mIRC Scripting

mIRC: Sockets

Sockets

A socket, in networking terms, is simply a combination of an IP address and a port number. For our purposes we can go with a one end-point of a two-way communication link between two processes running on the network.

An IP address is the numerical identification that is assigned to devices that utilize the Internet Protocol. A port number is a process-specific identifier that serves an end point.

For example, look at the following socket: 74.125.91.104:80. The first part is the IP address (in this example we used www.google.com). The number that follows the colon (:) is the port number. In this case it's port number 80, which happens to be the default HTTP port.

Ports:

A port number is a 16-bit unsigned integer, thus ranging from 0 to 65535. (2¹⁶-1), giving you a total of 65,536 ports. Ports 1-1023 are called well known ports, ports 1024-49151 are registered ports, and ports in the rage of 49152–65535 are dynamic and/or private they cannot be registered.

Be careful not to be confused between the client and server ports. The server port is the port in which the client (you) will attempt to establish a connection; the server listens to incoming connection on this port. The client port is the port at the client’s end, which are an incremental number and a much higher port number.

Here are a few commonly used ports:

mIRC Sockets:

mIRC gives you the ability to create a raw socket connections with an end point. This gives you the ability to do anything from getting information from a website (like the weather or games stats) to uploading or downloading files and posting on a forum.

mIRC lets you create two types of sockets: TCP and UDP. Both are core members of the Internet Protocol Suite (TCP/IP).

Here are a few basic points regarding TCP and UDP:

Transmission Control Protocol (TCP):
     - Connection-Oriented Protocols (Virtual Circuit Approach)
     - Reliable - guarantees data will be delivered in the same order as transmitted
     - Used when reliable transport required and speed is secondary

User Datagram Protocol (UDP):
     - Connectionless Service
     - No logical connection established between End Systems
     - Unreliable - "best effort" delivery
     - Used when speed is required and guaranteed delivery is secondary

mIRC TCP Sockets:

TCP is by large the major core member of the Internet Protocol Suite.

Creating A Connection

Since we are using the TCP protocol, we must first establish a connection with the server before any data can be transmitted.

The basic syntax for opening a TCP socket is:

For the purpose of this tutorial, we will create 3 different sockets to the following locations: Our own demo page, Wikipedia, and YouTube.

In example 3 I introduced another command. The /sockMark command. I suggest you take a note to its existence.

Sending Request

Once connection has been made the on SockOpen event will get triggered. This is where all our requests for pages or files go. The information we send is known as the request header.

There are two ways of sending data to the server: POST and GET. When requesting a normal page, you will most likely be using the GET method, when submitting a form, it depends. When dealing with forms, by simply looking at the source code you can tell if it’s a POST or a GET method:

The most basic GET request will follow this basic syntax:

Let’s take a look at the header a little closer:

This line is made up of three parts: method, path and version. The "GET", which SHOULD be always in uppercase letters, is the method. We will talk about the POST method later on. The next part is the path, relative to the root folder of the website. If our website is www.example.com/pub/foo/bar.html, our path would be /pub/foo/bar.html. Lastly, the final part of this line is the HTTP version, for all practical reasons, you will probably using version 1.1.

Next is the Host header

The Host header is required in HTTP version 1.1. Please note: it should be "Host:", not "host:" or "HOST:". If you forget to include this line, the server will send you an error 400 (Bad Request) status code.

The basic on sockopen event is as followed:

To send data to the server we use the /sockWrite command. The sockwrite command has the following syntax:

Let’s continue with our examples:

Coding style:

I would like to point out a few more things before we continue. Coding style is a personal thing and different people code things differently. For example:

A lot of scripters would prefer to write it like this:

It’s up to you to decide which one you like most.

URL Encoding

Specified by the RFC 1738:

We can go with this alias:

To decode:

When sending data in the header, ALL the value MUST be encoded. Their names should not. For example, if the URL is www.example.com/foo/bar.php?foo=<VALUE>

Reading Incoming Data

Once the server receives your request, it will send the response back to you. This will trigger the on SockRead event. The basic syntax of the on sockread event is:

It is important to remember that each time the server replies with a line, the sockread event will trigger.

For debugging purposes I will echo all the information to a window (@ $+ $sockName). This makes it easier to find the section of html we want to retrieve and parse.

Let’s go back to our examples: (I would point out the User-Agent header in examples 2, Wikipedia.)

$noHTML Alias:

The noHTML alias is a very handy alias that strips html tags from a string:

For example:

Will output:

Error Handling

Errors can occur. It is your responsibility to check for them. The $sockerr identifier must be checked every on sockread event and after every /sockread command.

Connection Terminated

It is possible for the remote end to terminate a connection, the same way you can /sockclose a connection early. When this happens the on sockClose event will trigger. The syntax is

The sockclose event will not trigger by you closing the connection, but ONLY by the remote end.

Secured Socket

I am sure you have visited websites with the padlock icon next to the URL in your browser. That icon indicated that website uses secure http (also known as HTTPS). The default port for HTTPS is 443.

SSL:

mIRC lets you create an SSL socket as well using the following syntax:

The on sockopen and on sockread events are exactly the same as the regular http.

TLS:

mIRC does not yet support TLS sockets natively.

Multi-Sockets

When you create a script for a channel, for example a !google script. Using the method above you will only be able to initiate one socket at a time. If you recall, we actually /sockclose the socket to make sure it’s closed. Muti-Sockets is a method that will lets you open as many sockets as needed, not limiting it for one person to use at a time.

The basic idea of muti-socket is that every time the script initiates a new socket, it uses a unique name. This is usually done by appending a random sequence of numbers/letters to the end of the socket name.

For example, instead of using:

The problem with the example above is that only one person is able to use this google script at a time. If a second person types !google while another google socket is open, this script will close the socket of the first person and only reply to the second person.

An easy way to fix something like this is to add 6 number to the end of the socket way. For example we can do Google.###### where ###### are the 6 random. In the example below we use $ticks, which will ensure these 6 numbers will not show up for quite a while.

If you look closely at the sockread event, you will notice I have a google.* as the socket name, the * wildcard can be sued to represent "anything".

You now have to remember that because we are dealing with a dynamic socket name, all the variables will have to be dynamic as well. For example:

Making a dynamic variable called %varName.sockName.######

POST Method

PLease see the Advanced sockets tutorial.

mIRC UDP Sockets:

Please see the UDP socket tutorial.