Information Technology Tips

Identify Country From IP Address Many people sometimes would like to identify country from IP address when you check access log or something. Most of the people google with keywords like "ip address country" or "whois ip" or something, and then use the internet service which they find. In this post, I will show you program for identifying country from IP address. I wrote the program in Java, but if you an average developer you can easily translate into the program language you prefer. Using File Provided by RIR IP address is allocated, registered and managed by regional internet registry ( RIR ). There are five organization based on covering region: African Network Information Centre (AfriNIC): Africa American Registry for Internet Numbers (ARIN): the United States, Canada, several parts of the Caribbean region, and Antarctica. Asia-Pacific Network Information Centre (APNIC): Asia, Australia, New Zealand, and neighboring countries Latin America and ...

IPv6 Address to Long I have written code for converting coloned IPv6 IP address to BigInteger value in Java. I have already written similar code for IPv4 IP address (see this post ). The function is useful when you compare IP addresses based on numeric magnitude relationship. Java Code public static BigInteger colonIpV6_to_BigInteger(String colonedIP) { String[] addrArray = colonedIP.split(":", -1); BigInteger num = BigInteger.ZERO; BigInteger block = BigInteger.valueOf(65536); for (int i = 0; i < addrArray.length; i++) { if(!addrArray[i].equals("")) { int power = 8-i; BigInteger value = BigInteger.valueOf(Long.parseLong(addrArray[i], 16) % 65536L); value = value.multiply(block.pow(power)); num = num.add(value); } } return num; } Here is an example. // following code output "22170076769632982771575277020213308075606016"...

IPv4 Address to Long I have written code for converting dotted IPv4 IP address to BigInteger value in Java. This code is inspired by PHP's ip2long function. The function is useful when you compare IP addresses based on numeric magnitude relationship. Java Code public static BigInteger dotIPv4_to_BigInteger(String dottedIP) { String[] addrArray = dottedIP.split("\\."); BigInteger num = BigInteger.ZERO; BigInteger block = BigInteger.valueOf(256); for (int i = 0; i < addrArray.length; i++) { int power = 3-i; BigInteger value = BigInteger.valueOf(Integer.parseInt(addrArray[i]) % 256); value = value.multiply(block.pow(power)); num = num.add(value); } return num; } Here is an example. // following code output "2071690107" System.out.println(dotIPv4_to_BigInteger("123.123.123.123"));

Introduction In this post, I'm going to write about "Why & How to measure your code of software project. And improve it." I am going to mainly write about this topic from the static code analysis point. Why Measure? There are number of reasons to measure your code. For me especially following reasons (or intentions). Daily Health Check Keep code base clean See impact on entire code base by your code change Detect problems as soon as possible Feel improvement! Let every team members show what happens Monitor test result status Follow coding standard Especially in team based software development, a lot of people change code for different task. And each developer is hard to know what each developer change the code for what purpose. If the source code measurement is public for everyone, it helps everyone to know affect of entire project which the other developers make. What to Measure? There are a lot of measurement is proposed but from static...

Symfony 1.4 Action plus View Rendering PHPUnit Test I wrote test case for executing action and rendering view test. However testing action plus final rendering result is quite not easy because you need to understand how Symfony 1.4 framework handles web request and rendering model to view internally. I have investigated in the framework a bit and found a solution. Please see the test case example in the next section. Code <?php $basePath = dirname(__FILE__).'/../../../../apps/your_app_name/modules/'; $modulePaths = glob($basePath.'*', GLOB_ONLYDIR); foreach($modulePaths as $modulePath) { require_once $modulePath.'/actions/actions.class.php'; } class ActionsTest extends PHPUnit_Framework_TestCase { public function testActions() { // create stub web request $request = $this->createStubfWebRequest(); // action you would like to test. // you should pass module and action name refelctively $actions = new TargetActions($this...

Motivation: Visualize 2 Dimensional Data with Lightweight Way I wrote small java program for calculating Jaccard Similarity among source code in this post . And map into them 2 dimensional map using Multi Dimensional Scaling technique. I have used MDSJ – Multidimensional Scaling for Java . (By the way the library is quite simple and meet my requirement perfectly!! Excellent!!)> Next step is how to visualize the bunch of 2 dimensional (x,y) coordinate data so that human can easily understand. Of course, I am good at Java, I can write some code for visualize data in Java using Swing or Java FX etc. But it's not lightweight way. So, I decided to use HTML5 Canvas + Javascript. Viewer: Html5 Canvas + Javascript The features of the Data Viewer are: Visualize CSV data Expected 3 columns without header row: name...

