mylar/lib/rtorrent/rpc/__init__.py

# Copyright (c) 2013 Chris Lucas, <chris@chrisjlucas.com>
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import inspect
import lib.rtorrent
import re
from lib.rtorrent.common import bool_to_int, convert_version_tuple_to_str,\
    safe_repr
from lib.rtorrent.err import MethodError
from lib.rtorrent.compat import xmlrpclib


def get_varname(rpc_call):
    """Transform rpc method into variable name.

    @newfield example: Example
    @example: if the name of the rpc method is 'p.get_down_rate', the variable
    name will be 'down_rate'
    """
    # extract variable name from xmlrpc func name
    r = re.search(
        "([ptdf]\.|system\.|get\_|is\_|set\_)+([^=]*)", rpc_call, re.I)
    if r:
        return(r.groups()[-1])
    else:
        return(None)


def _handle_unavailable_rpc_method(method, rt_obj):
    msg = "Method isn't available."
    if rt_obj._get_client_version_tuple() < method.min_version:
        msg = "This method is only available in " \
            "RTorrent version v{0} or later".format(
            convert_version_tuple_to_str(method.min_version))

    raise MethodError(msg)


class DummyClass:
    def __init__(self):
        pass


class Method:
    """Represents an individual RPC method"""

    def __init__(self, _class, method_name,
                 rpc_call, docstring=None, varname=None, **kwargs):
        self._class = _class  # : Class this method is associated with
        self.class_name = _class.__name__
        self.method_name = method_name  # : name of public-facing method
        self.rpc_call = rpc_call  # : name of rpc method
        self.docstring = docstring  # : docstring for rpc method (optional)
        self.varname = varname  # : variable for the result of the method call, usually set to self.varname
        self.min_version = kwargs.get("min_version", (
            0, 0, 0))  # : Minimum version of rTorrent required
        self.boolean = kwargs.get("boolean", False)  # : returns boolean value?
        self.post_process_func = kwargs.get(
            "post_process_func", None)  # : custom post process function
        self.aliases = kwargs.get(
            "aliases", [])  # : aliases for method (optional)
        self.required_args = []
            #: Arguments required when calling the method (not utilized)

        self.method_type = self._get_method_type()

        if self.varname is None:
            self.varname = get_varname(self.rpc_call)
        assert self.varname is not None, "Couldn't get variable name."

    def __repr__(self):
        return safe_repr("Method(method_name='{0}', rpc_call='{1}')",
                        self.method_name, self.rpc_call)

    def _get_method_type(self):
        """Determine whether method is a modifier or a retriever"""
        if self.method_name[:4] == "set_": return('m')  # modifier
        else:
            return('r')  # retriever

    def is_modifier(self):
        if self.method_type == 'm':
            return(True)
        else:
            return(False)

    def is_retriever(self):
        if self.method_type == 'r':
            return(True)
        else:
            return(False)

    def is_available(self, rt_obj):
        if rt_obj._get_client_version_tuple() < self.min_version or \
                self.rpc_call not in rt_obj._get_rpc_methods():
            return(False)
        else:
            return(True)


class Multicall:
    def __init__(self, class_obj, **kwargs):
        self.class_obj = class_obj
        if class_obj.__class__.__name__ == "RTorrent":
            self.rt_obj = class_obj
        else:
            self.rt_obj = class_obj._rt_obj
        self.calls = []

    def add(self, method, *args):
        """Add call to multicall

        @param method: L{Method} instance or name of raw RPC method
        @type method: Method or str

        @param args: call arguments
        """
        # if a raw rpc method was given instead of a Method instance,
        # try and find the instance for it. And if all else fails, create a
        # dummy Method instance
        if isinstance(method, str):
            result = find_method(method)
            # if result not found
            if result == -1:
                method = Method(DummyClass, method, method)
            else:
                method = result

