Workshop (CREW)

1. Introduction
    1.1 Assumptions
    1.2 NOTICE!
    1.3 Features and limitations
    1.4 Backgrounds

2. CREW for pupils and teachers
    2.1 Add a CREW page
        2.1.1 Header and Introduction
        2.1.2 Visibility: World or Authenticated
        2.1.3 Visibility: Individuals
    2.2 Who sees what?
    2.3 Enter CREW
    2.4 "It does'nt work!"
    2.5 Advanced options

3. CREW for the webmaster
    3.1 Configure CREW
    3.2 Check your work

4. CREW for the systems administrator
    4.1 Which server and port?
    4.2 Firewalls
    4.3 Server installation
        4.3.1 The readme.txt
        4.3.2 The crewserver-example.conf text
        4.3.3 Init script
        4.3.4 /var/log/messages
        4.3.5 Help!
    4.4 "After x I got y"

1. Introduction

CREW (Collaborative Remote Educational Workshop) is a browser-based, real-time collaborative editor (RTCE), allowing several people to simultaneously edit the same text file.

1.1 Assumptions

This chapter elaborates on other chapters. We assume you have at least done the Basic procedures for beginners of the Website@School Users' Guide.


For pupils and teachers working with CREW is easy. However, setting up CREW is not a piece of cake. If you are unfamiliar with securely opening one, and only one! port on the schools firewall, feel unconfortable when installing software on a production server and configuring files, please seek help at your local Linux User Group (LUG). They are virtually everywhere and are most willing to perform a small service for the school that (probably) teaches their children.

1.3 Features and limitations

Features in no specific order: Limitations:

1.4 Backgrounds

CREW is based on: a. the Websocket protocol, a rather new (2011-now) web technology, b. on HTML5, the latest (2012-now) markup standard for web content, as well as c. on Javascript (1999?), a well-known programming language to control the browser, communicate asynchronously and alter the document content that is displayed.
CREW skins are created with 4.2.2. Bazaar Style Style, our own (2011) implementation of CSS Cascading Style Sheets, (1996) a language used for describing the look and formatting of a document written in a markup language. It is designed primarily to enable the separation of document content from document presentation. This separation can improve content accessibility.
The Basic Multilanguage Plane (BMP) contains characters for almost all modern languages, and a large number of special characters. A primary objective for the BMP is to support the unification of prior character sets as well as characters for writing. Most of the allocated code points in the BMP are used to encode Chinese, Japanese, and Korean (CJK) characters.


2. CREW for pupils and teachers

In this paragraph we assume that

2.1 Add a CREW page

Adding a page supposes that you have sufficient permissions to add a page. This is specially important for non-webmasters like pupils and teachers who often have limited permissions. These permissions are set in the Account Manager, most times by the webmaster Wilhelmina Bladergroen.

In the Page Manager, select the Area or section and click on the Add a page link to enter the Add a page dialogue:

[ CREW add page and module ]

Fill out the fields as described in Page Manager, paragraph 3.1 Add a page.
In the Module dropdown menu, select the module. Do not forget to select Visible, Hidden or Embargo. Click [Save] to save your work and return to the Page Manager.
Now click on the Page Name to enter the Module Name (modulename) configuration dialogue. In the next paragraph the module will be configured.

2.1.1 Header and introduction

In this part only the Header and Introduction are discussed:
[ CREW page configuration header and intro ]

in the Menu the link Content is selected.

2.1.2 Visibility: World or Authenticated

Here, with the options, World and Authenticated, only the visibility, i.e the read permissions for the viewers of this page can be set.
[ CREW page configuration visibility: world + authenticated ]

2.1.3 Visibility: Individuals

[ CREW page configuration page visibility: individueals ]


In the Account Manager Wilhelmina has given Herbert Spencer permissions: his Admin permissions on Basic and Page Manager. His Page Manager permissions were set to Sectionmaster (so he can add pages) for the Area 'Pupils of Grade 8'. Herbert creates the page, sets the Visibility on Individuals ( because he thinks that work in progress should not be visible to the world or people with an account) and sees:
[ CREW page configuration page visibility: individueals, herberts view ]

