlparse.urlparse(url) (scheme, host, path, parm, query, frag) = parts if not scheme or (len(scheme) == 1 and scheme in string.letters): # if a scheme isn't specified, we guess that it's "file:" if url[0] not in '/\\': url = os.path.abspath(url) url = 'file:' + urllib.pathname2url(url) parts = urlparse.urlparse(url) quote = 0 # pathname2url quotes, so we won't do it again if scheme in ['http', 'https']: parts = self.process_http(parts) if quote is None: quote = self.guess_should_quote(parts) if quote: parts = self.quote(parts) url = urlparse.urlunparse(parts) return url, parts def add_prefix(self, url, prefix): if prefix[-1] == '/' or url[0] == '/': url = prefix + url else: url = prefix + '/' + url return url def process_http(self, parts): (scheme, host, path, parm, query, frag) = parts if '@' in host and auth_handler: try: user_pass, host = host.split('@', 1) if ':' in user_pass: user, password = user_pass.split(':', 1) user = urllib.unquote(user) password = urllib.unquote(password) except ValueError, e: raise URLGrabError(1, _('Bad URL: %s') % url) if DEBUG: DEBUG.info('adding HTTP auth: %s, %s', user, password) auth_handler.add_password(None, host, user, password) return (scheme, host, path, parm, query, frag) def quote(self, parts): """quote the URL This method quotes ONLY the path part. If you need to quote other parts, you should override this and pass in your derived class. The other alternative is to quote other parts before passing into urlgrabber. """ (scheme, host, path, parm, query, frag) = parts path = urllib.quote(path) return (scheme, host, path, parm, query, frag) hexvals = '0123456789ABCDEF' def guess_should_quote(self, parts): """ Guess whether we should quote a path. This amounts to guessing whether it's already quoted. find ' ' -> 1 find '%' -> 1 find '%XX' -> 0 else -> 1 """ (scheme, host, path, parm, query, frag) = parts if ' ' in path: return 1 ind = string.find(path, '%') if ind > -1: while ind > -1: if len(path) < ind+3: return 1 code = path[ind+1:ind+3].upper() if code[0] not in self.hexvals or \ code[1] not in self.hexvals: return 1 ind = string.find(path, '%', ind+1) return 0 return 1 class URLGrabberOptions: """Class to ease kwargs handling.""" def __init__(self, delegate=None, **kwargs): """Initialize URLGrabberOptions object. Set default values for all options and then update options specified in kwargs. """ self.delegate = delegate if delegate is None: self._set_defaults() self._set_attributes(**kwargs) def __getattr__(self, name): if self.delegate and hasattr(self.delegate, name): return getattr(self.delegate, name) raise AttributeError, name def raw_throttle(self): """Calculate raw throttle value from throttle and bandwidth values. """ if self.throttle <= 0: return 0 elif type(self.throttle) == type(0): return float(self.throttle) else: # throttle is a float return self.bandwidth * self.throttle def derive(self, **kwargs): """Create a derived URLGrabberOptions instance. This method creates a new instance and overrides the options specified in kwargs. """ return URLGrabberOptions(delegate=self, **kwargs) def _set_attributes(self, **kwargs): """Update object attributes with those provided in kwargs.""" self.__dict__.update(kwargs) if have_range and kwargs.has_key('range'): # normalize the supplied range value self.range = range_tuple_normalize(self.range) if not self.reget in [None, 'simple', 'check_timestamp']: raise URLGrabError(11, _('Illegal reget mode: %s') \ % (self.reget, )) def _set_defaults(self): """Set all options to their default values. When adding new options, make sure a default is provided here. """ self.progress_obj = None self.throttle = 1.0 self.bandwidth = 0 self.retry = None self.retrycodes = [-1,2,4,5,6,7] self.checkfunc = None self.copy_local = 0 self.close_connection = 0 self.range = None self.user_agent = 'urlgrabber/%s' % __version__ self.keepalive = 1 self.proxies = None self.reget = None self.failure_callback = None self.interrupt_callback = None self.prefix = None self.opener = None self.cache_openers = True self.timeout = None self.text = None