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mop/yahoo_market.go

198 lines
6.7 KiB

// Copyright (c) 2013 by Michael Dvorkin. All Rights Reserved.
// Use of this source code is governed by a MIT-style license that can
// be found in the LICENSE file.
package mop
import (
`bytes`
`fmt`
`io/ioutil`
`net/http`
`regexp`
`strings`
)
const marketURL = `http://finance.yahoo.com/marketupdate/overview`
// Market stores current market information displayed in the top three lines of
// the screen. The market data is fetched and parsed from the HTML page above.
type Market struct {
IsClosed bool // True when U.S. markets are closed.
Dow map[string]string // Hash of Dow Jones indicators.
Nasdaq map[string]string // Hash of NASDAQ indicators.
Sp500 map[string]string // Hash of S&P 500 indicators.
Advances map[string]string // Number of advanced stocks on NYSE and NASDAQ.
Declines map[string]string // Ditto for declines.
Unchanged map[string]string // Ditto for unchanged.
Highs map[string]string // Number of new highs on NYSE and NASDAQ.
Lows map[string]string // Ditto for new lows.
regex *regexp.Regexp // Regex to parse market data from HTML.
errors string // Error(s), if any.
}
// Initialize creates empty hashes and builds regular expression used to parse
// market data from HTML page.
func (market *Market) Initialize() *Market {
market.IsClosed = false
market.Dow = make(map[string]string)
market.Nasdaq = make(map[string]string)
market.Sp500 = make(map[string]string)
market.Advances = make(map[string]string)
market.Declines = make(map[string]string)
market.Unchanged = make(map[string]string)
market.Highs = make(map[string]string)
market.Lows = make(map[string]string)
market.errors = ``
const any = `\s*<.+?>`
const some = `<.+?`
const space = `\s*`
const color = `#([08c]{6});">\s*`
const price = `([\d\.,]+)`
const percent = `\(([\d\.,%]+)\)`
rules := []string{
`(Dow)`, any, price, some, color, price, some, percent, any,
`(Nasdaq)`, any, price, some, color, price, some, percent, any,
`(S&P 500)`, any, price, some, color, price, some, percent, any,
`(Advances)`, any, price, space, percent, any, price, space, percent, any,
`(Declines)`, any, price, space, percent, any, price, space, percent, any,
`(Unchanged)`, any, price, space, percent, any, price, space, percent, any,
`(New Hi's)`, any, price, any, price, any,
`(New Lo's)`, any, price, any, price, any,
}
market.regex = regexp.MustCompile(strings.Join(rules, ``))
return market
}
// Fetch downloads HTML page from the 'marketURL', parses it, and stores resulting data
// in internal hashes. If download or data parsing fails Fetch populates 'market.errors'.
func (market *Market) Fetch() (self *Market) {
self = market // <-- This ensures we return correct market after recover() from panic().
defer func() {
if err := recover(); err != nil {
market.errors = fmt.Sprintf("Error fetching market data...\n%s", err)
}
}()
response, err := http.Get(marketURL)
if err != nil {
panic(err)
}
defer response.Body.Close()
body, err := ioutil.ReadAll(response.Body)
if err != nil {
panic(err)
}
body = market.checkIfMarketIsOpen(body)
return market.extract(market.trim(body))
}
// Ok returns two values: 1) boolean indicating whether the error has occured,
// and 2) the error text itself.
func (market *Market) Ok() (bool, string) {
return market.errors == ``, market.errors
}
//-----------------------------------------------------------------------------
func (market *Market) checkIfMarketIsOpen(body []byte) []byte {
start := bytes.Index(body, []byte(`id="yfs_market_time"`))
finish := start + bytes.Index(body[start:], []byte(`</span>`))
snippet := body[start:finish]
market.IsClosed = bytes.Contains(snippet, []byte(`closed`)) || bytes.Contains(snippet, []byte(`open in`))
return body[finish:]
}
//-----------------------------------------------------------------------------
func (market *Market) trim(body []byte) []byte {
start := bytes.Index(body, []byte(`<table id="yfimktsumm"`))
finish := bytes.LastIndex(body, []byte(`<table id="yfimktsumm"`))
snippet := bytes.Replace(body[start:finish], []byte{'\n'}, []byte{}, -1)
snippet = bytes.Replace(snippet, []byte(`&amp;`), []byte{'&'}, -1)
return snippet
}
//-----------------------------------------------------------------------------
func (market *Market) extract(snippet []byte) *Market {
matches := market.regex.FindAllStringSubmatch(string(snippet), -1)
if len(matches) < 1 || len(matches[0]) < 37 {
panic(`Unable to parse ` + marketURL)
}
market.Dow[`name`] = matches[0][1]
market.Dow[`latest`] = matches[0][2]
market.Dow[`change`] = matches[0][4]
switch matches[0][3] {
case `008800`:
market.Dow[`change`] = `+` + matches[0][4]
market.Dow[`percent`] = `+` + matches[0][5]
case `cc0000`:
market.Dow[`change`] = `-` + matches[0][4]
market.Dow[`percent`] = `-` + matches[0][5]
default:
market.Dow[`change`] = matches[0][4]
market.Dow[`percent`] = matches[0][5]
}
market.Nasdaq[`name`] = matches[0][6]
market.Nasdaq[`latest`] = matches[0][7]
switch matches[0][8] {
case `008800`:
market.Nasdaq[`change`] = `+` + matches[0][9]
market.Nasdaq[`percent`] = `+` + matches[0][10]
case `cc0000`:
market.Nasdaq[`change`] = `-` + matches[0][9]
market.Nasdaq[`percent`] = `-` + matches[0][10]
default:
market.Nasdaq[`change`] = matches[0][9]
market.Nasdaq[`percent`] = matches[0][10]
}
market.Sp500[`name`] = matches[0][11]
market.Sp500[`latest`] = matches[0][12]
switch matches[0][13] {
case `008800`:
market.Sp500[`change`] = `+` + matches[0][14]
market.Sp500[`percent`] = `+` + matches[0][15]
case `cc0000`:
market.Sp500[`change`] = `-` + matches[0][14]
market.Sp500[`percent`] = `-` + matches[0][15]
default:
market.Sp500[`change`] = matches[0][14]
market.Sp500[`percent`] = matches[0][15]
}
market.Advances[`name`] = matches[0][16]
market.Advances[`nyse`] = matches[0][17]
market.Advances[`nysep`] = matches[0][18]
market.Advances[`nasdaq`] = matches[0][19]
market.Advances[`nasdaqp`] = matches[0][20]
market.Declines[`name`] = matches[0][21]
market.Declines[`nyse`] = matches[0][22]
market.Declines[`nysep`] = matches[0][23]
market.Declines[`nasdaq`] = matches[0][24]
market.Declines[`nasdaqp`] = matches[0][25]
market.Unchanged[`name`] = matches[0][26]
market.Unchanged[`nyse`] = matches[0][27]
market.Unchanged[`nysep`] = matches[0][28]
market.Unchanged[`nasdaq`] = matches[0][29]
market.Unchanged[`nasdaqp`] = matches[0][30]
market.Highs[`name`] = matches[0][31]
market.Highs[`nyse`] = matches[0][32]
market.Highs[`nasdaq`] = matches[0][33]
market.Lows[`name`] = matches[0][34]
market.Lows[`nyse`] = matches[0][35]
market.Lows[`nasdaq`] = matches[0][36]
return market
}