/scrapy/tests/test_engine.py

"""
Scrapy engine tests

This starts a testing web server (using twisted.server.Site) and then crawls it
with the Scrapy crawler.

To view the testing web server in a browser you can start it by running this
module with the ``runserver`` argument::

    python test_engine.py runserver
"""

import sys, os, re, urlparse

from twisted.internet import reactor, defer
from twisted.web import server, static, util
from twisted.trial import unittest

from scrapy import signals
from scrapy.utils.test import get_crawler
from scrapy.xlib.pydispatch import dispatcher
from scrapy.tests import tests_datadir
from scrapy.spider import BaseSpider
from scrapy.item import Item, Field
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.http import Request
from scrapy.utils.signal import disconnect_all

class TestItem(Item):
    name = Field()
    url = Field()
    price = Field()

class TestSpider(BaseSpider):
    name = "scrapytest.org"
    allowed_domains = ["scrapytest.org", "localhost"]

    itemurl_re = re.compile("item\d+.html")
    name_re = re.compile("<h1>(.*?)</h1>", re.M)
    price_re = re.compile(">Price: \$(.*?)<", re.M)

    def parse(self, response):
        xlink = SgmlLinkExtractor()
        itemre = re.compile(self.itemurl_re)
        for link in xlink.extract_links(response):
            if itemre.search(link.url):
                yield Request(url=link.url, callback=self.parse_item)

    def parse_item(self, response):
        item = TestItem()
        m = self.name_re.search(response.body)
        if m:
            item['name'] = m.group(1)
        item['url'] = response.url
        m = self.price_re.search(response.body)
        if m:
            item['price'] = m.group(1)
        return item

def start_test_site(debug=False):
    root_dir = os.path.join(tests_datadir, "test_site")
    r = static.File(root_dir)
    r.putChild("redirect", util.Redirect("/redirected"))
    r.putChild("redirected", static.Data("Redirected here", "text/plain"))

    port = reactor.listenTCP(0, server.Site(r), interface="127.0.0.1")
    if debug:
        print "Test server running at http://localhost:%d/ - hit Ctrl-C to finish." \
            % port.getHost().port
    return port


class CrawlerRun(object):
    """A class to run the crawler and keep track of events occurred"""

    def __init__(self):
        self.spider = None
        self.respplug = []
        self.reqplug = []
        self.itemresp = []
        self.signals_catched = {}

    def run(self):
        self.port = start_test_site()
        self.portno = self.port.getHost().port

        start_urls = [self.geturl("/"), self.geturl("/redirect")]
        self.spider = TestSpider(start_urls=start_urls)

        for name, signal in vars(signals).items():
            if not name.startswith('_'):
                dispatcher.connect(self.record_signal, signal)
        dispatcher.connect(self.item_scraped, signals.item_scraped)
        dispatcher.connect(self.request_received, signals.request_received)
        dispatcher.connect(self.response_downloaded, signals.response_downloaded)

        self.crawler = get_crawler()
        self.crawler.install()
        self.crawler.configure()
        self.crawler.crawl(self.spider)
        self.crawler.start()

        self.deferred = defer.Deferred()
        dispatcher.connect(self.stop, signals.engine_stopped)
        return self.deferred

    def stop(self):
        self.port.stopListening()
        for name, signal in vars(signals).items():
            if not name.startswith('_'):
                disconnect_all(signal)
        self.crawler.uninstall()
        self.deferred.callback(None)

    def geturl(self, path):
        return "http://localhost:%s%s" % (self.portno, path)

    def getpath(self, url):
        u = urlparse.urlparse(url)
        return u.path

    def item_scraped(self, item, spider, response):
        self.itemresp.append((item, response))

    def request_received(self, request, spider):
        self.reqplug.append((request, spider))

    def response_downloaded(self, response, spider):
        self.respplug.append((response, spider))

    def record_signal(self, *args, **kwargs):
        """Record a signal and its parameters"""
        signalargs = kwargs.copy()
        sig = signalargs.pop('signal')
        signalargs.pop('sender', None)
        self.signals_catched[sig] = signalargs


class EngineTest(unittest.TestCase):

    @defer.inlineCallbacks
    def test_crawler(self):
        self.run = CrawlerRun()
        yield self.run.run()
        self._assert_visited_urls()
        self._assert_received_requests()
        self._assert_downloaded_responses()
        self._assert_scraped_items()
        self._assert_signals_catched()

    def _assert_visited_urls(self):
        must_be_visited = ["/", "/redirect", "/redirected", 
                           "/item1.html", "/item2.html", "/item999.html"]
        urls_visited = set([rp[0].url for rp in self.run.respplug])
        urls_expected = set([self.run.geturl(p) for p in must_be_visited])
        assert urls_expected <= urls_visited, "URLs not visited: %s" % list(urls_expected - urls_visited)

    def _assert_received_requests(self):
        # 3 requests should be received from the spider. start_urls and redirects don't count
        self.assertEqual(3, len(self.run.reqplug))

        paths_expected = ['/item999.html', '/item2.html', '/item1.html']

        urls_requested = set([rq[0].url for rq in self.run.reqplug])
        urls_expected = set([self.run.geturl(p) for p in paths_expected])
        assert urls_expected <= urls_requested

    def _assert_downloaded_responses(self):
        # response tests
        self.assertEqual(6, len(self.run.respplug))

        for response, _ in self.run.respplug:
            if self.run.getpath(response.url) == '/item999.html':
                self.assertEqual(404, response.status)
            if self.run.getpath(response.url) == '/redirect':
                self.assertEqual(302, response.status)

    def _assert_scraped_items(self):
        self.assertEqual(2, len(self.run.itemresp))
        for item, response in self.run.itemresp:
            self.assertEqual(item['url'], response.url)
            if 'item1.html' in item['url']:
                self.assertEqual('Item 1 name', item['name'])
                self.assertEqual('100', item['price'])
            if 'item2.html' in item['url']:
                self.assertEqual('Item 2 name', item['name'])
                self.assertEqual('200', item['price'])

    def _assert_signals_catched(self):
        assert signals.engine_started in self.run.signals_catched
        assert signals.engine_stopped in self.run.signals_catched
        assert signals.spider_opened in self.run.signals_catched
        assert signals.spider_idle in self.run.signals_catched
        assert signals.spider_closed in self.run.signals_catched

        self.assertEqual({'spider': self.run.spider},
                         self.run.signals_catched[signals.spider_opened])
        self.assertEqual({'spider': self.run.spider},
                         self.run.signals_catched[signals.spider_idle])
        self.assertEqual({'spider': self.run.spider, 'reason': 'finished'},
                         self.run.signals_catched[signals.spider_closed])


if __name__ == "__main__":
    if len(sys.argv) > 1 and sys.argv[1] == 'runserver':
        start_test_site(debug=True)
        reactor.run()