a checker of links in python - python

I have to create a function in python which searches links in an HTML page and then for every link, check if the link is broken or not.
Firstly I've created a function which searches every link (broken or not), no problem and stores them in a array called "g".
Secondly, I thought to create an array "a" which contains only the broken links by checking every item/element in array "g".
I don't know why, the check link by link doesn't work in the function. But if I copy a link and paste it like a parameter in function on the shell, it works.
import urllib.request
import re
import urllib.error
def check(url):
try:
f= urllib.request.urlopen(url)
except urllib.error.HTTPError :
return False
return True
def trouveurdurls(url):
f= urllib.request.urlopen(url)
b=(f.read().decode('utf-8'))
d=re.findall('<a href=".*</a>',b)
liste=[]
f.close()
for el in d:
g=re.findall('"https?://.*\.*"',el)
liste.append(g)
a=[]
for el in liste:
chaine= ''.join(map(str,el))
url=chaine.replace('\'','')
print(url)
#check(url)
b=trouveurdurls("http://127.0.0.1/")

I'd be very surprised if the line
d=re.findall('<a href=".*</a>',b)
worked correctly. The asterisk is doing a greedy match, meaning that it finds the longest possible match. If you have more than a single link in your document, this regex will gobble up everything between the first and the end of the last link.
You should probably use the non-greedy version of the asterisk, e.g. *?.
Also, you're only interested in the href attribute, so
d = re.findall('<a href=".*?"', b)
is probably what you want. This will make the following code easier; you won't need to try and look for urls starting with http:// because you'll already have them in the d array. Your code as it is would also find urls that weren't part of an a's href attribute but just part of the normal text, or part of an image reference, etc.
Note that even the regex <a href=".*?" won't constantly produce matches, because HTML is very lazy with it's syntax, so you might also encounter strings like <A HREF='.....'>, <a href = "....., <a id="something" href="......"> and so on.
You'll have to either improve the regex to match all such cases, or turn to BeautifulSoup like Evan's answer or a full-fledged HTML parser that takes care of it for you.

Here's a version that uses "requests." It scrapes the page for urls, then checks each of the urls for their Response codes (200 means it worked, etc).
import requests
from bs4 import BeautifulSoup
page = 'http://the.web.site'
r = requests.get(page)
data = r.text
soup = BeautifulSoup(data, 'lxml')
urls = []
for a in soup.find_all('a'):
urls.append(a.get('href'))
url_responses = {}
for url in urls:
temp_r = requests.get(url)
url_responses[url] = temp_r.status_code

Related

Extracting a specific substring from a specific hyper-reference using Python

I'm new to Python, and for my second attempt at a project, I wanted to extract a substring – specifically, an identifying number – from a hyper-reference on a url.
For example, this url is the result of my search query, giving the hyper-reference http://www.chessgames.com/perl/chessgame?gid=1012809. From this I want to extract the identifying number "1012809" and append it to navigate to the url http://www.chessgames.com/perl/chessgame?gid=1012809, after which I plan to download the file at the url http://www.chessgames.com/pgn/alekhine_naegeli_1932.pgn?gid=1012809 . But I am currently stuck a few steps behind this because I can't figure out a way to extract the identifier.
Here is my MWE:
from bs4 import BeautifulSoup
url = 'http://www.chessgames.com/perl/chess.pl?yearcomp=exactly&year=1932&playercomp=white&pid=&player=Alekhine&pid2=&player2=Naegeli&movescomp=exactly&moves=&opening=&eco=&result=1%2F2-1%2F2'
page = urllib2.urlopen(url)
soup = BeautifulSoup(page, 'html.parser')
import re
y = str(soup)
x = re.findall("gid=[0-9]+",y)
print x
z = re.sub("gid=", "", x(1)) #At this point, things have completely broken down...
As Albin Paul commented, re.findall return a list, you need to extract elements from it. By the way, you don't need BeautifulSoup here, use urllib2.urlopen(url).read() to get the string of the content, and the re.sub is also not needed here, one regex pattern (?:gid=)([0-9]+) is enough.
import re
import urllib2
url = 'http://www.chessgames.com/perl/chess.pl?yearcomp=exactly&year=1932&playercomp=white&pid=&player=Alekhine&pid2=&player2=Naegeli&movescomp=exactly&moves=&opening=&eco=&result=1%2F2-1%2F2'
page = urllib2.urlopen(url).read()
result = re.findall(r"(?:gid=)([0-9]+)",page)
print(result[0])
#'1012809'
You don't need regex here at all. Css selector along with string manipulation will lead you to the right direction. Try the below script:
import requests
from bs4 import BeautifulSoup
page_link = 'http://www.chessgames.com/perl/chess.pl?yearcomp=exactly&year=1932&playercomp=white&pid=&player=Alekhine&pid2=&player2=Naegeli&movescomp=exactly&moves=&opening=&eco=&result=1%2F2-1%2F2'
soup = BeautifulSoup(requests.get(page_link).text, 'lxml')
item_num = soup.select_one("[href*='gid=']")['href'].split("gid=")[1]
print(item_num)
Output:
1012809