self.http_headers = None self.ftp_headers = None self.data = None self.urlparser = URLParser() self.quote = None self.ssl_ca_cert = None self.ssl_context = None class URLGrabber: """Provides easy opening of URLs with a variety of options. All options are specified as kwargs. Options may be specified when the class is created and may be overridden on a per request basis. New objects inherit default values from default_grabber. """ def __init__(self, **kwargs): self.opts = URLGrabberOptions(**kwargs) def _retry(self, opts, func, *args): tries = 0 while 1: # there are only two ways out of this loop. The second has # several "sub-ways" # 1) via the return in the "try" block # 2) by some exception being raised # a) an excepton is raised that we don't "except" # b) a callback raises ANY exception # c) we're not retry-ing or have run out of retries # d) the URLGrabError code is not in retrycodes # beware of infinite loops :) tries = tries + 1 exception = None retrycode = None callback = None if DEBUG: DEBUG.info('attempt %i/%s: %s', tries, opts.retry, args[0]) try: r = apply(func, (opts,) + args, {}) if DEBUG: DEBUG.info('success') return r except URLGrabError, e: exception = e callback = opts.failure_callback retrycode = e.errno except KeyboardInterrupt, e: exception = e callback = opts.interrupt_callback if DEBUG: DEBUG.info('exception: %s', exception) if callback: if DEBUG: DEBUG.info('calling callback: %s', callback) cb_func, cb_args, cb_kwargs = self._make_callback(callback) obj = CallbackObject(exception=exception, url=args[0], tries=tries, retry=opts.retry) cb_func(obj, *cb_args, **cb_kwargs) if (opts.retry is None) or (tries == opts.retry): if DEBUG: DEBUG.info('retries exceeded, re-raising') raise if (retrycode is not None) and (retrycode not in opts.retrycodes): if DEBUG: DEBUG.info('retrycode (%i) not in list %s, re-raising', retrycode, opts.retrycodes) raise def urlopen(self, url, **kwargs): """open the url and return a file object If a progress object or throttle value specified when this object was created, then a special file object will be returned that supports them. The file object can be treated like any other file object. """ opts = self.opts.derive(**kwargs) (url,parts) = opts.urlparser.parse(url, opts) def retryfunc(opts, url): return URLGrabberFileObject(url, filename=None, opts=opts) return self._retry(opts, retryfunc, url) def urlgrab(self, url, filename=None, **kwargs): """grab the file at <url> and make a local copy at <filename> If filename is none, the basename of the url is used. urlgrab returns the filename of the local file, which may be different from the passed-in filename if copy_local == 0. """ opts = self.opts.derive(**kwargs) (url,parts) = opts.urlparser.parse(url, opts) (scheme, host, path, parm, query, frag) = parts if filename is None: filename = os.path.basename( urllib.unquote(path) ) if scheme == 'file' and not opts.copy_local: # just return the name of the local file - don't make a # copy currently path = urllib.url2pathname(path) if host: path = os.path.normpath('//' + host + path) if not os.path.exists(path): raise URLGrabError(2, _('Local file does not exist: %s') % (path, )) elif not os.path.isfile(path): raise URLGrabError(3, _('Not a normal file: %s') % (path, )) elif not opts.range: return path def retryfunc(opts, url, filename): fo = URLGrabberFileObject(url, filename, opts) try: fo._do_grab() if not opts.checkfunc is None: cb_func, cb_args, cb_kwargs = \ self._make_callback(opts.checkfunc) obj = CallbackObject() obj.filename = filename obj.url = url apply(cb_func, (obj, )+cb_args, cb_kwargs) finally: fo.close() return filename return self._retry(opts, retryfunc, url, filename) def urlread(self, url, limit=None, **kwargs): """read the url into a string, up to 'limit' bytes If the limit is exceeded, an exception will be thrown. Note that urlread is NOT intended to be used as a way of saying "I want the first N bytes" but rather 'read the whole file into memory, but don't use too much' """ opts = self.opts.derive(**kwargs) (url,parts) = opts.urlparser.parse(url, opts) if