Herbert belongs to the group Juniors which consists of pupil Georgina and teacher Helen. Herbert can change these permissions.
However, he does not belong to the group Seniors, so he can neither change the permissions of Catherine Hayes or any other member of that group, nor can he change the permissions of Honorine, the dolphins expert, who just received an account to visit the website and get access to the dolphins page via MyPage on the site. Honorine did not receive any permissions in her Admin and Page Manager.
For details of the EPS groups, please see 1.3 The Exemplum Primary School in the Account Manager.

2.2 Who sees what?

In this paragraph we show you the results of the possible settings in the CREW configuration page.

For the Dolphins project Wilhelmina has set the page permissions as follows:

[ CREW page configuration page visibility: individueals, wilhelmina's view ]

Individuals selected, Catherine, Herbert and Honorine have Read and edit permissions, all other EPS users have none.

[ CREW webpage: for anonymous visitor: no access ]

CREW page on the Area of Grade 8. No header, no introduction, no text, just: Sorry, you currently have no permissions to view this page.

This is the Dolphnins page as seen by:

[ CREW webpage: for visitor with login account: header, intro, text ]

Same page. The header, introduction and text are visible.

This is the Dolphins page as seen by:

[ CREW webpage: for visitor with read+ write permissions: status message, header, intro, text, skins droopdown menu, edit button ]

Yellow status message: Last updated: yyyy-mm-dd hh:mm:ss by Firstname Lastname (username), header, introduction, text, Last updated: yyyy-mm-dd hh:mm:ss by Firstname Lastname (username), Skins dropdown menu (default: Base), [Edit] button.

This is the Dolphins page as seen by:

Even when the visibility is set to World or Authenticated, the Skin and [Edit] button are not available. This is a security feature, preventing anonymous or unauthenticated users to enter the CREW page.

2.3 Enter CREW

Select skin and press the [Edit] button to enter the CREW editor:
[ CREW editor: skin base ]


Herbert has also entered the CREW page and gives his input. He uses the LowVision skin:

[ CREW editor: skin lowvision ]

And Honorine uses the RedGreyBlue skin:

[ CREW editor: skin redgreyblue ]

When they terminate the session, Catherine was the last one who edited and saved. Also notice the yellow status message:

[ CREW page after saving: status message, header, intro, text, skins dropdown menu, edit button ]

Try the Mondriaan skin, named after the famous Dutch painter Piet Mondriaan (Amersfoort, 7 maart 1872 - New York, 1 februari 1944) yourself.

2.4 "It doesn't work!"

We created CREW to be used with the Firefox browser. Reason: CREW then functions on Linux, Mac, FreeBSD, HPUX, Windows and many others.

Some reasons why CREW does not work, even with Firefox:

2.5 Advanced options

The advanced options also apply to this module. In particular it means that you can use Bazaar Style Style (BSS) to get rid of aweful colors that mismatch with the school site or with the pictures on the page.
More about the background of BSS can be found in chapter Viewpoints, paragraph 4. On form and content.
More on the practical work can be found in Configuration Manager, paragraph 3.4 Configure theme 'Theme Name' for area n. The other advanced options are discussed in chapter Page Manager, paragraph 3.3 Advanced: edit advanced properties of page nn.


3. CREW for the webamaster

The webmaster Wilhelmina Bladergroen, has to do a simple task before anyone can do anything with CREW: configure the CREW module. Do not worry, the values below are given to you by the systems administrator, the person who installed the CREW server.

3.1 Configure CREW

Go to the Module Manager and, in the Menu, select the Workshop (CREW) module. The link becomes underlined. The parameters below need to be set correctly, otherwise it is not possible to use CREW:
[ CREW module configuration ]


Most times you will have received these parameters from a systems administrator.

3.2 Check your work

Before handing over CREW to users who trust their valuable collaborative efforts to their browsers, it's a sensible idea to test CREW.