Beautiful Soup Nested Tag Search

I am trying to write a python program that will count the words on a web page. I use Beautiful Soup 4 to scrape the page but I have difficulties accessing nested HTML tags (for example: <p class="hello"> inside <div>).
Every time I try finding such tag using page.findAll() (page is Beautiful Soup object containing the whole page) method it simply doesn't find any, although there are. Is there any simple method or another way to do it?
Maybe I'm guessing what you are trying to do is first looking in a specific div tag and the search all p tags in it and count them or do whatever you want. For example:
soup = bs4.BeautifulSoup(content, 'html.parser')
# This will get the div
div_container = soup.find('div', class_='some_class')
# Then search in that div_container for all p tags with class "hello"
for ptag in div_container.find_all('p', class_='hello'):
# prints the p tag content
print(ptag.text)
Hope that helps
Try this one :
data = []
for nested_soup in soup.find_all('xyz'):
data = data + nested_soup.find_all('abc')
Maybe you can turn in into lambda and make it cool, but this works. Thanks.
UPDATE: I noticed that text does not always return the expected result, at the same time, I realized there was a built-in way to get the text, sure enough reading the docs
we read that there is a method called get_text(), use it as:
from bs4 import BeautifulSoup
fd = open('index.html', 'r')
website= fd.read()
fd.close()
soup = BeautifulSoup(website)
contents= soup.get_text(separator=" ")
print "number of words %d" %len(contents.split(" "))
INCORRECT, please read above.Supposing that you have your html file locally in index.html you can:
from bs4 import BeautifulSoup
import re
BLACKLIST = ["html", "head", "title", "script"] # tags to be ignored
fd = open('index.html', 'r')
website= fd.read()
soup = BeautifulSoup(website)
tags=soup.find_all(True) # find everything
print "there are %d" %len(tags)
count= 0
matcher= re.compile("(\s|\n|<br>)+")
for tag in tags:
if tag.name.lower() in BLACKLIST:
continue
temp = matcher.split(tag.text) # Split using tokens such as \s and \n
temp = filter(None, temp) # remove empty elements in the list
count +=len(temp)
print "number of words in the document %d" %count
fd.close()
Please note that it may not be accurate, maybe because of errors in formatting, false positives(it detects any word, even if it is code), text that is shown dynamically using javascript or css, or other reason
You can find all <p> tags using regular expressions (re module).
Note that r.content is a string which contains the whole html of the site.
for eg:
r = requests.get(url,headers=headers)
p_tags = re.findall(r'<p>.*?</p>',r.content)
this should get you all the <p> tags irrespective of whether they are nested or not. And if you want the a tags specifically inside the tags you can add that whole tag as a string in the second argument instead of r.content.
Alternatively if you just want just the text you can try this:
from readability import Document #pip install readability-lxml
import requests
r = requests.get(url,headers=headers)
doc = Document(r.content)
simplified_html = doc.summary()
this will get you a more bare bones form of the html from the site, and now proceed with the parsing.

How to find all (complete) sublinks from a web page using lxml in Python

The following code takes a URL and returns a list of links to pages that are contained on the original url page.
import urllib
import lxml.html
def getSubLinks(url):
sublinks = []
connection = urllib.urlopen(url)
dom = lxml.html.fromstring(connection.read())
for link in dom.xpath('//a/#href'):
sublinks.append(link)
return sublinks
This seems to work, except for, for pages on the same domain it strips the domain from the URL and this is not what I want. I want to get the full unaltered link back. For example, using this on the webpage:
"http://www.nufc.com"
returns the list (and much more):
['http://www.altoonativetravel.com/', 'index.htm', '2015-16html/fixtures.html', .....
However as you can see the preceding "http://www.nufc.com" has been stripped from '2015-16html/fixtures.html' and others whereas I do not want this to happen, I want 'http://www.nufc.com/2015-16html/fixtures.html'. How can I fix this?
You could use the following:
import urllib
import lxml.html
def getSubLinks(url):
sublinks = []
connection = urllib.urlopen(url)
dom = lxml.html.fromstring(connection.read())
for link in dom.xpath('//a/#href'):
if not link.startswith('http'):
sublinks.append(url+link)
else:
sublinks.append(link)
return sublinks
When calling your function, use getSubLinks('http://www.nufc.com/') (note the / at the end of the URL).
This loops over each of the href attributes of the a tags on the page. For each link, if the link doesn't start with "http", it will append url+link, ie "http://www.nufc.com/" + link. This will generate your desired results set.

