[Guide] Coding for CoEmu/Cofuture

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11/13/2009 23:30 pro4never#1
CONTENTS OF THREAD:
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saving/loading/updating databases using SQL

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(By Yashi)

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(By Grasshoppa)

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So I figured I'd post some basic guides and tutorials for coding. These are NOT source dependent. You will simply need to understand how to modify the codes.

Nothing in here is a working feature, when I use things like Pk events as an example I have NOT posted full working codes to add a pk event to your server. I'm giving you examples of how to program parts of these events yourself.

These are all intended as basic conceptual help for coding. If I made a mistake in my explanations, please let me know (flame if you want, I'm far from sensitive lol). I am by no means an expert coder and especially not so at C#. I am working with the 1.0 source simply because it's what has been interesting me lately, feel free to apply these theories to sources you use though.


That being said, enjoy.
If you have any requests for advice (again, NOT FULL CODES) let me know
If I got something wrong, please let me know and I'll fix it (and give credit obviously)

Note: this thread will be updated in time. These are just some basic things I had time to write up right now.

--------------------------------------------------

How to do something to/retrieve all online players [CoFuture: 4267 source]

Finding online players can be useful for all sorts of things, random events, pk wars, finding number of players online and countless other things. Here is a brief explanation of how to go about it.

*Note* These structures will work for all sorts of sources, you just need to know how to modify it.


Code:
Start.Clients
Start.Clients can be used in a number of ways such as to find out how many players are online (Start.Clients.Count). Perhaps the most useful way to apply this though is to use of "foreach".

foreach means exactly what it says. The loop occurs once for each item in the structure (in this case a Dictionary named Clients)

The way to use this to execute code once for each player connected to the server is as follows


In this example if you want the code inside the loop to effect only the character, you are going to want to do Player.Value.Char.*Extension*

The possible extensions are ANYTHING under Character.cs (Name, Level, Reborn, GuildID etcetcetc)

here is an example of how the foreach loop can be used


Hopefully that will help you understand how to do that a little bit better. To do it in other sources should function exactly the same! You will just need to modify the variable names.


--------------------------------------------------


Intro to hashtables:
(Just starting to learn these myself so bear with me)

Hashtables can be thought of a bit like an in-source database. They are data structures that are intended to map keys (player name for example) to certain values (player score in an event)

To make a new hashtable all you have to do [CoFuture: 4267 source, should be identical in others though] is place something like this in the Start.cs file (will differ with other sources)


This creates the initial Hashtable known as PkWarScore.

To enter an initial value for a character into this hashtable, you simply need to use something like this:

Start.PkWarScore.Add(Client.Char.Name, #); (where # is the score to set that char name to)

If you are updating a value for a character in a hashtable (already exists in the structure) you want to use something like this:

Start.PkWarScore[Client.Char.Name] = (int)Start.PkWarScore[Client.Char.Name] + 1;

This is saying that Where Char.Name exists in PkWarScore, add 1 to their score (number modifiable obviously)



To find out if the player is already in the hashtable or not you simply want to use some if statements to control logic flow.



To reiterate: When using hashtables you have multiple ways to modify things.

Add (adds a new item to a hashtable)
Clear (clears/wipes entire hashtable)
Contains (checks if hashtable contains something)
Remove (Removes/clears a specific entry to a hashtable)
PkWarScore[Client.Char.Name] (updates an existing entry for lack of a better explanation. Just look at the code. It will help you more.)

So for example to clear an entire hashtable (event is over for example) just do
Start.PkWarScore.Clear



If there are any further questions on the basics behind hashtables please let me know, bearing in mind that I am just picking up some of this stuff myself still.


--------------------------------------------------

Credits:

Pro4Never (me)
Will add names as people help correct shit.


