Recursive function gives no output - python

I'm scraping all the URL of my domain with recursive function.
But it outputs nothing, without any error.
#usr/bin/python
from bs4 import BeautifulSoup
import requests
import tldextract
def scrape(url):
for links in url:
main_domain = tldextract.extract(links)
r = requests.get(links)
data = r.text
soup = BeautifulSoup(data)
for href in soup.find_all('a'):
href = href.get('href')
if not href:
continue
link_domain = tldextract.extract(href)
if link_domain.domain == main_domain.domain :
problem.append(href)
elif not href == '#' and link_domain.tld == '':
new = 'http://www.'+ main_domain.domain + '.' + main_domain.tld + '/' + href
problem.append(new)
return len(problem)
return scrape(problem)
problem = ["http://xyzdomain.com"]
print(scrape(problem))
When I create a new list, it works, but I don't want to make a list every time for every loop.

You need to structure your code so that it meets the pattern for recursion as your current code doesn't - you also should not call variables the same name as libraries, e.g. href = href.get() because this will usually stop the library working as it becomes the variable, your code as it currently is will only ever return the len() as this return is unconditionally reached before: return scrap(problem).:
def Recursive(Factorable_problem)
if Factorable_problem is Simplest_Case:
return AnswerToSimplestCase
else:
return Rule_For_Generating_From_Simpler_Case(Recursive(Simpler_Case))
for example:
def Factorial(n):
""" Recursively Generate Factorials """
if n < 2:
return 1
else:
return n * Factorial(n-1)

Hello I've made a none recursive version of this that appears to get all the links on the same domain.
The code below I've tested using the problem included in the code. When I'd solved the problems with the recursive version the next problem was hitting the recursion depth limit so I rewrote it so it ran in an iterative fashion, the code and result below:
from bs4 import BeautifulSoup
import requests
import tldextract
def print_domain_info(d):
print "Main Domain:{0} \nSub Domain:{1} \nSuffix:{2}".format(d.domain,d.subdomain,d.suffix)
SEARCHED_URLS = []
problem = [ "http://Noelkd.neocities.org/", "http://youpi.neocities.org/"]
while problem:
# Get a link from the stack of links
link = problem.pop()
# Check we haven't been to this address before
if link in SEARCHED_URLS:
continue
# We don't want to come back here again after this point
SEARCHED_URLS.append(link)
# Try and get the website
try:
req = requests.get(link)
except:
# If its not working i don't care for it
print "borked website found: {0}".format(link)
continue
# Now we get to this point worth printing something
print "Trying to parse:{0}".format(link)
print "Status Code:{0} Thats: {1}".format(req.status_code, "A-OK" if req.status_code == 200 else "SOMTHINGS UP" )
# Get the domain info
dInfo = tldextract.extract(link)
print_domain_info(dInfo)
# I like utf-8
data = req.text.encode("utf-8")
print "Lenght Of Data Retrived:{0}".format(len(data)) # More info
soup = BeautifulSoup(data) # This was here before so i left it.
print "Found {0} link{1}".format(len(soup.find_all('a')),"s" if len(soup.find_all('a')) > 1 else "")
FOUND_THIS_ITERATION = [] # Getting the same links over and over was boring
found_links = [x for x in soup.find_all('a') if x.get('href') not in SEARCHED_URLS] # Find me all the links i don't got
for href in found_links:
href = href.get('href') # You wrote this seems to work well
if not href:
continue
link_domain = tldextract.extract(href)
if link_domain.domain == dInfo.domain: # JUST FINDING STUFF ON SAME DOMAIN RIGHT?!
if href not in FOUND_THIS_ITERATION: # I'ma check you out next time
print "Check out this link: {0}".format(href)
print_domain_info(link_domain)
FOUND_THIS_ITERATION.append(href)
problem.append(href)
else: # I got you already
print "DUPE LINK!"
else:
print "Not on same domain moving on"
# Count down
print "We have {0} more sites to search".format(len(problem))
if problem:
continue
else:
print "Its been fun"
print "Lets see the URLS we've visited:"
for url in SEARCHED_URLS:
print url
Which prints, after a lot of other logging loads of neocities websites!
What's happening is the script is popping a value of the list of websites yet to visit, it then gets all the links on the page which are on the same domain. If those links are to pages we haven't visited we add the link to the list of links to be visited. After we do that we pop the next page and do the same thing again until there are no pages left to visit.
Think this is what your looking for, get back to us in the comments if this doesn't work in the way that you want or if anyone can improve please leave a comment.

