--- /dev/null
+
+"""Manage a cache of downloaded files.
+
+@var DECOMPRESS_EXTS: a list of file extensions that need to be decompressed
+@var DECOMPRESS_FILES: a list of file names that need to be decompressed
+"""
+
+from bz2 import BZ2Decompressor
+from zlib import decompressobj, MAX_WBITS
+from gzip import FCOMMENT, FEXTRA, FHCRC, FNAME, FTEXT
+from urlparse import urlparse
+import os
+
+from twisted.python import log
+from twisted.python.filepath import FilePath
+from twisted.internet import defer, reactor
+from twisted.trial import unittest
+from twisted.web2 import stream
+from twisted.web2.http import splitHostPort
+
+from Hash import HashObject
+
+DECOMPRESS_EXTS = ['.gz', '.bz2']
+DECOMPRESS_FILES = ['release', 'sources', 'packages']
+
+class ProxyFileStream(stream.SimpleStream):
+ """Saves a stream to a file while providing a new stream.
+
+ Also optionally decompresses the file while it is being downloaded.
+
+ @type stream: L{twisted.web2.stream.IByteStream}
+ @ivar stream: the input stream being read
+ @type outFile: L{twisted.python.filepath.FilePath}
+ @ivar outFile: the file being written
+ @type hash: L{Hash.HashObject}
+ @ivar hash: the hash object for the file
+ @type gzfile: C{file}
+ @ivar gzfile: the open file to write decompressed gzip data to
+ @type gzdec: L{zlib.decompressobj}
+ @ivar gzdec: the decompressor to use for the compressed gzip data
+ @type gzheader: C{boolean}
+ @ivar gzheader: whether the gzip header still needs to be removed from
+ the zlib compressed data
+ @type bz2file: C{file}
+ @ivar bz2file: the open file to write decompressed bz2 data to
+ @type bz2dec: L{bz2.BZ2Decompressor}
+ @ivar bz2dec: the decompressor to use for the compressed bz2 data
+ @type length: C{int}
+ @ivar length: the length of the original (compressed) file
+ @type doneDefer: L{twisted.internet.defer.Deferred}
+ @ivar doneDefer: the deferred that will fire when done streaming
+
+ @group Stream implementation: read, close
+
+ """
+
+ def __init__(self, stream, outFile, hash, decompress = None, decFile = None):
+ """Initializes the proxy.
+
+ @type stream: L{twisted.web2.stream.IByteStream}
+ @param stream: the input stream to read from
+ @type outFile: L{twisted.python.filepath.FilePath}
+ @param outFile: the file to write to
+ @type hash: L{Hash.HashObject}
+ @param hash: the hash object to use for the file
+ @type decompress: C{string}
+ @param decompress: also decompress the file as this type
+ (currently only '.gz' and '.bz2' are supported)
+ @type decFile: C{twisted.python.FilePath}
+ @param decFile: the file to write the decompressed data to
+ """
+ self.stream = stream
+ self.outFile = outFile.open('w')
+ self.hash = hash
+ self.hash.new()
+ self.gzfile = None
+ self.bz2file = None
+ if decompress == ".gz":
+ self.gzheader = True
+ self.gzfile = decFile.open('w')
+ self.gzdec = decompressobj(-MAX_WBITS)
+ elif decompress == ".bz2":
+ self.bz2file = decFile.open('w')
+ self.bz2dec = BZ2Decompressor()
+ self.length = self.stream.length
+ self.doneDefer = defer.Deferred()
+
+ def _done(self):
+ """Close all the output files, return the result."""
+ if not self.outFile.closed:
+ self.outFile.close()
+ self.hash.digest()
+ if self.gzfile:
+ # Finish the decompression
+ data_dec = self.gzdec.flush()
+ self.gzfile.write(data_dec)
+ self.gzfile.close()
+ self.gzfile = None
+ if self.bz2file:
+ self.bz2file.close()
+ self.bz2file = None
+
+ self.doneDefer.callback(self.hash)
+
+ def read(self):
+ """Read some data from the stream."""
