表单提交后Scrapy下载MIME类型文件

Question

在页面http://comunicacion.movistarplus.es/guiaProgramacion/exportarProgramacion 中有一个表单，用户必须输入一些字段才能下载最重要的西班牙广播公司的频道时间表。用户填写表格并点击Exportar按钮后，浏览器会自动开始下载formato下拉列表中带有扩展名的文件。

现在，从我的 Chrome 浏览器中获取文件非常容易。然而，我想用一个 Scrapy 脚本来自动化它，你可以在下面找到我到目前为止所做的事情：

from scrapy.item import Item, Field
from scrapy.http import FormRequest
from scrapy.spiders import Spider
from scrapy.selector import Selector
from scrapy.http import Request

class ProgramacionSpider(Spider):
    name = "Programacion"
    allowed_domains = ["comunicacion.movistarplus.es"]
    start_urls = ["http://comunicacion.movistarplus.es/guiaProgramacion/exportarProgramacion"]

    def parse(self, response):
        yield FormRequest.from_response(response, formname='formExportar', formdata={"fechaInicio": "2017-01-05", "fechaFin": "2017-01-19", "genero" : "0", "selPredefinicion": "0", "formato": "csv", "cadena[]": "{INTECO, ETB}"}, callback=self.parse1)

    def parse1(self, response):
        print response

现在，在使用需要与表单一起发送的 POST 参数执行 FormRequest.from_response 之后，Scrapy 会使用以下文本进行响应：

2017-01-05 13:19:11 [scrapy] INFO: Scrapy 1.1.2 started (bot: Programacion)
2017-01-05 13:19:11 [scrapy] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'Programacion.spiders', 'FEED_URI': 'sss.csv', 'DUPEFILTER_CLASS': 'scrapy_splash.SplashAwareDupeFilter', 'SPIDER_MODULES': ['Programacion.spiders'], 'BOT_NAME': 'Programacion', 'FEED_FORMAT': 'csv', 'HTTPCACHE_STORAGE': 'scrapy_splash.SplashAwareFSCacheStorage'}
2017-01-05 13:19:11 [scrapy] INFO: Enabled extensions:
['scrapy.extensions.feedexport.FeedExporter',
 'scrapy.extensions.logstats.LogStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.corestats.CoreStats']
2017-01-05 13:19:12 [scrapy] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy_splash.SplashCookiesMiddleware',
 'scrapy_splash.SplashMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.chunked.ChunkedTransferMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2017-01-05 13:19:12 [scrapy] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy_splash.SplashDeduplicateArgsMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2017-01-05 13:19:12 [scrapy] INFO: Enabled item pipelines:
[]
2017-01-05 13:19:12 [scrapy] INFO: Spider opened
2017-01-05 13:19:12 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2017-01-05 13:19:12 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6023
2017-01-05 13:19:12 [scrapy] DEBUG: Crawled (200) <GET http://comunicacion.movistarplus.es/guiaProgramacion/exportarProgramacion> (referer: None)
2017-01-05 13:19:12 [scrapy] DEBUG: Crawled (200) <POST http://comunicacion.movistarplus.es/guiaProgramacion/exportar> (referer: http://comunicacion.movistarplus.es/guiaProgramacion/exportarProgramacion)
<200 http://comunicacion.movistarplus.es/guiaProgramacion/exportar>
2017-01-05 13:19:12 [scrapy] INFO: Closing spider (finished)
2017-01-05 13:19:12 [scrapy] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 822,
 'downloader/request_count': 2,
 'downloader/request_method_count/GET': 1,
 'downloader/request_method_count/POST': 1,
 'downloader/response_bytes': 6603,
 'downloader/response_count': 2,
 'downloader/response_status_count/200': 2,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2017, 1, 5, 12, 19, 12, 783383),
 'log_count/DEBUG': 3,
 'log_count/INFO': 7,
 'request_depth_max': 1,
 'response_received_count': 2,
 'scheduler/dequeued': 2,
 'scheduler/dequeued/memory': 2,
 'scheduler/enqueued': 2,
 'scheduler/enqueued/memory': 2,
 'start_time': datetime.datetime(2017, 1, 5, 12, 19, 12, 204111)}
2017-01-05 13:19:12 [scrapy] INFO: Spider closed (finished)

显然，爬虫似乎工作正常，因为它没有响应 500 错误（即它接受表单中的 POST 变量）。

问题

我想知道如何使用 Scrapy 直接下载文件，但对如何执行此操作一无所知。谢谢。

Answer 1

您正在谈论的文件在您收到的响应中，更准确地说是在response.body 属性中。

您可以简单地打开一个文件并将response.body 的内容写入其中。像这样：

def parse(self, response):
    # check if response is valid
    if response.status != 200:
        print("failed to get schedule")
        return
    # save to file valid response
    with open('results.csv', 'w') as f:
        f.write(response.body)    

编辑：我发现您的表单数据存在问题，这是返回空文件的原因：

def parse(self, response):
    formdata={"fechaInicio": "2017-01-05", 
              "fechaFin": "2017-01-19", 
              "genero": "0",
              "selPredefinicion": "0", 
              "formato": "csv",
              # "cadena[]": "{INTECO, ETB}",  # incorrect
              "cadena[]": ["INTECO", "ETB"]}  # <---- this is correct
    yield FormRequest.from_response(response, formname='formExportar', 
                                    formdata=formdata,
                                    callback=self.parse1)

您在此处提供了错误的字符串而不是列表，上面的示例是正确的，并且正在正确返回/保存结果。