Ubuntu 10.10 - Developing C# 4.0

I recently changed to Linux, still a fresh user of this system... and since I'm a coder, I thought that programming in C# was a windows thing, and damn how wrong was I!!!

So if you have openSUSE you can program C# 4.0 using the standard repositories, but in ubuntu that isn't the case.. so here is a simple tutorial in how to set your development scenario.

first download and install the monodevelop(using ubuntu software manager).

then you go here: http://www.integratedwebsystems.com/2010/10/mono-2-8-install-script-for-ubuntu-fedora/ (Thx for your hard work Nathan Bridgewater keep up the good work)and follow the steps to compile mono 2.8 in your system... is easy as 1-2-3

then open monodevelop and Edit->Preferences -> .Net Runtimes

press Add and locate '/opt/mono-2.8'

then set as default and you are good to go.

I haven't tested the webserver yet as soon as I do I will post an how to.

Cheers and happy ubuntu programming...

Virtuozzo venet0 Failed to start

In the release of CentOS after installed virtuozzo 4.0 I decided to change the gateway for the machine, it worked for the machine but the containers didn't access the network anymore.

After another reboot I notice an error on the startup:

starting venet0 failed to start

It was trying to get DHCP information, but no IP was given to the machine, it's suppose to be like this.

So I googled and googled but no answer.

I decided to take a look at the /etc/sysconfig/network-scripts/ifcfg-venet0 and the setup command line of CentOS messed it up..

so here is how the file should look for venet0:

DEVICE=venet0

ONBOOT=yes

STARTMODE='onboot'

A reboot and all was working again...

Bind9 with chroot simple version

Having my first steps in Linux, I will just posting the easiest ways to do things with this system.

So I wanted to install a DNS(nameserver) into a CentOS 5.5 machine, the easiest way is:

using Bind9 with chroot as installed by default in the CentOS server.

# cd /var/named/chroot/etc/

edit/create the file

# nano named.conf

put this in the file

options {

directory "/var/named";

forwarders { 8.8.8.8; };

};

# service named start

# dig google.com

the service should be all ok and responding, don't forget to change the /etc/resolv.conf to point to the new nameserver

Multicasting UPnP Messages in the network

If you like and use it don't forget the credits and please leave a comment. Thanks

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;

namespace UPnP.Server
{
public delegate void ReceivedUPnPMSearchHandler(IPEndPoint from, String message);

public class SSDP
{
public Int32 DefaultPort { get; set; }

//OnReceived M-Search

public event ReceivedUPnPMSearchHandler OnReceivedMSearch;

//Holds the ip addresses of the currentMachine
List<IPAddress> MachineIPAddresses;
//Holds the multicast updclient sessions
Dictionary<IPAddress, UdpClient> MulticastSessions;
//Holds the unicast updclient sessions
Dictionary<IPAddress, UdpClient> UnicastSessions;

//Static variables to initialize sessions
private static IPAddress MulticastV4IPAddress = IPAddress.Parse("239.255.255.250");
private static IPEndPoint MulticastV4EndPoint = new IPEndPoint(MulticastV4IPAddress, 1900);

/// <summary>
/// Initializes the class and goes into initializing the sockets to use in the multicast.
/// </summary>

public SSDP()
{
InitializeSockets();
}

/// <summary>
/// Gets all the IPv4 addresses for the current machine
/// We will use this IPv4 Addresses in order to bind the Sockets
/// </summary>

private void InitializeIPAddresses()
{
MachineIPAddresses = new
List<IPAddress>();
foreach (IPAddress ipAddress in
Dns.GetHostAddresses(Dns.GetHostName()))
if (ipAddress.AddressFamily == AddressFamily.InterNetwork)
{
Console.WriteLine("Adding IP: {0}", ipAddress.ToString());
MachineIPAddresses.Add(ipAddress);
}
}

/// <summary>
/// Initializes the sockets, both unicast as multicast
/// Multicast will be used to broadcast informations about our service into the network
/// </summary>
private void InitializeSockets()
{
//Verifies if we have initialized the MachineIPAddresses for usage.
if (MachineIPAddresses == null)
this.InitializeIPAddresses();
MulticastSessions = new Dictionary<IPAddress, UdpClient>();
UnicastSessions = new Dictionary<IPAddress, UdpClient>();
//We will create a multicast and unicast socket for each machine ip address
foreach (IPAddress ipAddress in MachineIPAddresses)
{
//Creates the UdpClient for multicast
UdpClient multicastSession = new
UdpClient(AddressFamily.InterNetwork);
//this will allow us to connect to an port where other service is already connected. multicastSession.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
//Binding the UdpClient to the IPv4 Address and to the defaultPort
multicastSession.Client.Bind(new IPEndPoint(ipAddress, DefaultPort));
//Defining as a multicast socket and joining the default group.
multicastSession.EnableBroadcast = true;
multicastSession.JoinMulticastGroup(MulticastV4IPAddress);
//Will allow us to listen to messages in the multicast group
multicastSession.BeginReceive(new AsyncCallback(ReceiveMessage), multicastSession);
MulticastSessions.Add(ipAddress, multicastSession);

