scrapy/tests/spiders.py

"""
Some spiders used for testing and benchmarking
"""
import asyncio
import time
from urllib.parse import urlencode

from twisted.internet import defer

from scrapy.http import Request
from scrapy.item import Item
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import Spider
from scrapy.spiders.crawl import CrawlSpider, Rule
from scrapy.utils.test import get_from_asyncio_queue


class MockServerSpider(Spider):
    def __init__(self, mockserver=None, *args, **kwargs):
        super(MockServerSpider, self).__init__(*args, **kwargs)
        self.mockserver = mockserver


class MetaSpider(MockServerSpider):

    name = 'meta'

    def __init__(self, *args, **kwargs):
        super(MetaSpider, self).__init__(*args, **kwargs)
        self.meta = {}

    def closed(self, reason):
        self.meta['close_reason'] = reason


class FollowAllSpider(MetaSpider):

    name = 'follow'
    link_extractor = LinkExtractor()

    def __init__(self, total=10, show=20, order="rand", maxlatency=0.0, *args, **kwargs):
        super(FollowAllSpider, self).__init__(*args, **kwargs)
        self.urls_visited = []
        self.times = []
        qargs = {'total': total, 'show': show, 'order': order, 'maxlatency': maxlatency}
        url = self.mockserver.url("/follow?%s" % urlencode(qargs, doseq=1))
        self.start_urls = [url]

    def parse(self, response):
        self.urls_visited.append(response.url)
        self.times.append(time.time())
        for link in self.link_extractor.extract_links(response):
            yield Request(link.url, callback=self.parse)


class DelaySpider(MetaSpider):

    name = 'delay'

    def __init__(self, n=1, b=0, *args, **kwargs):
        super(DelaySpider, self).__init__(*args, **kwargs)
        self.n = n
        self.b = b
        self.t1 = self.t2 = self.t2_err = 0

    def start_requests(self):
        self.t1 = time.time()
        url = self.mockserver.url("/delay?n=%s&b=%s" % (self.n, self.b))
        yield Request(url, callback=self.parse, errback=self.errback)

    def parse(self, response):
        self.t2 = time.time()

    def errback(self, failure):
        self.t2_err = time.time()


class SimpleSpider(MetaSpider):

    name = 'simple'

    def __init__(self, url="http://localhost:8998", *args, **kwargs):
        super(SimpleSpider, self).__init__(*args, **kwargs)
        self.start_urls = [url]

    def parse(self, response):
        self.logger.info("Got response %d" % response.status)


class AsyncDefSpider(SimpleSpider):

    name = 'asyncdef'

    async def parse(self, response):
        await defer.succeed(42)
        self.logger.info("Got response %d" % response.status)


class AsyncDefAsyncioSpider(SimpleSpider):

    name = 'asyncdef_asyncio'

    async def parse(self, response):
        await asyncio.sleep(0.2)
        status = await get_from_asyncio_queue(response.status)
        self.logger.info("Got response %d" % status)


class AsyncDefAsyncioReturnSpider(SimpleSpider):

    name = 'asyncdef_asyncio_return'

    async def parse(self, response):
        await asyncio.sleep(0.2)
        status = await get_from_asyncio_queue(response.status)
        self.logger.info("Got response %d" % status)
        return [{'id': 1}, {'id': 2}]


class ItemSpider(FollowAllSpider):

    name = 'item'

    def parse(self, response):
        for request in super(ItemSpider, self).parse(response):
            yield request
            yield Item()
            yield {}


class DefaultError(Exception):
    pass


class ErrorSpider(FollowAllSpider):

    name = 'error'
    exception_cls = DefaultError

    def raise_exception(self):
        raise self.exception_cls('Expected exception')

    def parse(self, response):
        for request in super(ErrorSpider, self).parse(response):
            yield request
            self.raise_exception()


class BrokenStartRequestsSpider(FollowAllSpider):

    fail_before_yield = False
    fail_yielding = False

    def __init__(self, *a, **kw):
        super(BrokenStartRequestsSpider, self).__init__(*a, **kw)
        self.seedsseen = []

    def start_requests(self):
        if self.fail_before_yield:
            1 / 0

        for s in range(100):
            qargs = {'total': 10, 'seed': s}
            url = self.mockserver.url("/follow?%s") % urlencode(qargs, doseq=1)
            yield Request(url, meta={'seed': s})
            if self.fail_yielding:
                2 / 0

        assert self.seedsseen, \
                'All start requests consumed before any download happened'

    def parse(self, response):
        self.seedsseen.append(response.meta.get('seed'))
        for req in super(BrokenStartRequestsSpider, self).parse(response):
            yield req


class SingleRequestSpider(MetaSpider):

    seed = None
    callback_func = None
    errback_func = None

    def start_requests(self):
        if isinstance(self.seed, Request):
            yield self.seed.replace(callback=self.parse, errback=self.on_error)
        else:
            yield Request(self.seed, callback=self.parse, errback=self.on_error)

    def parse(self, response):
        self.meta.setdefault('responses', []).append(response)
        if callable(self.callback_func):
            return self.callback_func(response)
        if 'next' in response.meta:
            return response.meta['next']

    def on_error(self, failure):
        self.meta['failure'] = failure
        if callable(self.errback_func):
            return self.errback_func(failure)


class DuplicateStartRequestsSpider(MockServerSpider):
    dont_filter = True
    name = 'duplicatestartrequests'
    distinct_urls = 2
    dupe_factor = 3

    def start_requests(self):
        for i in range(0, self.distinct_urls):
            for j in range(0, self.dupe_factor):
                url = self.mockserver.url("/echo?headers=1&body=test%d" % i)
                yield Request(url, dont_filter=self.dont_filter)

    def __init__(self, url="http://localhost:8998", *args, **kwargs):
        super(DuplicateStartRequestsSpider, self).__init__(*args, **kwargs)
        self.visited = 0

    def parse(self, response):
        self.visited += 1


class CrawlSpiderWithErrback(MockServerSpider, CrawlSpider):
    name = 'crawl_spider_with_errback'
    custom_settings = {
        'RETRY_HTTP_CODES': [],  # no need to retry
    }
    rules = (
        Rule(LinkExtractor(), callback='callback', errback='errback', follow=True),
    )

    def start_requests(self):
        test_body = b"""
        <html>
            <head><title>Page title<title></head>
            <body>
                <p><a href="/status?n=200">Item 200</a></p>  <!-- callback -->
                <p><a href="/status?n=201">Item 201</a></p>  <!-- callback -->
                <p><a href="/status?n=404">Item 404</a></p>  <!-- errback -->
                <p><a href="/status?n=500">Item 500</a></p>  <!-- errback -->
                <p><a href="/status?n=501">Item 501</a></p>  <!-- errback -->
            </body>
        </html>
        """
        url = self.mockserver.url("/alpayload")
        yield Request(url, method="POST", body=test_body)

    def callback(self, response):
        self.logger.info('[callback] status %i', response.status)

    def errback(self, failure):
        self.logger.info('[errback] status %i', failure.value.response.status)