Downloading files from multiple websites.

This is my first Python project so it is very basic and rudimentary.
I often have to clean off viruses for friends and the free programs that I use are updated often. Instead of manually downloading each program, I was trying to create a simple way to automate the process. Since I am also trying to learn python I thought it would be a good opportunity to practice.
Questions:
I have to find the .exe file with some of the links. I can find the correct URL, but I get an error when it tries to download.
Is there a way to add all of the links into a list, and then create a function to go through the list and run the function on each url? I've Google'd quite a bit and I just cannot seem to make it work. Maybe I am not thinking in the right direction?
import urllib, urllib2, re, os
from BeautifulSoup import BeautifulSoup
# Website List
sas = 'http://cdn.superantispyware.com/SUPERAntiSpyware.exe'
tds = 'http://support.kaspersky.com/downloads/utils/tdsskiller.exe'
mbam = 'http://www.bleepingcomputer.com/download/malwarebytes-anti-malware/dl/7/?1'
tr = 'http://www.simplysup.com/tremover/download.html'
urllist = [sas, tr, tds, tr]
urrllist2 = []
# Find exe files to download
match = re.compile('\.exe')
data = urllib2.urlopen(urllist)
page = BeautifulSoup(data)
# Check links
#def findexe():
for link in page.findAll('a'):
try:
href = link['href']
if re.search(match, href):
urllist2.append(href)
except KeyError:
pass
os.chdir(r"C:\_VirusFixes")
urllib.urlretrieve(urllist2, os.path.basename(urllist2))
As you can see, I have left the function commented out as I cannot get it to work correctly.
Should I abandon the list and just download them individually? I was trying to be efficient.
Any suggestions or if you could point me in the right direction, it would be most appreciated.
In addition to mikez302's answer, here's a slightly more readable way to write your code:
import os
import re
import urllib
import urllib2
from BeautifulSoup import BeautifulSoup
websites = [
'http://cdn.superantispyware.com/SUPERAntiSpyware.exe'
'http://support.kaspersky.com/downloads/utils/tdsskiller.exe'
'http://www.bleepingcomputer.com/download/malwarebytes-anti-malware/dl/7/?1'
'http://www.simplysup.com/tremover/download.html'
]
download_links = []
for url in websites:
connection = urllib2.urlopen(url)
soup = BeautifulSoup(connection)
connection.close()
for link in soup.findAll('a', {href: re.compile(r'\.exe$')}):
download_links.append(link['href'])
for url in download_links:
urllib.urlretrieve(url, r'C:\_VirusFixes', os.path.basename(url))
urllib2.urlopen is a function for accessing a single URL. If you want to access multiple ones, you should loop over the list. You should do something like this:
for url in urllist:
data = urllib2.urlopen(url)
page = BeautifulSoup(data)
# Check links
for link in page.findAll('a'):
try:
href = link['href']
if re.search(match, href):
urllist2.append(href)
except KeyError:
pass
os.chdir(r"C:\_VirusFixes")
urllib.urlretrieve(urllist2, os.path.basename(urllist2))
The code above didn't work for me, in my case it was because the pages assemble their links through a script instead of including it in the code. When I ran into that problem I used the following code which is just a scraper:
import os
import re
import urllib
import urllib2
from bs4 import BeautifulSoup
url = ''
connection = urllib2.urlopen(url)
soup = BeautifulSoup(connection) #Everything the same up to here
regex = '(.+?).zip' #Here we insert the pattern we are looking for
pattern = re.compile(regex)
link = re.findall(pattern,str(soup)) #This finds all the .zip (.exe) in the text
x=0
for i in link:
link[x]=i.split(' ')[len(i.split(' '))-1]
# When it finds all the .zip, it usually comes back with a lot of undesirable
# text, luckily the file name is almost always separated by a space from the
# rest of the text which is why we do the split
x+=1
os.chdir("F:\Documents")
# This is the filepath where I want to save everything I download
for i in link:
urllib.urlretrieve(url,filename=i+".zip") # Remember that the text we found doesn't include the .zip (or .exe in your case) so we want to reestablish that.
This is not as efficient as the codes in the previous answers but it will work for most almost any site.

