137 lines
10 KiB
Markdown
137 lines
10 KiB
Markdown
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---
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## questions
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- mettre les fonctions specifiques a la requete, dans la class client ?
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- où est-ce que j'inclus le cgi ?
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- est-ce que le cgi est appellé par `/cgi-bin` ?
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- non
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- g rajouté `char ** env` dans client.cpp
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- non
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- ajouter un champ "message body" dans client ?
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- non
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- comment organiser la creation du message reponse (cgi ou pas) et des headers ?
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- comment je gere le path `/cgi-bin/` avec la suite ?
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- qu'est-ce que le cgi renvoit comme headers ? comment c'est géré ?
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- https://www.rfc-editor.org/rfc/rfc3875
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---
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## man
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- **htons, htonl, ntohs, ntohl :** converts the unsigned short or integer argument between host byte order and network byte order
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- **poll :** waits for one of a set of file descriptors to become ready to perform I/O
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- alternatives : select, epoll (epoll_create, epoll_ctl, epoll_wait), kqueue (kqueue, kevent)
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- **socket :** creates an endpoint for communication and returns a file descriptor that refers to that endpoint
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- **listen :** marks a socket as a passive socket, that is, as a socket that will be used to accept incoming connection requests using accept()
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- **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
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- **send :** (~write) 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()
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- **recv :** (~read) 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()
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- **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())
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- **connect :** connects a socket fd to a remote address
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- **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()
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- **setsockopt :** manipulate options for a socket fd. Options may exist at multiple protocol levels; they are always present at the uppermost socket level
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- **getsockname :** returns the current address to which a socket fd is bound
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- **fcntl :** manipulate an open fd, by performing some actions, like duplicate it or changing its flags
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---
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## todo
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- [ ] read the RFC and do some tests with telnet and NGINX
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#### parsing config
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- [ ] Your program has to take a configuration file as argument, or use a default path.
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- [ ] Choose the port and host of each ’server’.
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- [ ] Setup the server_names or not.
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- [ ] 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).
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- [ ] Setup default error pages.
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- [ ] Limit client body size.
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- [ ] Setup routes with one or multiple of the following rules/configuration (routes wont be using regexp):
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- [ ] Define a list of accepted HTTP methods for the route.
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- [ ] Define a HTTP redirection.
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- [ ] 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).
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- [ ] Turn on or off directory listing.
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- [ ] Set a default file to answer if the request is a directory.
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- [ ] Execute CGI based on certain file extension (for example .php).
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- [ ] Make the route able to accept uploaded files and configure where they should be saved.
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#### connection basic
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- [ ] You can’t execve another web server.
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- [ ] Your server must never block and the client can be bounced properly if necessary.
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- [ ] 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).
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- [ ] poll() (or equivalent) must check read and write at the same time.
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- [ ] You must never do a read or a write operation without going through poll() (or equivalent).
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- [ ] Checking the value of errno is strictly forbidden after a read or a write operation.
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- [ ] 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.
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- [ ] 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).
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- [ ] A request to your server should never hang forever.
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- [ ] Your server must be compatible with the web browser of your choice.
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#### parsing request HTTP (fields, ...)
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- [ ] We will consider that NGINX is HTTP 1.1 compliant and may be used to compare headers and answer behaviors.
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#### response HTTP (fields, ...)
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- [ ] Your HTTP response status codes must be accurate.
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- [ ] You server must have default error pages if none are provided.
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- [ ] You can’t use fork for something else than CGI (like PHP, or Python, and so forth).
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- [ ] You must be able to serve a fully static website.
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#### upload files
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- [ ] Clients must be able to upload files.
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#### CGI
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- [ ] You need at least GET, POST, and DELETE methods.
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- [ ] Do you wonder what a CGI is?
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- [ ] Because you won’t call the CGI directly, use the full path as PATH_INFO.
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- [ ] Just remember that, for chunked request, your server needs to unchunked it and the CGI will expect EOF as end of the body.
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- [ ] 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.
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- [ ] Your program should call the CGI with the file requested as first argument.
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- [ ] The CGI should be run in the correct directory for relative path file access.