Related

attribute error in web scraping in python

Written some code to scrape a website: https://books.toscrape.com/catalogue/page-1.html but I'm getting an error:
Nontype object has no attribute text
Failed to find a solution for this so how can I can fix this error?
import requests
from bs4 import BeautifulSoup
import pandas as pd
all_books=[]
url='https://books.toscrape.com/catalogue/page-1.html'
headers=('https://developers.whatismybrowser.com/useragents/parse/22526098chrome-windows-blink')
def get_page(url):
page=requests.get(url,headers)
status=page.status_code
soup=BeautifulSoup(page.text,'html.parser')
return [soup,status]
#get all books links
def get_links(soup):
links=[]
listings=soup.find_all(class_='product_pod')
for listing in listings:
bk_link=listing.find("h3").a.get("href")
base_url='https://books.toscrape.com/catalogue/page-1.html'
cmplt_link=base_url+bk_link
links.append(cmplt_link)
return links
#extraxt info from each link
def extract_info(links):
for link in links:
r=requests.get(link).text
book_soup=BeautifulSoup(r,'html.parser')
name=book_soup.find(class_='col-sm-6 product_main').text.strip()
price=book_soup.find(class_='col-sm-6 product_main').text.strip()
desc=book_soup.find(class_='sub-header').text.strip()
cat=book_soup.find('"../category/books/poetry_23/index.html">Poetry').text.strip()
book={'name':name,'price':price,'desc':desc,'cat':cat}
all_books.append(book)
pg=48
while True:
url=f'https://books.toscrape.com/catalogue/page-{pg}.html'
soup_status=get_page(url)
if soup_status[1]==200:
print(f"scrapping page{pg}")
extract_info(get_links(soup_status[0]))
pg+=1
else:
print("The End")
break
df=pd.DataFrame(all_books)
print(df)
Note First of all, always take a look at your soup - therein lies the truth. The contents can always differ slightly to extremely from the view in the dev tools.
What happens?
There are different issues you should keep in mind:
base_url='https://books.toscrape.com/catalogue/page-1.html' will lead to 404 errors and is the first reason causing your "Nontype object has no attribute text"
You try to find the category like this cat=book_soup.find('"../category/books/poetry_23/index.html">Poetry').text.strip() what won't work to and will lead to same error
There some more selection that will not lead to an expected result, take a look in my example edited them to give you a clue how to get the goal.
How to fix?
Change base_url='https://books.toscrape.com/catalogue/page-1.html' to base_url='https://books.toscrape.com/catalogue/'
Select the category more specific, it is the last <a> in breadcrumb:
cat=book_soup.select('.breadcrumb a')[-1].text.strip()
Example
import requests
from bs4 import BeautifulSoup
import pandas as pd
all_books=[]
url='https://books.toscrape.com/catalogue/page-1.html'
headers=('https://developers.whatismybrowser.com/useragents/parse/22526098chrome-windows-blink')
def get_page(url):
page=requests.get(url,headers)
status=page.status_code
soup=BeautifulSoup(page.text,'html.parser')
return [soup,status]
#get all books links
def get_links(soup):
links=[]
listings=soup.find_all(class_='product_pod')
for listing in listings:
bk_link=listing.find("h3").a.get("href")
base_url='https://books.toscrape.com/catalogue/'
cmplt_link=base_url+bk_link
links.append(cmplt_link)
return links
#extraxt info from each link
def extract_info(links):
for link in links:
r=requests.get(link).text
book_soup=BeautifulSoup(r,'html.parser')
name= name.text.strip() if (name := book_soup.h1) else None
price= price.text.strip() if (price := book_soup.select_one('h1 + p')) else None
desc= desc.text.strip() if (desc := book_soup.select_one('#product_description + p')) else None
cat= cat.text.strip() if (cat := book_soup.select('.breadcrumb a')[-1]) else None
book={'name':name,'price':price,'desc':desc,'cat':cat}
all_books.append(book)
pg=48
while True:
url=f'https://books.toscrape.com/catalogue/page-{pg}.html'
soup_status=get_page(url)
if soup_status[1]==200:
print(f"scrapping page{pg}")
extract_info(get_links(soup_status[0]))
pg+=1
else:
print("The End")
break
all_books
Use the function below when you need to grab the text of element.
It will protect you from None elements
def get_text(book_soup,clazz):
ele = book_soup.find(class_=clazz)
return ele.text.strip() if ele is not None else ''
Example.Instead of
name=book_soup.find(class_='col-sm-6 product_main').text.strip()
do
name=get_text(book_soup,'col-sm-6 product_main')

