example - Python Scrapy: convierte rutas relativas en rutas absolutas

scrapy spider

Question

He enmendado el código en base a las soluciones que se ofrecen a continuación por la gran gente aquí; Me sale el error que se muestra debajo del código aquí.

from scrapy.spider import BaseSpider
from scrapy.selector import HtmlXPathSelector
from scrapy.utils.response import get_base_url
from scrapy.utils.url import urljoin_rfc
from dmoz2.items import DmozItem

class DmozSpider(BaseSpider):
   name = "namastecopy2"
   allowed_domains = ["namastefoods.com"]
   start_urls = [
    "http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=1",
    "http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=12",    

]

def parse(self, response):
    hxs = HtmlXPathSelector(response)
    sites = hxs.select(''/html/body/div/div[2]/table/tr/td[2]/table/tr'')
    items = []
    for site in sites:
        item = DmozItem()
        item[''manufacturer''] = ''Namaste Foods''
        item[''productname''] = site.select(''td/h1/text()'').extract()
        item[''description''] = site.select(''//*[@id="info-col"]/p[7]/strong/text()'').extract()
        item[''ingredients''] = site.select(''td[1]/table/tr/td[2]/text()'').extract()
        item[''ninfo''] = site.select(''td[2]/ul/li[3]/img/@src'').extract()
        #insert code that will save the above image path for ninfo as an absolute path
        base_url = get_base_url(response)
        relative_url = site.select(''//*[@id="showImage"]/@src'').extract()
        item[''image_urls''] = urljoin_rfc(base_url, relative_url)
        items.append(item)
    return items

Mis items.py se ve así:

from scrapy.item import Item, Field

class DmozItem(Item):
    # define the fields for your item here like:
    productid = Field()
    manufacturer = Field()
    productname = Field()
    description = Field()
    ingredients = Field()
    ninfo = Field()
    imagename = Field()
    image_paths = Field()
    relative_images = Field()
    image_urls = Field()
    pass

Necesito las rutas relativas que la araña está obteniendo para los elementos [''relative_images''] convertidas en rutas absolutas y guardadas en elementos [''image_urls''] para poder descargar las imágenes desde dentro de esta araña. Por ejemplo, la ruta de imágenes relativas que la araña obtiene es ''../../files/images/small/8270-BrowniesHiResClip.jpg'', esto se debe convertir a ''http://namastefoods.com/files/images/small /8270-BrowniesHiResClip.jpg '', y almacenado en elementos ['' image_urls '']

También necesitaré la ruta de los elementos [''ninfo''] para que se almacene como una ruta absoluta.

Error al ejecutar el código anterior:

2011-06-28 17:18:11-0400 [scrapy] INFO: Scrapy 0.12.0.2541 started (bot: dmoz2)
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Enabled extensions: TelnetConsole, SpiderContext, WebService, CoreStats, CloseSpider
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Enabled scheduler middlewares: DuplicatesFilterMiddleware
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, RedirectMiddleware, CookiesMiddleware, HttpCompressionMiddleware, DownloaderStats
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Enabled item pipelines: MyImagesPipeline
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Telnet console listening on 0.0.0.0:6023
2011-06-28 17:18:11-0400 [scrapy] DEBUG: Web service listening on 0.0.0.0:6080
2011-06-28 17:18:11-0400 [namastecopy2] INFO: Spider opened
2011-06-28 17:18:12-0400 [namastecopy2] DEBUG: Crawled (200) <GET http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=12> (referer: None)
2011-06-28 17:18:12-0400 [namastecopy2] ERROR: Spider error processing <http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=12> (referer: <None>)
    Traceback (most recent call last):
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/base.py", line 1137, in mainLoop
        self.runUntilCurrent()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/base.py", line 757, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 243, in callback
        self._startRunCallbacks(result)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 312, in _startRunCallbacks
        self._runCallbacks()
    --- <exception caught here> ---
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 328, in _runCallbacks
        self.result = callback(self.result, *args, **kw)
      File "/***/***/***/***/***/***/spiders/namaste_copy2.py", line 30, in parse
        item[''image_urls''] = urljoin_rfc(base_url, relative_url)
      File "/Library/Python/2.6/site-packages/Scrapy-0.12.0.2541-py2.6.egg/scrapy/utils/url.py", line 37, in urljoin_rfc
        unicode_to_str(ref, encoding))
      File "/Library/Python/2.6/site-packages/Scrapy-0.12.0.2541-py2.6.egg/scrapy/utils/python.py", line 96, in unicode_to_str
        raise TypeError(''unicode_to_str must receive a unicode or str object, got %s'' % type(text).__name__)
    exceptions.TypeError: unicode_to_str must receive a unicode or str object, got list

