Merge 028777d617 into d8ba1571e7

docs/topics/commands.rst

@@ -645,25 +645,88 @@ Custom project commands
 =======================
 
 You can also add your custom project commands by using the
-:setting:`COMMANDS_MODULE` setting. See the Scrapy commands in
+:setting:`COMMANDS_MODULE` setting. This allows you to create project-specific
-`scrapy/commands`_ for examples on how to implement your commands.
+commands that are automatically discovered and made available through the
+``scrapy`` command-line tool.
 
-.. _scrapy/commands: https://github.com/scrapy/scrapy/tree/master/scrapy/commands
+Creating custom commands
-.. setting:: COMMANDS_MODULE
+------------------------
 
-COMMANDS_MODULE
+To create a custom command, inherit from the :class:`~scrapy.commands.ScrapyCommand` class
----------------
+and implement the required methods. This allows you to extend Scrapy's command-line
+interface with your own functionality, such as project-specific utilities, data
+processing tools, or deployment helpers.
 
-Default: ``''`` (empty string)
+When you create a custom command, you define its behavior by setting class attributes
+and overriding specific methods. Here's what you need to know:
 
-A module to use for looking up custom Scrapy commands. This is used to add custom
+**Attributes you can set:**
-commands for your Scrapy project.
 
-Example:
+* :attr:`~scrapy.commands.ScrapyCommand.requires_project` (bool): If ``True``,
+  the command only runs inside a Scrapy project (default: ``False``).
+* :attr:`~scrapy.commands.ScrapyCommand.requires_crawler_process` (bool): If
+  ``True``, a :class:`~scrapy.crawler.AsyncCrawlerProcess` or
+  :class:`~scrapy.crawler.CrawlerProcess` instance will be created by Scrapy
+  when the command runs and made available in the
+  :attr:`~scrapy.commands.ScrapyCommand.crawler_process` attribute (default:
+  ``True``).
+* :attr:`~scrapy.commands.ScrapyCommand.default_settings` (dict): Settings that
+  will override the default ones when running this command (default: ``{}``).
+* :attr:`~scrapy.commands.ScrapyCommand.exitcode` (int): Process exit code to
+  set when the command completes (default: ``0``).
+
+**Methods you must override:**
+
+* :meth:`~scrapy.commands.ScrapyCommand.short_desc`: Return a short description
+  of the command.
+* :meth:`~scrapy.commands.ScrapyCommand.run`: Main entry point for the command
+  execution.
+
+**Methods you can override:**
+
+* :meth:`~scrapy.commands.ScrapyCommand.syntax`: Return command syntax
+  (preferably one-line, without command name).
+* :meth:`~scrapy.commands.ScrapyCommand.long_desc`: Return a detailed command
+  description.
+* :meth:`~scrapy.commands.ScrapyCommand.add_options`: Add command-specific
+  options to the argument parser.
+* :meth:`~scrapy.commands.ScrapyCommand.process_options`: Process parsed
+  command-line options and set settings before
+  :attr:`~scrapy.commands.ScrapyCommand.crawler_process` is instantiated.
+
+**Example custom command:**
 
 .. code-block:: python
 
-    COMMANDS_MODULE = "mybot.commands"
+    from scrapy.commands import ScrapyCommand
+    import argparse
+
+
+    class MyCustomCommand(ScrapyCommand):
+        requires_project = True
+
+        def syntax(self):
+            return "[options] <spider_name>"
+
+        def short_desc(self):
+            return "Run my custom command"
+
+        def add_options(self, parser):
+            super().add_options(parser)
+            parser.add_argument("--my-option", help="My custom option")
+
+        def run(self, args, opts):
+            # Command implementation here
+            spider_name = args[0] if args else None
+            print(f"Running custom command for spider: {spider_name}")
+
+For real examples, see the built-in Scrapy commands in the `scrapy/commands`_ directory.
+
+.. _scrapy/commands: https://github.com/scrapy/scrapy/tree/master/scrapy/commands
+
+.. autoclass:: scrapy.commands.ScrapyCommand
+   :members:
+   :undoc-members:
 
 .. _Deploying your project: https://scrapyd.readthedocs.io/en/latest/deploy.html
 
@@ -690,3 +753,19 @@ The following example adds ``my_command`` command:
           ],
       },
   )
+
+.. setting:: COMMANDS_MODULE
+
+COMMANDS_MODULE
+---------------
+
+Default: ``''`` (empty string)
+
+A module to use for looking up custom Scrapy commands. This is used to add custom
+commands for your Scrapy project.
+
+Example:
+
+.. code-block:: python
+
+    COMMANDS_MODULE = "mybot.commands"

scrapy/commands/__init__.py

@@ -27,6 +27,8 @@ if TYPE_CHECKING:
 
 
 class ScrapyCommand(ABC):
+    """Base class for all Scrapy commands."""
+
     requires_project: bool = False
     requires_crawler_process: bool = True
     crawler_process: CrawlerProcessBase | None = None  # set in scrapy.cmdline
@@ -58,16 +60,12 @@ class ScrapyCommand(ABC):
         self._crawler: Crawler = crawler
 
     def syntax(self) -> str:
-        """
+        """Command syntax (preferably one-line). Do not include command name."""
-        Command syntax (preferably one-line). Do not include command name.
-        """
         return ""
 
     @abstractmethod
     def short_desc(self) -> str:
-        """
+        """A short description of the command."""
-        A short description of the command
-        """
         return ""
 
     def long_desc(self) -> str:
@@ -86,9 +84,7 @@ class ScrapyCommand(ABC):
         return self.long_desc()
 
     def add_options(self, parser: argparse.ArgumentParser) -> None:
-        """
+        """Populate the option parser with the options available for this command."""
-        Populate option parse with options available for this command
-        """
         assert self.settings is not None
         group = parser.add_argument_group(title="Global Options")
         group.add_argument(
@@ -122,6 +118,7 @@ class ScrapyCommand(ABC):
         group.add_argument("--pdb", action="store_true", help="enable pdb on failure")
 
     def process_options(self, args: list[str], opts: argparse.Namespace) -> None:
+        """Set settings based on the command line options."""
         assert self.settings is not None
         try:
             self.settings.setdict(arglist_to_dict(opts.set), priority="cmdline")
@@ -151,9 +148,7 @@ class ScrapyCommand(ABC):
 
     @abstractmethod
     def run(self, args: list[str], opts: argparse.Namespace) -> None:
-        """
+        """Entry point for running commands."""
-        Entry point for running commands
-        """
         raise NotImplementedError