This test must be done on two workstations, each with their own browser. One for the webmaster Wilhelmina Bladergroen (username: wblader) and one for user Herbert Spencer (username: herbert).
Reason for two PC's: you cannot be logged in and, at the same time on the same browser, be logged out. This is a feature of the browser.
The workstation for the webmaster can be an old one, with an old browser that does not support CREW.

Proceed as follows:

Now either she or Herbert can create a CREW page for the Dolphins project.

Wilhelmina doesn't forget to set the test area to inactive.


4. CREW for the systems administrator

For the schools systems administrator, having root access to 'his' server, the installation of the CREW websocket server is quite straightforward; please go directly to paragraph 4.3 Server installation.
To facilitate schools using
ServerAtSchool we provide extra information about servers and ports, their firewall and an init script; please read on.

4.1 Which server and port?

Before the installation can take place, there are a few questions to answer.

The CREW websocket server is in fact a small server program. It can be installed on several locations:

4.2 Firewalls

There are hundreds types of firewalls, so it's impossible to give a prescription. In general, when using the CREW server on port 8008, the firewall must allow inbound TCP traffic from all unprivileged ports for new and established connection to initiate a connection to port 8008. And the firewall must enable outbound traffic, i.e. answers from your server on port 8008, just for established connections.

ServerAtSchool uses the GIPTables firewall. From the blurb: "GIPTables Firewall is a free set of shell scripts that helps you generate iptables rules for Linux 2.4.x and newer kernels. It is very easy to configure and at present, designed to run on hosts with one or two network cards. It doesn't require you to install any additional components to make it work with your GNU/Linux system. All you need to set-up a very secure firewall for your GNU/Linux machines its iptables and GIPTables Firewall."

When you you use GIPTables, you only have to add this to your /etc/rc.d/rc.giptables.custom file, before the line
# ---- THE END OF THE FIREWALL ----, save and restart the firewall with service giptables restart.

# --- begin open poort 8008 ---
# 2012-12-19/PF

for WS_PORT in 8008; do
   echo -ne "\n - with support for port $WS_PORT on $INTERFACE1_IPADDR

    $IPTABLES -A interface1_in -p TCP \
        -s $ANY_IPADDR --sport $UNPRIV_PORTS \
        -d $INTERFACE1_IPADDR --dport $WS_PORT \
        -m state --state NEW,ESTABLISHED \
        -j ACCEPT

    $IPTABLES -A interface1_out -p TCP \
        -s $INTERFACE1_IPADDR --sport $WS_PORT \
        -d $ANY_IPADDR --dport $UNPRIV_PORTS \
        -m state --state ESTABLISHED \
        -j ACCEPT
    $IPTABLES -A interface0_in -p TCP \
        -s $ANY_IPADDR --sport $UNPRIV_PORTS \
        -d $INTERFACE0_IPADDR --dport $WS_PORT \
        -m state --state NEW,ESTABLISHED \
        -j ACCEPT

    $IPTABLES -A interface0_out -p TCP \
        -s $INTERFACE0_IPADDR --sport $WS_PORT \
        -d $ANY_IPADDR --dport $UNPRIV_PORTS \
        -m state --state ESTABLISHED \
        -j ACCEPT
# ---end open poort 8008 ---

The above 4 rules appear, and we explain the first one, line by line:

Allow on eth1 inbound TCP traffic
from any IP address and from any unprivileged source port [*],
destinated for eht1's IP address' for port 8008
for new and established connections

Now the other three rules can be interpreted in the same way.

[*] Privileged ports (0-1023) are for certain services and can only be used by root. Unprivileged ports (1024-65534) can be used by any user.

More on this subject can be found in: Securing and Optimizing Linux: The Hacking Solution, Gerhard Mourani, 2002, Open Network Architecture, Inc., Montreal, Canada, ISBN 0-9688793-1-4
With its 47 chapters and 1200+ pages this book is the ultimate reference documentation for OpenNA Linux. In a simple and structured way the book explains the ways a server can be configured in a safe way. A lot of popular Linux-based services are discussed in extenso. Nowadayas the book can be downloaded in PDF format from: Highly recommended.