+ if self.outFile.closed:
+ return None
+
+ # Read data from the stream, deal with the possible deferred
+ data = self.stream.read()
+ if isinstance(data, defer.Deferred):
+ data.addCallbacks(self._write, self._done)
+ return data
+
+ self._write(data)
+ return data
+
+ def _write(self, data):
+ """Write the stream data to the file and return it for others to use.
+
+ Also optionally decompresses it.
+ """
+ if data is None:
+ self._done()
+ return data
+
+ # Write and hash the streamed data
+ self.outFile.write(data)
+ self.hash.update(data)
+
+ if self.gzfile:
+ # Decompress the zlib portion of the file
+ if self.gzheader:
+ # Remove the gzip header junk
+ self.gzheader = False
+ new_data = self._remove_gzip_header(data)
+ dec_data = self.gzdec.decompress(new_data)
+ else:
+ dec_data = self.gzdec.decompress(data)
+ self.gzfile.write(dec_data)
+ if self.bz2file:
+ # Decompress the bz2 file
+ dec_data = self.bz2dec.decompress(data)
+ self.bz2file.write(dec_data)
+
+ return data
+
+ def _remove_gzip_header(self, data):
+ """Remove the gzip header from the zlib compressed data."""
+ # Read, check & discard the header fields
+ if data[:2] != '\037\213':
+ raise IOError, 'Not a gzipped file'
+ if ord(data[2]) != 8:
+ raise IOError, 'Unknown compression method'
+ flag = ord(data[3])
+ # modtime = self.fileobj.read(4)
+ # extraflag = self.fileobj.read(1)
+ # os = self.fileobj.read(1)
+
+ skip = 10
+ if flag & FEXTRA:
+ # Read & discard the extra field
+ xlen = ord(data[10])
+ xlen = xlen + 256*ord(data[11])
+ skip = skip + 2 + xlen
+ if flag & FNAME:
+ # Read and discard a null-terminated string containing the filename
+ while True:
+ if not data[skip] or data[skip] == '\000':
+ break
+ skip += 1
+ skip += 1
+ if flag & FCOMMENT:
+ # Read and discard a null-terminated string containing a comment
+ while True:
+ if not data[skip] or data[skip] == '\000':
+ break
+ skip += 1
+ skip += 1
+ if flag & FHCRC:
+ skip += 2 # Read & discard the 16-bit header CRC
+
+ return data[skip:]
+
+ def close(self):
+ """Clean everything up and return None to future reads."""
+ self.length = 0
+ self._done()
+ self.stream.close()
+
+class CacheManager:
+ """Manages all downloaded files and requests for cached objects.
+
+ @type cache_dir: L{twisted.python.filepath.FilePath}
+ @ivar cache_dir: the directory to use for storing all files
+ @type other_dirs: C{list} of L{twisted.python.filepath.FilePath}
+ @ivar other_dirs: the other directories that have shared files in them
+ @type all_dirs: C{list} of L{twisted.python.filepath.FilePath}
+ @ivar all_dirs: all the directories that have cached files in them
+ @type db: L{db.DB}
+ @ivar db: the database to use for tracking files and hashes
+ @type manager: L{apt_p2p.AptP2P}
+ @ivar manager: the main program object to send requests to
+ @type scanning: C{list} of L{twisted.python.filepath.FilePath}
+ @ivar scanning: all the directories that are currectly being scanned or waiting to be scanned
+ """
+
+ def __init__(self, cache_dir, db, other_dirs = [], manager = None):
+ """Initialize the instance and remove any untracked files from the DB..
+
+ @type cache_dir: L{twisted.python.filepath.FilePath}
+ @param cache_dir: the directory to use for storing all files
+ @type db: L{db.DB}
+ @param db: the database to use for tracking files and hashes
+ @type other_dirs: C{list} of L{twisted.python.filepath.FilePath}
+ @param other_dirs: the other directories that have shared files in them
+ (optional, defaults to only using the cache directory)
+ @type manager: L{apt_p2p.AptP2P}
+ @param manager: the main program object to send requests to
+ (optional, defaults to not calling back with cached files)
+ """
+ self.cache_dir = cache_dir
+ self.other_dirs = other_dirs
+ self.all_dirs = self.other_dirs[:]
+ self.all_dirs.insert(0, self.cache_dir)
+ self.db = db
+ self.manager = manager
+ self.scanning = []
+
+ # Init the database, remove old files
+ self.db.removeUntrackedFiles(self.all_dirs)
+
+ #{ Scanning directories
+ def scanDirectories(self):
+ """Scan the cache directories, hashing new and rehashing changed files."""
