Rizal Almashoor's Blog

Tolstoy for bedtime

Rizal Almashoor — Mon, 23 Aug 2010 21:25:21 +0000

Last night I read Tolstoy to my four-year-old.

No, it wasn’t Leo Tolstoy’s War and Peace; it was Alexei Tolstoy’s The Enormous Turnip.

Worthy of a Moleskine

Rizal Almashoor — Sun, 22 Aug 2010 05:31:36 +0000

When I first heard about Moleskines I immediately fell in love with them. Just the idea of carrying around these notebooks – the type used by van Gogh, Picasso and Hemingway, no less! – felt awe-inspiring.

They are available in Kuala Lumpur, and the prices are perhaps more awe-inspiring than the notebooks themselves. The smallest and thinnest costs RM25 for two (promotion price). Looking at what I scribble in my throwaway, sub-ringgit notebooks – random to-do items, shopping lists, phone numbers – it’s very obvious that Moleskines are not for me. They’re for poets, writers, and painters, not for ordinary people with everyday lives.

My wife, however, can paint. So yesterday we drove down to Czip Lee Bangsar and she got herself some art supplies plus a Moleskine Folio Watercolour Album A4. She has already filled two pages with her watercolours. Let me say this: she is worthy of a Moleskine.

I almost bought the RM25 set-of-two but put it back at the last minute. But I did get myself an RM9 Faber-Castell PITT artist pen. I’m using it to scribble random to-do items, shopping lists, phone numbers, etc. It’s so nice.

By value, by reference: by analogy

Rizal Almashoor — Tue, 20 Apr 2010 17:59:55 +0000

Here’s my best attempt to explain C# value types and reference types, and “pass by value” and “pass by reference” to a newbie. (Not you, of course.)

Value types

A piece of paper, on which is written the number 5. You use this number to calculate something.

Reference types

A piece of paper, on which is written a memory location. You then go to the memory location in order to access an object.

(Aside: the “object reference not set to an instance of an object” exception means that the piece of paper has the special value of “unspecified”, and when you try to use this piece of paper to access an object, you aren’t able to.)

(Another aside: in C#, by default, you aren’t able to do anything with references except to use it to access an object. In C and C++, however, you could perform arithmetic on references – powerful and dangerous.)

Pass by value

I’m a function. You hand me a piece of paper. I take out my own piece of paper, copy down what’s written on your piece of paper, and give your piece of paper back to you. Whatever I scribble on my piece of paper doesn’t affect your piece of paper.

Pass by reference

I’m a function. You hand me a piece of paper. I write on your piece of paper and give it back to you. Your piece of paper is definitely affected.

Passing reference types by value

I’m a function. You hand me a piece of paper with a memory location written on it. I take out my own piece of paper, copy down the memory location, and give your piece of paper back to you. I can’t change what’s on your piece of paper, but I can affect your object.

Passing reference types by reference

I’m a function. You hand me a piece of paper with a memory location written on it. I rub out the memory location, write a new memory location, and give back the piece of paper to you. You are now referencing another object in the new memory location.

Strings

Strings are a special case. Technically they’re reference types, but for the sake of convenience, we’re able to treat strings as value types. Although we’re passing the memory locations of our strings to functions, we don’t have to worry about these functions modifying our strings. This is because strings are immutable, like so:

class ImmutableType
{
    private int _value;

    public ImmutableType(int value)
    {
        _value = value;
    }

    public int Value
    {
        get
        {
            return _value;
        }
    }
}

class Program
{
    public static void Main()
    {
        ImmutableType x = new ImmutableType(5);
        // will output 5
        Console.WriteLine(x.Value);
        // set y to refer to the same object as x
        ImmutableType y = x;
        // will output 5
        Console.WriteLine(y.Value);
        // illegal, no set accessor, so our object is safe
        //y.Value = 6;
        // no choice but to create a new object
        y = new ImmutableType(6);
    }
}

When all you have is a hammer

Rizal Almashoor — Wed, 14 Apr 2010 19:08:04 +0000

… everything looks like a nail. The point I would like to make here is this: when all you know is C#, everything looks like a class.