NOTICE: There might be a pitfall. When the server is behind a router, the schools IP address and the IP address of eth0 can differ. In that case, traffic from the outside world to the router must be forwarded to the servers IP address with port forwarding in the router.

Some tests:
We assume the websockets server is properly working, and some user in the world has already successfully used the CREW page, for example Wilhelmina Bladergroen from her home address.

Start the browser and surf to, for example: The school page must be visible. Then add the port, i.e. When you don't receive the message '404 Bad request' (a CREW server message), you have a problem on your side, probably the browser or the modem refuses traffic on port 8008.

4.3 Server installation

After unzipping you will find the following files and directory:

[root@jh crewserver]# ls -l
total 277
-rw-r--r--    1 freddie     freddie         4706 Jun 11 13:25 about.html
-rw-r--r--    1 freddie     freddie         7219 Jun 12 15:06 crewserver-example.conf
-r--------    1 freddie     freddie         7382 Jun 13 11:16 crewserver.conf
-r-x------    1 freddie     freddie        45825 Jun 12 15:06 crewserver.php
drwxr-xr-x    2 freddie     freddie           88 Jun 12 23:07 graphics
-rw-r--r--    1 freddie     freddie        37466 Jun 11 13:25 license.html
-rw-rw----    1 freddie     freddie          395 Jun 13 18:53 logfile.log
-rw-r--r--    1 freddie     freddie         4812 Jun 12 15:06 readme.txt
-rw-r--r--    1 freddie     freddie       120659 Jun 11 13:26 utf8lib.php
-rw-r--r--    1 freddie     freddie        30954 Jun 11 13:26 zip.class.php
[root@jh crewserver]#

4.3.1 The readme.txt

Below is the readme.txt, copied from the
Date: 2013-06-12
Auth: Peter Fokker <>
File: readme.txt
Subj: Notes for CREW-server
Vers: 0.90.5

Download and install

You can install the crewserver as follows:

1. Download the file from your own Website@School website,
   e.g. from

2. Find a quiet place to unzip this file, perhaps your $HOME directory.
   Note that the file unpacks into a subdirectory called

   $ cd  $HOME
   $ unzip  /path/to/

   At this point you have all relevant files together in the directory

   Do NOT unpack this .ZIP-file in a directory that is accessible from the
   outside world and certainly not under the webserver's document root or the
   CMS Root Folder (where admin.php and index.php live).

3. Create crewserver.conf in the directory that was created while unzipping,
   i.e. in the same directory where crewserver.php resides. If you want you
   can use the example-configuration file as guidance and/or documentation.

   $ cd  crewserver/
   $ cp  crewserver-example.conf  crewserver.conf

   You can now edit crewserver.conf with your favourite editor. At the very
   least you MUST add an origin-line with the details for your server

4. If you are concerned about the confidentiality of the shared keys in your
   crewserver.conf, you can minimise the permissions to say 0600 or even 0400
   as long as that file is owned by the user that will be running the
   crewserver process. (The crewserver process periodically re-reads the
   configuration file that hence needs read permissions on that file)

Starting the server

You can now run the server as follows.

5. Check the permissions of the file crewserver.php and make sure that the
   read and execute permissions are set, at least for the user who will be
   running the crewserver process. The minimal permissions are 0500 but it is
   perfectly acceptable to set the permissions to 0700, 0750 or even 0755
   (there are no secrets in crewserver.php). Also make sure that the other
   files are readable by the server process, e.g. same owner and at least
   0400 or 0640 or 0644 if you want.

   The file crewserver.conf DOES contain privileged information; make sure
   permissions are as minimal as possible (preferably 0400).

6. Start the server (as ordinary user, you can do that!) by descending into
   the crewserver directory if you did not already do that in the previous
   step and execute the main program:

   $ cd  $HOME/crewserver
   $ ./crewserver.php  &

   The server will start in the background and -- with the default
   configuration -- a few messages will be written to the system's 
   log ('syslog'). You can check to see if the server is running by
   checking the entries in the system logfiles, e.g. /var/log/messages.

