Ubuntu insights, Programming in groovy, java, et als!

Monday, August 22, 2011

Retrieve the RSS Feed URL of a Webpage

/* A dirty code tweak that can search the meta tags
* of a webpage for its rss feed url.
* If a feed exists for the page,
* the rss feed link portion of the page source
* will be extracted using regex.

def getRSSFeedURLFor(String urlStr){
def url = urlStr.toURL()
def result = []
def str
def lookForStart = '''<link rel="alternate"'''
def lookForEnd = '''>\n'''

url.eachLine {
result << it + "\n"

if(it.contains(lookForStart)) {
strtIdx = it.indexOf(lookForStart)
lastIdx = (it.indexOf(lookForEnd)+2)
str = it.substring(strtIdx,lastIdx)

str = str.replaceAll(/(.*)(href.+)"(.*)"(.*)\n/,'$3')
str = str.trim()
return str

def urlStr = "http://www.ashes-phoenix.blogspot.com"
def rssURL = getRSSFeedURLFor(urlStr).toURL()
println rssURL

PS: For most of the standard websites, if an RSS feed exists for the page, it will be specified in one of the metatags of the page source that looks like:

<link rel = "alternate" type=atom/application/rss+xml href=''...>

The logic lies in extracting the link within the href attribute of this tag which is actually the rss feed of the page we are trying to retrieve


Post a Comment