(Note: When I say C#, I mean Java or C#. At the core both are the same. I only mean to avoid from having to repeatedly say “Java/C#” which is distracting.)

After having had to continually switch between PHP and C# over the course of a year, I’ve come to realize that different languages are better at solving different types of problems. Actually it’s not really about the language per se (which is just syntax), but the paradigm. PHP is excellent for UI-driven websites with fluid requirements and short release cycles. C# is excellent for Windows apps and web services. Java is excellent for mid-tier components that can run on Unix. C++ is excellent for writing device APIs. VBA on MS Access is excellent for form-driven apps that come with their own database on file. Perl is excellent for text processing.

Thus, the more languages you know, the higher the likelihood of your being able to use the best tool for the job. Ultimately, that’s all a programming language is: a tool, suited for a particular purpose.

For some reason there are people who identify themselves with a particular language. They have a mental block when it comes to learning new programming languages. I think that’s a mistake. Wouldn’t it be better to be able to use the best programming language for the job at hand, and to identify oneself with this ability?

Having said that, it isn’t easy to get the chance to practise a new language for a real project. But at the very least one should keep an open mind, and to jump in without hesitation when the opportunity arises.

P.S. There are also other variations to the first paragraph: when all you know is PHP, everything looks like an ordered map; when all you know is Lisp, everything looks like a linked list; when all you know is JavaScript, everything looks like a collection of named values.

Calling a SOAP web service from PHP

Rizal Almashoor — Wed, 14 Apr 2010 07:05:25 +0000

The SOAP binding is RPC/encoded, and the WSDL is not published.

Using the PHP SoapClient:

define('NEWLINE', "
\n");

// SOAP client

$options = array
(
	'location' => 'https://example.com:1234/sample/service',
	'uri' => 'http://example.com/sample/namespace/data',
	'style' => SOAP_RPC,
	'use' => SOAP_ENCODED,
	'trace' => true // in conjunction with $soapClient->__getLastRequest() below
);
$soapClient = new SoapClient(null, $options);

// SOAP header

$nsHeader = 'http://example.com/sample/namespace/security';
$elementName = 'Security';

$usernameToken->Username = new SoapVar('user9', XSD_STRING, null, null, null, $nsHeader);
$usernameToken->Password = new SoapVar('pass1234', XSD_STRING, null, null, null, $nsHeader);

$content->UsernameToken = new SoapVar($usernameToken, SOAP_ENC_OBJECT, null, null, null, $nsHeader);

$soapHeader = new SoapHeader($nsHeader, $elementName, $content);
$soapHeaders[] = $soapHeader;
$soapClient->__setSoapHeaders($soapHeaders);

// SOAP call

$method = 'getData';
$parameters = array
(
	new SoapParam('abcdef', 'param1'),
	new SoapParam(12345, 'param2')
);

$success = true;
try
{
	$result = $soapClient->__soapCall($method, $parameters);
}
catch (SoapFault $fault)
{
	echo "Fault code: {$fault->faultcode}" . NEWLINE;
	echo "Fault string: {$fault->faultstring}" . NEWLINE;
	$success = false;
}

echo $soapClient->__getLastRequest(); // output the request XML

if ($success)
{
	echo "\n";
	print_r($result);
	echo "\n";
}

if ($soapClient != null)
{
	$soapClient = null;
}

Using curl:

define('NEWLINE', "
\n");

$ch = curl_init();

$data = '
  
    
      
        user9
        pass1234
      
    
  
  
    
      abcdef
      12345
    
  
';

$fh = fopen('soap_response.txt', 'w'); 

curl_setopt($ch, CURLOPT_URL, 'https://example.com:1234/sample/service');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
//curl_setopt($ch, CURLOPT_VERBOSE, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_SSLKEY, 'sample.pem');
curl_setopt($ch, CURLOPT_FILE, $fh);

if (curl_exec($ch) === false)
{
    echo "Curl error: " . curl_error($ch) . NEWLINE;
}
else
{
    echo "Operation completed successfully" . NEWLINE;
}

curl_close($ch);
fclose($fh);

Calling a WCF service from PHP

Rizal Almashoor — Thu, 08 Apr 2010 06:55:06 +0000

The WCF service needs to use basicHttpBinding.