limit is not None: limit = limit + 1 def retryfunc(opts, url, limit): fo = URLGrabberFileObject(url, filename=None, opts=opts) s = '' try: # this is an unfortunate thing. Some file-like objects # have a default "limit" of None, while the built-in (real) # file objects have -1. They each break the other, so for # now, we just force the default if necessary. if limit is None: s = fo.read() else: s = fo.read(limit) if not opts.checkfunc is None: cb_func, cb_args, cb_kwargs = \ self._make_callback(opts.checkfunc) obj = CallbackObject() obj.data = s obj.url = url apply(cb_func, (obj, )+cb_args, cb_kwargs) finally: fo.close() return s s = self._retry(opts, retryfunc, url, limit) if limit and len(s) > limit: raise URLGrabError(8, _('Exceeded limit (%i): %s') % (limit, url)) return s def _make_callback(self, callback_obj): if callable(callback_obj): return callback_obj, (), {} else: return callback_obj # create the default URLGrabber used by urlXXX functions. # NOTE: actual defaults are set in URLGrabberOptions default_grabber = URLGrabber() class URLGrabberFileObject: """This is a file-object wrapper that supports progress objects and throttling. This exists to solve the following problem: lets say you want to drop-in replace a normal open with urlopen. You want to use a progress meter and/or throttling, but how do you do that without rewriting your code? Answer: urlopen will return a wrapped file object that does the progress meter and-or throttling internally. """ def __init__(self, url, filename, opts): self.url = url self.filename = filename self.opts = opts self.fo = None self._rbuf = '' self._rbufsize = 1024*8 self._ttime = time.time() self._tsize = 0 self._amount_read = 0 self._opener = None self._do_open() def __getattr__(self, name): """This effectively allows us to wrap at the instance level. Any attribute not found in _this_ object will be searched for in self.fo. This includes methods.""" if hasattr(self.fo, name): return getattr(self.fo, name) raise AttributeError, name def _get_opener(self): """Build a urllib2 OpenerDirector based on request options.""" if self.opts.opener: return self.opts.opener elif self._opener is None: handlers = [] need_keepalive_handler = (have_keepalive and self.opts.keepalive) need_range_handler = (range_handlers and \ (self.opts.range or self.opts.reget)) # if you specify a ProxyHandler when creating the opener # it _must_ come before all other handlers in the list or urllib2 # chokes. if self.opts.proxies: handlers.append( CachedProxyHandler(self.opts.proxies) ) # ------------------------------------------------------- # OK, these next few lines are a serious kludge to get # around what I think is a bug in python 2.2's # urllib2. The basic idea is that default handlers # get applied first. If you override one (like a # proxy handler), then the default gets pulled, but # the replacement goes on the end. In the case of # proxies, this means the normal handler picks it up # first and the proxy isn't used. Now, this probably # only happened with ftp or non-keepalive http, so not # many folks saw it. The simple approach to fixing it # is just to make sure you override the other # conflicting defaults as well. I would LOVE to see # these go way or be dealt with more elegantly. The # problem isn't there after 2.2. -MDS 2005/02/24 if not need_keepalive_handler: handlers.append( urllib2.HTTPHandler() ) if not need_range_handler: handlers.append( urllib2.FTPHandler() ) # ------------------------------------------------------- ssl_factory = sslfactory.get_factory(self.opts.ssl_ca_cert, self.opts.ssl_context) if need_keepalive_handler: handlers.append(keepalive_http_handler) handlers.append(HTTPSHandler(ssl_factory)) if need_range_handler: handlers.extend( range_handlers ) handlers.append( auth_handler ) if self.opts.cache_openers: self._opener = CachedOpenerDirector(ssl_factory, *handlers) else: self._opener = ssl_factory.create_opener(*handlers) # OK, I don't like to do this, but otherwise, we end up with # TWO user-agent headers. self._opener.addheaders = [] return self._opener def _do_open(self): opener = self._get_opener() req = urllib2.Request(self.url, self.opts.data) # build request object self._add_headers(req) # add misc headers that we need self._build_range(req) # take care of reget and byterange stuff def _checkNoReget(fo): # HTTP can disallow Range requests if self.opts.reget is None: return False if 'Range' not in req.headers: return False if not isinstance(fo, HTTPResponse): return False return fo.code != 206 fo, hdr = self._make_request(req, opener) fetch_again = 0 if self.reget_time and self.opts.reget == 'check_timestamp': # do this if we have a local file with known timestamp AND # we're in check_timestamp reget mode. fetch_again = 0 try: modified_tuple = hdr.getdate_tz('last-modified') modified_stamp = rfc822.mktime_tz(modified_tuple) if modified_stamp > self.reget_time: fetch_again = 1 except (TypeError,): fetch_again = 1 if _checkNoReget(fo): # doing a "reget" didn't work, so fixup fetch_again = 0 self.opts.reget = None self.append = 0 self._amount_read = 0 if True: if fetch_again: # the server version is newer than the (incomplete) local # version, so we should abandon the version we're getting # and fetch the whole thing again. fo.close() # Without this we'll have to read all of the previous request # data. For "large" requests, this is very bad. fo.close_connection() self.opts.reget = None del req.headers['Range'] self._build_range(req) # This doesn't get reset in _build_range() *sigh* self._amount_read = 0 fo, hdr = self._make_request(req, opener) (scheme, host, path, parm, query, frag) = urlparse.urlparse(self.url) path = urllib.unquote(path) if not (self.opts.progress_obj or self.opts.raw_throttle() \ or self.opts.timeout): # if we're not using the progress_obj, throttling, or timeout # we can get a performance boost by going directly to # the underlying fileobject for reads. self.read = fo.read if hasattr(fo, 'readline'): self.readline = fo.readline elif self.opts.progress_obj: try: length = int(hdr['Content-Length']) length = length + self._amount_read # Account for regets except (KeyError, ValueError, TypeError): length = None self.opts.progress_obj.start(str(self.filename), urllib.unquote(self.url), os.path.basename(path), length, text=self.opts.text) self.opts.progress_obj.update(0) (self.fo, self.hdr) = (fo, hdr) def _add_headers(self, req): if self.opts.user_agent: req.add_header('User-agent', self.opts.user_agent) try: req_type = req.get_type() except ValueError: req_type = None if self.opts.http_headers and req_type in ('http', 'https'): for h, v in self.opts.http_headers: req.add_header(h, v) if self.opts.ftp_headers and req_type == 'ftp': for h, v in self.opts.ftp_headers: req.add_header(h, v) def _build_range(self, req): self.reget_time = None self.append = 0 reget_length = 0 rt = None if have_range and self.opts.reget and type(self.filename) in types.StringTypes: # we have reget turned on and we're dumping to a file try: s = os.stat(self.filename) except OSError: pass else: self.reget_time = s[ST_MTIME] reget_length = s[ST_SIZE] # Set initial length when regetting self._amount_read = reget_length rt = reget_length, '' self.append = 1 if self.opts.range: if not have_range: raise URLGrabError(10, _('Byte range requested but range '\ 'support unavailable')) rt = self.opts.range if rt[0]: rt = (rt[0] + reget_length, rt[1]) if rt: header = range_tuple_to_header(rt) if header: req.add_header('Range', header) def _make_request(self, req, opener): try: if have_socket_timeout and self.opts.timeout: old_to = socket.getdefaulttimeout() socket.setdefaulttimeout(self.opts.timeout) try: fo = opener.open(req) finally: socket.setdefaulttimeout(old_to) else: fo = opener.open(req) hdr = fo.info() except ValueError, e: raise URLGrabError(1, _('Bad URL: %s') % (e, )) except RangeError, e: raise URLGrabError(9, str(e)) except urllib2.HTTPError, e: new_e = URLGrabError(14, str(e)) new_e.code = e.code new_e.exception = e raise new_e except IOError, e: if hasattr(e, 'reason') and have_socket_timeout and \ isinstance(e.reason, TimeoutError): raise URLGrabError(12, _('Timeout: %s') % (e, )) else: raise URLGrabError(4, _('IOError: %s') % (e, )) except OSError, e: raise URLGrabError(5, _('OSError: %s') % (e, )) except HTTPException, e: raise URLGrabError(7, _('HTTP Exception (%s): %s') % \ (e.