
## for correction

## man

- **htons, htonl, ntohs, ntohl :** converts the unsigned short or integer argument between host byte order and network byte order
- **poll :** waits for one of a set of file descriptors to become ready to perform I/O
	- alternatives : select, epoll (epoll_create, epoll_ctl, epoll_wait), kqueue (kqueue, kevent)
- **socket :** creates an endpoint for communication and returns a file descriptor that refers to that endpoint
- **listen :** marks a socket as a passive socket, that is, as a socket that will be used to accept incoming connection requests using accept()
- **accept :** used with connection-based socket types. It extracts the first connection request on the queue of pending connections for the listening socket, creates a new connected socket, and returns a new file descriptor referring to that socket. The newly created socket is not in the listening state. The original socket is unaffected by this call
- **send :** used to transmit a message to another socket. May be used only when the socket is in a connected state (so that the intended recipient is known). The only difference between send() and write() is the presence of flags. With a zero flags argument, send() is equivalent to write()
- **recv :** used to receive messages from a socket. May be used to receive data on both connectionless and connection-oriented sockets. The only difference between recv() and read() is the presence of flags. With a zero flags argument, recv() is generally equivalent to read()
- **bind :** associate a socket fd to a local address. When a socket is created with socket(), it exists in a name space (address family) but has no address assigned to it. It is normally necessary to assign a local address using bind() before a socket may receive connections (see accept())
- **connect :** connects a socket fd to a remote address
- **inet_addr :** converts the Internet host address cp from IPv4 numbers-and-dots notation into binary data in network byte order. Use of this function is problematic because in case of error it returns -1, wich is a valid address (255.255.255.255). Avoid its use in favor of inet_aton(), inet_pton(), or getaddrinfo()
- **setsockopt :** manipulate options for a socket fd. Options may exist at multiple protocol levels; they are always present at the uppermost socket level
- **getsockname :** returns the current address to which a socket fd is bound
- **fcntl :** manipulate an open fd, by performing some actions, like duplicate it or changing its flags

## todo

- [ ] read the RFC and do some tests with telnet and NGINX
- [ ] Your program has to take a configuration file as argument, or use a default path.
- [ ] You can’t execve another web server.
- [ ] Your server must never block and the client can be bounced properly if necessary.
- [ ] It must be non-blocking and use only 1 poll() (or equivalent) for all the I/O operations between the client and the server (listen included).
- [ ] poll() (or equivalent) must check read and write at the same time.
- [ ] You must never do a read or a write operation without going through poll() (or equivalent).
- [ ] Checking the value of errno is strictly forbidden after a read or a write operation.
- [ ] You don’t need to use poll() (or equivalent) before reading your configuration file. Because you have to use non-blocking file descriptors, it is possible to use read/recv or write/send functions with no poll() (or equivalent), and your server wouldn’t be blocking. But it would consume more system resources. Thus, if you try to read/recv or write/send in any file descriptor without using poll() (or equivalent), your grade will be 0.
- [ ] You can use every macro and define like FD_SET, FD_CLR, FD_ISSET, FD_ZERO (understanding what and how they do it is very useful).
- [ ] A request to your server should never hang forever.
- [ ] Your server must be compatible with the web browser of your choice.
- [ ] We will consider that NGINX is HTTP 1.1 compliant and may be used to compare headers and answer behaviors.
- [ ] Your HTTP response status codes must be accurate.
- [ ] You server must have default error pages if none are provided.
- [ ] You can’t use fork for something else than CGI (like PHP, or Python, and so forth).
- [ ] You must be able to serve a fully static website.
- [ ] Clients must be able to upload files.
- [ ] You need at least GET, POST, and DELETE methods.
- [ ] Stress tests your server. It must stay available at all cost.
- [ ] Your server must be able to listen to multiple ports (see Configuration file)
- [ ] Your server should never die.
- [ ] Do not test with only one program.
- [ ] Write your tests with a more convenient language such as Python or Golang, and so forth. Even in C or C++ if you want to
- [ ] You must provide some configuration files and default basic files to test and demonstrate every feature works during evaluation.

### In the configuration file, you should be able to:

- [ ] Choose the port and host of each ’server’.
- [ ] Setup the server_names or not.
- [ ] The first server for a host:port will be the default for this host:port (that means it will answer to all the requests that don’t belong to an other server).
- [ ] Setup default error pages.
- [ ] Limit client body size.
- [ ] Setup routes with one or multiple of the following rules/configuration (routes wont be using regexp):
	- [ ] Define a list of accepted HTTP methods for the route.
	- [ ] Define a HTTP redirection.
	- [ ] Define a directory or a file from where the file should be searched (for example, if url /kapouet is rooted to /tmp/www, url /kapouet/pouic/toto/pouet is /tmp/www/pouic/toto/pouet).
	- [ ] Turn on or off directory listing.
	- [ ] Set a default file to answer if the request is a directory.
	- [ ] Execute CGI based on certain file extension (for example .php).
	- [ ] Make the route able to accept uploaded files and configure where they should be saved.
		- [ ] Do you wonder what a CGI is?
		- [ ] Because you won’t call the CGI directly, use the full path as PATH_INFO.
		- [ ] Just remember that, for chunked request, your server needs to unchunked it and the CGI will expect EOF as end of the body.
		- [ ] Same things for the output of the CGI. If no content_length is returned from the CGI, EOF will mark the end of the returned data.
		- [ ] Your program should call the CGI with the file requested as first argument.
		- [ ] The CGI should be run in the correct directory for relative path file access.
		- [ ] Your server should work with one CGI (php-CGI, Python, and so forth).

## ressources

- [create an http server](https://medium.com/from-the-scratch/http-server-what-do-you-need-to-know-to-build-a-simple-http-server-from-scratch-d1ef8945e4fa)
- [guide to network programming](https://beej.us/guide/bgnet/)
- [same, translated in french](http://vidalc.chez.com/lf/socket.html)
- [bind() vs connect()](https://stackoverflow.com/questions/27014955/socket-connect-vs-bind)
- [INADDR_ANY for bind](https://stackoverflow.com/questions/16508685/understanding-inaddr-any-for-socket-programming)