//Creates the UdpClient for the unicast
UdpClient unicastSession = new UdpClient(AddressFamily.InterNetwork);
unicastSession.Client.Bind(new IPEndPoint(ipAddress, 0));
unicastSession.BeginReceive(new AsyncCallback(ReceiveMessage), unicastSession);
UnicastSessions.Add(ipAddress, unicastSession);
}
}

/// <summary>
/// Closes all the sockets
/// this is important to do before the application terminates.
/// </summary>
public void Dispose()
{
foreach (KeyValuePair<IPAddress, UdpClient> session in MulticastSessions)
session.Value.Close();
foreach (KeyValuePair<IPAddress, UdpClient> session in UnicastSessions)
session.Value.Close();
}

/// <summary>
/// Sends a message to the sockets in the multicast sessions
/// </summary>
/// &lt;param name="message">A preformated message to send to the multicast group</param>
public void SendMulticast(String message)
{
if (MachineIPAddresses == null)
InitializeIPAddresses();
foreach (IPAddress ipAddress in MachineIPAddresses)
SendMulticast(message, ipAddress);
}

/// <summary>
/// Sends a message to the sockets in the multicast sessions
/// </summary>
/// <param name="message">A preformated message to send to the multicast group</param>
/// <param name="to">The IPv4 of the socket group</param>
public void SendMulticast(String message, IPAddress to)
{
if (MulticastSessions == null)
InitializeSockets();

if (MulticastSessions[to] == null)
return;

UdpClient usession = MulticastSessions[to];
try { usession.Client.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastInterface, to.GetAddressBytes()); }
catch (SocketException) { }
byte[] buffer = System.Text.UTF8Encoding.UTF8.GetBytes(message);
usession.Send(buffer, buffer.Length, MulticastV4EndPoint);
usession.Send(buffer, buffer.Length, MulticastV4EndPoint);
}

/// <summary>
/// Sends a message to the sockets in the unicast group.
/// We will use this to send a message to a client requesting a M-Search
/// </summary>
/// <param name="message">A preformated message to send to the unicast group</param>
/// <param name="to">The IPv4 of the destination</param>
public void SendUnicast(String message, IPEndPoint to)
{
UdpClient usession = UnicastSessions[to.Address];
if (usession == null) return;

byte[] buffer = System.Text.UTF8Encoding.UTF8.GetBytes(message);
usession.Send(buffer, buffer.Length, to);
}

/// <summary>
/// The multicast sockets receives a message and will invoke the specified OnReceive

/// </summary>
/// <param name="result"></param>
private void ReceiveMessage(IAsyncResult result)
{
byte[] buffer;
IPEndPoint ep = null;
UdpClient session = (UdpClient)result.AsyncState;
buffer = session.EndReceive(result, ref ep);
try
{
String message = System.Text.UTF8Encoding.UTF8.GetString(buffer);
if (message.Contains("M-SEARCH"))
{
Console.WriteLine("Received M-SEARCH from {0}", ((IPEndPoint)ep).Address.ToString());
if (OnReceivedMSearch != null) OnReceivedMSearch(ep, message);
}
}
catch (Exception) { }
session.BeginReceive(new AsyncCallback(ReceiveMessage), session);
}
}
}

C# and UPnP Socket made easy

I used transcoding in my place for years, first I just used the Windows Media player and the wonderfull XBox 360, but then that wasn't enought because I needed soft subtitles, for several reasons that are not called in here.
So I've changed the Server to be a TVersity Server, and it worked well during some time, before the Windows 7 was released and the confusion of Windows Foundation Media and DirectShow codecs, basicly the sofsubtitles don't work anymore, but TVersity had some minor issues to me, but issues never the less.
1. I can't do imedite fastforward
2. The files don't have description
and now without subtitles it was no longer a solution to me, so I keep on searching and found a new media server that back in the days that I was trying to find one it wasn't good enough to me now it was very good...
PS3 Media Server
Well I've tried for ages to build one Media Server of my own so being PS3 Media Server an open source one, I dig my hands into it.
And opened Visual Studio and started to play around.
So the first problem was building the Multicast and making the devices on my network knows that I was here.

I wasn't easy but reading the manual from UPnP Forum I was one step closer to get there.

So here is my first stage.
Multicasting UPnP Messages in the network.

Windows 7 and SSD Disks

Well for all of you that have SSD disks should know that an SSD Disk has a limited life, and the much you write on it the faster it degrades.

