Use configurable import paths for todo models

README.md

@@ -290,6 +290,32 @@ LOGGING = {
 ```
 
 
+## Custom models
+
+It's possible to use your own models with the `DJANGO_TODO_MODELS` setting:
+
+```python
+DJANGO_TODO_MODELS = {
+    "Task": "my_app.models.MyTask",  # defaults to "todo.models.Task"
+    "TaskList": "my_app.models.MyTaskList",  # defaults to "todo.models.TaskList"
+    "Comment": "my_app.models.MyComment",  # defaults to "todo.models.Comment"
+    "Attachment": "my_app.models.MyAttachment",  # defaults to "todo.models.Attachment"
+}
+```
+
+When you define your own model by deriving from a model in django-todo,
+import from `todo.default_models` and not from `todo.models` otherwise you will get
+an error about having a circular import:
+
+
+```python
+from todo.default_models import Task
+
+class MyTask(Task):
+    pass
+```
+
+
 ## Running Tests
 
 django-todo uses pytest exclusively for testing. The best way to run the suite is to clone django-todo into its own directory, install pytest, then:

todo/default_models.py

@@ -0,0 +1,150 @@
+from __future__ import unicode_literals
+
+import datetime
+import os
+import textwrap
+
+from django.conf import settings
+from django.contrib.auth.models import Group
+from django.db import models
+from django.urls import reverse
+from django.utils import timezone
+
+
+def get_attachment_upload_dir(instance, filename):
+    """Determine upload dir for task attachment files.
+    """
+
+    return "/".join(["tasks", "attachments", str(instance.task.id), filename])
+
+
+class TaskList(models.Model):
+    name = models.CharField(max_length=60)
+    slug = models.SlugField(default="")
+    group = models.ForeignKey(Group, on_delete=models.CASCADE)
+
+    def __str__(self):
+        return self.name
+
+    class Meta:
+        ordering = ["name"]
+        verbose_name_plural = "Task Lists"
+
+        # Prevents (at the database level) creation of two lists with the same slug in the same group
+        unique_together = ("group", "slug")
+
+
+class Task(models.Model):
+    title = models.CharField(max_length=140)
+    task_list = models.ForeignKey(TaskList, on_delete=models.CASCADE, null=True)
+    created_date = models.DateField(default=timezone.now, blank=True, null=True)
+    due_date = models.DateField(blank=True, null=True)
+    completed = models.BooleanField(default=False)
+    completed_date = models.DateField(blank=True, null=True)
+    created_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        related_name="todo_created_by",
+        on_delete=models.CASCADE,
+    )
+    assigned_to = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        blank=True,
+        null=True,
+        related_name="todo_assigned_to",
+        on_delete=models.CASCADE,
+    )
+    note = models.TextField(blank=True, null=True)
+    priority = models.PositiveIntegerField(blank=True, null=True)
+
+    # Has due date for an instance of this object passed?
+    def overdue_status(self):
+        "Returns whether the Tasks's due date has passed or not."
+        if self.due_date and datetime.date.today() > self.due_date:
+            return True
+
+    def __str__(self):
+        return self.title
+
+    def get_absolute_url(self):
+        return reverse("todo:task_detail", kwargs={"task_id": self.id})
+
+    # Auto-set the Task creation / completed date
+    def save(self, **kwargs):
+        if self.completed:
+            self.completed_date = datetime.datetime.now()
+        super(Task, self).save()
+
+    def merge_into(self, merge_target):
+        if merge_target.pk == self.pk:
+            raise ValueError("can't merge a task with self")
+
+        # lock the comments to avoid concurrent additions of comments after the
+        # update request. these comments would be irremediably lost because of
+        # the cascade clause
+        with LockedAtomicTransaction(Comment):
+            Comment.objects.filter(task=self).update(task=merge_target)
+            self.delete()
+
+    class Meta:
+        ordering = ["priority", "created_date"]
+
+
+class Comment(models.Model):
+    """
+    Not using Django's built-in comments because we want to be able to save
+    a comment and change task details at the same time. Rolling our own since it's easy.
+    """
+
+    author = models.ForeignKey(
+        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, blank=True, null=True
+    )
+    task = models.ForeignKey(Task, on_delete=models.CASCADE)
+    date = models.DateTimeField(default=datetime.datetime.now)
+    email_from = models.CharField(max_length=320, blank=True, null=True)
+    email_message_id = models.CharField(max_length=255, blank=True, null=True)
+
+    body = models.TextField(blank=True)
+
+    class Meta:
+        # an email should only appear once per task
+        unique_together = ("task", "email_message_id")
+
+    @property
+    def author_text(self):
+        if self.author is not None:
+            return str(self.author)
+
+        assert self.email_message_id is not None
+        return str(self.email_from)
+
+    @property
+    def snippet(self):
+        body_snippet = textwrap.shorten(self.body, width=35, placeholder="...")
+        # Define here rather than in __str__ so we can use it in the admin list_display
+        return "{author} - {snippet}...".format(author=self.author_text, snippet=body_snippet)
+
+    def __str__(self):
+        return self.snippet
+
+
+class Attachment(models.Model):
+    """
+    Defines a generic file attachment for use in M2M relation with Task.
