the-screenless-office/screenless/bureau/bureau.py

# bureau
import configparser
import functools
import json
import os.path
import subprocess
import tempfile
import threading
import time

import zmq
from mako.template import Template


def update_commands(cls):
    """ this is some internal magic to keep track of our commands """
    for name, method in cls.__dict__.items():
        print("name %s method %s" % (name, method))
        if hasattr(method, "command"):
            comstr = method.command
            cls.commands[comstr] = method
    return cls


def add_command(comstr, name=""):
    """ decorator for making a method into a command """
    def decorator(func):
        """ the decorator itself """
        @functools.wraps(func)
        def func_wrap(*args, **kwargs):
            """ this is to avoid roaching the namespace """
            return func(*args, **kwargs)
        func_wrap.command = comstr
        func_wrap.name = name
        return func_wrap
    return decorator


def add_api(apistr, name=""):
    """ decorator for making a method into a public bureau api method"""
    def decorator(func):
        """ the decorator itself """
        @functools.wraps(func)
        def func_wrap(*args, **kwargs):
            """ this is to avoid roaching the namespace """
            return func(*args, **kwargs)
        func_wrap.api = apistr
        func_wrap.name = name
        return func_wrap
    return decorator


class Bureau(object):
    """ Bureau is a base class that implements standard methods for
        inter-bureau communication, IO, registration and some convenient stuff
        for printing. """
    name = "TEST"
    prefix = "00"
    version = 0

    default_config = {"smallprinter": "/dev/usb/lp0"}

    def __init__(self):
        """ set up ZeroMQ connections and register commands"""
        self.commands = {}
        self.api = {}

        basepath = os.path.expanduser("~/.screenless")
        if not os.path.exists(basepath):
            os.mkdir(basepath)
        os.chdir(basepath)

        self.config = configparser.ConfigParser()
        self.load_config()

        self.context = zmq.Context()
        self._recv = self.context.socket(zmq.REP)
        self._recv.bind("ipc://" + self.prefix + ".ipc")
        print(("bureau " + self.name + " waiting for messages"))
        print("commands: ")
        print(self.commands)

    def load_config(self):
        """
        load (or reload) config data from file
        """
        cfgfile = self.prefix + ".ini"
        if os.path.exists(cfgfile):
            self.config.read(cfgfile)
        else:
            self.config["DEFAULT"] = self.default_config
            self.config["bureau"] = self.default_config
            with open(cfgfile, "w") as configfile:
                self.config.write(configfile)

    def send(self, recipient, message, data=None):
        """
        send commands or API calls to another bureau.
            recipient: the 2-character bureau ID
            message: a text based message as used in many commands
            data: an optional dict, used in API calls

            returns either empty string, text or a json object
        """
        message += "."
        if data:
            message += json.dumps(data)
        sender = self.context.socket(zmq.REQ)
        sender.connect("ipc://" + recipient + ".ipc")
        sender.send_string(message)
        # TODO: retry this a few times with a proper sleep/timeout
        time.sleep(0.5)
        try:
            ret = json.loads(sender.recv(flags=zmq.NOBLOCK))
            # TODO: deal with non-json replies
        except zmq.ZMQError:
            print("message sent but got no reply...")
            ret = None
        return ret

    def _publish_methods(self):
        """
        this internal method registers all public commands and bureau API
        methods.  Inhuman Resources module can then display menus and docs.
        """
        # register bureau with Inhuman Resources
        bureau_detail = {"name": self.name, "prefix": self.prefix,
                         "desc": self.__doc__}
        self.send("IR", "addbureau", bureau_detail)

        # find and store all published methods
        for member in dir(self):
            method = getattr(self, member)
            # ignore anything that is not a method with command or api details
            if not (callable(method) and (hasattr(method, "command") or
                                          hasattr(method, "api"))):
                continue
            if hasattr(method, "command"):
                self.commands[method.command] = method
                cmd_detail = {"cmdname": method.name,
                              "prefix": self.prefix,
                              "cmd": method.command,
                              "desc": method.__doc__}
                self.send("IR", "addcommand", cmd_detail)
            elif hasattr(method, "api"):
                self.api[method.api] = method
                api_detail = {"apiname": method.name,
                              "prefix": self.prefix,
                              "api": method.api,
                              "desc": method.__doc__}
                self.send("IR", "addapi", api_detail)

        print("registered:")
        print(self.commands)
        print(self.api)

    def print_full(self, template, **kwargs):
        """print a full page (A4) document """
        # TODO: look up the printer LPR name

        lpname = kwargs.get("printer", "default")
        templ = Template(filename=template)

        texfile, texfilepath = tempfile.mkstemp(".tex")
        texfile.write(templ.render_unicode(
            **kwargs).encode('utf-8', 'replace'))

        texdir = os.path.dirname(texfilepath)

        subprocess.call("cd " + texdir + "; xelatex " + texfilepath)

        pdffile = texfilepath[0:-4] + ".pdf"

        subprocess.call("lpr -P " + lpname + " " + pdffile)

    def print_small(self, text, printer="/dev/usb/lp1"):
        """
        print on Thermal Line printer.
        """
        lp = open(printer, "w")
        text += "\r\n" * 10
        text += ".d0"
        lp.write(text)
        lp.close()

    @add_command("test")
    def test(self, data):
        """
        Standard test command.
        """
        # stupid test to see if modules work
        print(("hi! testing. " + self.name + " bureau seems to work!"))
        return b"seems to work."

    def run_io(self):
        """process hardware or timed input

        This method can be ignored for most Bureaus.
        It should be overloaded for any services that need to independently
        generate messages as this is just a placeholder.
        It is run in a separate thread and should handle any input or
        timed events.  Messages are then sent to other Bureaus via the
        self.send connection to the OfficeManager.  Don't forget to
        to consier thread safety issues when accessing data!
        """
        pass

    def run(self):
        """
        main loop for processing messages

        This runs all relelvant event processing loops.
        """

        # start the hardware input handler
        io_handler = threading.Thread(target=self.run_io)
        io_handler.start()

        # register commands and api methods
        self._publish_methods()

        while True:
            try:
                msg = self._recv.recv_string(flags=zmq.NOBLOCK)
            except zmq.ZMQError:
                time.sleep(0.05)  # don't waste CPU
                continue
            try:
                dot = msg.find(".")
                ref = msg[:dot]
                if (dot < len(msg) - 1) and (dot > 0):
                    data = msg[dot + 1:]
                else:
                    data = None
                print("data: " + str(data))
            except IndexError as err:
                print("invalid message: ", err)
                continue
            print(("got method: " + ref))

            if (ref in self.commands) or (ref in self.api):
                # catch TypeErrors for case of bogus params
                try:
                    if ref in self.api:
                        data = json.loads(data)
                        ret = self.api[ref](data)
                    else:
                        ret = self.commands[ref](data)
                    if ret is None:
                        ret = ""
                    ret = b"0" + ret
                    self._recv.send(ret)
                except TypeError as err:
                    print(err)
                    print("invalid data for command '{}': {}".format(ref, data))
                    self._recv.send_unicode("Error.  Invalid or missing data.")
                except KeyError as err:
                    print(err)
                    print("You are calling a command as an API or vice-versa.")
                    self._recv.send_unicode(
                        "Error. Command called as API or API as command.")
            else:
                print("error! Command/API %s not found", ref)
                self._recv.send_unicode("Error! Command/API not found.")


if __name__ == "__main__":
    buro = Bureau()
    buro.run()