use alpha vantage to extract stock information

Author: GustavoCaso

doc/dataflow_top_stock_calc.md

@@ -5,33 +5,51 @@ It as an example from chapter 1 "Introduction", section 1.2 "What's Scala?" of t
 ## What It Does
 
 This program takes a list of one or more stock symbols and a year. It then concurrently
-obtains the relevant stock data from Yahoo's iChart service for each symbol. Once all
+obtains the relevant stock data from Alpha Vantage service for each symbol. Once all
 the data has been retrieved the program determines which stock had the highest year-end
 closing price.
 
-* A sample of the data can be downloaded [here](http://ichart.finance.yahoo.com/table.csv?s=AAPL&a=11&b=01&c=2008&d=11&e=31&f=2008&g=m).
+To use this example you need to obtain a free api key in [AlphaVantage](https://www.alphavantage.co/support/#api-key).
+
 
 #### The Ruby Code
 
 ```ruby
 require 'concurrent'
+require 'csv'
 require 'open-uri'
 
-def get_year_end_closing(symbol, year)
-  uri = "http://ichart.finance.yahoo.com/table.csv?s=#{symbol}&a=11&b=01&c=#{year}&d=11&e=31&f=#{year}&g=m"
-  data = open(uri) {|f| f.collect{|line| line.strip } }
-  price = data[1].split(',')[4]
+def get_year_end_closing(symbol, year, api_key)
+  uri = "https://www.alphavantage.co/query?function=TIME_SERIES_MONTHLY&symbol=#{symbol}&apikey=#{api_key}&datatype=csv"
+  data = []
+  open(uri) do |f|
+    CSV.parse(f, headers: true) do |row|
+      data << row['close'] if row['timestamp'].include?(year.to_s)
+    end
+  end
+  price = data.max
   price.to_f
   [symbol, price.to_f]
 end
 
-def get_top_stock(symbols, year, timeout = 5)
-  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year) }}
+def get_top_stock(symbols, year, timeout = 10)
+  api_key = ENV['ALPHAVANTAGE_KEY']
+  abort(error_message) unless api_key
+
+  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year, api_key) }}
   Concurrent::dataflow(*stock_prices) { |*prices|
     prices.reduce(['', 0.0]){|highest, price| price.last > highest.last ? price : highest}
   }.value(timeout)
 end
 
+def error_message
+  <<~EOF
+    PLEASE provide a Alpha Vantage api key for the example to work
+    usage:
+      ALPHAVANTAGE_KEY=YOUR_API_KEY bundle exec ruby top-stock-scala/top-stock.rb
+  EOF
+end
+
 symbols = ['AAPL', 'GOOG', 'IBM', 'ORCL', 'MSFT']
 year = 2008
 
@@ -60,16 +78,16 @@ val (topStock, highestPrice) = getTopStock(symbols.length)
 printf("Top stock of %d is %s closing at price %f\n", year, topStock, highestPrice)
 //END:PART1
 
-//START:PART2    
+//START:PART2
 def getYearEndClosing(symbol : String, year : Int) = {
   val url = "http://ichart.finance.yahoo.com/table.csv?s=" +
     symbol + "&a=11&b=01&c=" + year + "&d=11&e=31&f=" + year + "&g=m"
-    
+
   val data = io.Source.fromURL(url).mkString
-  val price = data.split("\n")(1).split(",")(4).toDouble  
+  val price = data.split("\n")(1).split(",")(4).toDouble
   (symbol, price)
-} 
-//END:PART2    
+}
+//END:PART2
 
 //START:PART3
 def getTopStock(count : Int) : (String, Double) = {
@@ -79,6 +97,6 @@ def getTopStock(count : Int) : (String, Double) = {
         if (price > previousHigh._2) (symbol, price) else previousHigh
     }
   }
-} 
+}
 //START:PART3
 ```

doc/top-stock-scala/README.md

@@ -7,43 +7,62 @@ It as an example from chapter 1 "Introduction", section 1.2 "What's Scala?" of t
 ## What It Does
 
 This program takes a list of one or more stock symbols and a year. It then concurrently
-obtains the relevant stock data from Yahoo's iChart service for each symbol. Once all
+obtains the relevant stock data from Alpha Vantage service for each symbol. Once all
 the data has been retrieved the program determines which stock had the highest year-end
 closing price.
 