Again: hope this helps some people, if you have requests or questions just lemme know. I plan to add more stuff in time.
11/13/2009 23:34 hunterman01#2
Not bad will help the noobs that want to learn

But at the same time wont help anyone who isnt intrested in learning (if ur not intrested in learning u dont belong in the thread) plain and simple

Goodjob
11/13/2009 23:36 _legitimate_#3
ty
11/14/2009 00:04 -Shunsui-#4
OWNED helps me alot :D
11/14/2009 00:10 pro4never#5
Part 2:

Writing your own commands and Database functions (Thanks for correcting my old terminology Basser)

A very useful thing when adding new features, is having the ability to create new databases and modify existing ones

eg: adding composition co CoEmu you have to modify the Items database to have a field for progress. You then need to modify all the item related database functions in the source to understand what progress is and where/how to insert it into the database. If you were not able to do that you wouldn't be able to add, load or remove items from the database and have them with progress/composition.

On the flip side of adding Databases, a very useful feature for any beta server is the ability to quickly test new features in a controlled manner. This is an area where adding custom commands comes in very handy.

For this example I will explain how to add a quest to a new database (You would obviously have to create the database first) and add data to it using a gm command (npcs will function the exact same way but by doing it through a command we will get much better instant, customizable feedback.

NOTE: THIS IS COFUTURE: 4267 SOURCE. Other sources will need to convert the code to make it work the same BUT! The coding examples are still valid, this is THEORY, not copy/paste scripts.


--------------------------------------------------

Adding to a database:

To start I will paste a fully functional script and then break it down from there.


When first looking at this, it will look like a complete bitch (unless you already have some idea what you are doing with sql and database functions, in which case you have no point reading this most likely ^^).

To start we will focus on the void.

The function simply states what the command name is, and the parameters it requires to function (input)

public static means it can be accessed from anywhere in the source and is not instanced (no 'new' or '.this' + other changes... you want most of your functions to be static)

the data inside the brackets are the parameters. For a more simple example that you may be able to relate to lets write a small function (which is essentially what this is, again terminology differs between programing language but w/e!) to divide numbers.


Code:
public static void DivideXByY(double x, double y)
        {
            double z = x / y;
            Console.WriteLine(" X divided by Y = " + z);
        }
Can you understand how this tiny section of code works? It's quite simple really.

DivideXByY involves 2 inputs (x and y) which are both int (full numbers, no decimals)
z = x / y
simply sets variable z = to x divided by y (again, obvious, just stating it for people)

Console.WriteLine("text" + z); writes text to the console (game server window) saying "text *valueofz*"


This function can be called now from anywhere in the source (because we made it public!)

Seeing as in our example it's within the Database class, you would simply write

Database.DivideXByY(10, 2);

this would print out to the game server console " X divided by Y = 5" because 10 / 2 = 5

KEEP IN MIND YOU CAN STILL USE RETURN TYPES!
eg: instead of void make it double and then just do return (x/y);. Then you can do something like

Console.WriteLine("X divided by Y = "+ Database.DivideXByY(10,2));

>Jump Back< Ok: now that I've done my super basic explanation of voids/functions I'll go back to the AddQuest example.

Code:
lock (DatabaseConnection)
            {
                MySqlCommand Cmd = new MySqlCommand("insert into `quests`(`AccountId`, `PlayerName`, `QuestId`, `QuestName`, `QuestStage`, `QuestCompletion`) values (" + AccountId + ", '" + PlayerName + "', " + QuestId + ", '" + QuestName + "', " + QuestStage + ", " + QuestCompletion + ")", DatabaseConnection);

                Cmd.ExecuteNonQuery();
            }
Means it is going to Insert (add) into Quests (database name)
('DatabaseColumn1', 'DatabaseColumn 2', .......)
values (what to insert into the previous fields. They fit together so first database column = first entry into values)
then it builds the string of what it is trying to insert. THESE ARE LOADED FROM THE FUNCTION ITSELF. Notice that wherever the type of data was a string (text) it is surrounded by ' '. This is REQUIRED for Mysql to view it as a string. if not it will throw an exception (we will get to exceptions later)

I know this explanation of mysql wasn't perfect but I'm tired and it's always a ugly mess whenever I look at sql. If anyone has a description of Sql queries that is more legible, go for it.