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- [ ] Your server should work with one CGI (php-CGI, Python, and so forth).
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#### write tests
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- [ ] Stress tests your server. It must stay available at all cost.
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- [ ] Do not test with only one program.
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- [ ] 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
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#### persistent connexion
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- [ ] Your server must be able to listen to multiple ports (see Configuration file)
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- [ ] Your server should never die.
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---
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## cgi env variables
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[cgi env variables](http://www.faqs.org/rfcs/rfc3875.html)
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[wikipedia variables environnements cgi](https://fr.wikipedia.org/wiki/Variables_d%27environnement_CGI)
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[cgi server variables on adobe](https://helpx.adobe.com/coldfusion/cfml-reference/reserved-words-and-variables/cgi-environment-cgi-scope-variables/cgi-server-variables.html)
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```
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AUTH_TYPE : if the srcipt is protected, the authentification method used to validate the user
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CONTENT_LENGTH : length of the request content
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CONTENT_TYPE : if there is attached information, as with method POST or PUT, this is the content type of the data (e.g. "text/plain", it is set by the attribute "enctype" in html <form> as three values : "application/x-www-form-urlencoded", "multipart/form-data", "text/plain")
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GATEWAY_INTERFACE : CGI version (e.g. CGI/1.1)
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PATH_INFO : if any, path of the resquest in addition to the cgi script path (e.g. for cgi script path = "/usr/web/cgi-bin/script.cgi", and the url = "http://server.org/cgi-bin/script.cgi/house", the PATH-INFO would be "house")
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PATH_TRANSLATED : full path of the request, like path-to-cgi/PATH_INFO, null if PATH_INFO is null (e.g. for "http://server.org/cgi-bin/prog/the/path", PATH_INFO would be : "/the/path" and PATH_TRANSLATED would be : "/usr/web/cgi-bin/prog/the/path")
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QUERY_STRING : everything following the ? in the url sent by client (e.g. for url "http://server.org/query?var1=val2&var2=val2", it would be : "var1=val2&var2=val2")
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REMOTE_ADDR : ip address of the client
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REMOTE_HOST : host name of the client, empty if not known, or equal to REMOTE_ADDR
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REMOTE_IDENT : if known, username of the client, otherwise empty, use for logging only
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REMOTE_USER : username of client, if script is protected and the server support user authentification
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REQUEST_METHOD : method used for the request (for http, usually POST or GET)
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SCRIPT_NAME : path to the cgi, relative to the root, used for self-referencing URLs (e.g. "/cgi-bin/script.cgi")
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SERVER_NAME : name of the server, as hostname, IP address, or DNS (e.g. dns : "www.server.org")
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SERVER_PORT : the port number your server is listening on (e.g. 80)
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SERVER_PROTOCOL : protocol used for the request (e.g. HTTP/1.1)
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SERVER_SOFTWARE : the server software you're using (e.g. Apache 1.3)
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```
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[redirect status for php-cgi](https://woozle.org/papers/php-cgi.html)
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```
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REDIRECT_STATUS : for exemple, 200
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```
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---
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## ressources
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- [correction](https://github.com/AliMaskar96/42-Correction-Sheets/blob/master/ng_5_webserv.pdf)
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- [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)
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- [guide to network programming](https://beej.us/guide/bgnet/)
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- [same, translated in french](http://vidalc.chez.com/lf/socket.html)
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- [bind() vs connect()](https://stackoverflow.com/questions/27014955/socket-connect-vs-bind)
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- [INADDR_ANY for bind](https://stackoverflow.com/questions/16508685/understanding-inaddr-any-for-socket-programming)
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- [hack with CGI](https://www.youtube.com/watch?v=ph6-AKByBU4)
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- [http headers](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers)
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- [list of http headers fields](https://en.wikipedia.org/wiki/List_of_HTTP_header_fields)
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- [http request ibm](https://www.ibm.com/docs/en/cics-ts/5.3?topic=protocol-http-requests)
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- [http request other](https://www.tutorialspoint.com/http/http_requests.htm)
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- [request line uri](https://stackoverflow.com/questions/40311306/when-is-absoluteuri-used-from-the-http-request-specs)
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