Howto: Automatic webcam image upload to remote server

[esaym]

I had this idea planned out before I even bought my one. I run my own webserver and I now have a webcam so why not put them to work?

Prereqs:
Web server
linux
ruby interpreter (yum install ruby/aptitude install ruby, ect)
working web cam (need module uvcvideo loaded)
uvccapture

I am running debian testing and to get the webcam running I had to install linux-uvc-source and then run module-assistant and select, build, and install linux-uvc

uvccapture works good with this webcam driver:

uvccapture -q97 -x320 -y240 -o/home/user/cam/snap.jpg

-q is the percent jpg quality. 97% gives ~35kb size image and 100% gives about 52kb size, couldn't really tell the difference between the two. You can also capture 640x480 images. uvccapture is kinda buggy so you will have to play with it

Next up I am using a ruby script to upload the image to remote host:

cam.rb

#! /usr/bin/ruby


require 'net/sftp'

  Net::SFTP.start('host','user',:port => '22') do |sftp|
    # upload a file or directory to the remote host
    sftp.upload!("/local/cam/snap.jpg", "/remote/snap.jpg")
end

You will need ruby gems net::ssh and net::sftp installed. In debian you can install rubygems which is a front end for downloading and installing gems but it wouldn't work right so I did it the manual way. Just download the tar.gz and run the setup.rb:
http://rubyforge.org/frs/download.php/3 ... 0.3.tar.gz
http://rubyforge.org/frs/download.php/3 ... 0.1.tar.gz

Note that no password is supplied, everything works fine with ssh shared keys. Yea can use a password if you want though, more syntax here: http://net-ssh.rubyforge.org/

Now to add all this to cron. You can just run crontab -e as a regular user to open an editor and install a crontab to /var/spool/crontabs/

*/5 * * * * uvccapture -q97 -x320 -y240 -o/home/user/cam/snap.jpg && ruby /home/user/cam.rb

Also note, just to be fancy I stuck /home/user/cam onto a 100kb ram disk just to keep any disk activity from slowing my poor slow intel ssd down more. Easy to do, just add to fstab:

tmpfs		/home/user/cam	tmpfs	user,size=100k	0	0

(#note user parm denotes any user can mount/unmount)

And yet another note, in the directory on my webserver I added in the .htaccess file:

Options -Indexes
<Files *>
Header set Cache-Control: "private, pre-check=0, post-check=0, max-age=0"
Header set Expires: 0
Header set Pragma: no-cache
</Files>

to prevent the image from be cached into a browser. For that to work you have to make sure that you have the apache header module loaded.

Now testing 1..2...3....

whoa spooky! :mrgreen:

From as far as I can tell very little system resources are used!