   If you have configured the server to write logmessages to stderr,
   the messages will be written on your screen.

   If the server does not start you may have to change the path to the
   PHP-interpreter on the first line of crewserver.php (see below).

Notes and troubleshooting

If you have configured the server to log information to stderr, you can
capture the output of the server as follows:

  $ ./crewserver.php 2>&1 | tee -a logfile.log

Alternatively you can script your session:

  $ script logfile.log
  $ ./crewserver.php

If you want to run crewserver.php in the background while keeping an eye
on the log use this:

  $ ./crewserver.php >logfile.log 2>&1 &
  $ tail -f logfile.log

You can use Ctrl-C to kill the server (or use kill if it is running in
the background).

If you have configured the server to log information to syslog, you can try to
follow the tail of the logfile, e.g. tail -f /var/log/message.

Note that the crewserver.php file is configured to use the php command line
interpreter located in /usr/bin/php. If php is located elsewhere on your
machine, you need to adjust the first line in crewserver.php accordingly.

If you use the crewserver on a non-standard port (like the proposed port 8008
in the example configuration) you may need to adjust your firewall too before
the server can be used.

Source code

The source code of the crewserver program is served by the crewserver program
itself if you know where to look. If you point your browser at you receive a .ZIP-file with the
code, in compliance with the GNU AGPLv3+Additional Terms (see about.html and
license.html). Note that this works best if you leave all supporting files
(about.html, crewserver-example.conf, etc.) exactly where you unpacked them in
step 2 above. Note: your private configuration file crewserver.conf is never
made available to the outside world via this mechanism.

More information

Please refer to the manual that documents CREW for more information.

[eof readme.txt]

4.3.2 The crewserver-example.conf file

Below is the crewserver-example.conf file. The line that minimally MUST be edited in the file is around line 80:
# ORIGIN =, ThisIsTheSharedSecret, 3, 7.
# crewserver-example.conf -- example configuration file for crewserver.php
# Peter Fokker -- 2013-06-12
# This file contains the configuration information for the
# websocket server contained in crewserver.php. The following
# parameters can be configured:
# ORIGIN = url, secret, shops, workers
# DEBUG = level
# SERVER_ADDRESS = ip-address
# SERVER_PORT = port-number
# LOG2SYSLOG = flag
# MARK_TIME = interval-in-seconds
# MAX_DELTA = time-window-in-seconds
# See below for more information per item.
# The format of this file is as follows.
# - leading and trailing spaces are not significant
# - empty lines are discarded
# - lines starting with a hash character '#' are comments
# - comment lines are ignored
# - parameters are specified as key=value-pairs
# - keys are caseINsensitive
# - key=value-pairs cannot span lines (i.e. no line continuation with backslash)

#   Format: ORIGIN = url, secret, shops, workers
#   with
#   url        origin, e.g.
#   secret     plain text password (see below)
#   shops      maximum # of workshops allowed for this origin (default 1)
#   workers    maximum # of concurrent members per workshop (default 4)
#   The origin must match the origin as it is presented to the socket server
#   by the user's browser. It is used as part of the authentication of users.
#   This means that you cannot just use any random URL; it must match the URL
#   of your webserver as it is seen by the user's browser.
#   The password (indicated with secret above) is the plain text password
#   used for authentication. This password must be shared between the
#   webserver and the socket server and therefore it must --unfortunately--
#   be stored in plain text. Because of the format of the configuration file
#   the password should not contain commas or spaces. If you wish you could
#   substitute the hexadecimal value ('%20' for space, '%2C' for a comma).
#   You could also use a password consisting of only hexadecimal values, e.g.
#   '%53%65%63%72%65%74' for 'Secret'. However, it is important that both
#   the websocket server and the webserver agree on the password.
#   The shops parameter indicates the maximum number of workshops that
#   can be used concurrently with this origin. The default value is 1 and
#   the value should be between 1 and 32 inclusive.
#   The workers parameter indicates the maximum number of workshop members.
#   This number must lie between 1 and 26.
#   Note:
#   If your server can be reached under different names, you should add
#   an entry for every name. However, the workshops will be considered
#   distinct, ie. the workshop is
#   not the same as workshop
#   Also note that an origin entry is valid per server, i.e. if there are two
#   different installations of Website@School on the same server, e.g.
# and, both 
#   installations share a single origin-entry and hence a single password.
#   Note: the url in the ORIGIN identifies the webserver, not
#   the socket server.
#   The line below has an example entry for This
#   entry uses the password "SecretExemplumKey", the maximum number
#   of workshops is 3 and the maximum number of workers is 7.
#   ORIGIN =, ThisIsTheSharedSecret, 3, 7
#   You should select a secret password that is not easy to guess for
#   outsiders, so pick a long password. You only have to configure it
#   once (in both client and server configuration) so there is no need
#   to make this password easy for you to remember, as long as the computer
#   can remember it. You are problably OK when  you simply add a handful
#   of plain words for a total length of say 25 characters, e.g. 
#   "CorrectHorseBatteryStaple" or a quasi-random string like 
#   "aHR0cDovL20ueGtjZC5jb20vOTM2".

