Get News

GetNews.R

getNews <- function(symbol, number){

	# Warn about length
	if (number>300) {
		warning("May only get 300 stories from google")
	}

	# load libraries
	library(XML); library(plyr); library(stringr); library(lubridate);
	library(xts); library(RDSTK)

	# construct url to news feed rss and encode it correctly
	url.b1 = 'http://www.google.com/finance/company_news?q='
	url    = paste(url.b1, symbol, '&output=rss', "&start=", 1,
				"&num=", number, sep = '')
	url    = URLencode(url)

	# parse xml tree, get item nodes, extract data and return data frame
	doc   = xmlTreeParse(url, useInternalNodes = TRUE)
	nodes = getNodeSet(doc, "//item")
	mydf  = ldply(nodes, as.data.frame(xmlToList))

	# clean up names of data frame
	names(mydf) = str_replace_all(names(mydf), "value\\.", "")

	# convert pubDate to date-time object and convert time zone
	pubDate = strptime(mydf$pubDate, 
						format = '%a, %d %b %Y %H:%M:%S', tz = 'GMT')
	pubDate = with_tz(pubDate, tz = 'America/New_york')
	mydf$pubDate = NULL
	
	#Parse the description field
	mydf$description <- as.character(mydf$description)
	parseDescription <- function(x) {
		out <- html2text(x)$text
		out <- strsplit(out,'\n|--')[[1]]
		
		#Find Lead
		TextLength <- sapply(out,nchar)
		Lead <- out[TextLength==max(TextLength)]
		
		#Find Site
		Site <- out[3]

		#Return cleaned fields
		out <- c(Site,Lead)
		names(out) <- c('Site','Lead')
		out
	}
	description <- lapply(mydf$description,parseDescription)
	description <- do.call(rbind,description)
	mydf <- cbind(mydf,description)

	#Format as XTS object
	mydf = xts(mydf,order.by=pubDate)
	
	# drop Extra attributes that we don't use yet
	mydf$guid.text = mydf$guid..attrs = mydf$description = mydf$link = NULL
	return(mydf) 

}
news <- getNews('SPY',10)
news