You must write a HTTP server in C++ 98.

Your executable will be run as follows: ./webserv [configuration file]

Even if the subject and rating scale mention poll(), you can use any equivalent such as select(), kqueue(), or epoll().

Please read the RFC and run some tests with telnet and NGINX before starting this project. Even if you don't need to implement every RFC, reading it will help you develop the features you need.

• Your program must accept a configuration file as an argument, or use the default path.
• You cannot execve another web server
• Your server should never block and the client can be properly returned if needed.
• It must be non-blocking and use only 1 poll() (or equivalent) for all I/O operations between client and server (including listening).
• poll() (or similar) should check for read and write at the same time.
• You should never perform a read or write operation without going through poll() (or similar).
• Checking the value of errno is strictly prohibited after a read or write operation.
• You don't need to use poll() (or equivalent) before reading the config file.

Because you have to use non-blocking file descriptors, you can use the read/get or write/send functions without poll() (or equivalent) and your server won't block. But it will consume more system resources. Thus, if you try to read/get or write/send any file descriptor without using poll() (or similar), your score will be 0.

• You can use any macro and define as FD_SET, FD_CLR, FD_ISSET, FD_ZERO (understanding what and how they do is very helpful).
• A request to your server should never hang forever.
• Your server must be compatible with the web browser of your choice.
• We will assume that NGINX is compatible with HTTP 1.1 and can be used to compare headers and behavior of responses.
• Your HTTP response status codes must be accurate.
• Your server should have default error pages if not provided.
• You cannot use fork for anything other than CGI (like PHP or Python, etc.).
• You must be able to maintain a completely static website.
• Clients must be able to upload files.
• You need at least the GET, POST and DELETE methods.
• Stress tests of your server. It must be available at any cost.
• Your server must be able to listen on multiple ports (see configuration file).

Since MacOS does not implement write() in the same way as other Unix OSes, you are allowed to use fcntl(). You must use file descriptors in non-blocking mode to get behavior similar to other Unix operating systems.

However, you are only allowed to use fcntl() like this: fcntl(fd, F_SETFL, O_NONBLOCK); Any other flags are prohibited.

You can get some inspiration from the "server" part of the NGINX configuration file.

In the config file you should be able to:

• Select the port and host of each server.
• Set server_names or not.
• The first server for host:port will be the default for that host:port (meaning it will respond to all requests that do not belong to another server).
• Customize default error pages.
• Limit body size client.
• Set up routes with one or more of the following rules/configurations (routes will not use regex):
  • Define a list of valid HTTP methods for the route.
  • Define HTTP redirect
  • Specify the directory or file in which to look for the file (for example, if the URL /kapouet is linked to /tmp/www, the URL /kapouet/pouic/toto/pouet is /tmp/ www/pouic/toto/pouet).
  • Turn the directory listing on or off.
  • Execute CGI based on a specific file extension (eg .php).
  • Make it possible for the route to accept downloaded files, and configure where they are saved.
    • Are you wondering what is CGI?
    • Since you won't be calling CGI directly, use the full path as PATH_INFO.
    • Just remember that for a fragmented request, your server must unblock it, and CGI will expect EOF as the end of body.
    • Same for CGI output. If no content_length is returned from CGI, EOF marks the end of the returned data.
    • Your program must call CGI with the requested file as the first argument.
    • CGI must run in the correct directory to access relative path files.
    • Your server must work with one CGI (php-CGI, Python, etc.).

You must provide some configuration files and default base files for testing and demonstrating how each feature works during evaluation.

If you have a question about one behavior, you should compare your program's behavior with that of NGINX. For example, check how server_name works. We have shared with you a small tester. It is not necessary to go through it if everything works fine with your browser and tests, but it can help you find some errors.

The main thing is sustainability. Your server should never die.

Don't test with just one program. Write tests in a more convenient language like Python or Golang etc. Even in C or C++ if you want.

Here are additional features you can add:

• Support for cookies and session_management files (prepare short examples).
• Handling multiple CGI.

The bonus part will only be evaluated if the required part is "EXCELLENT". Perfect means that the required part has been fully completed and is running smoothly. If you have not met ALL of the mandatory requirements, your bonus portion will not be evaluated at all.