#   Format: DEBUG = level
#   with
#   level      debug level
#   The debug level must be a number between 0 and 7.
#   The default level is 6 (LOG_INFO) and the other
#   realistic option is 7 (LOG_DEBUG). If you set this
#   value to a value lower than 3 the server will not
#   log nothing. The recommend value is 6 (LOG_INFO).
#   The default value for DEBUG is 6 (LOG_INFO).

#   Format: SERVER_ADDRESS = ip-address
#   with
#   ip-address the IP-address to which the server will be listening.
#   This IP-address can be one of the IP-addresses of your server,
#   or the special value indicating that the server must listen
#   to all available interfaces.
#   The default value for SERVER_ADDRESS is

#    Format SERVER_PORT = port-number
#    with
#    port-number the number of the port to listen to
#    This port-number can be any available portnumber above 1024
#    (if the server will be running under your own user account)
#    or even a port under 1024 if it is running as root.
#   The default value for SERVER_PORT is 8008.

#   Format: LOG2SYSLOG = flag
#   with
#   flag indicating whether to log to syslog (flag=1) or stderr (flag-0)
#   Default value is 1 (log to syslog).

#   Format: MARK_TIME = interval
#   with
#   interval the number of seconds between MARK-messages
#   This configures the time between logging a MARK-message
#   as an indication of the server still being alive. Also,
#   whenever a MARK-message is output the server checks to
#   see if the configuration file crewserver.conf has changed
#   since the last time the server checked it. If that is the
#   case, the configuration file is re-read and any changed
#   parameters are processed if possible.
#   Note: some parameters can not be changed while the server
#   is running, notably SERVER_ADDRESS and SERVER_PORT and
#   LOG2SYSLOG. You can change the values but any changes are
#   discarded when the configuration file is re-read at MARK-time.
#   Default value is 900 seconds (15 minutes)

#  Format: MAX_DELTA = time-window
#  with
#  time-window a time interval in seconds
#  This parameter is used to limit the validity of authentication
#  of users. Because the time on the webserver and the socket
#  server may differ just a little bit, and because it may take
#  some time for a websocket request reaching the server, the
#  necessary token has to have a certain time during which it
#  is considered valid. After this time has passed, the token
#  is no longer valid. This makes it impossible to trick the
#  socket server using a captured token in a replay-attack.
#  The default value for this time window is 120 seconds (2 minutes)

# Final note
# The server periodically emits a MARK message.
# Whenever this event occurs the server also re-reads this
# configuration file. That implies that eventually the
# changed configuration will reach the server. This means
# that you can add (or delete) origins and that the 
# websocket server will follow.

4.3.3 Init script

Some hints on making an init script. For most of you known stuff.
[root@jh root]# touch crew
[root@jh root]# chmod 700 crew
[root@jh root]# chown root.root crew
[root@jh root]# vi crew

With your favorite text editor, copy and paste the script in the file.


