Cow Computing

Ever get stuck in deciding whether to use white list or black list during application development? Imagine, when you have to create an user management module, where certain users would have more access than the others. Will you pick white list or black list when you are writing the logic? e.g.

White List

<?php

// White List
// userid from 1 to 10
if ($userid == 1 || 3 || 5) {
// then allow access to manager admin module
} else {
// normal member module
}

?>

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As we all know, HTML 5 is on its way, and there’s going to be a huge addition to the current syntax. In this post, i shall share with you about the “nth-child” feature. Often, we would like to create a table or list with alternate row color as follow:

// HTML Snippet
<div id="test-area">
  <ul>
    <li>row 1</li>
    <li class="even-row">row 2</li>
    <li>row 3</li>
    <li class="even-row">row 4</li>
    <li>row 5</li>
    <li class="even-row">row 6</li>
    <li>row 7</li>
    <li class="even-row">row 8</li>
    <li>row 9</li>
    <li class="even-row">row 10</li>
  </ul>
</div>

// CSS Snippet
ul {
  list-style: none;
}

// color the even rows
.even-row {
  background-color: #ccc;
}

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Recently, i have been working on an productizing an product of my working company. It involves developing an extension for Thunderbird. During the development process, i have discovered there has been inadequate resources out there for Thunderbird Extension, especially when most developers are interested in working on another Mozilla’s flagship product — FireFox. So, i would like to share my experience on this

To begin, we have to prepare the appropriate directory.

sample.xpi

/install.rdf
/components/
/defaults/
/plugins/
/chrome.manifest
/chrome/icons/default/
/chrome/
/chrome/content
/chrome/skin

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There’s a moment when you have been given an InputStream, with its markSupported returned “False”. This means you could only read the stream one and only once, as you can’t call “reset” on it. So, what to do if you want to read the stream for more than one time and be able to re-read the previously read data. The answer is “CLONE”. My very own approach would be to use Apache Commons to turn the stream into string in which it acts as a base. Whenever i need that InputStream, i turns the string back into an stream without affecting the read position and data lost. OK, here’s the steps.

Suppose you got a request object with InputStream.

// request is the Request Object
// Turns InputStream into string
String base = IOUtils.toString(request.getInputStream());

// Whenever you need the InputStream
// Turn the string back to InputStream this way
InputStream in = new ByteArrayInputStream(base.getBytes());

Recently, i am working on a library to allow .NET developer to interact with a web service built on Java. It’s a SwA (Soap with Attachment). The reason for me to do this is because there’s been no support for such operation in .NET framework and users who want to deal with such scenario will have to write their own code bit by bit to accomplish the job, which is TEDIOUS…

The library i built relies on an open source library called PocketSoap. Its support on Attachment and its ease of use is appealing and i at last chosen to give it a try and build a POC on top of it. Below is a simple usage sample for the PocketSoap library.

using System;
using PocketSOAP;
using PocketSOAPAttachments;

namespace PSTryout
{
    public class psWS
    {
        CoEnvelope e = new CoEnvelopeClass();
        e.Body.Create("id", 1, "", null, null);
        e.EncodingStyle = "";

        HTTPTransport h = new HTTPTransport();
        h.SOAPAction = "query";
        h.Timeout = 30000;
        h.Send("http://localhost:8080/ws/", e.Serialize());

        string enc = "";
        e.Parse(h, enc);
    }
}