程序代写代做代考 python Java database junit javascript Assignment 2.0 Scraping the Web
Assignment 2.0 Scraping the Web
Overview
This week, you will be scraping Wikipedia and storing information about actors and movies into
a data structure of your design. You will also write a graph library and a function for converting
your data to a graph. Then you will store the relevant information as a JSON file so you can load
it again without rescraping the website. Finally, you should be able to provide basic information
from your data structure through console output.
Programming Language
Unlike past weeks, this week, you should implement your project in a programming
language which you have not used. For more information, see #Programming Language
Selection.
Motivation and Goals
There are many methods of data collection in the rapidlyevolving world of information and
technology, but web scraping is among the most popular and accurate. In layman’s terms, web
scraping is the act of using bots to extract specific content and data from a website. Web
scraping is especially useful because it has the ability to convert nontabular, nonsensical and
poorly constructed data into something both in format and in content. Web scraping is also
championed for its ability to acquire previouslyinaccessible data. However, webscraping is not
about mere acquisition it can also assist you to track changes, analyze trends and keep tabs
on certain patterns in specific fields.
The purpose of this particular assignment is to introduce you to the realworld application of
webscraping tech, as well as get you thinking about the creative process that accompanies the
tasks you are assigned. There will be a number of directives that you will have to solve both in
this assignment as well as when you graduate and break into industrystandard workplaces, so
keep this in mind as you work on this assignment. Web scraping may be the focus of this
particular assignment, but it very well may be a potential, reallife approach you use in the
future.
For this practice assignment, we will be using Wikipedia as our web source, for a number of
reasons. Although Wikipedia provides database dumps for everything, it is the best source to
use for this exercise because not only does it have fairly uptodate information, it is also legal to
scrape Wikipedia without ramifications or complicated restrictions.
Programming Language Selection
Whatever language you choose, you should use an IDE of your choice (suggestions of Ruby &
Python below):
● Python Consider using PyDev for Eclipse or PyCharm (from the makers of IntelliJ)
● Ruby Consider using a plugin for eclipse or RubyMine (from the makers of IntellIJ)
● Javascript
You can also select a language you would like to learn (ideally something not too obscure), and
contact your moderator or the TAs to ensure that this language is appropriate to use.
Language Selection
http://www.python.org/
http://pydev.org/
http://pydev.org/
http://www.jetbrains.com/pycharm/
http://www.jetbrains.com/pycharm/
http://www.ruby-lang.org/en/
http://stackoverflow.com/questions/524021/preferred-ruby-plugin-for-eclipse
http://stackoverflow.com/questions/524021/preferred-ruby-plugin-for-eclipse
http://www.jetbrains.com/ruby/
http://www.jetbrains.com/ruby/
https://www.javascript.com/
Be aware that the TAs are not familiar with every programming language out there, so
we may or may not be able to provide indepth help with the language you choose. If we
cannot help you, post your question to Piazza since there may be other people in the
course that can help with your problem.
Background
Logging
We are asking you to perform logging as part of your web scraping code.
What is logging?
When a function is called, I log that it has been called along with any passed in arguments,
the time it was called, and in Javascript, the name of the function that called it. I also log
before a function returns, along with the time and any relevant return data. I log when
asynchronous calls return. I log when significant logic changes happen. Erik Hazzard,
How Logging Made me a Better Developer
In short, logging is adding output or log statements to your code that indicates the status of what
is going on while your code is running. Log statements are helpful because they decrease code
complexity, help debugging, increase visibility and assist communication with other developers.
There are several different log levels.
You are not required to use all of these log levels when writing your code, but we expect you to
use at least 3 of the available log levels in the language you are using. For example, for Python
you could log a WARNING level log when you encounter a strangely formatted page that cannot
be understood by your scraper. In addition, we expect you to write meaningful log messages. In
other words, your log message should not be ” logging . warning( ‘Some error’ )” or
” logging . warning( i )”; if we see vague or meaningless messages like this we will take off points.
Using the above example, an acceptable message could be “logging . warning( ‘[page] was not
able to be parsed because filmography section was not found.’ )”. Since the pages you are
scraping will not be uniform in their HTML markup, it is very likely that you will encounter errors
and edge cases as you scrape. Take advantage of logging for these cases!
