PyESCPOS 0.2

Support for Epson ESC/POS printer command system.

PyESCPOS
========

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-------

A Python support for Epson |copy| ESC/POS |reg| compatible printers. Read more
at `Epson ESCPOS FAQ`_ (PDF document).

This project is inspired on Manuel F. Martinez work for `python-escpos`_
implementation, among other projects, whose specific bits of work (available
here on Github and many other open-source repositories) has helped so much.

The ESC/POS |reg| is a standard that every manufacturer tend to modify to suit
their (even already implemented) needs. Indeed, there is no standard but
something awkward, an illusion of a standard. On the surface, one can say
that it's pretty much the same, but when you look just a little bit more deeper,
you quickly realize that they are almost completely different, even between
models belonging to the same manufacturer.

This project aims to make viable the use, at the *point-of-sale* (POS), of
different printers (the most common ones, at least) that are minimally based on
ESC/POS |reg| standard, without need to modify the client application code. To
achieve this, it is necessary to set a lowest common denominator between
needed features and provide implementations that seek to meet this minimum.


Current Implementations
=======================

Current implementations was tested against following hardware:

+-------------------------+-------------------+-------------------+-----------------------------------------+
| Manufacturer | Models | Firmware Versions | Notes |
+=========================+===================+===================+=========================================+
| `Bematech S/A`_ | MP-4200 TH | 1.3, 1.6 | |
| | | | |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Epson`_ | TM-T20 | 1.14 | |
| | | | |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Elgin`_ | Elgin i9 | 1.03.20, | |
| | | 1.03.24, | |
| | | 1.03.31 | |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Elgin`_ | Elgin i7 | 1.00.08 | |
| | | | |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Elgin`_ | Elgin RM-22 | 1.00.09 | Elgin RM-22 portable thermal mini |
| | | | printer |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Nitere`_ | NPDV-1020 | - | Multifunction Terminal model TMF-101/IG |
| | | | (an alias for CB55-C model) |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| Unknown OEM | CB55-C | 1.3.5 | Embedded in `Nitere`_ NPDV-1020 (model |
| | | | TMF-101/IG) |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Urmet Daruma`_ | DR700 L/H/M and | 02.51.00, | |
| | DR700 L-e/H-e | 01.20.00, | |
| | | 01.21.00 | |
+-------------------------+-------------------+-------------------+-----------------------------------------+
| `Urmet Daruma`_ | DR800 L/H | 03.13.01 | |
| | | | |
| | | | |
+-------------------------+-------------------+-------------------+-----------------------------------------+

You can get a list of all available implementations with the following snippet:

.. sourcecode:: python

from escpos import helpers

for impl in helpers.find_implementations(sort_by='model.name'):
print('{:.<25} {}'.format(impl.model.name, impl.fqname))

Which produces an output similar to::

Bematech MP-4200 TH...... escpos.impl.bematech.MP4200TH
CB55-C................... escpos.impl.unknown.CB55C
Daruma DR700............. escpos.impl.daruma.DR700
Daruma DR800............. escpos.impl.daruma.DR800
Elgin I7................. escpos.impl.elgin.ElginI7
Elgin I9................. escpos.impl.elgin.ElginI9
Elgin RM-22.............. escpos.impl.elgin.ElginRM22
Epson TM-T20............. escpos.impl.epson.TMT20
Generic Daruma........... escpos.impl.daruma.DarumaGeneric
Generic ESC/POS.......... escpos.impl.epson.GenericESCPOS
Generic Elgin............ escpos.impl.elgin.ElginGeneric
Nitere NPDV-1020......... escpos.impl.nitere.NitereNPDV1020


Usage Examples
==============

Serial RS232 Example
--------------------

Serial communications support requires `PySerial`_ version 2.7 or later.

.. sourcecode:: python

from escpos import SerialConnection
from escpos.impl.epson import GenericESCPOS

# assumes RTS/CTS for 'ttyS5' and infers an instance of RTSCTSConnection
conn = SerialConnection.create('/dev/ttyS5:9600,8,1,N')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')


Network TCP/IP Example
----------------------

You can connect to your printer through network TCP/IP interface.

.. sourcecode:: python

from escpos import NetworkConnection
from escpos.impl.epson import GenericESCPOS

conn = NetworkConnection.create('10.0.0.101:9100')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')


Bluetooth Example
-----------------

You can connect to your printer through a bluetooth interface (only via RFCOMM).
Bluetooth support requires `PyBluez`_ version 0.22.

.. sourcecode:: python

from escpos import BluetoothConnection
from escpos.impl.epson import GenericESCPOS

# uses SPD (service port discovery) services to find which port to connect to
conn = BluetoothConnection.create('00:01:02:03:04:05')
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')

If you know in which port you can connect beforehand, just pass its number after
device address using a forward slash, for example ``00:01:02:03:04:05/4``, will
connect to port ``4`` on ``00:01:02:03:04:05`` address.


