rApacheLogin

Login form using rApache and svSocket

This simple web site contains a login form and an index web pages which can be used to display any result from an R script only to those users having a password.

setting up the files

Save these file in a folder called 'rApacheLogin' under your localhost folder (which in general is /var/www/).

• login.html
• checklogin.html
• index.html
• logout.html

Apache setting

Once saved the above files in /var/www/rApacheLogin go to your apache setting, /etc/apache2/httpd.conf and add these lines

REvalOnStartup "library(brew)"

<Directory /var/www/rApacheLogin>
	DirectoryIndex index.html
        <FilesMatch "\.(html|rhtml|r)">
        	SetHandler r-script
        	RHandler brew::brew
        </FilesMatch>
</Directory>

Probably you already have the first one.

Server set-up

Differently than Rook, where all requested files are parsed in the same environment, in rApache no variables are guaranteed to be alive in a new page request. A simple usage of this feature would be a hit counter, where you count how many hits (possibly per users) a page had. In PHP this is possible without any server connection to store the counts. In Rook is possible even without assigning to the global environment. A normal count <- count + 1 will suffice.

Even though the R internal web server is not very powerful, the way Rook works gives users an incredible help in setting up very quickly a web application showing a shed full of data. In fact, being the environment rook requests are responsed inside a normal rsession, users can benefit from having the webserver, server-side scripting, and database server all in one place. No connections to other application are needed (for small/internal projects). From personal experience Rook is capable to serve more than 10 users at the same time, each of them requesting some table joins using data.table followed by some stats and ggplot creation (i5 3470 @3.2). However to increase this capabilities and have more functionalities rApache is a natural move. In rApache you'll have basically everytihing Apache http can offer you. Security in primis.

To have the possibility to store data in rApache, accross different page requests we need a database connection. An rsession can function like that thanks to svSocket package. We just have to open an r session and run:

require(svSocket)
startSocketServer()

and it's done. You can also change the default 8888 port to which the r socket server listens to and other parameters, please check ?startSocketServer. Every time a file is brew()ed, if needed, we can connect to the above mentioned rsession (left constantly open) by adding

require(svSocket)
con <- socketConnection(host = "localhost", port = 8888, blocking = FALSE)

possibly at the beginning of your scripts. If your Apache web server and the r socket server are 'physically' in different servers just specify the ip of your r socket server via the host parameter (which by default is set to "localhost").