-http://ichart.finance.yahoo.com/table.csv?s=AAPL&a=11&b=01&c=2008&d=11&e=31&f=2008&g=m
+To use this example you need to obtain a free api key in [AlphaVantage](https://www.alphavantage.co/support/#api-key).
+
+https://www.alphavantage.co/query?function=TIME_SERIES_MONTHLY&symbol=AAPL&apikey=1234567&datatype=csv"
 
 ### Run It
 
 This example can be run from the console. From the root of the repo run:
 
-> $ bundle exec ruby top-stock-scala/top-stock.rb
+> $ ALPHAVANTAGE_KEY=YOUR_API_KEY bundle exec ruby top-stock-scala/top-stock.rb
 
 The output should be:
 
-> Top stock of 2008 is GOOG closing at price $307.65 
+> Top stock of 2008 is GOOG closing at price $307.65
 
 #### The Ruby Code
 
 ```ruby
 require 'concurrent'
+require 'csv'
 require 'open-uri'
 
-def get_year_end_closing(symbol, year)
-  uri = "http://ichart.finance.yahoo.com/table.csv?s=#{symbol}&a=11&b=01&c=#{year}&d=11&e=31&f=#{year}&g=m"
-  data = open(uri) {|f| f.collect{|line| line.strip } }
-  price = data[1].split(',')[4]
+def get_year_end_closing(symbol, year, api_key)
+  uri = "https://www.alphavantage.co/query?function=TIME_SERIES_MONTHLY&symbol=#{symbol}&apikey=#{api_key}&datatype=csv"
+  data = []
+  open(uri) do |f|
+    CSV.parse(f, headers: true) do |row|
+      data << row['close'] if row['timestamp'].include?(year.to_s)
+    end
+  end
+  price = data.max
   price.to_f
   [symbol, price.to_f]
 end
 
-def get_top_stock(symbols, year, timeout = 5)
-  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year) }}
+def get_top_stock(symbols, year, timeout = 10)
+  api_key = ENV['ALPHAVANTAGE_KEY']
+  abort(error_message) unless api_key
+
+  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year, api_key) }}
   Concurrent::dataflow(*stock_prices) { |*prices|
     prices.reduce(['', 0.0]){|highest, price| price.last > highest.last ? price : highest}
   }.value(timeout)
 end
 
+def error_message
+  <<~EOF
+    PLEASE provide a Alpha Vantage api key for the example to work
+    usage:
+      ALPHAVANTAGE_KEY=YOUR_API_KEY bundle exec ruby top-stock-scala/top-stock.rb
+  EOF
+end
+
 symbols = ['AAPL', 'GOOG', 'IBM', 'ORCL', 'MSFT']
 year = 2008
 
@@ -72,16 +91,16 @@ val (topStock, highestPrice) = getTopStock(symbols.length)
 printf("Top stock of %d is %s closing at price %f\n", year, topStock, highestPrice)
 //END:PART1
 
-//START:PART2    
+//START:PART2
 def getYearEndClosing(symbol : String, year : Int) = {
   val url = "http://ichart.finance.yahoo.com/table.csv?s=" +
     symbol + "&a=11&b=01&c=" + year + "&d=11&e=31&f=" + year + "&g=m"
-    
+
   val data = io.Source.fromURL(url).mkString
-  val price = data.split("\n")(1).split(",")(4).toDouble  
+  val price = data.split("\n")(1).split(",")(4).toDouble
   (symbol, price)
-} 
-//END:PART2    
+}
+//END:PART2
 
 //START:PART3
 def getTopStock(count : Int) : (String, Double) = {
@@ -91,6 +110,6 @@ def getTopStock(count : Int) : (String, Double) = {
         if (price > previousHigh._2) (symbol, price) else previousHigh
     }
   }
-} 
+}
 //END:PART3
 ```

doc/top-stock-scala/top-stock.rb

@@ -1,21 +1,38 @@
 require 'concurrent'
+require 'csv'
 require 'open-uri'
 
-def get_year_end_closing(symbol, year)
-  uri = "http://ichart.finance.yahoo.com/table.csv?s=#{symbol}&a=11&b=01&c=#{year}&d=11&e=31&f=#{year}&g=m"
-  data = open(uri) {|f| f.collect{|line| line.strip } }
-  price = data[1].split(',')[4]
+def get_year_end_closing(symbol, year, api_key)
+  uri = "https://www.alphavantage.co/query?function=TIME_SERIES_MONTHLY&symbol=#{symbol}&apikey=#{api_key}&datatype=csv"
+  data = []
+  open(uri) do |f|
+    CSV.parse(f, headers: true) do |row|
+      data << row['close'] if row['timestamp'].include?(year.to_s)
+    end
+  end
+  price = data.max
   price.to_f
   [symbol, price.to_f]
 end
 
-def get_top_stock(symbols, year, timeout = 5)
-  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year) }}
+def get_top_stock(symbols, year, timeout = 10)
+  api_key = ENV['ALPHAVANTAGE_KEY']
+  abort(error_message) unless api_key
+
+  stock_prices = symbols.collect{|symbol| Concurrent::dataflow{ get_year_end_closing(symbol, year, api_key) }}
   Concurrent::dataflow(*stock_prices) { |*prices|
     prices.reduce(['', 0.0]){|highest, price| price.last > highest.last ? price : highest}
   }.value(timeout)
 end
 
+def error_message
+  <<~EOF
+    PLEASE provide a Alpha Vantage api key for the example to work
+    usage:
+      ALPHAVANTAGE_KEY=YOUR_API_KEY bundle exec ruby top-stock-scala/top-stock.rb
+  EOF
+end
+
 symbols = ['AAPL', 'GOOG', 'IBM', 'ORCL', 'MSFT']
 year = 2008