What is the deal about https when using lxml? - python

I am using lxml to parse html files given urls.
For example:
link = 'https://abc.com/def'
htmltree = lxml.html.parse(link)
My code is working well for most of the cases, the ones with http://. However, I found for every https:// url, lxml simply gets an IOError. Does anyone know the reason? And possibly, how to correct this problem?
BTW, I want to stick to lxml than switch to BeautifulSoup given I've already got a quick finished programme.

I don't know what's happening, but I get the same errors. HTTPS is probably not supported. You can easily work around this with urllib2, though:
from lxml import html
from urllib2 import urlopen
html.parse(urlopen('https://duckduckgo.com'))

From the lxml documentation:
lxml can parse from a local file, an HTTP URL or an FTP URL
I don't see HTTPS in that sentence anywhere, so I assume it is not supported.
An easy workaround would be to retrieve the file using some other library that does support HTTPS, such as urllib2, and pass the retrieved document as a string to lxml.

Related

Python 404'ing on urllib.request

The basics of the code are below. I know for a fact how I'm retrieving these pages works for other URLs, as I just wrote a script scraping a different page in the same way. However with this specific URL it keeps throwing "urllib.error.HTTPError: HTTP Error 404: Not Found" in my face. I replaced the URL with a different one (https://www.premierleague.com/clubs), and it works completely fine. I'm very new to python so perhaps there's a really basic step or piece of knowledge I haven't found, but resources I've found on line relating to this didn't seem relevant. Any advice would be great, thanks.
Below is the barebones of the script:
import bs4
from urllib.request import urlopen as uReq
from bs4 import BeautifulSoup as soup
import csv
myurl = "https://www.transfermarkt.co.uk/premier-league/startseite/wettbewerb/GB1"
uClient = uReq(myurl)
The problem is most likely that the site you are trying to access is actively blocking spiders crawling; you can change the user agent to circumvent it. See this question for more information (the solution prescribed in that post seems to work for your url too).
If you want to use urllib this post tells you how to alter the user agent.
It is showing a 404 because it thinks the website doesn't exist.
You can try with a different module like requests.
This is the code for requests
import requests
resp = requests.get("https://www.transfermarkt.co.uk/premier-league/startseite/wettbewerb/GB1")
print(resp.text) # gets source code
I hope it works!

How to get live stream url from script

I need to get the live stream url using a scripting language such as python or shell
eg: http://rt.com/on-air/
I can get the url by using a tool such as the network monitor on Firefox, but i need to be able to get it via a script
After quick look on requests documentation:
from contextlib import closing
with closing(requests.get('http://rt.com/on-air/', stream=True)) as r:
# Do things with the response here.
If it doesn't help, please check another way:
import requests
r = requests.get('http://rt.com/on-air/', stream=True)
for line in r.iter_lines():
# filter out keep-alive new lines
if line:
# do some sort of things
You need to identify it in the source of the page. It is pretty much the same as using the network tool from FF.
For python you can use beautifulsoup to parse the page and get more info out of it... or a simple regex.

Extracting a table from a website

I've tried many times to retrieve the table at this website:
http://www.whoscored.com/Players/845/History/Tomas-Rosicky
(the one under "Historical Participations")
import urllib2
from bs4 import BeautifulSoup
soup = BeautifulSoup(urllib2.urlopen('http://www.whoscored.com/Players/845/').read())
This is the Python code I am using to retrieve the table html, but I am getting an empty string. Help me out!
The desired table is formed via an asynchronous API call to the http://www.whoscored.com/StatisticsFeed/1/GetPlayerStatistics endpoint request to which returns a JSON response. In other words, urllib2 would return you an initial HTML content of the page without the "dynamic" part. In other words, urllib2 is not a browser.
You can study the request using browser developer tools:
Now, you need to simulate this request in your code. requests package is something you should consider using.
Here is a similar question about whoscored.com I've answered before, there is a sample working code you can use as a starting point:
XHR request URL says does not exist when attempting to parse it's content

Unable to get page source code in python

I'm trying to get the source code of a page by using:
import urllib2
url="http://france.meteofrance.com/france/meteo?PREVISIONS_PORTLET.path=previsionsville/750560"
page =urllib2.urlopen(url)
data=page.read()
print data
and also by using a user_agent(headers)
I did not succeed to get the source code of the page!
Have you guys any ideas what can be done?
Thanks in Advance
I tried it and the requests works, but the content that you receive says that your browser must accept cookies (in french). You could probably get around that with urllib2, but I think the easiest way would be to use the requests lib (if you don't mind having an additional dependency).
To install requests:
pip install requests
And then in your script:
import requests
url = 'http://france.meteofrance.com/france/meteo?PREVISIONS_PORTLET.path=previsionsville/750560'
response = requests.get(url)
print(response.content)
I'm pretty sure the source code of the page will be what you expect then.
requests library worked for me as Martin Maillard showed.
Also in another thread I have noticed this note by leoluk here:
Edit: It's 2014 now, and most of the important libraries have been
ported and you should definitely use Python 3 if you can.
python-requests is a very nice high-level library which is easier to
use than urllib2.
So I wrote this get_page procedure:
import requests
def get_page (website_url):
response = requests.get(website_url)
return response.content
print get_page('http://example.com')
Cheers!
I tried a lot of things, "urllib" "urllib2" and many other things, but one thing worked for me for everything I needed and solved any problem I faced. It was Mechanize .This library simulates using a real browser, so it handles a lot of issues in that area.

Python Web Crawlers and "getting" html source code

So my brother wanted me to write a web crawler in Python (self-taught) and I know C++, Java, and a bit of html. I'm using version 2.7 and reading the python library, but I have a few problems
1. httplib.HTTPConnection and request concept to me is new and I don't understand if it downloads an html script like cookie or an instance. If you do both of those, do you get the source for a website page? And what are some words that I would need to know to modify the page and return the modified page.
Just for background, I need to download a page and replace any img with ones I have
And it would be nice if you guys could tell me your opinion of 2.7 and 3.1
Use Python 2.7, is has more 3rd party libs at the moment. (Edit: see below).
I recommend you using the stdlib module urllib2, it will allow you to comfortably get web resources.
Example:
import urllib2
response = urllib2.urlopen("http://google.de")
page_source = response.read()
For parsing the code, have a look at BeautifulSoup.
BTW: what exactly do you want to do:
Just for background, I need to download a page and replace any img with ones I have
Edit: It's 2014 now, most of the important libraries have been ported, and you should definitely use Python 3 if you can. python-requests is a very nice high-level library which is easier to use than urllib2.
An Example with python3 and the requests library as mentioned by #leoluk:
pip install requests
Script req.py:
import requests
url='http://localhost'
# in case you need a session
cd = { 'sessionid': '123..'}
r = requests.get(url, cookies=cd)
# or without a session: r = requests.get(url)
r.content
Now,execute it and you will get the html source of localhost!
python3 req.py
If you are using Python > 3.x you don't need to install any libraries, this is directly built in the python framework. The old urllib2 package has been renamed to urllib:
from urllib import request
response = request.urlopen("https://www.google.com")
# set the correct charset below
page_source = response.read().decode('utf-8')
print(page_source)
The first thing you need to do is read the HTTP spec which will explain what you can expect to receive over the wire. The data returned inside the content will be the "rendered" web page, not the source. The source could be a JSP, a servlet, a CGI script, in short, just about anything, and you have no access to that. You only get the HTML that the server sent you. In the case of a static HTML page, then yes, you will be seeing the "source". But for anything else you see the generated HTML, not the source.
When you say modify the page and return the modified page what do you mean?

Categories

Resources