Description
ISTA 350
Introduction. This homework is the first part of an introduction to the art of web scraping. It is a threepart assignment. In the first part, you will grab the data you need from the web, put it into an html
parser, and save the result into a file. Along the way, you will meet the os, requests, bs4, and zlib
(or gzip) modules. The test will take a really long time to run and generate a huge number of
warnings. Just wait.
Instructions. Create a module named hw6.py. Below is the spec for three functions and main.
Implement them and upload your module to the D2L dropbox.
Testing. Download hw6_test.py and the associated files necessary for testing and put them in the
same folder as your hw6.py module. Run it from the command line to see your current correctness
score. Each of the four functions in hw6.py is worth 25% of your correctness score. The test file we
will use to grade your program will be different and may uncover failings in your work not evident upon
testing with the provided file. Add any necessary tests to make sure your code works in all cases.
Documentation. Your modules must contain a header docstring containing your name, your section
leader’s name, the date, ISTA 350 Hw6, and a brief summary of the module. Each method/function
must contain a docstring. Each docstring should include a description of the function’s purpose, the
name, type, and purpose of each parameter, and the type and meaning of the function’s return value.
Grading. Your module will be graded on correctness, documentation, and coding style. Code should be
clear and concise. You will only lose style points if your code is a real mess. Include inline comments to
explain tricky lines and summarize sections of code (not necessary on this assignment).
Collaboration. Collaboration is allowed. You are responsible for your learning. Depending too much on
others will hurt you on the tests. “Helping” others too much harms them in reality. Cite any
sources/collaborators in your header docstring. Leaving this out is dishonest.
Resources.
https://docs.python.org/3.7/library/os.html
https://stackoverflow.com/questions/27803503/get-html-using-python-requests
https://requests.readthedocs.io/en/master/
https://realpython.com/python-requests/
https://pypi.python.org/pypi/beautifulsoup4/
http://www.crummy.com/software/BeautifulSoup/bs4/doc/
http://www.zlib.net/manual.html
https://docs.python.org/3.7/library/zlib.html
hw6.py:
get_soup: this function has three parameters. The first is a string representing a URL and has a
default argument of None. The second is a string named fname representing a filename also with
default argument of None. The third is a Boolean named gzipped with a default value of False.
True is passed to this parameter if the html to be parsed is gzipped. If the filename is not None, open
the file, pass the resulting file pointer to the BeautifulSoup constructor, and return the resulting
object. Otherwise, if the url is None, raise a RuntimeError with the message ‘Either url or
filename must be specified.’ If it is not None, send a get request to the server. If the
response content is zipped (third parameter), unzip it. Pass the content to the BeautifulSoup
constructor and return the resulting object.
save_soup: this function takes two arguments, a filename and a soup object. Save a textual
representation of the soup object in the file.
scrape_and_save: this function scrapes the following addresses, soupifies the contents, and stores
a textual representation of these objects in the files ‘wrcc_pcpn.html’, ‘wrcc_mint.html’,
and ‘wrcc_maxt.html’, respectively:
http://www.wrcc.dri.edu/WRCCWrappers.py?sodxtrmts+028815+por+por+pcpn+none+msum+5+01+F
http://www.wrcc.dri.edu/WRCCWrappers.py?sodxtrmts+028815+por+por+mint+none+mave+5+01+F
http://www.wrcc.dri.edu/WRCCWrappers.py?sodxtrmts+028815+por+por+maxt+none+mave+5+01+F
main: check the current directory for any one of the files that scrape_and_save creates. If it is not
there, print ‘—- scraping and saving —-‘ and scrape and save the addresses. You can
find out if a file exists in the current working directory using functionality provided by either the os
module or the os.path module. Google them to learn more.