Here are some resources to get you started:
● Python: Python 2 Logging , Python 3 Logging
● Ruby: Logging with Ruby
● Javascript: Logging with Javascript
You are free to use any library you like for logging in addition to those suggested above.
https://piazza.com/class#spring2013/cs242
https://piazza.com/class#spring2013/cs242
http://vasir.net/blog/development/how-logging-made-me-a-better-developer
http://vasir.net/blog/development/how-logging-made-me-a-better-developer
https://docs.python.org/2/howto/logging.html
https://docs.python.org/2/howto/logging.html
https://docs.python.org/3/howto/logging.html
https://docs.python.org/3/howto/logging.html
https://ruby-doc.org/stdlib-2.1.0/libdoc/logger/rdoc/Logger.html
https://ruby-doc.org/stdlib-2.1.0/libdoc/logger/rdoc/Logger.html
http://log4javascript.org/
http://log4javascript.org/
Graphs
A graph , at least to computer scientists, is a set of vertices and a set of edges that connect
them. Each vertex in a (directed) graph has a set of outgoing edges and a set of incoming
edges. There are many ways to represent a graph in memory, it is up to you to determine which
representation you would like to use. See the image below for a graphical representation of
what your graph might look like:
For this assignment, you should be able to represent each actor and movie as a vertex in your
graph. The weight of an edge should represent the amount of money the actor made from the
movie. However, since this information is not readily available on the Wikipedia page, we leave
the choice of how to represent this up to you. You should not assign the same weight to all your
edges for a given vertex. Here are some examples of what you can do:
● Represent the weight of an edge as the grossing value of the movie, with actors at the top
of the cast list having more weight than those at the bottom of the list.
● Represent the weight of an edge as the grossing value of the movie, with young actors
being weighed more than older actors
● Represent the weight of an edge as the grossing value of the movie, with actors who have
been in more movies having more weight than those who have been in fewer movies.
Also, your graph will need to be augmented to hold extra data about each movie. You will have
to adapt your implementation to handle this extra data. Note that in our case the graph is
undirected because if an actor is in the movie then the movie definitely contains that actor.
JSON
We are asking you to store your scraped data as a JSON file.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight datainterchange format. It is easy for
humans to read and write. It is easy for machines to parse and generate. json.org
JSON is most commonly used in web applications, as a lightweight format to transfer data
asynchronously between a client and server. For instance, Facebook transmits status updates
to your newsfeed using JSON so that new posts appear without having to reload the page. But,
JSON is not limited to web applications. Parsers for JSON are available for just about every
language out there. See http://www.json.org for parsers for some of the most common
programming languages. It would be wise for you to pick a language for this assignment that
already has well developed parser. For instance, JSON parsing is built into Python’s core library.
https://secure.wikimedia.org/wikipedia/en/wiki/Graph_%28data_structure%29
https://secure.wikimedia.org/wikipedia/en/wiki/Graph_%28data_structure%29
http://json.org/
http://json.org/
http://www.json.org/
http://www.json.org/
You can read more about JSON on Wikipedia .
Part 0: Reading
Before you begin web scraping, make sure to read the following links:
● https://www.scrapehero.com/howtopreventgettingblacklistedwhilescraping/
● https://www.promptcloud.com/blog/dontgetblacklistedlegitimatewebscrapingprocess
● https://www.promptcloud.com/blog/sometrapstoavoidinwebscraping/
To avoid harming the website, please avoid extensive scraping. Be a responsible scraper!
Part I: Web Scraping
Here’s what you will need to do:
● Write a web scraper to gather information from pages on Wikipedia. You should gather
information from a large amount of movies page (>125) and actor pages (>250). The
choice of the starting page is up to you, but feel free to start here:
https://en.wikipedia.org/wiki/Morgan_Freeman
● Store grossing information for movies and age for actors.
● Log messages to a log file as you scrape. You should log at least three different levels of
messages; messages should be appropriate and meaningful .
You can not use the Wikipedia API; however, feel free to use whatever scraping API your
language supports. Here are some of our recommended libraries:
● Python: BeautifulSoup ( Documentation ), Scrapy
● Ruby: Nokogiri
● Javascript: Node.js , Scraping with Node.js
Your web scraper should not run for longer than 10 minutes with the requirements we have
given you. For your live testing in section, if your scraper takes longer than your time slot (20
minutes in a 6 person section), you will not receive credit for that part of the rubric!
Part II: Graph Library
Next, you will need to create a general graph library for your application.
You can not use any existing graph library to handle the representation of your graph in
memory. That is, you need to write your own graph implementation for this assignment. For
this section, implement a general graph library that will hold the data you parse and interact with
in the following sections.
Testing
Just as with past assignments, you should test your code thoroughly using unit tests. Your
tests should be automated, and perform asserts similar to jUnit, using a unit test library
available in your language of choice. Contact the course staff or post on Piazza if you have
trouble finding a test suite in your language.
