FastCGI Redirector is the backend app for URL redirection. It uses MySQL for redirection rules and Memcached for caching.

Made as take-home assignment.

0. I've tested the application only on Debian 10 Buster, so I can guarantee it works on this distro.

1. Make sure you have installed the dependencies:

   • gcc
   • libfcgi-dev
   • MySQL and libmysqlclient-dev
   • memcached and libmemcached-dev
   • Nginx

2. Clone the source code with git:

   $ git clone https://github.com/cobsea/fcgi-redir.git
   $ cd fcgi-redir
   

3. Build the source code to a binary with make:

   $ make
   

   The resulting binary is now in fcgi-redir/build/ directory. Also this directory contains a config/ folder.

   If you want to change the directory which a binary should be built to, you can simply change the BUILD_DIR variable in the Makefile.

1. Install the binary.

   Makefile installs everything we built into /var/www/fcgi/app. You can change this path to yours by rewriting the INSTALL_DIR variable in the Makefile. Once you done it don't forget to change the root parameter in Nginx configuration file (fcgi_redir_nginx.conf if you are going to use Nginx configuration file from this repository).

   Then begin the installation with root privileges:

   $ sudo make install
   

2. Configure your Nginx.

   If you are going to use this repo's configuraion just copy the fcgi_redir_nginx.conf to the target directory:

   $ sudo cp fcgi_redir_nginx.conf /etc/nginx/conf.d/
   

   Please note that the FastCGI Redirector is installed in /var/www/fcgi/app by default, so you'll need to go to something like http://1.2.3.4/app/fcgi_redir?your_query to get access to the application. The Nginx is configured to have this app/ subdirectory.

3. Set up MySQL.

   To install the given database, log in to your mysql user:

   $ mysql -h your_host -u your_user -p
   

   Then type:

   mysql> CREATE DATABASE your_database_name;
   mysql> USE your_database_name
   mysql> source fcgi_redir_data.sql
   

   If you want to work with your own database, make sure it has a table called "pairs" and this table contains at least 2 columns: name and url. The first one is used for search and it represents anything after username in the CGI query ...?username=Anil&ran.... The second one is the URL string which begins with http:// or https:// and used for primary redirection.

4. Configure FastCGI Redirector.

   There is a configuration file in /var/www/fcgi/app/config by default. It uses such format:

   key1 value1
   key2 {
     subkey1 subvalue1
     subkey2 subvalue2
   }
   

   Every parameter that can be configured is already here, you can just change the values to yours. Note that parameter names are case-sensitive.

FastCGI Redirector works with URLs which satisfy the following template:

http://1.2.3.4/app/fcgi_redir?username=Anil&ran=0.97584378943&pageURL=http://xyz.com

If a database on the host contains a given username and the URL paired with this username is correct, it redirects to this URL. Otherwise it redirects to a fallback URL which is pageURL parameter in CGI query. The ran parameter is nedded to avoid browser caching. All the redirections are cached to Memcached with a configurable timeout.

To shut down the application use kill program. After killing, FastCGI Redirector serves another one query and then shuts down.