+ assert not self.scanning, "a directory scan is already under way"
+ self.scanning = self.all_dirs[:]
+ self._scanDirectories()
+
+ def _scanDirectories(self, result = None, walker = None):
+ """Walk each directory looking for cached files.
+
+ @param result: the result of a DHT store request, not used (optional)
+ @param walker: the walker to use to traverse the current directory
+ (optional, defaults to creating a new walker from the first
+ directory in the L{CacheManager.scanning} list)
+ """
+ # Need to start walking a new directory
+ if walker is None:
+ # If there are any left, get them
+ if self.scanning:
+ log.msg('started scanning directory: %s' % self.scanning[0].path)
+ walker = self.scanning[0].walk()
+ else:
+ log.msg('cache directory scan complete')
+ return
+
+ try:
+ # Get the next file in the directory
+ file = walker.next()
+ except StopIteration:
+ # No files left, go to the next directory
+ log.msg('done scanning directory: %s' % self.scanning[0].path)
+ self.scanning.pop(0)
+ reactor.callLater(0, self._scanDirectories)
+ return
+
+ # If it's not a file ignore it
+ if not file.isfile():
+ log.msg('entering directory: %s' % file.path)
+ reactor.callLater(0, self._scanDirectories, None, walker)
+ return
+
+ # If it's already properly in the DB, ignore it
+ db_status = self.db.isUnchanged(file)
+ if db_status:
+ log.msg('file is unchanged: %s' % file.path)
+ reactor.callLater(0, self._scanDirectories, None, walker)
+ return
+
+ # Don't hash files in the cache that are not in the DB
+ if self.scanning[0] == self.cache_dir:
+ if db_status is None:
+ log.msg('ignoring unknown cache file: %s' % file.path)
+ else:
+ log.msg('removing changed cache file: %s' % file.path)
+ file.remove()
+ reactor.callLater(0, self._scanDirectories, None, walker)
+ return
+
+ # Otherwise hash it
+ log.msg('start hash checking file: %s' % file.path)
+ hash = HashObject()
+ df = hash.hashInThread(file)
+ df.addBoth(self._doneHashing, file, walker)
+ df.addErrback(log.err)
+
+ def _doneHashing(self, result, file, walker):
+ """If successful, add the hashed file to the DB and inform the main program."""
+ if isinstance(result, HashObject):
+ log.msg('hash check of %s completed with hash: %s' % (file.path, result.hexdigest()))
+
+ # Only set a URL if this is a downloaded file
+ url = None
+ if self.scanning[0] == self.cache_dir:
+ url = 'http:/' + file.path[len(self.cache_dir.path):]
+
+ # Store the hashed file in the database
+ new_hash = self.db.storeFile(file, result.digest())
+
+ # Tell the main program to handle the new cache file
+ df = self.manager.new_cached_file(file, result, new_hash, url, True)
+ if df is None:
+ reactor.callLater(0, self._scanDirectories, None, walker)
+ else:
+ df.addBoth(self._scanDirectories, walker)
+ else:
+ # Must have returned an error
+ log.msg('hash check of %s failed' % file.path)
+ log.err(result)
+ reactor.callLater(0, self._scanDirectories, None, walker)
+
+ #{ Downloading files
+ def save_file(self, response, hash, url):
+ """Save a downloaded file to the cache and stream it.