Reusable Code for Execute Any DB Access Code in Transaction In this post, I will show you highly reusable utility code for wrapping and executing original db access code in transaction. Anyway let's show you the code. function executeInTransaction(callable $func) { $conn = new PDO(SERVER_NAME, USERNAME, PASSWORD, DBNAME); try { $conn->beginTransaction(); $func($conn); $conn->commit(); } catch (Exception $ex) { $conn->rollBack(); throw $ex; } } Oh, how to use? You just simply passing your core DB access code as the callable $func argument. Okay, let me show you example in next section. Example Usage First, assume you have following 2 methods for inserting data to DB. CONST SERVER_NAME = 'localhost'; CONST USERNAME = "username"; CONST PASSWORD = "password"; CONS...

Compute Source Code Similarity I have tried to analyze source code by various methods recently. In this post, I will show you my artifact - Compute source code similarity based on Jaccard Similarity Coefficient. Jaccard Similarity Coefficient is an common and quick techniqueto compute similarity between 2 documents. You can see more details in Jaccard index or MinHash . My similarity computation strategy is below: Calculate hash value for each line for each files. Create set which contains hashes calculated in the above process for the each files. Compute Jaccard Similarity Coefficient for all combinations of the files. Source Code Now I can show you code snippets for compute source code similarity based on Jaccard Similarity Coefficient. Jaccard Simlarity package com.dukesoftware.utils.text; import java.util.HashSet; import java.util.Set; /** * Jaccard similarity coefficient http://en.wikipedia.org/wiki/MinHash */ public class JaccardSimlarity<T> { priv...

Here is the code for iterating each line in file. You simply write lambda expression for processing line and doing something nice. private static void processLine(File file, Consumer<String> lineProcessor) throws IOException{ try(FileReader in = new FileReader(file); BufferedReader br = new BufferedReader(in)){ String line; while ((line = br.readLine()) != null) { lineProcessor.accept(line); } } } The below code is an example usage of processLine method. The code simply print out lines in file. public static void main(String[] args) throws IOException { processLine(new File("c:/temp/test.txt"), System.out::println); }

Introduction There are 2 ways to control files on multiple machines in the software development world. Deploy or build file from version control system Backup files to version control system In my opinion, ideally, everything should be done by the way 1 because it ensures the files are same across the all machines. However in the real world, sometime it is hard to deploy all files from version control system because of the various reasons - such as linux/unix permission or organization structure or too difficult to automating deployment or etc. etc.... In that case, we should take the way 2. In this post, I will introduce simple bash script for back up files to Subversion. Of course you can use your favorite version control system such as Git instead of Subversion ;) If you are a software developer, you can easily refine my bash script and create git version quickly ;) Bash Script for Back Up Files to Subversion See below script! You just save the script and simply execut...

I have written Java code for removing comments, annotations and extra spaces from Java source code. package com.dukesoftware.utils.text; import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import com.dukesoftware.utils.io.IOUtils; public class JavaSourceUtils { public static void main(String[] args) throws FileNotFoundException, IOException { String cleanedUpSource = removeCommentAndAnnotation(IOUtils.userDirectory( "workspace2/DukeSoftwareUtils/src/main/java/com/dukesoftware/utils/text/JavaSourceUtils.java" )); System.out.println(cleanedUpSource); } public static final String removeCommentAndAnnotation(File file) throws IOException { try(BufferedReader br = new BufferedReader(new FileReader(file))) { return removeCommentAndAnnotation(br); } } private final static int COD...

