Aggregating data with Portia
Itsy, Bitsy Spider
Are you interested in retrieving stock quotes in machine-readable form off the Internet? No problem: After a few mouse clicks, Portia weaves a command line and wraps the data in JSON format.
The Internet is a treasure trove of useful information, often residing on colorful HTML pages that are not easily extracted and processed. If you want to automate processing of current stock quotes or aggregate news, for example, you need to dismantle the HTML code of news portals such as CNN or Slashdot. This can be pretty ugly work.
Portia, a tool written in Python [1], promises a remedy; its name also refers to a genus of spiders, which would seem to make sense on the World Wide Web. The tool consists of a web application that, with a simple click, allows a user to select stock quotes, messages, and any other desired content. Portia then extracts this data and outputs it in JSON format.
Supported by a supplied web crawler, Portia can also ransack complete websites. As an example, if you need the headings from all Wikipedia articles, you show Portia exactly once where the headline resides on a Wikipedia page. The crawler then traverses the entire website and returns all matching headings in JSON format (see the "Warning" box for more information).
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