Write a python script that goes through the links on a page recursively

I'm doing a project for my school in which I would like to compare scam mails. I found this website: http://www.419scam.org/emails/
Now what I would like to do is to save every scam in apart documents then later on I can analyse them.
Here is my code so far:
import BeautifulSoup, urllib2
address='http://www.419scam.org/emails/'
html = urllib2.urlopen(address).read()
f = open('test.txt', 'wb')
f.write(html)
f.close()
This saves me the whole html file in a text format, now I would like to strip the file and save the content of the html links to the scams:
01
02
03
etc.
If i get that, I would still need to go a step further and open save another href. Any idea how do I do it in one python code?
Thank you!
You picked the right tool in BeautifulSoup. Technically you could do it all do it in one script, but you might want to segment it, because it looks like you'll be dealing with tens of thousands of e-mails, all of which are seperate requests - and that will take a while.
This page is gonna help you a lot, but here's just a little code snippet to get you started. This gets all of the html tags that are index pages for the e-mails, extracts their href links and appends a bit to the front of the url so they can be accessed directly.
from bs4 import BeautifulSoup
import re
import urllib2
soup = BeautifulSoup(urllib2.urlopen("http://www.419scam.org/emails/"))
tags = soup.find_all(href=re.compile("20......../index\.htm")
links = []
for t in tags:
links.append("http://www.419scam.org/emails/" + t['href'])
're' is a Python's regular expressions module. In the fifth line, I told BeautifulSoup to find all the tags in the soup whose href attribute match that regular expression. I chose this regular expression to get only the e-mail index pages rather than all of the href links on that page. I noticed that the index page links had that pattern for all of their URLs.
Having all the proper 'a' tags, I then looped through them, extracting the string from the href attribute by doing t['href'] and appending the rest of the URL to the front of the string, to get raw string URLs.
Reading through that documentation, you should get an idea of how to expand these techniques to grab the individual e-mails.
You might also find value in requests and lxml.html. Requests is another way to make http requests and lxml is an alternative for parsing xml and html content.
There are many ways to search the html document but you might want to start with cssselect.
import requests
from lxml.html import fromstring
url = 'http://www.419scam.org/emails/'
doc = fromstring(requests.get(url).content)
atags = doc.cssselect('a')
# using .get('href', '') syntax because not all a tags will have an href
hrefs = (a.attrib.get('href', '') for a in atags)
Or as suggested in the comments using .iterlinks(). Note that you will still need to filter if you only want 'a' tags. Either way the .make_links_absolute() call is probably going to be helpful. It is your homework though, so play around with it.
doc.make_links_absolute(base_url=url)
hrefs = (l[2] for l in doc.iterlinks() if l[0].tag == 'a')
Next up for you... how to loop through and open all of the individual spam links.
To get all links on the page you could use BeautifulSoup. Take a look at this page, it can help. It actually tells how to do exactly what you need.
To save all pages, you could do the same as what you do in your current code, but within a loop that would iterate over all links you'll have extracted and stored, say, in a list.
Heres a solution using lxml + XPath and urllib2 :
#!/usr/bin/env python2 -u
# -*- coding: utf8 -*-
import cookielib, urllib2
from lxml import etree
cj = cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
page = opener.open("http://www.419scam.org/emails/")
page.addheaders = [('User-agent', 'Mozilla/5.0')]
reddit = etree.HTML(page.read())
# XPath expression : we get all links under body/p[2] containing *.htm
for node in reddit.xpath('/html/body/p[2]/a[contains(#href,".htm")]'):
for i in node.items():
url = 'http://www.419scam.org/emails/' + i[1]
page = opener.open(url)
page.addheaders = [('User-agent', 'Mozilla/5.0')]
lst = url.split('/')
try:
if lst[6]: # else it's a "month" link
filename = '/tmp/' + url.split('/')[4] + '-' + url.split('/')[5]
f = open(filename, 'w')
f.write(page.read())
f.close()
except:
pass
# vim:ts=4:sw=4
You could use HTML parser and specify the type of object you are searching for.
from HTMLParser import HTMLParser
import urllib2
class MyHTMLParser(HTMLParser):
def handle_starttag(self, tag, attrs):
if tag == 'a':
for attr in attrs:
if attr[0] == 'href':
print attr[1]
address='http://www.419scam.org/emails/'
html = urllib2.urlopen(address).read()
f = open('test.txt', 'wb')
f.write(html)
f.close()
parser = MyHTMLParser()
parser.feed(html)

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