FastCGI Redirector

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

Made as take-home assignment.

Building

I've tested the application only on Debian 10 Buster, so I can guarantee it works on this distro.
Make sure you have installed the dependencies:
- gcc
- libfcgi-dev
- MySQL and libmysqlclient-dev
- memcached and libmemcached-dev
- Nginx

Clone the source code with git:

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

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.

Setting up

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
```
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.
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.
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.

Usage

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.

krikuff/fcgi-redir

FastCGI Redirector

Building

Setting up

Usage