NOTE: Using immune's sexy mysql wrapper is strongly suggested. It simplifies the use of database functions and makes everything far more efficient and reduces the chance of you doing something stupid which may crash sql.

--------------------------------------------------


Adding commands
Very useful for testing database functions, you get to see if there are all sorts of lovely errors!


As with the last SQL statement, I'll post the fully functioning command that I wrote to go along with it and then break it down into more simple stages after that.


Now first of all notice the 'try' and 'catch'. Those will be your new best friend when FINALIZING new features. It keeps major errors from popping up. The downside to that is that if you are initially testing something you may WANT those nasty error messages (in his case if it was invalid input or not working correctly it would give you a Mysql error with a bit of data concerning what was wrong. This can help you fix things!)


How try/catch works:

When you write a program and tell it to do something such as converting between data types (int, float, string), the program will take your word ass god and not check for errors. If you mess something up it can crash the entire program or at the very least print out a very unfriendly error message. When dealing with user input especially (yay input fields and player commands!!!!), we want to be able to check for validity and if something goes wrong, provide a more user friendly feedback.


[code]
try
{
//code
}[/quote]
Does exactly what it says, it TRIES to do what code you have entered.

catch
{
//nice friendly error msg or other code
}
Does exactly what it says also. Catch will only run if try ran into an exception (error) and could not complete its code. Instead the program will jump to the catch section of code and execute it in its place.

>Jump< Back into the topic of this command. (re-pasting in spoiler for reference)


To recap: When looking at creating new player commands you use [number] to determine position in the player chat.

Eg: /Quest 123 name 100 999

/quest = spliter[0]
123 = spliter[1]
name = splitter[2]
100 = splitter[3]
999 = splitter[4]

For use in our database these need to be converted to the correct type. This can be done through Convert.Totype(data)



I should take a break because I think I'm becoming less and less understandable. Hope this helps people but again if you have a question/error to point out/request. Lemme know!



<edit>

Slightly updated thanks to Basser pointing out some of my very poor knowledge of terminology. I did write this many months ago but it really is laughable how poor most of my terminology was. I've updated a few sections of it but I'm not going to re-write the entire post right now. Basically take it as is but don't limit yourself to this knowledge. These are meant as examples + explanation of them more than an actual "tutorial" on how to add something. When I write these I intend to simply draw attention to some certain tools that C# has and then demonstrate how to use them in a very basic way. Where you go from there is up to you. I strongly recommend a quick google of them and then attempt using them yourself in some different ways so that you are comfortable with them down the line.
11/14/2009 01:00 #*=DarkAngeL=*##6
Nice man :) Goodwork
11/14/2009 02:39 MexicanoCoder#7
Nice guide pro4never
11/14/2009 03:17 pro4never#8
Now some more basic stuff for people just getting into Servers: Seeing as the bulk of people are using CoEmu I'll do this one on the base CoEmu source.


Npc Coding:
Npcs in CoEmu are rather easy to code but alot of newcomers can find them intimidating. I'll try to break down exactly how they can be coded (this is less theory and more structure for people who don't know what they are doing)


In CoEmu, npc codes can be found under GameServer>Handlers>NpcTalk.cs

The first thing you should know about NPC coding is how to determine which script goes to which npc.

This is done through the case number.

Eg: case 10050: //TC - Conductress

everything inside

Case CaseNumber:
{
//npccode
break;
}

Will be the script for the npc in question.

Here is an example of a very simple npc.


All codes start at LinkBack == 0 (this is the code that will pop up when you talk to an npc)

Lines of code consisting of: Text("", CSocket); are simply npc output (that is what the npc says)
Each line of Text creates a new line of text ingame, you can force a new line by typing \n in the npc text code

Eg:

Lines of code consisting of Link("text", #, CSocket); are user options. 255 closes the dialogue, all other numbers go to the corresponding LinkBack number!

End(CSocket); ends the current section of code (required for each link back to avoid fucking up the script)


---------

Now that we've covered a little bit of how the npc scripts are laid out all that is left to do is checks.

