Finds the price of retail items online, either by scraping the web page or through product APIs.

const PriceFinder = require('price-finder');
const priceFinder = new PriceFinder();

// Atoms for Peace : Amok  (from Amazon)
const uri = 'http://www.amazon.com/Amok/dp/B00BIQ1EL4';
priceFinder.findItemPrice(uri, function(err, price) {
    console.log(price); // 8.91
});

const PriceFinder = require('price-finder');
const priceFinder = new PriceFinder();

// Plants vs Zombies  (from Google Play)
let uri = 'https://play.google.com/store/apps/details?id=com.popcap.pvz_na';
priceFinder.findItemDetails(uri, function(err, itemDetails) {
    console.log(itemDetails.price);    // 0.99
    console.log(itemDetails.name);     // Plants vs. Zombies™
    console.log(itemDetails.category); // Mobile Apps
});

// Don't Starve  (from Steam)
uri = 'http://store.steampowered.com/app/219740';
priceFinder.findItemDetails(uri, function(err, itemDetails) {
    console.log(itemDetails.price);    // 14.99
    console.log(itemDetails.name);     // Don't Starve
    console.log(itemDetails.category); // Video Games
});

• Configuration Options
• API
  • findItemPrice(uri, callback)
  • findItemDetails(uri, callback)
• Debugging Price Finder
• Supported Sites
• Contributing
  • Tests
  • Adding Sites

When creating a new PriceFinder object, a configuration object can be specified. The following options are configurable:

• retryStatusCodes : An array of status codes (Numbers) which when returned from the page scrape request, will trigger a retry request (meaning it will attempt to scrape the page again). Defaults to [503].
• retrySleepTime : If a retry status code is returned from a page scrape request, this is the amount of time (in milliseconds) that the code will sleep prior to re-issuing the request. Defaults to 1000 (ms).

For example:

const PriceFinder = require('price-finder');

const priceFinder = new PriceFinder({
  retrySleepTime: 2000,
});

Given a uri (that is for a supported site), this function will scrape the page and attempt to find the current price listed on the page, sending it to the callback. The callback's arguments are:

• error : If an error occurred during processing, this will contain the error information. If no errors occurred, this will be null.
• price : The current price of the item listed on the page (a Number).

Given a uri (that is for a supported site), this function will scrape the page and attempt to find the item details listed on the page, sending it to the callback. The callback's arguments are:

• error : If an error occurred during processing, this will contain the error information. If no errors occurred, this will be null.
• itemDetails : This object contains three things:
  • price : The current price of the item listed on the page (a Number).
  • name : The name of the product (if supported by the site implementation).
  • category : The category of the product (if supported by the site implementation).

The debug package is used within price-finder to output debugging information useful in tracking down any potential issues. To enable, export the DEBUG environment variable set to price-finder* to pick up all files (or include a specific library to only enable a certain module). For example:

$ DEBUG=price-finder* node app.js

The current supported sites are listed below.

• Amazon
• Best Buy
  • API support is available but requires an API key. To enable, set the BESTBUY_KEY environment variable to the value of the API key. For more information on how to obtain an API key, refer to the Best Buy developer documentation.
• Crutchfield
• eBags
• GameStop
• GOG
• Google Play
• Greenman Gaming
• Infibeam
• Newegg
• Nintendo
• PriceMinister
• Snapdeal
• Sony Playstation
• Steam
• Target
• Thinkgeek
• Walmart

Don't see your site listed? Please consider contributing to the project!

The price-finder project is a Node.js module, so before cloning the repository make sure node is installed. Once cloned, install dependencies by issuing:

$ npm install

The project uses the Mocha test framework along with the Should assertion library for tests (please add tests for any new features).

To run the unit tests execute:

$ npm test

These tests can be run in watch mode, listening for any file changes and re-running when that occurs. To do so execute:

$ npm run test-watch

End-to-end tests exist which will test the price-finder module using real URIs, scraping the pages to verify the code works correctly. Because these tests can take a while to run, debug logging has been enabled in the npm script.

Note that these tests should be run on a limited basis while coding since some sites have been known to throw up CAPTCHA's after repeated, automated page requests.

To execute the end to end tests run:

$ npm run test-e2e

If you would like to run a single end to end test (rather than all of them), use the test-e2e-single script. For example:

$ npm run test-e2e-single test/e2e/amazon-uris-test.js

This project was built to easily drop in support for new sites. The site-manager iterates over all files contained within the sites directory, and adds it to the list of available sites. When a request is issued to price-finder to look up a price, it asks each site if the uri is supported by the site, and if so, uses that site to find the price (or name, category).

A generator exists to create the site, along with the site's unit and end to end test. For more information on this generator, please see the project page: https://github.com/dylants/generator-price-finder-site

For reference, the site interface is:

class Site {
  constructor(uri) {
    // init Site, save off uri
  }

  /**
   * Returns the URI used to find the page data
   * (most likely the same URI used in constructing this Site)
   *
   * @return {String} The URI used to find the page data
   */
  getURIForPageData();

  /**
   * Returns true if the page data is JSON
   *
   * @return {Boolean} true if the page data is JSON, false otherwise
   */
  isJSON();

  /**
   * Returns the price found on the page
   *
   * @param  {Object} $/pageData jQuery object used to search the page, or
   *                             JSON page data if JSON based site
   * @return {String}            The price found on the page
   */
  findPriceOnPage($);

  /**
   * Returns the category of the item found on the page
   *
   * @param  {Object} $/pageData jQuery object used to search the page, or
   *                             JSON page data if JSON based site
   * @return {String}            The category found on the page
   */
  findCategoryOnPage($);

  /**
   * Returns the name of the item found on the page
   *
   * @param  {Object} $/pageData jQuery object used to search the page,
   *                             or JSON page data if JSON based site
   * @param  {String} category   The product's category
   * @return {String}            The name found on the page
   */
  findNameOnPage($, category);

  /**
   * Returns true if this site supports the incoming URI
   *
   * @param  {String}  uri The URI to test
   * @return {Boolean}     true if this Site supports the URI, false otherwise
   */
  static isSite(uri);
}

• Contributors
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