Downloading articles from pubmed

pubmed.groovy

#!/usr/bin/env groovy
def searchUrl = 'https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=("2016/09/01"[PDAT]:"2016/09/02"[PDAT])+AND+cancer[sb]&usehistory=y'

def parser = new XmlSlurper()
parser.setFeature("http://apache.org/xml/features/disallow-doctype-decl", false)
parser.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false)

def eSearchResult = parser.parse(new URL(searchUrl).openStream())
def webEnv = eSearchResult.WebEnv.toString()
int queryKey = eSearchResult.QueryKey.toInteger()
int amountOfArticles = eSearchResult.Count.toInteger()

def retMax = 1000
def xmlFile = new File("articles.xml")
(0..amountOfArticles).step(retMax) { retstart ->
    URL url = new URL("https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&query_key=$queryKey&WebEnv=$webEnv&retstart=${retstart}&retmax=$retMax&retmode=xml")
    println url
    xmlFile << url.openStream()
}