From: Rob Golding Date: Sun, 14 Apr 2013 20:18:56 +0000 (+0100) Subject: Emulate django's QuerySet API for filtering tasks X-Git-Url: https://git.madduck.net/etc/taskwarrior.git/commitdiff_plain/86e0329a1e477c8bb59eb033cc7a8f821067b426 Emulate django's QuerySet API for filtering tasks --- diff --git a/tasklib/task.py b/tasklib/task.py index a220264..cd4b92f 100644 --- a/tasklib/task.py +++ b/tasklib/task.py @@ -1,3 +1,4 @@ +import copy import json import os import subprocess @@ -5,6 +6,7 @@ import tempfile import uuid +REPR_OUTPUT_SIZE = 10 PENDING = 'pending' @@ -14,6 +16,9 @@ class TaskWarriorException(Exception): class Task(object): + class DoesNotExist(Exception): + pass + def __init__(self, warrior, data={}): self.warrior = warrior self._data = data @@ -46,6 +51,131 @@ class Task(object): __repr__ = __unicode__ +class TaskFilter(object): + """ + A set of parameters to filter the task list with. + """ + + def __init__(self, filter_params=()): + self.filter_params = filter_params + + def add_filter(self, param, value): + self.filter_params += ((param, value),) + + def get_filter_params(self): + return self.filter_params + + def clone(self): + c = self.__class__() + c.filter_params = tuple(self.filter_params) + return c + + +class TaskQuerySet(object): + """ + Represents a lazy lookup for a task objects. + """ + + def __init__(self, warrior=None, filter_obj=None): + self.warrior = warrior + self._result_cache = None + self.filter_obj = filter_obj or TaskFilter() + + def __deepcopy__(self, memo): + """ + Deep copy of a QuerySet doesn't populate the cache + """ + obj = self.__class__() + for k,v in self.__dict__.items(): + if k in ('_iter','_result_cache'): + obj.__dict__[k] = None + else: + obj.__dict__[k] = copy.deepcopy(v, memo) + return obj + + def __repr__(self): + data = list(self[:REPR_OUTPUT_SIZE + 1]) + if len(data) > REPR_OUTPUT_SIZE: + data[-1] = "...(remaining elements truncated)..." + return repr(data) + + def __len__(self): + if self._result_cache is None: + self._result_cache = list(self) + return len(self._result_cache) + + def __iter__(self): + if self._result_cache is None: + self._result_cache = self._execute() + return iter(self._result_cache) + + def __getitem__(self, k): + if self._result_cache is None: + self._result_cache = list(self) + return self._result_cache.__getitem__(k) + + def __bool__(self): + if self._result_cache is not None: + return bool(self._result_cache) + try: + next(iter(self)) + except StopIteration: + return False + return True + + def __nonzero__(self): + return type(self).__bool__(self) + + def _clone(self, klass=None, **kwargs): + if klass is None: + klass = self.__class__ + filter_obj = self.filter_obj.clone() + c = klass(warrior=self.warrior, filter_obj=filter_obj) + c.__dict__.update(kwargs) + return c + + def _execute(self): + """ + Fetch the tasks which match the current filters. + """ + return self.warrior._execute_filter(self.filter_obj) + + def all(self): + """ + Returns a new TaskQuerySet that is a copy of the current one. + """ + return self._clone() + + def pending(self): + return self.filter(status=PENDING) + + def filter(self, **kwargs): + """ + Returns a new TaskQuerySet with the given filters added. + """ + clone = self._clone() + for param, value in kwargs.items(): + clone.filter_obj.add_filter(param, value) + return clone + + def get(self, **kwargs): + """ + Performs the query and returns a single object matching the given + keyword arguments. + """ + clone = self.filter(**kwargs) + num = len(clone) + if num == 1: + return clone._result_cache[0] + if not num: + raise Task.DoesNotExist( + 'Task matching query does not exist. ' + 'Lookup parameters were {0}'.format(kwargs)) + raise ValueError( + 'get() returned more than one Task -- it returned {0}! ' + 'Lookup parameters were {1}'.format(num, kwargs)) + + class TaskWarrior(object): DEFAULT_FILTERS = { 'status': 'pending', @@ -57,6 +187,7 @@ class TaskWarrior(object): self.config = { 'data.location': os.path.expanduser(data_location), } + self.tasks = TaskQuerySet(self) def _generate_command(self, command): args = ['task', 'rc:/'] @@ -65,7 +196,7 @@ class TaskWarrior(object): args.append(command) return ' '.join(args) - def _execute(self, command): + def _execute_command(self, command): p = subprocess.Popen(self._generate_command(command), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE) stdout, stderr = p.communicate() @@ -75,41 +206,33 @@ class TaskWarrior(object): def _format_filter_kwarg(self, kwarg): key, val = kwarg[0], kwarg[1] - if key in ['tag', 'tags']: - key = 'tags.equal' key = key.replace('__', '.') return '{0}:{1}'.format(key, val) - def get_tasks(self, **filter_kwargs): - filters = dict(self.DEFAULT_FILTERS) - filters.update(filter_kwargs) + def _execute_filter(self, filter_obj): filter_commands = ' '.join(map(self._format_filter_kwarg, - filters.items())) + filter_obj.get_filter_params())) command = '{0} export'.format(filter_commands) tasks = [] - for line in self._execute(command): + for line in self._execute_command(command): if line: tasks.append(Task(self, json.loads(line.strip(',')))) return tasks - def get_task(self, task_id): - command = '{0} export'.format(task_id) - return Task(self, json.loads(self._execute(command)[0])) - def add_task(self, description, project=None): args = ['add', description] if project is not None: args.append('project:{0}'.format(project)) - self._execute(' '.join(args)) + self._execute_command(' '.join(args)) def delete_task(self, task_id): - self._execute('{0} rc.confirmation:no delete'.format(task_id)) + self._execute_command('{0} rc.confirmation:no delete'.format(task_id)) def complete_task(self, task_id): - self._execute('{0} done'.format(task_id)) + self._execute_command('{0} done'.format(task_id)) def import_tasks(self, tasks): fd, path = tempfile.mkstemp() with open(path, 'w') as f: f.write(json.dumps(tasks)) - self._execute('import {0}'.format(path)) + self._execute_command('import {0}'.format(path))