yahoo-stock-client/src/stockclient.coffee

Module to fetch stock information via yahoo's stock api. Returns data in csv format.

Promise = require('bluebird')
request = Promise.promisifyAll(require('request'))
formats = require('./formats.js')
querystring = require('querystring')
stream = require 'stream'
util = require 'util'

class ArrayStream
  constructor: (@arr) ->
    stream.Readable.call(@, {objectMode:true})
    @_init = false
  util.inherits(ArrayStream, stream.Readable)

  init : (arr) ->
    @_init = true
    @arr = arr if arr?
    @_read()

  _read : () ->
    if not @_init
      return
    if @arr.length > 0
      this.push(@arr.shift())
    else
      this.push(null)

class StockClient
  constructor: (formatOpts, config = {})->
    @_formatOpts = formatOpts if formatOpts instanceof Array
    @_formatOpts = formats.Categories[formatOpts] if typeof(formatOpts) is 'string'
    throw Error('FormatOpts must be Array or Category String.  Got: ' + formatOpts) if not @_formatOpts?
    @_config = config
    @_formatString = ""
    @_formatString += symbol for symbol in formats.formatsToFormatSymbols(@_formatOpts)

  _yahooUrl : "http://finance.yahoo.com/d/quote.csv"

  _historicalUrl: 'http://ichart.finance.yahoo.com/table.csv?'

  getHistorical : (symbol, cb) ->
    if typeof symbol is 'string'
      symbolStr = symbol
    queryObj =
      s:symbol
    if @_config.Stream? and @_config.Stream
      arrStream = new ArrayStream([])
      request.getAsync(@_historicalUrl + querystring.stringify(queryObj))
        .then(
          (() ->
            arrS = arrStream
            (data) ->
              dat = data[1].replace(/\r/g, '').split('\n')
              dat.pop()
              arrS.init(dat)
          )()
      )
      return arrStream

    if @_config.Async? and @_config.Async
      return request.getAsync(@_historicalUrl + querystring.stringify(queryObj))
    request.get(@_historicalUrl + querystring.stringify(queryObj), cb)


  getData : (symbol, cb) ->
    if typeof symbol is 'string'
      symbolStr = symbol
    if symbol instanceof Array
      symbolStr = ""
      symbolStr += stock + '+' for stock in symbol
      symbolStr = symbolStr.slice(0, -1)
    if @_config.Stream? and @_config.Stream
      arrStream = new ArrayStream([])
      request.getAsync(@_yahooUrl + '?s=' + symbolStr + '&f=' + @_formatString)
        .then(
          (() ->
            arrS = arrStream
            (data) ->
              dat = data[1].replace(/\r/g, '').split('\n')
              dat.pop()
              arrS.init(dat)
          )()
      )
      return arrStream
    if @_config.Async? and @_config.Async
      return request.getAsync(@_yahooUrl + '?s=' + symbolStr + '&f=' + @_formatString)
    request.get(@_yahooUrl + '?s=' + symbolStr + '&f=' + @_formatString, cb)

###
  formatOpts is either a string or array
  if its a string it is taken to be a category
  else its taken to be an array of format options
###
exports.createClient = (formatOpts, config) ->
  new StockClient(formatOpts, config)