The PHP code:

define('NEWLINE', "
\n");

// SOAP client

$wsdl = 'http://example.com/SampleWcfService.SampleService.Service?wsdl';
$soapClient = new SoapClient($wsdl, array('cache_wsdl' => 0));

// SOAP call

$sampleData->SampleProperty = "abc";

$parameters->sampleId = 123;
$parameters->sampleData = $sampleData;

try
{
	$result = $soapClient->GetData($parameters);
}
catch (SoapFault $fault)
{
	echo "Fault code: {$fault->faultcode}" . NEWLINE;
	echo "Fault string: {$fault->faultstring}" . NEWLINE;
	if ($soapClient != null)
	{
		$soapClient = null;
	}
	exit();
}
$soapClient = null;

//echo "\n";
//print_r($result);
//echo "\n";

echo "Return value: {$result->GetDataResult}" . NEWLINE;

IService.cs:

using System.ServiceModel;

namespace SampleWcfService.SampleService
{
    [ServiceContract(Namespace = "http://example.com/SampleWcfService/SampleService")]
    public interface IService
    {
        [OperationContract(Name = "GetData")]
        string GetData(int sampleId, SampleType sampleData);
    }
}

Service.cs:

namespace SampleWcfService.SampleService
{
    public class Service : IService
    {
        public string GetData(int sampleId, SampleType sampleData)
        {
            return string.Format("sampleId = {0}, sampleType.SampleProperty = {1}", sampleId, sampleData.SampleProperty);
        }
    }
}

SampleType.cs:

using System.Runtime.Serialization;

namespace SampleWcfService.SampleService
{
    [DataContract(Namespace = "http://example.com/SampleWcfService/SampleService", Name = "SampleType")]
    public class SampleType
    {
        [DataMember(Name = "SampleProperty")]
        public string SampleProperty { get; set; }
    }
}

App.config:

Using log4php

Rizal Almashoor — Fri, 26 Mar 2010 23:46:13 +0000

A how-to for the excellent log4php:

Rolling daily file
Log error statements into one file, and info statements into another
Send emails

Usage

include_once('/var/www/example/components/log4php/2.0.0/Logger.php');

class Example
{
	private $logger;

	function __construct()
	{
		$loggerConfig = '/var/www/example/config/log4php.xml';
		Logger::configure($loggerConfig);
		$this->logger = Logger::getLogger('example');
	}

	public function doSomething()
	{
		$var = $this->getSomeValue();
		$this->logger->debug('in doSomething: $var = ' . $var);
		try
		{
			$this->doSomethingSpecific();
		}
		catch (Exception $ex)
		{
			$this->logger->error($ex->getMessage());
			throw new Exception("There is a problem with Something. We apologize for any inconvenience caused.");
		}
		$this->logger->info("doSomething successful");
	}
}

log4php.xml

Calling a .NET asmx web service over https from PHP

Rizal Almashoor — Fri, 26 Mar 2010 13:44:08 +0000

Enable SOAP by uncommenting “extension=php_soap.dll” in php.ini
https should be included in “Registered PHP Streams” (phpinfo) – uncomment “extension=php_openssl.dll” in php.ini

// SOAP client

$wsdl = 'https://www.example.com/services/ProductManagement.asmx?wsdl';
$endpoint = array
(
	'location' => 'https://www.example.com/services/ProductManagement.asmx'
);
$soapClient = new SoapClient($wsdl, $endpoint);

// SOAP header

$soapHeaders = array();

$namespace = 'http://www.example.com/services/ProductManagement';
$elementName = 'Authentication';
$authenticationHeader = array
(
	'Username' => 'user9',
	'Password' => 'pass1234',
);
$soapHeader = new SoapHeader($namespace, $elementName, $authenticationHeader);
$soapHeaders[] = $soapHeader;

$soapClient->__setSoapHeaders($soapHeaders);

// SOAP call

$parameters->productCode = '9555170408350';

try
{
	$result = $soapClient->GetProduct($parameters);
}
catch (SoapFault $fault)
{
	echo "Fault code: {$fault->faultcode}
\n";
	echo "Fault string: {$fault->faultstring}
\n";
	if ($soapClient != null)
	{
		$soapClient = null;
	}
	exit();
}
$soapClient = null;

