YahooFinance library

YahooFinance lib is a gem that fetches stock quotes, key statistics, company profile, company events, analyst opinion, and analyst estimates from Yahoo (TM) API and financial HTML pages. Additionally, it has interfaces for historical data, and financial statements. The loading of stock quotes uses the excellent nas/yahoo_stock gem. This gem provides a 'unified' attribute based interface, and abstracts the source of the information, i.e. the user only needs to specify an attribute without the need to specify the page source of the attribute. This gem leverages to the highest extend possible the YahooStock (yahoo_stock_nas) gem for all the attributes provided by that gem, and fails over to HTML scraping when the data is unavailable there. Naturally, this has an implication on performance; YahooStock queries bundle 50 stocks in each query, whereas HTML scraping happens one page per stock at a time.

This gem is currently still in development. HTML scraping now supports many attributes from Key Statistics, supports earnings announcements from the Company Events page, and most attributes from Analyst Opinion -- additional pages will be added as I find time.

Caveat: HTML parsing is susceptible to HTML encoding of Yahoo Finance pages; when these pages change, parsing will break. Core Yahoo API attributes from YahooStock will entirely depend on YahooStock continuing to support the Yahoo APIs.

Use the code entirely at your own risk, and subject to copyright & trademark restrictions on Yahoo Finance(TM). I am quite sure that are additional Yahoo restrictions which you will need to investigate (http://finance.yahoo.com/badges/tos). From past experience I know you cannot redistribute Yahoo Finance data, or use it for commercial purposes.

Installation

Add this line to your application's Gemfile:

gem 'yahoo_finance_lib'

And then execute:

$ bundle update

Or install it yourself as:

$ gem install yahoo_finance_lib

Test Before You Use

Web pages get occasionally updated -- updates could break any or all of the classes in the gem. Do not use any classes that don't pass the RSpec tests. To test, run the rspec tests from the root directory:

    rspec -c -f d

Beware that because the tests are based on actually fetching the data from yahoo, when the data structures fail, some tests that used to work may not work anymore. To be certain, you will need to investiage errors and subsequently investigate the yahoo page -- only then can you determine if the test works properly.

Usage

Example:

    irb
    require 'yahoo_finance'

    stock = YahooFinance::Stock.new(['AAPL', 'YHOO'], [:market_cap, :bid, :brokers_count, :upgrades_downgrades_history])
    # look at available fields you could fetch with this library
    stock.available_fields

    stock.add_field(:last_trade_price_only)

    results = stock.fetch
    aapl_bid = results["AAPL"][:bid]
    yhoo_last = results["YHOO"][:last_trade_price_only]

A simple interface using yahoo_stock to fetch history. It returns history as an array of hashes, e.g.

    irb
    require 'yahoo_finance'
    require 'date'

    start_date = Date.today - 30
    history = YahooFinance::StockHistory.new('AAPL', start_date) # when you don't specify end date, end date = today - 1
    history.fetch

A simple interface to scrape financial statements - Income Statement, Balance Sheet, and Cash Flow. It can fetch either quarterly or annual data, and it returns the value in a hash. e.g.

    irb
    require 'yahoo_finance'

    income_stmt = YahooFinance::FinancialStatement::QuarterlyIncomeStatementPage.new 'YHOO'
    result = income_stmt.fetch
    most_recent_qtr = income_stmt.statement_periods[0]
    available_fields = income_stmt.available_fields

    puts "Net income for the most recent quarter ending on #{most_recent_qtr.to_s} is #{result[:net_income][0]}"

The classes for the financial statement are: QuarterlyIncomeStatementPage, AnnualIncomeStatementPage, AnnualBalanceSheetPage, QuarterlyBalanceSheetPage, QuarterlyCashFlowStatementPage, AnnualCashFlowStatementPage

Release 1.0 brings a number of bug fixes from using the gem for almost a year now, as well as the addition of scraping the Analyst Estimates page. Each table in the analyst page is returned as a separate "field", namely :earnings_est, :revenue_est, :earnings_history, :EPS_trends, :EPS_revisions, and :growth_est. Fields are returned as hashes, with two keys: :columns and :values. The latter - :values - is another hash with keys the name of the row, and the value being that of an array of values (one for each column). For example:

    irb
    require 'yahoo_finance'

    st = YahooFinance::Stock.new(['AAPL'])
    st.add_field(:earnings_est)
    result = st.fetch
    ## result => {"AAPL"=>{:earnings_est=>{:columns=>["Current Qtr.Dec 15", "Next Qtr.Mar 16", "Current YearSep 16", "Next YearSep 17"], :values=>{"Avg. Estimate"=>[3.25, 2.38, 9.75, 10.7], "No. of Analysts"=>[40.0, 38.0, 49.0, 40.0], "Low Estimate"=>[2.96, 2.12, 8.92, 9.48], "High Estimate"=>[3.38, 2.84, 10.65, 12.26], "Year Ago EPS"=>[3.06, 2.33, 9.22, 9.75]}}}}
    result['AAPL'][:earnings_est][:values]["Year Ago EPS"]
    ## prints: [3.06, 2.33, 9.22, 9.75]
    result['AAPL'][:earnings_est][:columns]
    ## prints: ["Current Qtr.Dec 15", "Next Qtr.Mar 16", "Current YearSep 16", "Next YearSep 17"]

!-- ## Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request -->