        # ensure method is available before adding
        if not method.is_available(self.rt_obj):
            _handle_unavailable_rpc_method(method, self.rt_obj)

        self.calls.append((method, args))

    def list_calls(self):
        for c in self.calls:
            print(c)

    def call(self):
        """Execute added multicall calls

        @return: the results (post-processed), in the order they were added
        @rtype: tuple
        """
        m = xmlrpclib.MultiCall(self.rt_obj._get_conn())
        for call in self.calls:
            method, args = call
            rpc_call = getattr(method, "rpc_call")
            getattr(m, rpc_call)(*args)

        results = m()
        results = tuple(results)
        results_processed = []

        for r, c in zip(results, self.calls):
            method = c[0]  # Method instance
            result = process_result(method, r)
            results_processed.append(result)
            # assign result to class_obj
            exists = hasattr(self.class_obj, method.varname)
            if not exists or not inspect.ismethod(getattr(self.class_obj, method.varname)):
                setattr(self.class_obj, method.varname, result)

        return(tuple(results_processed))


def call_method(class_obj, method, *args):
    """Handles single RPC calls

    @param class_obj: Peer/File/Torrent/Tracker/RTorrent instance
    @type class_obj: object

    @param method: L{Method} instance or name of raw RPC method
    @type method: Method or str
    """
    if method.is_retriever():
        args = args[:-1]
    else:
        assert args[-1] is not None, "No argument given."

    if class_obj.__class__.__name__ == "RTorrent":
        rt_obj = class_obj
    else:
        rt_obj = class_obj._rt_obj

    # check if rpc method is even available
    if not method.is_available(rt_obj):
        _handle_unavailable_rpc_method(method, rt_obj)

    m = Multicall(class_obj)
    m.add(method, *args)
    # only added one method, only getting one result back
    ret_value = m.call()[0]

    ####### OBSOLETE ##########################################################
    # if method.is_retriever():
    #    #value = process_result(method, ret_value)
    #    value = ret_value #MultiCall already processed the result
    # else:
    #    # we're setting the user's input to method.varname
    #    # but we'll return the value that xmlrpc gives us
    #    value = process_result(method, args[-1])
    ##########################################################################

    return(ret_value)


def find_method(rpc_call):
    """Return L{Method} instance associated with given RPC call"""
    method_lists = [
        lib.rtorrent.methods,
        lib.rtorrent.file.methods,
        lib.rtorrent.tracker.methods,
        lib.rtorrent.peer.methods,
        lib.rtorrent.torrent.methods,
    ]

    for l in method_lists:
        for m in l:
            if m.rpc_call.lower() == rpc_call.lower():
                return(m)

    return(-1)


def process_result(method, result):
    """Process given C{B{result}} based on flags set in C{B{method}}

    @param method: L{Method} instance
    @type method: Method

    @param result: result to be processed (the result of given L{Method} instance)

    @note: Supported Processing:
        - boolean - convert ones and zeros returned by rTorrent and
        convert to python boolean values
    """
    # handle custom post processing function
    if method.post_process_func is not None:
        result = method.post_process_func(result)

    # is boolean?
    if method.boolean:
        if result in [1, '1']:
            result = True
        elif result in [0, '0']:
            result = False

    return(result)


def _build_rpc_methods(class_, method_list):
    """Build glorified aliases to raw RPC methods"""
    instance = None
    if not inspect.isclass(class_):
        instance = class_
        class_ = instance.__class__

    for m in method_list:
        class_name = m.class_name
        if class_name != class_.__name__:
            continue

        if class_name == "RTorrent":
            caller = lambda self, arg = None, method = m:\
                call_method(self, method, bool_to_int(arg))
        elif class_name == "Torrent":
            caller = lambda self, arg = None, method = m:\
                call_method(self, method, self.rpc_id,
                            bool_to_int(arg))
        elif class_name in ["Tracker", "File"]:
            caller = lambda self, arg = None, method = m:\
                call_method(self, method, self.rpc_id,
                            bool_to_int(arg))

        elif class_name == "Peer":
            caller = lambda self, arg = None, method = m:\
                call_method(self, method, self.rpc_id,
                            bool_to_int(arg))

        elif class_name == "Group":
            caller = lambda arg = None, method = m: \
                call_method(instance, method, bool_to_int(arg))

        if m.docstring is None:
            m.docstring = ""

        # print(m)
        docstring = """{0}

        @note: Variable where the result for this method is stored: {1}.{2}""".format(
            m.docstring,
            class_name,
            m.varname)

        caller.__doc__ = docstring

        for method_name in [m.method_name] + list(m.aliases):
            if instance is None:
                setattr(class_, method_name, caller)
            else:
                setattr(instance, method_name, caller)