recoll/src/filters/rclzip

#!/usr/bin/env python

# Zip file filter for Recoll

import os
import fnmatch
import rclexecm
from zipfile import ZipFile

try:
    from recoll import rclconfig
    hasrclconfig = True
except:
    hasrclconfig = False
# As a temporary measure, we also look for rclconfig as a bare
# module. This is so that the intermediate releases of the filter can
# ship and use rclconfig.py with the filter code
if not hasrclconfig:
    try:
        import rclconfig
        hasrclconfig = True
    except:
        pass

# Note about file names (python 2.6. 2.7, don't know about 3.)
#
# There is a bit in zip entries to indicate if the filename is encoded
# as utf-8 or not. If the bit is set, zipfile decodes the file name
# and stores it in the catalog as an unicode object. Else it uses a
# binary string.
#
# When reading the file, the input file name is used directly as an
# index into the catalog.
#
# When we send the file name data to the indexer, we have to serialize
# it as byte string, we can't pass unicode objects to and fro. This
# means that we have to test if the name is unicode. If it is, we send
# the string encoded as utf-8. When reading, if the input is utf-8, we
# turn it to unicode and use this to access the zip member, else we
# use the binary string.
# 
# In the case where an archive member name is a valid non-ascii utf-8
# string, but the flag is not set (which could probably happen if the
# archiver did not try to detect utf-8 file names), this will fail,
# because we'll convert back the utf-8 string to unicode and pass this
# to zipfile, but an utf-8 string, not a unicode object is actually in
# the catalog in this case, so the access will fail (will be seen at
# preview or open time). This does not affect ascii file names because
# the representation is the same anyway.
#
# To avoid this problem, we'd need to pass a separate bit of
# information indicating that encoding was performed, not just rely on
# the utf-8 validity test (ie have a 1st char switch), but this would be
# incompatible with existing indexes. Instead we try both ways...
#
class ZipExtractor:
    def __init__(self, em):
        self.currentindex = 0
        self.em = em
            
    def extractone(self, ipath):
        #self.em.rclog("extractone: [%s]" % ipath)
        docdata = ""
        try:
            info = self.zip.getinfo(ipath)
            # There could be a 4GB Iso in the zip. We have to set a limit
            if info.file_size > self.em.maxmembersize:
                self.em.rclog("extractone: entry %s size %d too big" %
                              (ipath, info.file_size))
                docdata = ""
                #raise BadZipfile()
            else:
                docdata = self.zip.read(ipath)
            ok = True
        except Exception as err:
            self.em.rclog("extractone: failed: [%s]" % err)
            ok = False
        iseof = rclexecm.RclExecM.noteof
        if self.currentindex >= len(self.zip.namelist()) -1:
            iseof = rclexecm.RclExecM.eofnext
        if isinstance(ipath, unicode):
            ipath = ipath.encode("utf-8")
        return (ok, docdata, ipath, iseof)

    ###### File type handler api, used by rclexecm ---------->
    def openfile(self, params):
        filename = params["filename:"]
        self.currentindex = -1
        self.skiplist = []

        if hasrclconfig:
            config = rclconfig.RclConfig()
            config.setKeyDir(os.path.dirname(filename))
            skipped = config.getConfParam("zipSkippedNames")
            if skipped is not None:
                self.skiplist = skipped.split(" ")

        try:
            self.zip = ZipFile(filename)
            return True
        except Exception as err:
            self.em.rclog("openfile: failed: [%s]" % err)
            return False

    def getipath(self, params):
        ipath = params["ipath:"]
        ok, data, ipath, eof = self.extractone(ipath)
        if ok:
            return (ok, data, ipath, eof)
        # Not found. Maybe we need to decode the path?
        try:
            ipath = ipath.decode("utf-8")
            return self.extractone(ipath)
        except Exception as err:
            return (ok, data, ipath, eof)
        
    def getnext(self, params):
        if self.currentindex == -1:
            # Return "self" doc
            self.currentindex = 0
            self.em.setmimetype('text/plain')
            if len(self.zip.namelist()) == 0:
                eof = rclexecm.RclExecM.eofnext
            else:
                eof = rclexecm.RclExecM.noteof
            return (True, "", "", eof)

        if self.currentindex >= len(self.zip.namelist()):
            #self.em.rclog("getnext: EOF hit")
            return (False, "", "", rclexecm.RclExecM.eofnow)
        else:
            entryname = self.zip.namelist()[self.currentindex]

            if hasrclconfig and len(self.skiplist) != 0:
                while self.currentindex < len(self.zip.namelist()):
                    entryname = self.zip.namelist()[self.currentindex]
                    for pat in self.skiplist:
                        if fnmatch.fnmatch(entryname, pat):
                            entryname = None
                            break
                    if entryname is not None:
                        break
                    self.currentindex += 1
                if entryname is None:
                    return (False, "", "", rclexecm.RclExecM.eofnow)
                
            ret= self.extractone(entryname)
            self.currentindex += 1
            return ret

# Main program: create protocol handler and extractor and run them
proto = rclexecm.RclExecM()
extract = ZipExtractor(proto)
rclexecm.main(proto, extract)