Flux multi-user server

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Definition[edit | edit source]

Flux multi-user server (alias Hydra) is Open Virtual Worlds Web Server made by Media Machines. Currently as on July 2007 in late alpha/early beta.

For the moment, this page is only of interest to technical folks. Hydra is not ready for the masses as on July 2007.

Installation[edit | edit source]

Daniel K. Schneider tried on his personal Linux Desktop (Ubuntu 6.10). Disclaimer: I am not a programmer nor a sysadmin. Also, I use root to do command-line installations (can't get myself to type sudo in repetition).

In progress so to speak ...

Downloads[edit | edit source]

1. Get the Hawk Network Library version 1.7 by Phil Frisbie (LGPL). You can find it in the downloads section.
2. Get Hydra, Flux Multi-User.
3. Get MySQL development libraries and MySQL is you don't have these (see below).
4. Also install Flux Player 2.1 if you don't have it already.

Preparation of installation[edit | edit source]

MySQL

• Install MySQL and the development libraries!
• Use Synaptic Package Manger or apt-get and install these

I took:

mysql-server
libmysqlclient15-dev

If don't want to type command-lines to mysql, you also may want to install a mysql administration client. I tried (but then only used it to change the root password of the mysql server).

mysqladmin

This tool then will show up under Applications/Systems tools. First time you connect you can use 'root' without password.

Then, open a terminal and become root:

su

Hydras (files)

Currently (July 2007) you have to compile Hydras and HawkNL it yourself.

• unzip into a folder, e.g. I used

/usr/local/flux/hydra

Modify some source code

• I suggest to make a change to scenemodel.c (else you will have to use database, user and password for MySQL... Change line 51 from:

(&hydra_db, "localhost", "user", "password", "database", 0, NULL, 0) != NULL);

to:

(&hydra_db, "localhost", "hydrausr", "SECRET", "hydra", 0, NULL, 0) != NULL);

• Edit hydras.c, i.e. replace

char *url = "http://worlds.webers.org/content/testbed/";

by something of your own

HawkNL

• Put it in a folder named "HawkNL" at the same level as the folder containing the Hydra sources. E.g. I used

/usr/local/flux/HawkNL

unzip HawkNL17b1src.zip [-d "flux directory"]
cd "flux directory"
ln -s HawkNL1.70 HawkNL

Result is something like this

/usr/local/flux
lrwxrwxrwx 1 root root 10 2007-07-06 15:28 HawkNL -> HawkNL1.70
drwxr-xr-x 7 root root 4096 2007-07-06 15:27 HawkNL1.70
drwxr-xr-x 2 root root 4096 2007-07-06 15:40 hydra
drwxr-xr-x 2 root root 4096 2007-07-06 15:39 src

Compilation[edit | edit source]

HawNL

cd HawkNL
make -f makefile.linux
make -f makefile.linux install

It will also copy the libraries in /usr/local/lib and header to /usr/local/include/nl.h

Hydras

• On Windows, load the hydras.sln or hydrac.sln solution files into MSVC 2003 or later (not tested).
• On Linux (I used Ubuntu) run make on the Makefile with gcc installed.

cd hydra
make

Result:

gcc -I/usr/include/mysql -DUSE_MYSQL -c scenemodel.c
gcc -I/usr/include/mysql -DUSE_MYSQL -c netcontroller.c
gcc -c netview.c
gcc -c -ggdb swamp.c
gcc -o hydras -pthread hydras.o clients.o scenemodel.o netcontroller.o netview.o swamp.o ../HawkNL/src/libNL.a -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient
gcc -c -ggdb hydrac.c
gcc -o hydrac -pthread hydrac.o swamp.o ../HawkNL/src/libNL.a
hydrac.o: In function `printErrorExit':
/usr/local/flux/hydra/hydrac.c:76: warning: the `gets' function is dangerous and should not be used.
make: *** No rule to make target `hydrabot', needed by `all'. Stop.

This doesn't seem to be harmful (for the moment) since hydras (the server) is built.

MySQL database[edit | edit source]

I presuppose that both MySQL and your Hydra will run on the same machine.

