Application to download web pages and extract bits through regex?

littlebigman · 05-13-2015, 06:06 AM

Hello

I need to download a few pages regularly and extract some parts by using a regular expression and save them into files.

Before writing a script in eg. Python, I was wondering if there were a Linux app that could do this.

I was thinking of using a batch file such as the following pseudo-code, with a way to loop through a list of URLs, and run this script through CRON every night:

Code:

wget -O page1.html http://www.acme.com/page1.html
regex -O page1.infos "<title>(.+?)</title>" page1.html

Is there some tool that can do this simply?

Thank you.

millgates · 05-13-2015, 06:45 AM

It is generally not a good idea to parse xml, html, etc. with regexp unless the document is very simple and you put considerable constraints on its format and you can define very well what you're looking for. There are some command line utilities such as xmlstarlet better suited for the job. Also, any advanced scripting language (perl, python, ruby,...) will have a selection of modules available for parsing xml, html, etc.

littlebigman · 05-14-2015, 05:11 AM

Thanks for the tip.

At this point, XMLStarlet stops while downloading and parsing a web page I threw at it, but I'll keep trying, possibly with other similar tools (Xidel, etc.)

syg00 · 05-14-2015, 06:55 AM

Must admit I just use sed and/or grep. Perl has a module to handle {HT,X}ML, but for simple stuff I keep it simple.
And pages seem to change as fashions change, so editting (of scripts) is needed anyway.

schneidz · 05-14-2015, 07:13 AM

i usually just carve things up with wget grep sed awk cut ...

heres an example of an xbmc site scraper that i made for the onion that used to work before they updated their site:

Code:

'''This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
'''

import re
import urllib2
import xbmcgui, xbmcplugin

plugin_handle = int(sys.argv[1])

def add_video_item(url, infolabels, img=''):
    listitem = xbmcgui.ListItem(infolabels['title'], iconImage=img, 
                                thumbnailImage=img)
    listitem.setInfo('video', infolabels)
    listitem.setProperty('IsPlayable', 'true')
    xbmcplugin.addDirectoryItem(plugin_handle, url, listitem, isFolder=False)
                                
html = urllib2.urlopen('http://www.theonion.com/feeds/onn/').read()
for v in re.finditer('file=(http.+?.mp4)|<title>(.+?)<\/title>|<pubDate>(.+?)<\/pubDate>', html):
    filename, title, date = v.groups()
    if filename:
       s1 = filename
    if title:
       s2 = title
    if date:
       y = date.split(" ")[3]
       if date.split(" ")[2] == 'Jan':
          m = "01"
       if date.split(" ")[2] == 'Feb':
          m = "02"
       if date.split(" ")[2] == 'Mar':
          m = "03"
       if date.split(" ")[2] == 'Apr':
          m = "04"
       if date.split(" ")[2] == 'May':
          m = "05"
       if date.split(" ")[2] == 'Jun':
          m = "06"
       if date.split(" ")[2] == 'Jul':
          m = "07"
       if date.split(" ")[2] == 'Aug':
          m = "08"
       if date.split(" ")[2] == 'Sep':
          m = "09"
       if date.split(" ")[2] == 'Oct':
          m = "10"
       if date.split(" ")[2] == 'Nov':
          m = "11"
       if date.split(" ")[2] == 'Dec':
          m = "12"
       d = date.split(" ")[1]
#       print "s1 = ", s1, " s2 = ", s2, " date = ", date, " y = ", y, " m = ", m, " d = ", d
#       add_video_item('s'  (s1), {'title': 's (%s)' % (s2, date), 'aired': '%s-%s-%s' % y, m, d}, 'http://o.onionstatic.com/img/onn/podcast_300300.jpg')  # for some reason it crashes on this line so i stubbed in the random date below.
       add_video_item('%s' % (s1), {'title': '%s (%s)' % (s2, date), 'aired': '11-11-2010'}, 'http://o.onionstatic.com/img/onn/podcast_300300.jpg')


xbmcplugin.endOfDirectory(plugin_handle)

littlebigman · 05-14-2015, 08:18 AM

Thanks much. I was indeed thinking of going the wget + grep/sed, although XML parsers look like a better way provided the HTML source file is clean enough.