Nested while loops does not break as expected

I have a list of links and for each link I want to check if it contains a specific sublink and add this sublink to the initial list. I have this code:
def getAllLinks():
i = 0
baseUrl = 'http://www.cdep.ro/pls/legis/'
sourcePaths = ['legis_pck.lista_anuala?an=2012&emi=3&tip=18&rep=0','legis_pck.lista_anuala?an=2020&emi=3&tip=18&rep=0&nrc=1', 'legis_pck.lista_anuala?an=2010&emi=3&tip=18&rep=0']
while i < len(sourcePaths)+1:
for path in sourcePaths:
res = requests.get(f'{baseUrl}{path}')
soup = BeautifulSoup(res.text)
next_btn = soup.find(lambda e: e.name == 'td' and '1..99' in e.text)
if next_btn:
for a in next_btn.find_all('a', href=True):
linkNextPage = a['href']
sourcePaths.append(linkNextPage)
i += 1
break
else:
i += 1
continue
break
return sourcePaths
print(getAllLinks())
The first link in the list does not contain the sublink, so it's an else case. The code does this OK. However, the second link in the list does contain the sublink, but it gets stuck here:
for a in next_btn.find_all('a', href=True):
linkNextPage = a['href']
sourcePaths.append(linkNextPage)
i += 1
The third link contains the sublink but my code does not get to look at that link. At the end I am getting a list containing the initial links plus 4 times the sublink of the second link.
I think I'm breaking incorrectly somewhere but I can't figure out how to fix it.
Remove the while. It's not needed. Change the selectors
import requests
from bs4 import BeautifulSoup
def getAllLinks():
baseUrl = 'http://www.cdep.ro/pls/legis/'
sourcePaths = ['legis_pck.lista_anuala?an=2012&emi=3&tip=18&rep=0','legis_pck.lista_anuala?an=2020&emi=3&tip=18&rep=0&nrc=1', 'legis_pck.lista_anuala?an=2010&emi=3&tip=18&rep=0']
for path in sourcePaths:
res = requests.get(f'{baseUrl}{path}')
soup = BeautifulSoup(res.text, "html.parser")
next_btn = soup.find("p",class_="headline").find("table", {"align":"center"})
if next_btn:
anchor = next_btn.find_all("td")[-1].find("a")
if anchor: sourcePaths.append(anchor["href"])
return sourcePaths
print(getAllLinks())
Output:
['legis_pck.lista_anuala?an=2012&emi=3&tip=18&rep=0', 'legis_pck.lista_anuala?an=2020&emi=3&tip=18&rep=0&nrc=1', 'legis_pck.lista_anuala?an=2010&emi=3&tip=18&rep=0', 'legis_pck.lista_anuala?an=2020&emi=3&tip=18&rep=0&nrc=100', 'legis_pck.lista_anuala?an=2010&emi=3&tip=18&rep=0&nrc=100']
Your second break statement never gets executed because the first "for" loop is already broken by the first break statement and never reaches the second break statement. Put condition which break the while loop.