# From
# Modified for ServerAtSchool by Dirk Schouten
# <dirk (at) websiteatschool  (dot) eu> 2013-06-06

# This shell script takes care of starting and stopping CREW server.

# chkconfig: 345 99 10
# description: Control the CREW server: crewserver.php
# processname: crew
# file: crewserver.php
# config: crewserver.conf 
# pidfile: /var/spool/


if [ -f /etc/init.d/functions ]; then
     . /etc/init.d/functions
elif [ -f /etc/rc.d/init.d/functions ]; then
    . /etc/rc.d/init.d/functions
    exit 0

. /etc/sysconfig/network

[ ${NETWORKING} = "no" ] && exit 0


start() {
    echo -n "Starting $PROG server: "
    $CREW_CMD &
    [ $RETVAL -eq 0 ] && success || failure
    [ $RETVAL -eq 0 ] && touch /var/lock/subsys/creditor
    return $RETVAL

stop() {
    echo -n $"Stopping $PROG server: "
    killproc $CREW_CMD 
    [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/creditor
    return $RETVAL

case "$1" in
        echo "Usage: $0 {start|stop|restart}"
        exit 1

exit $RETVAL

Move the file to /etc/rc.d/init.d/ or the place where the rc files reside on your system.
Run chkconfig to create the appropriate symbolic links in the various /etc/rc*.d directories and set runlevels. Finally, check your work.

[root@jh init.d]# chkconfig --add crew
 init.d]# chkconfig --level 345 crew on
[root@jh init.d]# chkconfig --list crew
crew        0:off   1:off   2:off   3:on    4:on    5:on    6:off

And start the server:

[root@jh init.d]# service crew start
Starting CREW server:          [  OK  ]
[root@jh init.d]#

4.3.4 /var/log/messages

Below examples, cut from /var/log/messages.


A successfull intern session.

Jun 24 18:10:01 jh crew: crewserver.php shutdown succeeded
Jun 24 18:10:27 jh crew:  succeeded
Jun 24 18:10:27 jh crewserver[21701]: starting server: CREW-server 0.90.5
Jun 24 18:10:27 jh crewserver[21701]: This program is free software: you can redistribute it and/or modify it under
Jun 24 18:10:27 jh crewserver[21701]: the terms of the GNU Affero General Public License version 3 as published by
Jun 24 18:10:27 jh crewserver[21701]: the Free Software Foundation supplemented with the Additional Terms, as set
Jun 24 18:10:27 jh crewserver[21701]: forth in the License Agreement for Website@School (see license.html and about.html).
Jun 24 18:10:27 jh crewserver[21701]: crewserver.conf:134: setting server address to
Jun 24 18:10:27 jh crewserver[21701]: crewserver.conf:151: setting server port to 8008
Jun 24 18:10:27 jh crewserver[21701]: crewserver.conf:163: setting log destination to syslog
Jun 24 18:10:27 jh crewserver[21701]: crewserver.conf: origins: 2 added, 0 modified, 0 unchanged, 0 deleted
Jun 24 18:10:27 jh crewserver[21701]: server address  =
Jun 24 18:10:27 jh crewserver[21701]: server port     = 8008
Jun 24 18:10:27 jh crewserver[21701]: log destination = syslog
Jun 24 18:10:27 jh crewserver[21701]: debug-level     = 6
Jun 24 18:10:27 jh crewserver[21701]: maximum delta   = 120 s
Jun 24 18:10:27 jh crewserver[21701]: mark-interval   = 900 s
Jun 24 18:10:27 jh crewserver[21701]: currently serving 2 origin(s)
Jun 24 18:10:27 jh crewserver[21701]: logmessages go to syslog
Jun 24 18:10:27 jh crewserver[21701]: initialising socket for listening success (id=#0)
Jun 24 18:10:27 jh crewserver[21701]: waiting for connections
Jun 24 18:10:40 jh crewserver[21701]: new client #1: []
Jun 24 18:10:50 jh crewserver[21701]: new client #2: []
Jun 24 18:10:59 jh crewserver[21701]: new client #3: []
Jun 24 18:11:49 jh crewserver[21701]: removing client #2 (herbert) from workshop #1
Jun 24 18:11:54 jh crewserver[21701]: new client #4: []
Jun 24 18:12:25 jh crewserver[21701]: removing client #4 (herbert) from workshop #1
Jun 24 18:12:35 jh crewserver[21701]: removing client #3 (honorine) from workshop #1
Jun 24 18:12:43 jh crewserver[21701]: removing client #1 (catherine) from workshop #1
Jun 24 18:12:43 jh crewserver[21701]: removing empty workshop #1