File Print Example
------------------

This printer “prints” just into a file-handle. Especially on *nix-systems this
comes very handy. A common use case is when you hava parallel port printer or
any other printer that are directly attached to the filesystem. Note that you
may want to stay away from using USB-to- Parallel-Adapters since they are
extremely unreliable and produce many arbitrary errors.

.. sourcecode:: python

from escpos import FileConnection
from escpos.impl.elgin import ElginI9

conn = FileConnection('/dev/usb/lp1')
printer = ElginI9(conn)
printer.init()
printer.text('Hello World!')
print(printer.device.output)


Dummy Print Example
-------------------

The Dummy-printer is mainly for testing- and debugging-purposes. It stores all
of the “output” as raw ESC/POS in a string and returns that.

.. sourcecode:: python

from escpos import DummyConnection
from escpos.impl.epson import GenericESCPOS

conn = DummyConnection()
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')
print(printer.device.output)


Printing Barcodes
-----------------

There is a default set of parameters for printing barcodes. Each ESC/POS
implementation will take care of the details and try their best to print your
barcode as you asked.

.. sourcecode:: python

from escpos import barcode
from escpos import SerialConnection
from escpos.impl.epson import GenericESCPOS

conn = SerialConnection.create('COM1:9600,8,1,N')
printer = GenericESCPOS(conn)
printer.init()
printer.code128('0123456789',
barcode_height=96, # ~12mm (~1/2")
barcode_width=barcode.BARCODE_DOUBLE_WIDTH,
barcode_hri=barcode.BARCODE_HRI_BOTTOM)

printer.lf()

printer.ean13('4007817525074',
barcode_height=120, # ~15mm (~9/16"),
barcode_width=barcode.BARCODE_NORMAL_WIDTH,
barcode_hri=barcode.BARCODE_HRI_TOP)

printer.cut()

The barcode data should be complete including check digits and any other payload
data required that makes that data valid for the symbology you're dealing with.
Thus, if you need to print an EAN-13 barcode, for example, you need to provide
all thirteen digits.


Configuring Resilient Connections
---------------------------------

Network (TCP/IP) and Bluetooth (RFCOMM) connections provided by PyESCPOS both
use a simple `exponential backoff`_ algorithm to implement a (more) resilient
connection to the device. Your application or your users can configure *backoff*
retry parameters through a well-known INI-like file format:

.. sourcecode:: ini

[retry]
max_tries = 3
delay = 3
factor = 2

Whose parameters are:

* ``max_tries`` (integer ``> 0``) Number of tries before give up;
* ``delay`` (integer ``> 0``) Delay between retries (in seconds);
* ``factor`` (integer ``> 1``) Multiply factor in which delay will be increased
for the next retry.

Normally that file lives in ``~/.escpos/config.cfg`` but you can determine
where you want to put this file. For that you must call ``config.configure``
function indicating full path to the configuration file, for example:

.. sourcecode:: python

from escpos import config
config.configure(filename='/path/to/config.cfg')

Your application must call ``config.configure`` before importing anything else.


More Examples
-------------

Eventually you may find more examples in the `PyESCPOS wiki`_ pages.


Disclaimer
==========

It is important that you read this **disclaimer**.

None of the vendors cited in this project agree or endorse any of the
patterns or implementations. Its names are used only to maintain context.

..
Sphinx Documentation: Substitutions at
http://sphinx-doc.org/rest.html#substitutions
Codes copied from reStructuredText Standard Definition Files at
http://docutils.sourceforge.net/docutils/parsers/rst/include/isonum.txt

.. |copy| unicode:: U+00A9 .. COPYRIGHT SIGN
:ltrim:

.. |reg| unicode:: U+00AE .. REGISTERED SIGN
:ltrim:

.. _`PyESCPOS wiki`: https://github.com/base4sistemas/pyescpos/wiki
.. _`Epson ESCPOS FAQ`: http://content.epson.de/fileadmin/content/files/RSD/downloads/escpos.pdf
.. _`python-escpos`: https://github.com/manpaz/python-escpos
.. _`PySerial`: http://pyserial.sourceforge.net/
.. _`PyBluez`: http://karulis.github.io/pybluez/
.. _`Epson`: http://www.epson.com/
.. _`Elgin`: http://www.elgin.com.br/
.. _`Nitere`: http://www.nitere.com.br/
.. _`Bematech S/A`: http://www.bematechus.com/
.. _`Urmet Daruma`: http://daruma.com.br/
.. _`exponential backoff`: https://en.wikipedia.org/wiki/Exponential_backoff