Googling on the web I found some tweeks that could help you guys out there in configuring the Windows 7 System to minimize writes and improve system performace.

Increase System Speed
Disable indexing
Description:
Indexing creates and maintains a database of file attributes. This can lead to multiple small writes when creating/deleting/modifying files. Searching for files will still work.
Instructions:
Start Menu -> Right-Click Computer -> Manage -> Services and Applications -> Services - > Right-Click Windows Search -> Startup type: Disabled -> OK

Disable defragmentation
Description:
Defragmenting a hard disk's used space is only useful on mechanical disks with multi-millisecond latencies. Free-space defragmentation may be useful to SSDs, but this feature is not available in the default Windows Defragmenter.
Instructions:
Start Menu -> Right-Click Computer -> Manage -> Services and Applications -> Services - > Right-Click Disk Defragmenter -> Startup type: Disabled -> OK

Disable Write Caching
Description:
There is no cache on the SSD, so there are no benefits to write caching. There are conflicting reports on whether this gains speed or not.
Instructions:
Start Menu -> Right-Click Computer -> Manage -> Device Manager -> Disk drives -> Right-Click STEC PATA -> Properties -> Policies Tab -> Uncheck Enable write caching -> OK

Configure Superfetch
Description:
Frees up RAM by not preloading program files.
Instructions:
On second glance, I would recommend leaving this one alone. However, there are some customizations that you can follow in the post below.

Firefox - Use memory cache instead of disk cache
Description:
If you use Firefox, there's a way to write cached files to RAM instead of the hard disk. This is not only faster, but will significantly reduce writes to the SSD while using the browser.
Instructions:
Open Firefox -> Type about:config into the address bar -> Enter -> double-click browser.cache.disk.enable to set the value to False -> Right-Click anywhere -> New -> Integer -> Preference Name "disk.cache.memory.capacity" -> value memory size in KB. Enter 32768 for 32MB, 65536 for 64MB, 131072 for 128MB, etc. -> restart Firefox

Free up extra drive space

Disable the Page File
Description:
Eliminate writing memory to the SSD, free over 2GB of disk space. Warning - If you run out of memory the program you're using will crash.
Instructions:
Start Menu -> Right-Click Computer -> Properties -> Advanced System Settings -> Settings (Performance) -> Advanced Tab -> Change -> Uncheck Automatically manage -> No paging file -> Set -> OK -> Restart your computer
Alternatively, if you want to play it safer, you can set a custom size of 200MB min and max.

Disable System Restore
Description:
Don't write backup copies of files when installing new programs or making system changes. Can free up between a few hundred MB to a couple GB. Warning - Although unlikely, if a driver installation corrupts your system, there won't be an automatic way to recover.
Instructions:
Start Menu -> Right-Click Computer -> Properties -> Advanced System Settings -> System Protection Tab -> Configure -> Turn off system protection -> Delete -> OK

Disable Hibernate
Description:
You may free up 1GB of space on the SSD if you have 1GB of memory, 2GB of space if you have 2GB memory. You will lose the hibernation feature which allows the equivalent of quick boots and shutdowns.
Instructions:
Start Menu -> Type cmd -> Right-Click the cmd Icon -> Run as Administrator -> Type powercfg -h off -> Type exit

(http://www.mydellmini.com/forum/windows-7/2441-windows-7-ultimate-solid-state-drive-speed-tweaks.html)

Change IE Cache Disk
Description:
If you have a second disk you can pass the cache to the other disk(not SSD) in order to minimize de writes to the SSDDisk
Instructions:
IE -> Tools -> Internet Options -> Browser History -> Settings -> Move Folder -> Chose the new folder in the second disk -> Ok -> Ok

Encrypt and Decrypt Data in SQL Server

Well this is my first post, let's see if we can keep this running ehehe.

My first post is about encrypting and decrypting data in a column in SQL.
Since I had a bad time searching this in google so I decided this will be my post.

First we have to create the key so we can use it afterwards

Create symmetric key TheSymKeyName
with algorithm = TRIPLE_DES
encryption by password = 'apasswordyouchoose'

You have other choices for the algorithm but for that googleit i will not waist my time on it.

Then we will need to open the key:

Open symmetric key TheSymKeyName
decryption by password = 'apasswordyouchoose'

You can check if the key got open doing a simple query:


Select * from sys.openkeys

Then it's time for we to encrypt the data:

Select EncryptByKey(key_guid('TheSymKeyName'), 'valuetoencrypt')

Voilá, you have your value encrypted. And finally to decrypt the key, you can simply

Select convert(varchar(50), decryptbykey(0x00191422BC15934AB4D8BB81C175331E01000000855C1A81E18EAA0DAB9F32543AF832941324625F852AB0F6EAF12628D0A53D6C))

And don't forget to close the key using:


CLOSE SYMMETRIC KEY TheSymKeyName

Any doubt's???