+
+ @type response: L{twisted.web2.http.Response}
+ @param response: the response from the download
+ @type hash: L{Hash.HashObject}
+ @param hash: the hash object containing the expected hash for the file
+ @param url: the URI of the actual mirror request
+ @rtype: L{twisted.web2.http.Response}
+ @return: the final response from the download
+ """
+ if response.code != 200:
+ log.msg('File was not found (%r): %s' % (response, url))
+ return response
+
+ log.msg('Returning file: %s' % url)
+
+ # Set the destination path for the file
+ parsed = urlparse(url)
+ destFile = self.cache_dir.preauthChild(parsed[1] + parsed[2])
+ log.msg('Saving returned %r byte file to cache: %s' % (response.stream.length, destFile.path))
+
+ # Make sure there's a free place for the file
+ if destFile.exists():
+ log.msg('File already exists, removing: %s' % destFile.path)
+ destFile.remove()
+ elif not destFile.parent().exists():
+ destFile.parent().makedirs()
+
+ # Determine whether it needs to be decompressed and how
+ root, ext = os.path.splitext(destFile.basename())
+ if root.lower() in DECOMPRESS_FILES and ext.lower() in DECOMPRESS_EXTS:
+ ext = ext.lower()
+ decFile = destFile.sibling(root)
+ log.msg('Decompressing to: %s' % decFile.path)
+ if decFile.exists():
+ log.msg('File already exists, removing: %s' % decFile.path)
+ decFile.remove()
+ else:
+ ext = None
+ decFile = None
+
+ # Create the new stream from the old one.
+ orig_stream = response.stream
+ response.stream = ProxyFileStream(orig_stream, destFile, hash, ext, decFile)
+ response.stream.doneDefer.addCallback(self._save_complete, url, destFile,
+ response.headers.getHeader('Last-Modified'),
+ decFile)
+ response.stream.doneDefer.addErrback(self.save_error, url)
+
+ # Return the modified response with the new stream
+ return response
+
+ def _save_complete(self, hash, url, destFile, modtime = None, decFile = None):
+ """Update the modification time and inform the main program.
+
+ @type hash: L{Hash.HashObject}
+ @param hash: the hash object containing the expected hash for the file
+ @param url: the URI of the actual mirror request
+ @type destFile: C{twisted.python.FilePath}
+ @param destFile: the file where the download was written to
+ @type modtime: C{int}
+ @param modtime: the modified time of the cached file (seconds since epoch)
+ (optional, defaults to not setting the modification time of the file)
+ @type decFile: C{twisted.python.FilePath}
+ @param decFile: the file where the decompressed download was written to
+ (optional, defaults to the file not having been compressed)
+ """
+ if modtime:
+ os.utime(destFile.path, (modtime, modtime))
+ if decFile:
+ os.utime(decFile.path, (modtime, modtime))
+
+ result = hash.verify()
+ if result or result is None:
+ if result:
+ log.msg('Hashes match: %s' % url)
+ else:
+ log.msg('Hashed file to %s: %s' % (hash.hexdigest(), url))
+
+ new_hash = self.db.storeFile(destFile, hash.digest())
+ log.msg('now avaliable: %s' % (url))
+
+ if self.manager:
+ self.manager.new_cached_file(destFile, hash, new_hash, url)
+ if decFile:
+ ext_len = len(destFile.path) - len(decFile.path)
+ self.manager.new_cached_file(decFile, None, False, url[:-ext_len])
+ else:
+ log.msg("Hashes don't match %s != %s: %s" % (hash.hexexpected(), hash.hexdigest(), url))
+ destFile.remove()
+ if decFile:
+ decFile.remove()
+
+ def save_error(self, failure, url):
+ """An error has occurred in downloadign or saving the file."""
+ log.msg('Error occurred downloading %s' % url)
+ log.err(failure)
+ return failure
+
+class TestMirrorManager(unittest.TestCase):
+ """Unit tests for the mirror manager."""
+
+ timeout = 20
+ pending_calls = []
+ client = None
+
+ def setUp(self):
+ self.client = CacheManager(FilePath('/tmp/.apt-p2p'))
+
+ def tearDown(self):
+ for p in self.pending_calls:
+ if p.active():
+ p.cancel()
+ self.client = None
+
\ No newline at end of file
projects / quix0rs-apt-p2p.git / blobdiff