Scrapy Start_request parse - python

I am writing a scrapy script to search and scrape result from a website. I need to search items from website and parse each url from the search results. I started with Scrapy's start_requests where i'd pass the search query and redirect to another function parse which will retrieve the urls from the search result. Finally i called another function parse_item to parse the results. I'm able to extract the all the search results url but i'm not being able to parse the results ( parse_item is not working). Here is the code:
# -*- coding: utf-8 -*-
from scrapy.http.request import Request
from scrapy.spider import BaseSpider
class xyzspider(BaseSpider):
name = 'dspider'
allowed_domains = ["www.example.com"]
mylist = ['Search item 1','Search item 2']
url = 'https://example.com/search?q='
def start_requests(self):
for i in self.mylist:
i = i.replace(' ','+')
starturl = self.url+ i
yield Request(starturl,self.parse)
def parse(self,response):
itemurl = response.xpath(".//section[contains(#class, 'search-results')]/a/#href").extract()
for j in itemurl:
print j
yield Request(j,self.parse_item)
def parse_item(self,response):
print "hello"
'''rating = response.xpath(".//ul(#class = 'ratings')/li[1]/span[1]/text()").extract()
print rating'''
Could anyone please help me. Thank you.

I was getting a Filtered offsite request error. I changed the allowed domain from allowed_domains = www.xyz.com to
xyz.com and it worked perfectly.

Your code looks good. So you might need to use the Request attribute dont_filter set to True:
yield Request(j,self.parse_item, dont_filter=True)
From the docs:
dont_filter (boolean) – indicates that this request should not be filtered by the scheduler. This is used when you want to perform an identical request multiple times, to ignore the duplicates filter. Use it with care, or you will get into crawling loops. Default to False.
Anyway I recommend you to have a look at the item Pipelines.
Those are used to process scraped items using the command:
yield my_object
Item pipelines are used to post-process everything yielded by the spider.

Related

Scrapy one item with multiple parsing functions

I am using Scrapy with python to scrape a website and I face some difficulties with filling the item that I have created.
The products are properly scraped and everything is working well as long as the info is located within the response.xpath mentioned in the for loop.
'trend' and 'number' are properly added to the Item using ItemLoader.
However, the date of the product is not located within the response.xpath cited below but in the response.css as a title : response.css('title')
import scrapy
import datetime
from trends.items import Trend_item
from scrapy.loader import ItemLoader
#Initiate the spider
class trendspiders(scrapy.Spider):
name = 'milk'
start_urls = ['https://thewebsiteforthebestmilk/ireland/2022-03-16/7/']
def parse(self, response):
for milk_unique in response.xpath('/html/body/main/div/div[2]/div[1]/section[1]/div/div[3]/table/tbody/tr'):
l = ItemLoader(item=Milk_item(), selector=milk_unique, response=response)
l.add_css('milk', 'a::text')
l.add_css('number', 'span.small.text-muted::text')
return l.load_item()
How can I add the 'date' to my item please (found in response.css('title')?
I have tried to add l.add_css('date', "response.css('title')")in the for loop but it returns an error.
Should I create a new parsing function? If yes then how to send the info to the same Item?
I hope I’ve made myself clear.
Thank you very much for your help,
Since the date is outside of the selector you are using for each row, what you should do is extract that first before your for loop, since it doesn't need to be updated on each iteration.
Then with your item loader you can just use l.add_value to load it with the rest of the fields.
For example:
class trendspiders(scrapy.Spider):
name = 'trends'
start_urls = ['https://getdaytrends.com/ireland/2022-03-16/7/']
def parse(self, response):
date_str = response.xpath("//title/text()").get()
for trend_unique in response.xpath('/html/body/main/div/div[2]/div[1]/section[1]/div/div[3]/table/tbody/tr'):
l = ItemLoader(item=Trend_item(), selector=trend_unique, response=response)
l.add_css('trend', 'a::text')
l.add_css('number', 'span.small.text-muted::text')
l.add_value('date', date_str)
yield l.load_item()
If response.css('title').get() gives you the answer you need, why not use the same CSS with add_css:
l.add_css('date', 'title')
Also, .add_css('date', "response.css('title')") is invalid because the second argument a valid CSS selector.