+    """
+
+    task = models.ForeignKey(Task, on_delete=models.CASCADE)
+    added_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
+    timestamp = models.DateTimeField(default=datetime.datetime.now)
+    file = models.FileField(upload_to=get_attachment_upload_dir, max_length=255)
+
+    def filename(self):
+        return os.path.basename(self.file.name)
+
+    def extension(self):
+        name, extension = os.path.splitext(self.file.name)
+        return extension
+
+    def __str__(self):
+        return f"{self.task.id} - {self.file.name}"

todo/models.py

@@ -1,22 +1,9 @@
-from __future__ import unicode_literals
+import importlib
-
-import datetime
-import os
-import textwrap
 
 from django.conf import settings
-from django.contrib.auth.models import Group
+from django.db import DEFAULT_DB_ALIAS
-from django.db import DEFAULT_DB_ALIAS, models
 from django.db.transaction import Atomic, get_connection
-from django.urls import reverse
+from todo.default_models import get_attachment_upload_dir  # noqa
-from django.utils import timezone
-
-
-def get_attachment_upload_dir(instance, filename):
-    """Determine upload dir for task attachment files.
-    """
-
-    return "/".join(["tasks", "attachments", str(instance.task.id), filename])
 
 
 class LockedAtomicTransaction(Atomic):
@@ -52,134 +39,14 @@ class LockedAtomicTransaction(Atomic):
                     cursor.close()
 
 
-class TaskList(models.Model):
+def import_model(model_name):
-    name = models.CharField(max_length=60)
+    module_map = getattr(settings, "DJANGO_TODO_MODELS", {})
-    slug = models.SlugField(default="")
+    module, klass = module_map.get(model_name, "todo.default_models.%s" % model_name).rsplit(
-    group = models.ForeignKey(Group, on_delete=models.CASCADE)
+        ".", 1
-
-    def __str__(self):
-        return self.name
-
-    class Meta:
-        ordering = ["name"]
-        verbose_name_plural = "Task Lists"
-
-        # Prevents (at the database level) creation of two lists with the same slug in the same group
-        unique_together = ("group", "slug")
-
-
-class Task(models.Model):
-    title = models.CharField(max_length=140)
-    task_list = models.ForeignKey(TaskList, on_delete=models.CASCADE, null=True)
-    created_date = models.DateField(default=timezone.now, blank=True, null=True)
-    due_date = models.DateField(blank=True, null=True)
-    completed = models.BooleanField(default=False)
-    completed_date = models.DateField(blank=True, null=True)
-    created_by = models.ForeignKey(
-        settings.AUTH_USER_MODEL,
-        null=True,
-        blank=True,
-        related_name="todo_created_by",
-        on_delete=models.CASCADE,
     )
-    assigned_to = models.ForeignKey(
+    return getattr(importlib.import_module(module), klass)
-        settings.AUTH_USER_MODEL,
-        blank=True,
-        null=True,
-        related_name="todo_assigned_to",
-        on_delete=models.CASCADE,
-    )
-    note = models.TextField(blank=True, null=True)
-    priority = models.PositiveIntegerField(blank=True, null=True)
 
-    # Has due date for an instance of this object passed?
+TaskList = import_model("TaskList")
-    def overdue_status(self):
+Task = import_model("Task")
-        "Returns whether the Tasks's due date has passed or not."
+Comment = import_model("Comment")
-        if self.due_date and datetime.date.today() > self.due_date:
+Attachment = import_model("Attachment")
-            return True
-
-    def __str__(self):
-        return self.title
-
-    def get_absolute_url(self):
-        return reverse("todo:task_detail", kwargs={"task_id": self.id})
-
-    # Auto-set the Task creation / completed date
-    def save(self, **kwargs):
-        # If Task is being marked complete, set the completed_date
-        if self.completed:
-            self.completed_date = datetime.datetime.now()
-        super(Task, self).save()
-
-    def merge_into(self, merge_target):
-        if merge_target.pk == self.pk:
-            raise ValueError("can't merge a task with self")
-
-        # lock the comments to avoid concurrent additions of comments after the
-        # update request. these comments would be irremediably lost because of
-        # the cascade clause
-        with LockedAtomicTransaction(Comment):
-            Comment.objects.filter(task=self).update(task=merge_target)
-            self.delete()
-
-    class Meta:
-        ordering = ["priority", "created_date"]
-
-
-class Comment(models.Model):
-    """
-    Not using Django's built-in comments because we want to be able to save
-    a comment and change task details at the same time. Rolling our own since it's easy.
-    """
-
-    author = models.ForeignKey(
-        settings.AUTH_USER_MODEL, on_delete=models.CASCADE, blank=True, null=True
-    )
-    task = models.ForeignKey(Task, on_delete=models.CASCADE)
-    date = models.DateTimeField(default=datetime.datetime.now)
-    email_from = models.CharField(max_length=320, blank=True, null=True)
-    email_message_id = models.CharField(max_length=255, blank=True, null=True)
-
-    body = models.TextField(blank=True)
-
-    class Meta:
-        # an email should only appear once per task
-        unique_together = ("task", "email_message_id")
-
-    @property
-    def author_text(self):
-        if self.author is not None:
-            return str(self.author)
-
-        assert self.email_message_id is not None
-        return str(self.email_from)
-
-    @property
-    def snippet(self):
-        body_snippet = textwrap.shorten(self.body, width=35, placeholder="...")
-        # Define here rather than in __str__ so we can use it in the admin list_display
-        return "{author} - {snippet}...".format(author=self.author_text, snippet=body_snippet)
-
-    def __str__(self):
-        return self.snippet
-
-
-class Attachment(models.Model):
-    """
-    Defines a generic file attachment for use in M2M relation with Task.
-    """
-
-    task = models.ForeignKey(Task, on_delete=models.CASCADE)
-    added_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
-    timestamp = models.DateTimeField(default=datetime.datetime.now)
-    file = models.FileField(upload_to=get_attachment_upload_dir, max_length=255)
-
-    def filename(self):
-        return os.path.basename(self.file.name)
-
-    def extension(self):
-        name, extension = os.path.splitext(self.file.name)
-        return extension
-
-    def __str__(self):
-        return f"{self.task.id} - {self.file.name}"