chatServer/README.md

# Base-server
## TCP request syntax
A valid request contains a 4-byte (32-bit) big endian unsigned integer denoting the length of the data in bytes, not including the integer itself, a null-byte (`00000000`), which is also not included in the length, followed by the data. Responses are formed in the same format.

# Text-server
## Command data syntax
- The server accepts UTF-8/ASCII encoded messages.
- Each message may be formatted like: `command,argument 1,argument 2,...`
- The arguments are optional, depending on the command.
- Spaces between commas are parsed, so to the server, `command ,` would be "command " and `, argument` would be " argument".
- Commas may be escaped by use of a `\`
- Sending a `\`, without escaping the next character, can be done with `\\`
- Responses and other client-messages are formed in the same format.
- Responses may include UTF-8.

## Default commands
**Legend:** `commands`, `<required aguments>`, `[optional arguments]`
- **req**  
Execute a command with an associated request ID. Returns with the same ID, and the command's return value(s).  
*Arguments:* `req,<ID>,<command>,[argument 1],[argument 2],[...]`  
*Return:* `req,<ID>,[return value 1],[return value 2],[...]`
- **register**  
Register a new user on the server.  
*Arguments:* `<user>,<password>`
- **login**  
Log into an existing server.  
*Arguments:* `<user>,<password>`
- **whoami**  
Check which user this session is using.  
*Return:* `user,<user>`
- **send**  
Sends command to another user's clients. The command will arrive as-is, with the user switched to be the sender instead of the receiver. So if you are fier, and you execute `send,fier2,text,hello`, fier2 will get `send,fier,text,hello`  
*Arguments:* `<user>,<command>,[argument 1],[argument 2],[...]`
- **nop**  
Do (almost) nothing.  
*Return:* An "empty" response (four bytes denoting the message has a length of 0, the null byte, and no additional data, unless called with `req`)

If a return is not specified, the command will return `ok`. If arguments are not specified, the command does not take any arguments. Any command may return an error if malformed or an exception occurs.

The server may add, remove or change commands.

## Error responses
- An error returns as `error,<fatality>,<type>,[info]` or `req,<ID>,error,<fatality>,<type>,[info]` if `req` was used.
- `<fatality>` is either `fatal` or `nonfatal`. `fatal` usually results in the connection being dropped.
- `<type>` is the programmatic name of the error. These are usually lower-case. The types are listed below.
- `[info]` is additional info, meant to be read by a human.

## Error types
- **unhandled**  
An error occured on the server.
- **request_too_long**  
The request sent by the client is too long.
- **timeout**  
The request did not finish in a timely fashion, or the session timed out.  
- **command_not_found**  
The command is not available on this server.
- **syntax**  
The command's arguments are wrong in some way.
- **name_too_short**  
The user name is not long enough.
- **invalid_name**  
The user name contains invalid characters.
- **wrong_user_or_password**  
The user does not exist, or the password is incorrect.
- **not_logged_in**  
Action requires the session to log in.