You are required to be able to convert your web scraped data into a graph structure. This will be
important for next week. However, how you choose to represent your web scraped data in order
to do the following parts (III and IV) is up to your choice.
https://secure.wikimedia.org/wikipedia/en/wiki/JSON
https://secure.wikimedia.org/wikipedia/en/wiki/JSON
https://en.wikipedia.org/wiki/Morgan_Freeman
https://www.crummy.com/software/BeautifulSoup/
https://www.crummy.com/software/BeautifulSoup/
https://beautiful-soup-4.readthedocs.io/en/latest/
https://scrapy.org/
https://scrapy.org/
http://www.nokogiri.org/
http://www.nokogiri.org/
https://nodejs.org/en/
https://nodejs.org/en/
https://www.codementor.io/johnnyb/how-to-write-a-web-scraper-in-nodejs-du108266t
https://www.codementor.io/johnnyb/how-to-write-a-web-scraper-in-nodejs-du108266t
https://piazza.com/class#spring2013/cs242
https://piazza.com/class#spring2013/cs242
Part III : JSON Storage and Retrieval
You should be able to
1. Store your data structure as a JSON file
2. Load your data structure from a JSON file
You can use any existing JSON library you wish for this task.
Part IV : Graph Queries
Your code should have methods that allow the user to:
1. Find how much a movie has grossed
2. List which movies an actor has worked in
3. List which actors worked in a movie
4. List the top X actors with the most total grossing value
5. List the oldest X actors
6. List all the movies for a given year
7. List all the actors for a given year
All of this information should be calculated at query time and not be hardcoded into your
source. Be prepared to run these methods and produce console output for your moderator in
section.
Testing
As usual, we require that you write extensive unit tests for each part of this assignment. We
understand that it can be difficult to test for web scraping. However, make sure to exhaustively
test all other parts of your code. If your language does not have a testing framework (unlikely),
you will need to implement your own test runner and utilities to accomplish this part of the
assignment. In order to test your web scraper, your moderator will ask you to scrape an
actor/movie page of their choice in section, so be prepared .
Summary
Table of Contents
Reading
● Code Complete Chapter 7: HighQuality Routines
● Optional: The Pragmatic Programmer Chapter 526: Decoupling and the Law of Demeter
➔ The readings are due before lectures every Friday.
Submission
This assignment is due at the beginning of your discussion section the week of October
8th, 2018 . Please be sure to submit in GitLab, and ask your moderator or TA before the
deadline if you have any questions.
Objectives
● Learn about responsible web scraping
● Learn a new programming language
● Learn about graphs and how to implement them
● Learn to work with data in JSON format
● Learn how to effectively decompose your code into reusable modules
Resources
● Python
● Ruby
● Javascript
● JSON Homepage
● JSON Wikipedia
● Graphs
Grading
Category Weight Scorin
g
Notes
Basic
Preparation
2 01 Ready to go at the start of section
Cleverness 2 02 The hardest points on the rubric
Code
Submission
4 02 Submitted on time and to the correct location in the
repository
Decomposition 4 02 Reference Wiki Grading Page for more information
Documentation 4 02 Reference Wiki Grading Page for more information
Effort 2 02 Reference Wiki Grading Page for more information
Naming 2 02 Reference Wiki Grading Page for more information
Overall Design 5 02.5 Reference Wiki Grading Page for more information
Participation 5 02.5 Reference Wiki Grading Page for more information
Presentation 4 02 Reference Wiki Grading Page for more information
Requirements
Web scraping
and queries
5 02.5 ● 0 points: Lacks any form of a Web Scraper, or
utilizes nonscraping library to fetch
information
● 1 points: Has a semifunctional Web Scraper
(may crash on certain web pages, or fails to
reach threshold), lacks full querying
functionality
● 2 points: Functional Scraper reaches the
minimum threshold, allows for simple queries
● 2.5 points: Scraper is fully functional and
covers the various webpage designs, can
http://www.json.org/
http://www.json.org/
http://www.python.org/
http://www.ruby-lang.org/en/
https://www.javascript.com/
http://www.json.org/
https://secure.wikimedia.org/wikipedia/en/wiki/JSON
https://secure.wikimedia.org/wikipedia/en/wiki/Graph_%28data_structure%29
process advanced queries (beyond what is
mentioned on the wiki)
Requirements
Logging
2 01 ● 0 points: Lacks Logger or logger does not
provide relevant details
● 1 point: Logger uses tags to id messages and
provides relevant information to understand
programing execution
Requirements
Programming
Language
2 01 Using an appropriate programming language.
Requirements
Graph Library
2 01 ● 0 points: Data Structures hold no semblance to
a graph library
● 1 point: Data Structures follow some graph
library design, and allow for easy graph
traversal functionality
Requirements
JSON storage
and retrieval
2 01 ● 0 points: No JSON storage/retrieval
● 1 point: Functional JSON storage/retrieval
Testing Graph
Construction
4 02 ● 0 points: No unit tests
● 1 point: Sub 80% code coverage or unit tests
fail to cover graph related functionality
● 2 points: 80%+ code coverage on data
structures, unit tests cover graph related
functionality
Testing Live
Testing
4 02 ● 0 points: Scraper fails to grab any pertinent
information or fails immediately
● 1 point: Scraper fails to reach the required limit
● 2 points: Scraper succeeds in scraping enough
information to reach the specified limits
Total 55