//echo "\n";
//print_r($result);
//echo "\n";

echo "Product code: {$result->GetProductResult->ProductCode}
\n";
echo "Name: {$result->GetProductResult->Name}
\n";
echo "Description: {$result->GetProductResult->Description}
\n";
echo "Category: {$result->GetProductResult->Category}
\n";
echo "SKU: {$result->GetProductResult->SKU}
\n";
echo "Manufacturer: {$result->GetProductResult->Manufacturer}
\n" ;
echo "Brand: {$result->GetProductResult->Brand}
\n";
echo "In stock: ";
echo ($result->GetProductResult->IsInStock ? "Yes" : "No") . "
\n";

Data Sanitizer

Rizal Almashoor — Fri, 19 Mar 2010 09:44:11 +0000

I wrote a C# console app to sanitize CSV files. It replaces numbers with X’s so that social security number 123456 becomes XXXXXX and the address “49 Main St” becomes “XX Main St”. Both the input and the output are streamed to ensure that the program won’t run out of memory even with arbitrarily large files.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace DataSanitizer
{
    class Program
    {
        private const string Delimiter = "|";
        private const string ReplacementCharacter = "X";
        private const int NumFields = 15;

        static void Main(string[] args)
        {
            if (args.Length < 2)
            {
                Console.WriteLine("Usage: DataSanitizer.exe input_file output_file");
                return;
            }

            string inputFilePathAndName = args[0];
            string outputFilePathAndName = args[1];

            using (StreamReader sr = new StreamReader(inputFilePathAndName))
            using (StreamWriter sw = new StreamWriter(outputFilePathAndName, true))
            {
                string line;
                while ((line = sr.ReadLine()) != null)
                {
                    string[] fields = line.Split(Delimiter.ToCharArray());
                    string ssn = fields[2];
                    string addressLine1 = fields[4];
                    string addressLine2 = fields[5];
                    string addressLine3 = fields[6];
                    string telHome = fields[9];
                    string telOffice = fields[10];
                    string telMobile = fields[11];
                    Regex alphanumeric = new Regex(@"\w");
                    Regex numeric = new Regex(@"\d");
                    string ssnSanitized = alphanumeric.Replace(ssn, ReplacementCharacter);
                    string addressLine1Sanitized = numeric.Replace(addressLine1, ReplacementCharacter);
                    string addressLine2Sanitized = numeric.Replace(addressLine2, ReplacementCharacter);
                    string addressLine3Sanitized = numeric.Replace(addressLine3, ReplacementCharacter);
                    string telHomeSanitized = alphanumeric.Replace(telHome, ReplacementCharacter);
                    string telOfficeSanitized = alphanumeric.Replace(telOffice, ReplacementCharacter);
                    string telMobileSanitized = alphanumeric.Replace(telMobile, ReplacementCharacter);
                    StringBuilder sb = new StringBuilder();
                    for (int i = 0; i < NumFields; i++)
                    {
                        if (i > 0)
                        {
                            sb.Append(Delimiter);
                        }
                        switch (i)
                        {
                            case 2:
                                sb.Append(ssnSanitized);
                                break;
                            case 4:
                                sb.Append(addressLine1Sanitized);
                                break;
                            case 5:
                                sb.Append(addressLine2Sanitized);
                                break;
                            case 6:
                                sb.Append(addressLine3Sanitized);
                                break;
                            case 9:
                                sb.Append(telHomeSanitized);
                                break;
                            case 10:
                                sb.Append(telOfficeSanitized);
                                break;
                            case 11:
                                sb.Append(telMobileSanitized);
                                break;
                            default:
                                sb.Append(fields[i]);
                                break;
                        }
                    }
                    sw.WriteLine(sb.ToString());
                }
            }
        }
    }
}

Urgent

Rizal Almashoor — Wed, 17 Mar 2010 11:59:02 +0000

You don’t know the meaning of urgent until you’re stuck in a traffic jam with a small child who has just started potty training, who urgently needs to go …