I am trying to create a website downloader using python. I have the code for:
Finding all URLs from a page
Downloading a given URL
What I have to do is to recursively download a page, and if there's any other link in that page, I need to download them also. I tried combining the above two functions, but recursion thing doesn't work.
The codes are given below:
1)
*from sgmllib import SGMLParser
class URLLister(SGMLParser):
def reset(self):
SGMLParser.reset(self)
self.urls = []
def start_a(self, attrs):
href = [v for k, v in attrs if k=='href']
if href:
self.urls.extend(href)
if __name__ == "__main__":
import urllib
wanted_url=raw_input("Enter the URL: ")
usock = urllib.urlopen(wanted_url)
parser = URLLister()
parser.feed(usock.read())
parser.close()
usock.close()
for url in parser.urls: download(url)*
2) where download(url) function is defined as follows:
*def download(url):
import urllib
webFile = urllib.urlopen(url)
localFile = open(url.split('/')[-1], 'w')
localFile.write(webFile.read())
webFile.close()
localFile.cl开发者_运维技巧ose()
a=raw_input("Enter the URL")
download(a)
print "Done"*
Kindly help me on how to combine these two codes to "recursively" download the new links on a webpage that's being downloaded.
You may want to look into the Scrapy library.
It would make a task like this pretty trivial, and allow you to download multiple pages concurrently.
done_url = []
def download(url):
if url in done_url:return
...download url code...
done_url.append(url)
urls = sone_function_to_fetch_urls_from_this_page()
for url in urls:download(url)
This is a very sad/bad code. For example you will need to check if the url is within the domain you want to crawl or not. However, you asked for recursive.
Be mindful of the recursion depth.
There are just so many things wrong with my solution. :P
You must try some crawling library like Scrapy or something.
Generally, the idea is this:
def get_links_recursive(document, current_depth, max_depth):
links = document.get_links()
for link in links:
downloaded = link.download()
if current_depth < max_depth:
get_links_recursive(downloaded, depth-1, max_depth)
Call get_links_recursive(document, 0, 3) to get things started.
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