__class__.__name__, e)) else: return (fo, hdr) def _do_grab(self): """dump the file to self.filename.""" if self.append: new_fo = open(self.filename, 'ab') else: new_fo = open(self.filename, 'wb') try: # if we have a known range, only try to read that much. (low, high) = self.opts.range amount = high - low except TypeError, ValueError: amount = None bs = 1024*8 size = 0 if amount is not None: bs = min(bs, amount - size) block = self.read(bs) size = size + len(block) while block: new_fo.write(block) if amount is not None: bs = min(bs, amount - size) block = self.read(bs) size = size + len(block) new_fo.close() try: modified_tuple = self.hdr.getdate_tz('last-modified') modified_stamp = rfc822.mktime_tz(modified_tuple) os.utime(self.filename, (modified_stamp, modified_stamp)) except (TypeError,), e: pass return size def _fill_buffer(self, amt=None): """fill the buffer to contain at least 'amt' bytes by reading from the underlying file object. If amt is None, then it will read until it gets nothing more. It updates the progress meter and throttles after every self._rbufsize bytes.""" # the _rbuf test is only in this first 'if' for speed. It's not # logically necessary if self._rbuf and not amt is None: L = len(self._rbuf) if amt > L: amt = amt - L else: return # if we've made it here, then we don't have enough in the buffer # and we need to read more. buf = [self._rbuf] bufsize = len(self._rbuf) while amt is None or amt: # first, delay if necessary for throttling reasons if self.opts.raw_throttle(): diff = self._tsize/self.opts.raw_throttle() - \ (time.time() - self._ttime) if diff > 0: time.sleep(diff) self._ttime = time.time() # now read some data, up to self._rbufsize if amt is None: readamount = self._rbufsize else: readamount = min(amt, self._rbufsize) try: new = self.fo.read(readamount) except socket.error, e: raise URLGrabError(4, _('Socket Error: %s') % (e, )) except TimeoutError, e: raise URLGrabError(12, _('Timeout: %s') % (e, )) except IOError, e: raise URLGrabError(4, _('IOError: %s') %(e,)) newsize = len(new) if not newsize: break # no more to read if amt: amt = amt - newsize buf.append(new) bufsize = bufsize + newsize self._tsize = newsize self._amount_read = self._amount_read + newsize if self.opts.progress_obj: self.opts.progress_obj.update(self._amount_read) self._rbuf = string.join(buf, '') return def read(self, amt=None): self._fill_buffer(amt) if amt is None: s, self._rbuf = self._rbuf, '' else: s, self._rbuf = self._rbuf[:amt], self._rbuf[amt:] return s def readline(self, limit=-1): i = string.find(self._rbuf, '\n') while i < 0 and not (0 < limit <= len(self._rbuf)): L = len(self._rbuf) self._fill_buffer(L + self._rbufsize) if not len(self._rbuf) > L: break i = string.find(self._rbuf, '\n', L) if i < 0: i = len(self._rbuf) else: i = i+1 if 0 <= limit < len(self._rbuf): i = limit s, self._rbuf = self._rbuf[:i], self._rbuf[i:] return s def close(self): if self.opts.progress_obj: self.opts.progress_obj.end(self._amount_read) self.fo.close() if self.opts.close_connection: try: self.fo.close_connection() except: pass _handler_cache = [] def CachedOpenerDirector(ssl_factory = None, *handlers): for (cached_handlers, opener) in _handler_cache: if cached_handlers == handlers: for handler in opener.handlers: handler.add_parent(opener) return opener if not ssl_factory: ssl_factory = sslfactory.get_factory() opener = ssl_factory.create_opener(*handlers) _handler_cache.append( (handlers, opener) ) return opener _proxy_cache = [] def CachedProxyHandler(proxies): for (pdict, handler) in _proxy_cache: if pdict == proxies: if DEBUG: DEBUG.debug('re-using proxy settings: %s', proxies) break else: for k, v in proxies.items(): utype, url = urllib.splittype(v) host, other = urllib.splithost(url) if (utype is None) or (host is None): raise URLGrabError(13, _('Bad proxy URL: %s') % v) if DEBUG: DEBUG.info('creating new proxy handler: %s', proxies) handler = urllib2.ProxyHandler(proxies) _proxy_cache.append( (proxies, handler) ) return handler ##################################################################### # DEPRECATED FUNCTIONS def set_throttle(new_throttle): """Deprecated. Use: default_grabber.throttle = new_throttle""" default_grabber.throttle = new_throttle def set_bandwidth(new_bandwidth): """Deprecated. Use: default_grabber.bandwidth = new_bandwidth""" default_grabber.bandwidth = new_bandwidth def set_progress_obj(new_progress_obj): """Deprecated. Use: default_grabber.progress_obj = new_progress_obj""" default_grabber.progress_obj = new_progress_obj def set_user_agent(new_user_agent): """Deprecated. Use: default_grabber.user_agent = new_user_agent""" default_grabber.user_agent = new_user_agent def retrygrab(url, filename=None, copy_local=0, close_connection=0, progress_obj=None, throttle=None, bandwidth=None, numtries=3, retrycodes=[-1,2,4,5,6,7], checkfunc=None): """Deprecated. Use: urlgrab() with the retry arg instead""" kwargs = {'copy_local' : copy_local, 'close_connection' : close_connection, 'progress_obj' : progress_obj, 'throttle' : throttle, 'bandwidth' : bandwidth, 'retry' : numtries, 'retrycodes' : retrycodes, 'checkfunc' : checkfunc } return urlgrab(url, filename, **kwargs) ##################################################################### # TESTING def _main_test(): import sys try: url, filename = sys.argv[1:3] except ValueError: print 'usage:', sys.argv[0], \ '<url> <filename> [copy_local=0|1] [close_connection=0|1]' sys.exit() kwargs = {} for a in sys.argv[3:]: k, v = string.split(a, '=', 1) kwargs[k] = int(v) set_throttle(1.0) set_bandwidth(32 * 1024) print "throttle: %s, throttle bandwidth: %s B/s" % (default_grabber.throttle, default_grabber.bandwidth) try: from progress import text_progress_meter except ImportError, e: pass else: kwargs['progress_obj'] = text_progress_meter() try: name = apply(urlgrab, (url, filename), kwargs) except URLGrabError, e: print e else: print 'LOCAL FILE:', name def _retry_test(): import sys try: url, filename = sys.argv[1:3] except ValueError: print 'usage:', sys.argv[0], \ '<url> <filename> [copy_local=0|1] [close_connection=0|1]' sys.exit() kwargs = {} for a in sys.argv[3:]: k, v = string.split(a, '=', 1) kwargs[k] = int(v) try: from progress import text_progress_meter except ImportError, e: pass else: kwargs['progress_obj'] = text_progress_meter() def cfunc(filename, hello, there='foo'): print hello, there import random rnum = random.random() if rnum < .5: print 'forcing retry' raise URLGrabError(-1, 'forcing retry') if rnum < .75: print 'forcing failure' raise URLGrabError(-2, 'forcing immediate failure') print 'success' return kwargs['checkfunc'] = (cfunc, ('hello',), {'there':'there'}) try: name = apply(retrygrab, (url, filename), kwargs) except URLGrabError, e: print e else: print 'LOCAL FILE:', name def _file_object_test(filename=None): import random, cStringIO, sys if filename is None: filename = __file__ print 'using file "%s" for comparisons' % filename fo = open(filename) s_input = fo.read() fo.close() for testfunc in [_test_file_object_smallread, _test_file_object_readall, _test_file_object_readline, _test_file_object_readlines]: fo_input = cStringIO.StringIO(s_input) fo_output = cStringIO.StringIO() wrapper = URLGrabberFileObject(fo_input, None, 0) print 'testing %-30s ' % testfunc.__name__, testfunc(wrapper, fo_output) s_output = fo_output.getvalue() if s_output == s_input: print 'passed' else: print 'FAILED' def _test_file_object_smallread(wrapper, fo_output): while 1: s = wrapper.read(23) fo_output.write(s) if not s: return def _test_file_object_readall(wrapper, fo_output): s = wrapper.read() fo_output.write(s) def _test_file_object_readline(wrapper, fo_output): while 1: s = wrapper.readline() fo_output.write(s) if not s: return def _test_file_object_readlines(wrapper, fo_output): li = wrapper.readlines() fo_output.write(string.join(li, '')) if __name__ == '__main__': _main_test() _retry_test() _file_object_test('test')