The simplest check is using an if statement. If statements are true or false statements

Eg

if (x > 10)
{
//code
}

means if (x > 10) is true (if x = 1, it is not > 10 so it is false. The statement is therefor not activated)


You can apply this to npc scripts by checking player levels, cash, job or any other character stat.


Lets write a little script that will tell the player their job, level and current map and charge them 1000 gold to do it (hehehe, pointless but a good code example)


Note: Not tested npc at all but should work fine. Besides its an EXAMPLE lol


Please note that all voids and database sections can be used in these scripts. What you want your npc to do is completely up to you!

No time to write more right now, hopefully a super basic Npc guide helps some ppl. I may finish it later.
11/15/2009 11:25 Santa#9
Holy shit, i thought you were kidding when you said you made some guides.
11/15/2009 12:03 pro4never#10
Quote:
Originally Posted by StarBucks View Post
Holy shit, i thought you were kidding when you said you made some guides.
Ahaha well they are far from finished but hopefully they will give some people insight into how to script their own things.
11/15/2009 12:49 ImmortalYashi#11
Heya,

I saw hundred of people mistaking in the defining of things and not being able to fix simple errors for example:
public bool RebornCount = ""; WRONG
So in this guide i will explain HOW-TO define.

I will explain the pre-types first.
*INT(eger)

I'm too lazy to finish the rest off maybe if i came back from school tomorrow.
11/15/2009 22:13 pro4never#12
Quote:
Originally Posted by ImmortalYashi View Post
Heya,

I saw hundred of people mistaking in the defining of things and not being able to fix simple errors for example:
public bool RebornCount = ""; WRONG
So in this guide i will explain HOW-TO define.

I will explain the pre-types first.
*INT(eger)

I'm too lazy to finish the rest off maybe if i came back from school tomorrow.
Ooh nice job, I didn't even think to go into definitions... I guess maybe it's just cause I've had to do it so much for other things that I don't even really think about having to declare what type of data they are holding....


Then again python has spoiled me because you don't have to define variables before use and it figures out what type of data it's holding all by itself.

+T for being helpful
11/15/2009 23:13 _tao4229_#13
Quote:
Originally Posted by pro4never View Post
Ooh nice job, I didn't even think to go into definitions... I guess maybe it's just cause I've had to do it so much for other things that I don't even really think about having to declare what type of data they are holding....


Then again python has spoiled me because you don't have to define variables before use and it figures out what type of data it's holding all by itself.

+T for being helpful
Python you do have to define them - it's just dynamically typed (well, it's pretty much the same thing, lol.)

Python ftw?
11/15/2009 23:18 pro4never#14
Quote:
Originally Posted by _tao4229_ View Post
Python you do have to define them - it's just dynamically typed (well, it's pretty much the same thing, lol.)

Python ftw?
Ahaha actually school has turned me off of python. I made the mistake of going into the advanced programing class w/o having any experience really other then some basic scripting and stuff...

Let's just say that didn't turn out well so I had to switch to the introductory one lol.


Spending like 8+ hours trying to write your FIRST assignment in like week 2.... not a fun experience. But yah, in general python is kinda nice.
11/16/2009 00:19 ImmortalYashi#15
Lesson 2.

Understanding timers

Timer.AutoReset

Timer.Enabled

Timer.Interval

Timer.Start

Timer.Stop

Timer.Elapsed Event

*SUBLESSON 2.1

Processing exampe:
Explaining them :

Next, we specifiy what program will be run. This could be done by assigning the program name to the FileName member of the IE's Process object's StartInfo property. For example:
The StartInfo property also has a member called Arguments, which is used to specify command-line options that are passed to the program. In the following example, the string "google.com" is passed as an argument, so IEX will know what url to open:
The program is being executed by invoking the Start(); command as shown below:
*SUBSHIT ( May save people some time )
The encryption for 5018+
Oh and you can use blowfish for the gameserver.

Correct Me if I missed anything,
Yashi.
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