HEAD HTTP Request

boolean isValidUrl(String url) {
 try {
  HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection()
  connection.setRequestMethod('HEAD')
  if (connection.getResponseCode() == 200) {
   return true
  }
 }
 catch(final MalformedURLException e) { }
 catch(final IOException e) { }

 return false
}

GZip HTTP Request/Response

import java.util.zip.GZIPInputStream

String pageUrl = "http://www.google.com"
BufferedInputStream buff = pageUrl.toURL().newInputStream(requestProperties: ['Accept-Encoding': 'gzip,deflate'])
BufferedReader reader = new BufferedReader(new InputStreamReader(new GZIPInputStream(buff)))
String resp = ""; reader.eachLine{ line -> resp += line }

Easy peasy file/URL binary downloading with Ant get

def ant = new AntBuilder()
ant.get(src: 'http://groovy.codehaus.org/a.jpg', dest: /C:\scrap\a.jpg/, skipexisting: 'true')

//or 

File destFile = new File(dest)
if (destFile.exists()) return
destFile.withOutputStream { it << src.toURL().openStream() }

csv-2-List for groovycsv

@Grab('com.xlson.groovycsv:groovycsv:1.0')
import com.xlson.groovycsv.CsvParser
 
// a normally parsed csv can only be searched through ONCE
// this is used to create a "re-searchable" object (List of Maps)
List csv2List( String filePath, boolean shouldTrim = true ) {
    new File( filePath ).withReader { r ->
        new CsvParser().parse( r ).with { csv ->
            return csv.collect { line ->
                line.columns.collectEntries { c, v ->
                    [ c, (shouldTrim ? line[ c ].trim() : line[ c ]) ]
                }
            }
        }
    }
}

File/Directory Traverse

//helpful file properties: http://groovy.codehaus.org/JN2015-Files

import groovy.io.FileType

def walkFiles = {filepath, filterOnly, onFind, onEnd = {} ->
    try {
        File f = new File(filepath)
        f.traverse([type:FileType.FILES, nameFilter:filterOnly], onFind)
        onEnd()
    }
    catch (FileNotFoundException e) { println "ERROR: invalid file/directory"}
}

def pf = { file ->
    if (file.name.contains("a"))
        println file.name
}

walkFiles("C:\\123", ~/.*\.ico/, pf)

Read Lines in Zip File's (File) Entries

//to read a file:

import java.io.*;
import java.util.*;
import java.util.zip.*;

String fname = "C:\\test.zip"

ZipFile zf = new ZipFile(fname)

zf.entries().each { entry ->
    if (!entry.directory) {
        String entryFileName = entry.name
        println entryFileName
        InputStream inp = zf.getInputStream(entryFileName);
        inp.eachLine { line -> println line }
    }
}

//to write a file:
new AntBuilder().zip(destfile:"zipped.zip", basedir=".", excludes="lib .svn plugins *.class")
//http://groovy-almanac.org/creating-a-zipfile-with-antbuilder/