From 0e11ad7fde30573740e8d97b98cff7515275c707 2012-08-01 07:48:28 From: Lance Edgar Date: 2012-08-01 07:48:28 Subject: [PATCH] add labels module --- diff --git a/rattail/labels.py b/rattail/labels.py new file mode 100644 index 0000000000000000000000000000000000000000..7998476bb75cefe47a0ffd78b5d10bd64df49adb --- /dev/null +++ b/rattail/labels.py @@ -0,0 +1,286 @@ +#!/usr/bin/env python +# -*- coding: utf-8 -*- +################################################################################ +# +# Rattail -- Retail Software Framework +# Copyright © 2010-2012 Lance Edgar +# +# This file is part of Rattail. +# +# Rattail is free software: you can redistribute it and/or modify it under the +# terms of the GNU Affero General Public License as published by the Free +# Software Foundation, either version 3 of the License, or (at your option) +# any later version. +# +# Rattail 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 Affero General Public License for +# more details. +# +# You should have received a copy of the GNU Affero General Public License +# along with Rattail. If not, see . +# +################################################################################ + +""" +``rattail.labels`` -- Label Printing +""" + +import os +import os.path +import socket +from cStringIO import StringIO + +try: + from collections import OrderedDict +except ImportError: + from ordereddict import OrderedDict + +import edbob +from edbob.util import requires_impl + + +_profiles = OrderedDict() + + +class LabelPrinter(edbob.Object): + """ + Base class for all label printers. + + Label printing devices which are "natively" supported by Rattail will each + derive from this class in order to provide implementation details specific + to the device. You will typically instantiate one of those subclasses (or + one of your own design) in order to send labels to your physical printer. + """ + + profile_name = None + formatter = None + + @requires_impl() + def print_labels(self, labels, *args, **kwargs): + """ + Prints labels found in ``labels``. + """ + + pass + + +class CommandFilePrinter(LabelPrinter): + """ + Generic :class:`LabelPrinter` subclass which "prints" labels to a file in + the form of native printer (textual) commands. The output file is then + expected to be picked up by a file monitor, and finally sent to the printer + from there. + """ + + def batch_header_commands(self): + """ + This method, if implemented, must return a sequence of string commands + to be interpreted by the printer. These commands will be the first + which are written to the file. + """ + + return None + + def batch_footer_commands(self): + """ + This method, if implemented, must return a sequence of string commands + to be interpreted by the printer. These commands will be the last + which are written to the file. + """ + + return None + + def print_labels(self, labels, output_dir=None): + """ + "Prints" ``labels`` by generating a command file in the output folder. + The full path of the output file to which commands are written will be + returned to the caller. + + If ``output_dir`` is not specified, and the printer instance is + associated with a :class:`LabelProfile` instance, then config will be + consulted for the output path. If a path still is not found, the + current (working) directory will be assumed. + """ + + if not output_dir and self.profile_name: + output_dir = edbob.config.get('rattail.labels', '%s.output_dir' % self.profile_name) + if not output_dir: + output_dir = os.getcwd() + + fn = '%s_%s.labels' % (socket.gethostname(), + edbob.local_time().strftime('%Y-%m-%d_%H-%M-%S')) + labels_path = os.path.join(output_dir, fn) + labels_file = open(labels_path, 'w') + + header = self.batch_header_commands() + if header: + print >> labels_file, '\n'.join(header) + + print >> labels_file, self.formatter.format_labels(labels) + + footer = self.batch_footer_commands() + if footer: + print >> labels_file, '\n'.join(footer) + + labels_file.close() + return labels_path + + +class LabelFormatter(edbob.Object): + """ + Base class for all label formatters. + """ + + format = None + + @requires_impl() + def format_labels(self, labels, *args, **kwargs): + """ + Formats ``labels`` and returns the result. + """ + + pass + + +class CommandFormatter(LabelFormatter): + """ + Generic subclass of :class:`LabelFormatter` which generates native printer + (textual) commands. + """ + + def label_header_commands(self): + """ + This method, if implemented, must return a sequence of string commands + to be interpreted by the printer. These commands will immediately + precede each *label* in one-up printing, and immediately precede each + *label pair* in two-up printing. + """ + + return None + + @requires_impl() + def label_body_commands(self): + pass + + def label_footer_commands(self): + """ + This method, if implemented, must return a sequence of string commands + to be interpreted by the printer. These commands will immedately + follow each *label* in one-up printing, and immediately follow each + *label pair* in two-up printing. + """ + + return None + + +class TwoUpCommandFormatter(CommandFormatter): + """ + Generic subclass of :class:`LabelFormatter` which generates native printer + (textual) commands. + + This class contains logic to implement "two-up" label printing. + """ + + @property + @requires_impl(is_property=True) + def half_offset(self): + """ + The X-coordinate value by which the second label should be offset, when + two labels are printed side-by-side. + """ + + pass + + def format_labels(self, labels): + fmt = StringIO() + + half_started = False + for product, quantity in labels: + for i in range(quantity): + if half_started: + print >> fmt, '\n'.join(self.label_body_commands(product, x=self.half_offset)) + footer = self.label_footer_commands() + if footer: + print >> fmt, '\n'.join(footer) + half_started = False + else: + header = self.label_header_commands() + if header: + print >> fmt, '\n'.join(header) + print >> fmt, '\n'.join(self.label_body_commands(product, x=0)) + half_started = True + + if half_started: + footer = self.label_footer_commands() + if footer: + print >> fmt, '\n'.join(footer) + + val = fmt.getvalue() + fmt.close() + return val + + +class LabelProfile(edbob.Object): + """ + Represents a label printing profile. This abstraction is used to define + not only the physical (or otherwise?) device to which label should be sent, + but the label formatting specifics as well. + """ + + name = None + display_name = None + printer_factory = None + formatter_factory = None + format = None + + def get_formatter(self): + if self.formatter_factory: + return self.formatter_factory(format=self.format) + return None + + def get_printer(self): + if self.printer_factory: + return self.printer_factory( + profile_name=self.name, + formatter=self.get_formatter()) + return None + + +def init(config): + """ + Initializes the label printing system. + + This reads label profiles from config and caches the corresponding + :class:`LabelProfile` instances in memory. + """ + + profiles = config.require('rattail.labels', 'profiles') + profiles = profiles.split(',') + for key in profiles: + key = key.strip() + profile = LabelProfile(name=key) + profile.display_name = config.require('rattail.labels', '%s.display' % key) + profile.printer_factory = edbob.load_spec( + config.require('rattail.labels', '%s.printer' % key)) + profile.formatter_factory = edbob.load_spec( + config.require('rattail.labels', '%s.formatter' % key)) + profile.format = config.get('rattail.labels', '%s.format' % key) + _profiles[key] = profile + + +def get_profile(name): + """ + Returns the :class:`LabelProfile` instance corresponding to ``name``. + """ + + return _profiles.get(name) + + +def iter_profiles(): + """ + Returns an iterator over the collection of :class:`LabelProfile` instances + which were read and created from config. + """ + + return _profiles.itervalues()