Create a hydra database and a user (same as in scenemodel.c)

(I used the command line since I couldn't figure out how to use the GUI.)

mysql -p

• You have to create a hydra_db databse called hydra

mysql> create database hydra;

• Then create the user called hydrausr (change secret of course)

mysql> create user hydrausr identified by 'secret';

• Then give it rights to the hydra database

mysql > GRANT SELECT,INSERT,UPDATE,DELETE,CREATE,DROP ON hydra.* TO 'hydrausr'@'localhost';

• Then reload the privileges

mysql > flush privileges;

Create a User table

This is needed for avatars, else you get something like:

Client connected with yourid=1, mytoken=/MM-6-12345678, uid=6
SELECT login_name,avatar FROM users WHERE uid=6
wrote 61 bytes to 1
Segmentation fault (core dumped)

So you go:

mysql -p
use hydra

Copy/paste this:

CREATE TABLE `users` (
`login_name` varchar(32) default NULL,
`password_hash` varchar(128) default NULL,
`uid` int(10) unsigned NOT NULL auto_increment,
`avatar` varchar(128) default NULL,
`email` varchar(255) default NULL,
`iconurl` varchar(255) default '/users/media/defaulticon.jpg',
terms smallint unsigned default 0, /* signifies which terms user agreed to, should always be > 0 */
mailings smallint unsigned default 0, /* signifies the level of mailings user agreed to, 0 is only essential */
PRIMARY KEY (`uid`)
);

To check it:

mysqlshow hydra -p
Enter password: 
Database: hydra
+--------+
| Tables |
+--------+
| users  |
+--------+

mysqlshow hydra users -p
.....

Run it to test if it may work[edit | edit source]

Type: hypdras

./hydras

You may see:

port is 13214
url is http://tecfa.unige.ch/guides/x3d/ex/hydra/testbed.html
connected to database
Listening on 13214

Note: if you didn't edit the *.c files as told above, you will get

url is http://worlds.webers.org/content/testbed/

From another terminal you also may launch a text client.

./hydrac -d

You may see:

read 4 bytes, messlen is 6
read 6 bytes, messlen is 6
hello yourid=0, mytoken=NA

... though I can't figure out how one could use this to test other things.

Run it with your own stuff[edit | edit source]

To test, get the Flux Multi-user test files from media machines and dezip on some webserver.

Then edit files localplane.x3d and testbed.x3d etc. and change from:

url="'swmp://localhost:13214/MM-6-12345678'"/>

to the URL of your Hydra server (not the webserver !)

The try with a Flux Player. E.g. enter a URL like

http://tecfa.unige.ch/guides/x3d/ex/hydra/localplane.html
http://tecfa.unige.ch/guides/x3d/ex/hydra/testbed.html

Note: The hydra URL runs on my desktop and will be mostly down ... So don't bet on the files / server I installed.

If you correctly created the MySQL users table you'll see something like:

./hydras -d
port is 13214
url is http://tecfa.unige.ch/guides/x3d/ex/hydra/testbed.html
connected to database
Listening on 13214
Client connected from 129.194.112.101:1032 on socket 1
read 18 bytes from 1
wrote 6 bytes to 1
Client connected with yourid=1, mytoken=/MM-6-12345678, uid=6
SELECT login_name,avatar FROM users WHERE uid=6
wrote 61 bytes to 1
read 35 bytes from 1
read 35 bytes from 1
read 35 bytes from 1
.....

Conclusion[edit | edit source]

I think I got it working somewhat. But the test scene has missing files and is sluggish (even on a good Dell XPS II laptop). I seem to wake up in the middle of an avatar etc. At some point I think I have seen 2 avatars, but it may have been a fatamorgana.

Maybe something to do with client stuff like avatars being identical from 2 different machines or so .... will look at it again at some point. Maybe something not correctly installed.

See also[edit | edit source]

• Flux single-user client

Links[edit | edit source]

Mediamachines

• http://www.mediamachines.com
• Flux Multi-User (essential reading)

Help for installation

• Experience installing, compiling and running Flux server and client by DragonMage, really useful !
• Developer Forums