.. _topics-webconsole: =========== Web Console =========== Scrapy comes with a built-in web server for monitoring and controlling a Scrapy running process. The web console is :ref:`built-in Scrapy extension ` which comes enabled by default, but you can also disable it if you're running tight on memory. For more information about this extension see :ref:`ref-extensions-webconsole`. Writing a web console extension =============================== Writing a web console extension is similar to writing any other :ref:`Scrapy extensions ` except that the extension class must: 1. catch the ``scrapy.management.web.webconsole_discover_module`` signal, and return itself in the handler. 2. have the following two attributes: .. attribute:: webconsole_id The id by which the Scrapy web interface will known this extension, and also the main dir under which this extension interface will work. For example, assuming Scrapy web server is listening on http://localhost:8000/ and the ``webconsole_id='extension1'`` the web main page for the interface of that extension will be: http://localhost:8000/extension1/ .. attribute:: webconsole_name The name by which the Scrapy web server will know that extension. That name will be displayed in the main web console index, as the text that links to the extension main page. 3. implement the following method: .. method:: webconsole_render(wc_request) ``wc_request`` is a `twisted.web.http.Request`_ object with the HTTP request sent to the web console. .. _twisted.web.http.Request: http://python.net/crew/mwh/apidocs/twisted.web.http.Request.html It must return a str with the web page to render, typically containing HTML code. Example web console extension ============================= Here's an example of a simple web console extension that just displays a "Hello world!" text:: from scrapy.xlib.pydispatch import dispatcher from scrapy.management.web import webconsole_discover_module class HelloWorldConsole(object): webconsole_id = 'helloworld' webconsole_name = 'Hello world' def __init__(self): dispatcher.connect(self.webconsole_discover_module, signal=webconsole_discover_module) def webconsole_discover_module(self): return self def webconsole_render(self, wc_request): return "

Hello world!

" If you start Scrapy with the web console enabled on http://localhost:8000/ and you access the URL: http://localhost:8000/helloworld/ You will see a page containing a big "Hello World!" text.