Can scrapy skip the error of empty data and keeping scraping?

I want to scrape product pages from its sitemap, the products page are similar, but not all of them are the same.
for example
Product A
https://www.vitalsource.com/products/environment-the-science-behind-the-stories-jay-h-withgott-matthew-v9780134446400
Product B
https://www.vitalsource.com/products/abnormal-psychology-susan-nolen-hoeksema-v9781259765667
we can see the product A has the subtitle but another one doesn't have.
So I get errors when I trying to scrape all the product pages.
My question is, is there a way to let the spider skip the error for returning no data?
There is a simple way to bypass it. that is not using strip()
But I am wondering if there is a better way to do the job.
import scrapy
import re
from VitalSource.items import VitalsourceItem
from scrapy.selector import Selector
from scrapy.spiders import SitemapSpider
class VsSpider(SitemapSpider):
name = 'VS'
allowed_domains = ['vitalsource.com']
sitemap_urls = ['https://storage.googleapis.com/vst-stargate-production/sitemap/sitemap1.xml.gz']
sitemap_rules = [
('/products/', 'parse_product'),
]
def parse_product(self, response):
selector = Selector(response=response)
item = VitalsourceItem()
item['Ebook_Title'] = response.css('.product-overview__title-header::text').extract()[1].strip
item['Ebook_SubTitle'] = response.css("div.subtitle.subtitle-pdp::text").extract().strip
print(item)
return item
error message
item['Ebook_SubTitle'] = response.css("div.subtitle.subtitle-pdp::text").extract().strip
AttributeError: 'list' object has no attribute 'strip'
Since you need only one subtitle you can use get() with setting default value to empty string. This will save you from errors about applying strip() function to empty element.
item['Ebook_SubTitle'] = response.css("div.subtitle.subtitle-pdp::text").get('').strip()
In general scrapy will not stop crawling if callbacks raise an exception. e.g.:
def start_requests(self):
for i in range(10):
yield Requst(
f'http://example.org/page/{i}',
callback=self.parse,
errback=self.errback,
)
def parse(self, response):
# first page
if 'page/1' in response.request.url:
raise ValueError()
yield {'url': response.url}
def errback(self, failure):
print(f"oh no, failed to parse {failure.request}")
In this example 10 requests will be made and 9 items will be scraped but 1 will fail and got o errback
In your case you have nothing to fear - any request that does not raise an exception will scrape as it should, for the ones that do you'll just see an exception traceback in your terminal/logs.
You could check if a value is returned before extracting:
if response.css("div.subtitle.subtitle-pdp::text"):
item['Ebook_SubTitle'] = response.css("div.subtitle.subtitle-pdp::text").get().strip
That way the subTitle code line would only run if a value was to be returned...

Scrapy not following the next parse function

I am trying to write a simple scraping script to scrape off google summer of code orgs with the tech that I require. Its work in progress. My parse function is working fine but whenever I callback into org function it doesn't throw any output.
# -*- coding: utf-8 -*-
import scrapy
class GsocSpider(scrapy.Spider):
name = 'gsoc'
allowed_domains = ['https://summerofcode.withgoogle.com/archive/2018/organizations/']
start_urls = ['https://summerofcode.withgoogle.com/archive/2018/organizations/']
def parse(self, response):
for href in response.css('li.organization-card__container a.organization-card__link::attr(href)'):
url = response.urljoin(href.extract())
yield scrapy.Request(url, callback = self.parse_org)
def parse_org(self,response):
tech=response.css('li.organization__tag organization__tag--technology::text').extract()
#if 'python' in tech:
yield
{
'name':response.css('title::text').extract_first()
#'ideas_list':response.css('')
}
first of all, you are configuring incorrectly the allowed_domains, as it specifies in the documentation:
An optional list of strings containing domains that this spider is
allowed to crawl. Requests for URLs not belonging to the domain names
specified in this list (or their subdomains) won’t be followed if
OffsiteMiddleware is enabled.
Let’s say your target url is https://www.example.com/1.html, then add
'example.com' to the list.
As you can see, you need to include only the domains, and this is a filtering functionality (so other domains don't get crawled). Also this is optional, so I would actually recommend to not include it.
Also your css for getting tech is incorrect, it should be:
li.organization__tag.organization__tag--technology