Issue with web crawler: IndexError: string index out of range

I am making a web crawler. I'm not using scrapy or anything, I'm trying to have my script do most things. I have tried doing a search for the issue however I can't seem to find anything that helps with the error. I've tried switching around some of the variable to try and narrow down the problem. I am getting an error on line 24 saying IndexError: string index out of range. The functions run on the first url, (the original url) then the second and fail on the third in the original array. I'm lost, any help would be appreciated greatly! Note, I'm only printing all of them for testing, I'll eventually have them printed to a text file.
import requests
from bs4 import BeautifulSoup
# creating requests from user input
url = raw_input("Please enter a domain to crawl, without the 'http://www' part : ")
def makeRequest(url):
r = requests.get('http://' + url)
# Adding in BS4 for finding a tags in HTML
soup = BeautifulSoup(r.content, 'html.parser')
# Writes a as the link found in the href
output = soup.find_all('a')
return output
def makeFilter(link):
# Creating array for our links
found_link = []
for a in link:
a = a.get('href')
a_string = str(a)
# if statement to filter our links
if a_string[0] == '/': # this is the line with the error
# Realtive Links
found_link.append(a_string)
if 'http://' + url in a_string:
# Links from the same site
found_link.append(a_string)
if 'https://' + url in a_string:
# Links from the same site with SSL
found_link.append(a_string)
if 'http://www.' + url in a_string:
# Links from the same site
found_link.append(a_string)
if 'https://www.' + url in a_string:
# Links from the same site with SSL
found_link.append(a_string)
#else:
# found_link.write(a_string + '\n') # testing only
output = found_link
return output
# Function for removing duplicates
def remove_duplicates(values):
output = []
seen = set()
for value in values:
if value not in seen:
output.append(value)
seen.add(value)
return output
# Run the function with our list in this order -> Makes the request -> Filters the links -> Removes duplicates
def createURLList(values):
requests = makeRequest(values)
new_list = makeFilter(requests)
filtered_list = remove_duplicates(new_list)
return filtered_list
result = createURLList(url)
# print result
# for verifying and crawling resulting pages
for b in result:
sub_directories = createURLList(url + b)
crawler = []
crawler.append(sub_directories)
print crawler
After a_string = str(a) try adding:
if not a_string:
continue

Web crawler does not open all links in a page

I'am trying to build a web crawler using beautifulsoup and urllib. The crawler is working, but it does not open all the pages in a site. It opens the first link and goes to that link, opens the first link of that page and so on.
Here's my code:
from bs4 import BeautifulSoup
from urllib.request import urlopen
from urllib.parse import urljoin
import json, sys
sys.setrecursionlimit(10000)
url = input('enter url ')
d = {}
d_2 = {}
l = []
url_base = url
count = 0
def f(url):
global count
global url_base
if count <= 100:
print("count: " + str(count))
print('now looking into: '+url+'\n')
count += 1
l.append(url)
html = urlopen(url).read()
soup = BeautifulSoup(html, "html.parser")
d[count] = soup
tags = soup('a')
for tag in tags:
meow = tag.get('href',None)
if (urljoin(url, meow) in l):
print("Skipping this one: " + urljoin(url,meow))
elif "mailto" in urljoin(url,meow):
print("Skipping this one with a mailer")
elif meow == None:
print("skipping 'None'")
elif meow.startswith('http') == False:
f(urljoin(url, meow))
else:
f(meow)
else:
return
f(url)
print('\n\n\n\n\n')
print('Scrapping Completed')
print('\n\n\n\n\n')
The reason you're seeing this behavior is due to when the code recursively calls your function. As soon as the code finds a valid link, the function f gets called again preventing the rest of the for loop from running until it returns.
What you're doing is a depth first search, but the internet is very deep. You want to do a breadth first search instead.
Probably the easiest way to modify your code to do that is to have a global list of links to follow. Have the for loop append all the scraped links to the end of this list and then outside of the for loop, remove the first element of the list and follow that link.
You may have to change your logic slightly for your max count.
If count reaches 100, no further links will be opened. Therefore I think you should decrease count by one after leaving the for loop. If you do this, count would be something like the current link depth (and 100 would be the maximum link depth).
If the variable count should refer to the number of opened links, then you might want to control the link depth in another way.

