webscraping an image with python but can't find image

Question

I'm trying to scrape stockcharts.com for the chart image from a url. For example from: http://stockcharts.com/h-sc/ui?s=AMZN

however, when inspecting the element in question, it is not a proper image src with a .jpg, .png, etc. suffix. For example the element in question from the above link is: http://stockcharts.com/c-sc/sc?s=AMZN&p=D&b=5&g=0&i=0&r=1479451634864

and therefore when I try to use the following code in python 2.7, I get an empty file in the directory sharing the script:

import urllib
url = "http://stockcharts.com/c-sc/sc?s=AMZN&p=D&b=5&g=0&i=0&r=1479451634864"
filename = "testimg.jpg"
urllib.urlretrieve(url, filename)

Is this a javascript rendered page, or is there something that I'm missing? A reference to elsewhere?

Answer 1

The site checks User-Agent header; It allows specific user-agents only.

You need to change the header to fetch the image. Otherwise, the site returns a 403 Forbidden response.

urllib.urlretrieve does not accept additional headers, you need to use urllib2.urlopen / urllib2.Request to specify custom headers and save file yourself:

import urllib2

url = "http://stockcharts.com/c-sc/sc?s=AMZN&p=D&b=5&g=0&i=0&r=1479451634864"
filename = "sc.png"
req = urllib2.Request(url, headers={'User-Agent': 'Mozilla/5.0'})
u = urllib2.urlopen(req)
with open(filename, 'wb') as f:
    f.write(u.read())