Scrapy only scrapes the first start url in a list of 15 start urls

I am new to Scrapy and am attempting to teach myself the basics. I have compiled a code that goes to the Louisiana Department of Natural Resources website to retrieve the serial number for certain oil wells.
I have each well's link listed in the start URLs command, but scrappy only downloads data from the first url. What am I doing wrong?
import scrapy
from scrapy import Spider
from scrapy.selector import Selector
from mike.items import MikeItem
class SonrisSpider(Spider):
name = "sspider"
start_urls = [
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=207899",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=971683",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=214206",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=159420",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=243671",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=248942",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=156613",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=972498",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=215443",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=248463",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=195136",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=179181",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=199930",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=203419",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=220454",
]
def parse(self, response):
item = MikeItem()
item['serial'] = response.xpath('/html/body/table[1]/tr[2]/td[1]/text()').extract()[0]
yield item
Thank you for any help you might be able to provide. If I have not explained my problem thoroughly, please let me know and I will attempt to clarify.
I think this code might help,
By default scrapy prevent duplicate requests. Since only the parameters are different in your start-url scrapy will consider the rest of the urls in the start-url as duplicate request of the first one. That's why your spider stops after fetching the first url. In order to parse the rest of the urls we have enable dont_filter flag in the scrapy request. (chek the start_request())
# -*- coding: utf-8 -*-
import scrapy
from scrapy.http import Request
from mike.items import MikeItem
class SonrisSpider(scrapy.Spider):
name = "sspider"
allowed_domains = ["sonlite.dnr.state.la.us"]
start_urls = [
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=207899",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=971683",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=214206",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=159420",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=243671",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=248942",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=156613",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=972498",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=215443",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=248463",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=195136",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=179181",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=199930",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=203419",
"http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_wellinfo2?p_WSN=220454",
]
def start_requests(self):
for url in self.start_urls:
yield Request(url=url, callback=self.parse_data, dont_filter=True)
def parse_data(self, response):
item = MikeItem()
serial = response.xpath(
'/html/body/table[1]/tr[2]/td[1]/text()').extract()
serial = serial[0] if serial else 'n/a'
item['serial'] = serial
yield item
sample output returned by this spider is as follows,
{'serial': u'207899'}
{'serial': u'971683'}
{'serial': u'214206'}
{'serial': u'159420'}
{'serial': u'248942'}
{'serial': u'243671'}
your code sounds good, try to add this function
class SonrisSpider(Spider):
def start_requests(self):
for url in self.start_urls:
print(url)
yield self.make_requests_from_url(url)
#the result of your code goes here
The URLs should be printed now. Test it, if not, say please

python scrapy parse() function, where is the return value returned to?

I am new on Scrapy, and I am sorry if this question is trivial. I have read the document on Scrapy from official webpage. And while I look through the document, I met this example:
import scrapy
from myproject.items import MyItem
class MySpider(scrapy.Spider):
name = ’example.com’
allowed_domains = [’example.com’]
start_urls = [
’http://www.example.com/1.html’,
’http://www.example.com/2.html’,
’http://www.example.com/3.html’,
]
def parse(self, response):
for h3 in response.xpath(’//h3’).extract():
yield MyItem(title=h3)
for url in response.xpath(’//a/#href’).extract():
yield scrapy.Request(url, callback=self.parse)
I know, the parse method must return an item or/and request, but where are these return values returned to?
One is an item and the other is request, I think these two type would be handled differently and in the case of CrawlSpider, it has Rule with callback. What about this callback's return value? where to ? same as parse()?
I am very confused on Scrapy procedure, even i read the document....
According to the documentation:
The parse() method is in charge of processing the response and
returning scraped data (as Item objects) and more URLs to follow (as
Request objects).
In other words, returned/yielded items and requests are handled differently, items are being handed to the item pipelines and item exporters, but requests are being put into the Scheduler which pipes the requests to the Downloader for making a request and returning a response. Then, the engine receives the response and gives it to the spider for processing (to the callback method).
The whole data-flow process is described in the Architecture Overview page in a very detailed manner.
Hope that helps.

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