PHP Code function processEachFileIn($path, callable $callback) { $objects = new RecursiveIteratorIterator( new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST); foreach ($objects as $object) { if (!$object->isDir() && $object->getFilename() != '.' && $object->getFilename() != '..') { $callback($object); } } } Example Usage The below code demonstrates print all file names in directory /tmp recursively. processEachFileIn('/tmp', function($file){ echo $file->getFilename()."\n"; });

As you know, if you would like to sort array, you should use Arrays.sort method. But if you would like to get sorted index, you should use your a brain a bit. In this post, I will show you the code snippet for getting sorted array index. The following is the simplest way to get sorted index. The disadvantages of the following code are autoboxing in compare process and returned array type is not int[] but Integer[]. /** * The most common & general way. But this method use autoboxing and need Integer[] not int[]. */ public static final <T>void sort(T[] array, Comparator<T> comparator, Integer[] sorted) { Arrays.sort(sorted, (i1, i2) -> comparator.compare(array[i1], array[i2])); } To solve these advantage, I wrote following array sort helper class which can get sorted array index as int[] type. You can call getSortedIndex method with source array and comparator as the arguments. The code uses lambda expression which was introduced in Java 8. packa...

Here is the code for count up string given as a second parameter appears on string given as a first parameter. public final static int countOccurrence(String src, String search) { for(int count = 0, fromIndex = 0;;) { fromIndex = src.indexOf(search, fromIndex); if(fromIndex < 0) return count; fromIndex++; count++; } }

Introduction In this post, I will demonstrate how to read image metadata using BitmapMetadata class in C#. Before staring explanation, we should notice there are two namespaces that can handle image in C#. System.Drawing namespace: I tested in this post System.Windows.Media.Imaging In this post, we will use classes under System.Windows.Media.Imaging. Code for Reading Image Metadata Actually code itself is quite simple :) Please see code below. using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Windows.Media.Imaging; using System.Diagnostics; namespace MetadataExample { public static class ReadImageMetadataExample { public static void a(string fileName) { var fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read); var img = BitmapFrame.Create(fs); var metadata = img.Metadata as BitmapMetadata; Debug.WriteLine("=== metadata ===...

In this post, I will show you the code snippet for extracting jpeg image exif metadata using metadata-extractor . Code package com.dukesoftware.image; import com.drew.imaging.ImageMetadataReader; import com.drew.imaging.ImageProcessingException; import com.drew.metadata.Directory; import com.drew.metadata.Metadata; import com.drew.metadata.Tag; import java.io.File; import java.io.IOException; public class MetaDataExtractor { public static void main(String[] args) throws IOException { printMetaData(new File("c:/temp/metadata_eample.jpg")); } private static void printMetaData(File file) throws IOException { try { Metadata drewmetadata = ImageMetadataReader.readMetadata(file); for (Directory directory : drewmetadata.getDirectories()) { System.out.println("==="+directory.getClass().getName()+"==="); for (Tag tag : directory.getTags()) { System.out.p...

Recently I have been investigating image library in Java. In this post, I will show you the code snippet for extracting jpeg image exif metadata using Sanselan . Code package com.dulesoftware.image; import java.io.File; import java.io.IOException; import java.util.List; import org.apache.sanselan.ImageReadException; import org.apache.sanselan.Sanselan; import org.apache.sanselan.common.IImageMetadata; import org.apache.sanselan.common.ImageMetadata.Item; import org.apache.sanselan.formats.jpeg.JpegImageMetadata; import org.apache.sanselan.formats.tiff.TiffField; import org.apache.sanselan.formats.tiff.TiffImageMetadata; public class SanselanMetadataExample { public static void main(String[] args) throws Exception { printMeatadata(new File("c:/temp/metadata_eample.jpg")); } public static void printMeatadata(File file) throws ImageReadException, IOException { IImageMetadata sanselanmetadata = Sanselan.getMetadata(file); if (sanselan...

Introduction In the previous post , I showed available tags in ExifTagConstants, TiffTagConstants, GpsTagConstants classes. In this post, I will show you code snippet for extracting metada from jpeg using the tags. In order to run example code, you should download commons-imaging.jar from here . Somehow the official homepage of Commons Imaging doesn't provide commons-imaging.jar!! Code package com.dulesoftware.image; import java.io.File; import java.io.IOException; import java.lang.reflect.Field; import java.lang.reflect.Modifier; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; import org.apache.commons.imaging.ImageReadException; import org.apache.commons.imaging.Imaging; import org.apache.commons.imaging.common.IImageMetadata; import org.apache.commons.imaging.common.IImageMetadata.IImageMetadataItem; import org.apache.commons.imaging.formats.jpeg.JpegImageMetadata; import org.apache.commons.imaging.formats.t...