Link Scraping Program Redundancy?

I am attempting to create a small script to simply take a given website along with a keyword, follow all the links a certain number of times(only links on website's domain), and finally search all the found links for the keyword and return any successful matches. Ultimately it's goal is if you remember a website where you saw something and know a good keyword that the page contained, this program might be able to help find the link to the lost page. Now my bug: upon looping through all these pages, extracting their URLs, and creating a list of them, it seems to somehow end up redundantly going over and removing the same links from the list. I did add a safeguard in place for this but it doesn't seem to be working as expected. I feel like some url(s) are mistakenly being duplicated into the list and end up being checked an infinite number of times.
Here's my full code(sorry about the length), problem area seems to be at the very end in the for loop:
import bs4, requests, sys
def getDomain(url):
if "www" in url:
domain = url[url.find('.')+1:url.rfind('.')]
elif "http" in url:
domain = url[url.find("//")+2:url.rfind('.')]
else:
domain = url[:url.rfind(".")]
return domain
def findHref(html):
'''Will find the link in a given BeautifulSoup match object.'''
link_start = html.find('href="')+6
link_end = html.find('"', link_start)
return html[link_start:link_end]
def pageExists(url):
'''Returns true if url returns a 200 response and doesn't redirect to a dns search.
url must be a requests.get() object.'''
response = requests.get(url)
try:
response.raise_for_status()
if response.text.find("dnsrsearch") >= 0:
print response.text.find("dnsrsearch")
print "Website does not exist"
return False
except Exception as e:
print "Bad response:",e
return False
return True
def extractURLs(url):
'''Returns list of urls in url that belong to same domain.'''
response = requests.get(url)
soup = bs4.BeautifulSoup(response.text)
matches = soup.find_all('a')
urls = []
for index, link in enumerate(matches):
match_url = findHref(str(link).lower())
if "." in match_url:
if not domain in match_url:
print "Removing",match_url
else:
urls.append(match_url)
else:
urls.append(url + match_url)
return urls
def searchURL(url):
'''Search url for keyword.'''
pass
print "Enter homepage:(no http://)"
homepage = "http://" + raw_input("> ")
homepage_response = requests.get(homepage)
if not pageExists(homepage):
sys.exit()
domain = getDomain(homepage)
print "Enter keyword:"
#keyword = raw_input("> ")
print "Enter maximum branches:"
max_branches = int(raw_input("> "))
links = [homepage]
for n in range(max_branches):
for link in links:
results = extractURLs(link)
for result in results:
if result not in links:
links.append(result)
Partial output(about .000000000001%):
Removing /store/apps/details?id=com.handmark.sportcaster
Removing /store/apps/details?id=com.handmark.sportcaster
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.mobisystems.office
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.joelapenna.foursquared
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.dashlabs.dash.android
Removing /store/apps/details?id=com.eweware.heard
Removing /store/apps/details?id=com.eweware.heard
Removing /store/apps/details?id=com.eweware.heard
You are repeatedly looping over the same link multiple times with your outer loop:
for n in range(max_branches):
for link in links:
results = extractURLs(link)
I would also be careful appending to a list you are iterating over or you could well end up with an infinite loop
Okay, I found a solution. All I did was change the links variable to a dictionary with the values 0 representing a not searched link and 1 representing a searched link. Then I iterated through a copy of the keys in order to preserve the branches and not let it wildly go follow every link that is added on in the loop. And finally if a link is found that is not already in links it is added and set to 0 to be searched.
links = {homepage: 0}
for n in range(max_branches):
for link in links.keys()[:]:
if not links[link]:
results = extractURLs(link)
for result in results:
if result not in links:
links[result] = 0

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