+"""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 Hash import HashObject
-aptpkg_dir='apt-packages'
-
DECOMPRESS_EXTS = ['.gz', '.bz2']
DECOMPRESS_FILES = ['release', 'sources', 'packages']
class ProxyFileStream(stream.SimpleStream):
- """Saves a stream to a file while providing a new stream."""
+ """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: C{twisted.web2.stream.IByteStream}
+ @type stream: L{twisted.web2.stream.IByteStream}
@param stream: the input stream to read from
- @type outFile: C{twisted.python.FilePath}
+ @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
self.bz2file = decFile.open('w')
self.bz2dec = BZ2Decompressor()
self.length = self.stream.length
- self.start = 0
self.doneDefer = defer.Deferred()
def _done(self):
- """Close the output file."""
+ """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()
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
def _write(self, data):
- """Write the stream data to the file and return it for others to use."""
+ """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)
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:
skip = 10
if flag & FEXTRA:
- # Read & discard the extra field, if present
+ # Read & discard the extra field
xlen = ord(data[10])
xlen = xlen + 256*ord(data[11])
skip = skip + 2 + xlen
skip += 1
if flag & FHCRC:
skip += 2 # Read & discard the 16-bit header CRC
+
return data[skip:]
def close(self):
self.stream.close()
class CacheManager:
- """Manages all requests for cached objects."""
+ """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_dht.AptDHT}
+ @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_dht.AptDHT}
+ @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[:]
# 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._scanDirectories()
def _scanDirectories(self, result = None, walker = None):
- # Need to start waling a new directory
+ """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:
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."""
+ """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()
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'),
- ext, decFile)
+ 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, ext = None, decFile = None):
- """Update the modification time and AptPackages."""
+ 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 ext:
+ if decFile:
os.utime(decFile.path, (modtime, modtime))
result = hash.verify()
if self.manager:
self.manager.new_cached_file(destFile, hash, new_hash, url)
- if ext:
- self.manager.new_cached_file(decFile, None, False, url[:-len(ext)])
+ 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 ext:
+ if decFile:
decFile.remove()
def save_error(self, failure, url):
projects / quix0rs-apt-p2p.git / commitdiff