2011-06-28 17:18:15-0400 [namastecopy2] DEBUG: Crawled (200) <GET http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=1> (referer: None)
2011-06-28 17:18:15-0400 [namastecopy2] ERROR: Spider error processing <http://www.namastefoods.com/products/cgi-bin/products.cgi?Function=show&Category_Id=4&Id=1> (referer: <None>)
    Traceback (most recent call last):
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/base.py", line 1137, in mainLoop
        self.runUntilCurrent()
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/base.py", line 757, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 243, in callback
        self._startRunCallbacks(result)
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 312, in _startRunCallbacks
        self._runCallbacks()
    --- <exception caught here> ---
      File "/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/twisted/internet/defer.py", line 328, in _runCallbacks
        self.result = callback(self.result, *args, **kw)
      File "/***/***/***/***/***/***/spiders/namaste_copy2.py", line 30, in parse
        item[''image_urls''] = urljoin_rfc(base_url, relative_url)
      File "/Library/Python/2.6/site-packages/Scrapy-0.12.0.2541-py2.6.egg/scrapy/utils/url.py", line 37, in urljoin_rfc
        unicode_to_str(ref, encoding))
      File "/Library/Python/2.6/site-packages/Scrapy-0.12.0.2541-py2.6.egg/scrapy/utils/python.py", line 96, in unicode_to_str
        raise TypeError(''unicode_to_str must receive a unicode or str object, got %s'' % type(text).__name__)
    exceptions.TypeError: unicode_to_str must receive a unicode or str object, got list

2    011-06-28 17:18:15-0400 [namastecopy2] INFO: Closing spider (finished)
2011-06-28 17:18:15-0400 [namastecopy2] INFO: Spider closed (finished)

Gracias.-TM

Answer 1

De documentos de Scrapy :

def parse(self, response):
    # ... code ommited
    next_page = response.urljoin(next_page)
    yield scrapy.Request(next_page, self.parse)

es decir, el objeto de response tiene un método para hacer exactamente esto.

Answer 2

Lo que hago es:

import urlparse
...

def parse(self, response):
    ...
    urlparse.urljoin(response.url, extractedLink.strip())
    ...

Note strip() , porque a veces me encuentro con enlaces extraños como:

<a href="
              /MID_BRAND_NEW!%c2%a0MID_70006_Google_Android_2.2_7%22%c2%a0Tablet_PC_Silver/a904326516.html
            ">MID BRAND NEW!&nbsp;MID 70006 Google Android 2.2 7"&nbsp;Tablet PC Silver</a>

Answer 3

Un enfoque más general para obtener una URL absoluta sería

import urlparse

def abs_url(url, response):
  """Return absolute link"""
  base = response.xpath(''//head/base/@href'').extract()
  if base:
    base = base[0]
  else:
    base = response.url
  return urlparse.urljoin(base, url)

Esto también funciona cuando un elemento base está presente.

En tu caso, lo usarías así:

def parse(self, response):
  # ...
  for site in sites:
    # ...
    image_urls = site.select(''//*[@id="showImage"]/@src'').extract()
    if image_urls: item[''image_urls''] = abs_url(image_urls[0], response)

Answer 4

Varias notas:

items = []
for site in sites:
    item = DmozItem()
    item[''manufacturer''] = ''Namaste Foods''
    ...
    items.append(item)
return items

Lo hago de manera diferente:

for site in sites:
    item = DmozItem()
    item[''manufacturer''] = ''Namaste Foods''
    ...
    yield item

Entonces:

relative_url = site.select(''//*[@id="showImage"]/@src'').extract()
item[''image_urls''] = urljoin_rfc(base_url, relative_url)

extract() siempre devuelve una lista, porque una consulta xpath siempre devuelve una lista de nodos seleccionados.

Hacer esto:

relative_url = site.select(''//*[@id="showImage"]/@src'').extract()[0]
item[''image_urls''] = urljoin_rfc(base_url, relative_url)

Answer 5

from scrapy.utils.response import get_base_url

base_url           = get_base_url(response)
relative_url       = site.select(''//*[@id="showImage"]/@src'').extract()
item[''image_urls''] = [urljoin_rfc(base_url,ru) for ru in relative_url]

o podrías extraer solo un elemento

base_url           = get_base_url(response)
relative_url       = site.select(''//*[@id="showImage"]/@src'').extract()[0]
item[''image_urls''] = urljoin_rfc(base_url,relative_url)

El error fue porque estaba pasando una lista en lugar de una cadena para la función urljoin.