Source code for dispass.labelfile

# Copyright (c) 2011-2012 Benjamin Althues <benjamin@babab.nl>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

import datetime
from os.path import expanduser

from dispass import versionStr

class FileHandler:
    '''Parsing of labelfiles and writing to labelfiles'''

    default_length = 30
    '''Default passphrase length'''

    default_hashname = 'dispass1'
    '''Name of hash to use by default'''

    filehandle = None
    '''File object, set on init if labelfile is found'''

    file_found = None
    '''Boolean value set on init'''

    file_location = None
    '''String of labelfile location, set on init'''

    file_stripped = []
    '''Labelfile contents with comments and blank lines removed'''

    labels = None
    '''Dict of `{label: length}`'''

    def __init__(self, write=False, file_location='~/.dispass'):
        '''Open file; if file is found: strip comments and parse()'''

        self.file_location = file_location

        try:
            if write:
                self.filehandle = open(expanduser(file_location), 'r+')
            else:
                self.filehandle = open(expanduser(file_location), 'r')
            self.file_found = True
        except IOError:
            self.file_found = False
            return

        # Strip comments and blank lines
        for i in self.filehandle:
            if i[0] != '\n' and i[0] != '#':
                self.file_stripped.append(i)

        if self.file_found:
            if not write:
                self.close()
            self.parse()

    def parse(self):
        '''Create dictionary of ``labels = {label: length, ...}``'''

        labels = []
        labels_dispass1 = []

        for i in self.file_stripped:
            wordlist = []
            line = i.rsplit(' ')
            for word in line:
                if word != '':
                    wordlist.append(word.strip('\n'))
            labels.append(wordlist)

        for line in labels:
            labelname = line.pop(0)
            length = self.default_length
            hashname = self.default_hashname

            for arg in line:
                if 'length=' in arg:
                    try:
                        length = int(arg.strip('length='))
                    except ValueError:
                        print "Warning: Invalid length in: '%s'" % line
                elif 'hash=' in arg:
                    hashname = arg.strip('hash=')

            if hashname == 'dispass1':
                labels_dispass1.append((labelname, length))

        self.labels = dict(labels_dispass1)
        return self

    def write(self, labels=None):

        if isinstance(labels, dict):
            self.labels = labels

        if self.labels:
            label_list = []
            for label, length in self.labels.iteritems():
                label_list.append(label)
                divlen = len(max(label_list, key=len)) + 2

            config = '# Generated by %s on %s\n\n' % \
                    (versionStr, datetime.datetime.now())
            for label, length in self.labels.iteritems():
                config += '{:{fill}} length={}\n'.format(label, length,
                                                         fill=divlen)
            self.filehandle.write(config)
            self.filehandle.close()
            return True
        else:
            return False

    def close(self):
        if self.filehandle:
            self.filehandle.close()

if __name__ == '__main__':
    fh = FileHandler(write=True)

    if fh.file_found:
        if fh.write():
            print 'Saved to %s' % fh.file_location
        else:
            print 'No labels found'
    else:
        print 'Labelfile not found'