Conclusion: works perfectly.

successfull extern session with MacBook Pro with Firefox v. 21.0.

Jun 25 15:03:40 jh crewserver[21701]: new client #20: []
Jun 25 15:03:40 jh crewserver[21701]: new client #21: []
Jun 25 15:03:58 jh crewserver[21701]: new client #22: []
Jun 25 15:08:35 jh crewserver[21701]: removing client #22 (name1) from workshop #12
Jun 25 15:08:41 jh crewserver[21701]: removing client #20 (name1) from workshop #12
Jun 25 15:08:41 jh crewserver[21701]: removing empty workshop #12

Conclusion: works perfectly.


The same Macbook Pro wiht Safari v. 6.0.5
Jun 25 15:14:01 jh crewserver[21701]: new client #23: []

whereafter ... nothing

The connection could not be established. 
Conclusion: the browser is guilty. A complaint from many Mac users.

4.3.5 Help!

A user called/mailed. Here is our answer, maybe it serves you. The test can only be executed when you are absolutely sure that your side (server, firewall, ports) cannot be the problem.

Subject: Unable to connect to CREW
To: H.H.Grønbech << 
From: Freddie Frinton ><

It seems impossible for you to work at your 
home/organisation with the Exemplum Primary Schools 
CREW page.
With this mail and your help, we will try to locate the 
problem. Sit behind your computer and have a telephone or 
Skype at hand.

1. You MUST use a recent Firefox browser version.
   Write down the version number under 'Help' 
   and 'About Firefox'

2. You MUST have Javascript enabled in Firefox.
   You MUST have popup windowns enabled in Firefox.
   Look for 'Edit', Preferences and Content.

3. Now surf to
   Question: What do you see under the words: 'Try it 

--In red color-------------------------------------------
X Uh-oh, the browser you're using doesn't have 
native support for WebSocket. That means you can't run 
this demo.


--In green color------------------------------------------
V This browser supports websockets

-If 'X', you must at least upgrade your browser. Call or
 mail us so we can send you details on how to do this.

-If 'V', go on with the connection test:

4. Connection
a. Look for the [Connect] button.
b. Press it. 
c. In the Log window (on the right side of the 
browser screen) you see: CONNECTED.

4. Write
a. Put your cursor in the Message field, where it says 
'Rock it with HTML5 Websocket'.
b. Type something.
c. Click the [Send] button.
d. Your text should appear in the Log.

Pick up the telephone and call us. Do not yet do the 
next steps. Together we will do the next tests. We can read 
our logfiles and perhaps find something.

5. With your webbrowser, surf to 
   Please tell us what you see in the browser.

6. Now add ':8008' to 
   Omit the quotes ' '.
   The line should now look like:
   Now press [Enter] on your keyboard.
   Please tell us what you see in the browser.

7. If asked, press F5 on your keyboard so we can 
observe if and/or how your request reaches the school 

Hopefully we can locate the problem and solve it, so 
you can participate in the workshop.

With kind regards,
Exemplum Primary School
Systems administrator
Freddie Frinton

If 1, 2, 3, 4 and 5 succeed and 6 fails, probably the users router must be enabled to send traffic to the servers IP address with port forwarding in the router.

4.4 "After x I got y"

Please report a bug at the address below.


Author: Dirk Schouten <dirk (at) websiteatschool (dot) eu>
Last updated: 2014-09-06