strands_webtools

An interface to access the real and/or simulated robot via web applications. It is suggested that you run the server on a separate computer and have that computer connect to the robot's roscore, e.g. by setting export ROS_MASTER_URI="http://robot-ip:11311/" accordingly.

Useful Information

Slides from ROSCon talk: here
Source of examples from ROSCon talk: here
ROS requirements on Ubuntu:

rosdep -y install -r strands_webtools

ROS requirements from source (e.g. OS X): rosbridge_suite, rosauth, tf2_web_republisher, mjpeg_server, robot_pose_publisher

Running as standalone (not as part of a web server)

roslaunch strands_webtools webtools.launch
(optional) rosrun topic_republisher republish_ptu_jointstate.py (republishes the PTU joint state on /ptu, only needed for MORSE; The package topic_republisher can be found in the strands_utils repository)
Open in web browser: http://localhost/

Running the webtools behind a firewall in Apache (for the marathon)

Install Apache2

sudo apt-get install apache2 libapache2-mod-proxy-html
install the mod_wstunnel for apache (the script roscd strands_webtools; sudo ./build_wstunnel.sh automates the following)

Check apache version (should be 2.2.20 as of writing, if not adjust the next step)

dpkg -s apache2

Checkout apache source

svn checkout http://svn.apache.org/repos/asf/httpd/httpd/tags/2.2.20/ httpd-2.2.20

Get patch and apply it

wget http://cafarelli.fr/gentoo/apache-2.2.24-wstunnel.patch cd httpd-2.2.20 patch -p1 < ../apache-2.2.24-wstunnel.patch

Build Apache

svn co http://svn.apache.org/repos/asf/apr/apr/branches/1.4.x srclib/apr svn co http://svn.apache.org/repos/asf/apr/apr-util/branches/1.3.x srclib/apr-util ./buildconf ./configure --enable-proxy=shared --enable-proxy_wstunnel=shared make

Copy the module and recompiled mod_proxy (for new symbols) to the ubuntu apache installation and update the permissions to match the other modules

sudo cp modules/proxy/.libs/mod_proxy{_wstunnel,}.so /usr/lib/apache2/modules/ sudo chmod 644 /usr/lib/apache2/modules/mod_proxy{_wstunnel,}.so echo -e "# Depends: proxy\nLoadModule proxy_wstunnel_module /usr/lib/apache2/modules/mod_proxy_wstunnel.so" | sudo tee -a /etc/apache2/mods-available/proxy_wstunnel.load

```

Afterwards, run: sudo a2enmod proxy* rewrite*

ROS setup

The marathon branch requires STRAND's own version of rosbridge_suite and mjpeg_server to added security features. Here's the rosinstall config:

- git: 
   local-name: rosbridge_suite
   uri: 'https://github.com/strands-project/rosbridge_suite.git'
   version: readonly_capabilities
   
- git: 
   local-name: mjpeg_server
   uri: 'https://github.com/strands-project/mjpeg_server.git'
   version: groovy-devel

Network and Server setup:

The setup is as follows:

There is a webhost called WH in the following, which is accessible from the internet on port 80, which fulfills these requirements:
- has Ubuntu 12.04LTS 64bit
- runs (part of) the STRANDS ROS system (everything in strands_webtools is the minimum) and it can connect to the robot's network
- it has a firewall in place to ensure that it only accepts port 80 from the outside worlds, but accepts everything from the robot (I use ufw to configure this easily)
There is the robot, called Linda here, that can connect to that server on all ports
WH uses Linda's ROS_MASTER_URI which needs to be configured to e.g. export ROS_MASTER_URI=http://linda:11311
On WH the html, css, etc. files are served in a dedicated repository, e.g. /opt/strands/lib/www is assumed in the following.
Apache needs to be configured to serve the files and act as a reverse proxy to allow to access ROS via port 80. Here's the Lincoln working file that resides under /etc/apache2/available-sites/strands.site

<VirtualHost *:80>
	DocumentRoot /var/www/
  # this tells apache that everything under "linda" is served from another location... that's where your html files should be
	Alias /linda /opt/strands/lib/www

	# just entering the server name will take you to your institutions website
	RedirectMatch permanent ^/$ http://robots.lincoln.ac.uk/
	
	# disable listing of directories in the strands dir
	<Directory /opt/strands/lib/www>
		Options -Indexes		
	</Directory>
	
	# rewrite engine is needed for the reverseproxy things to work
	RewriteEngine On
	
	Options -Indexes
	
	
	# serving mjpeg image streams under this URL. This needs to match the URL given in the HTML file. the mjpeg_server is running locally on port 8181 (as specified in the launch file)
	RewriteRule ^/linda/video http://localhost:8181/ [P]
	
  # reverse proxy for rosbridge (rosbridge is running locally on port 9090 (as specified in the launch file)
  ProxyPass /linda/rosws ws://localhost:9090/
  ProxyPassReverse /linda/rosws ws://localhost:9090/	
</VirtualHost>

You may want to adapt this (e.g. change 'linda' for something else), but be aware to change the marathon.html file correspondingly.

Running it

run all the nodes on the robot, e.g. openni, mapserver, etc.
On the robot make sure you run the nodes that throttle the network traffic: roslaunch strands_webtools webtools_robot.launch You want to include this in your usual robot setup. It just advertises a few other topics that have low bandwidth that WH is then connecting to.
On WH run roslaunch strands_webtools webtools_safe.launch with ROS_MASTER_URI=http://linda:11311/ (or whatever your robot is called, e.g. just its IP address)
goto the external URL (e.g. http://lcas.lincoln.ac.uk/linda/marathon.html) and check if everythin works

cburbridge/strands_webtools