Webserv CPP98

• 1. Get Started
• 2. Resume
• 3. Parsing
  • 3.1 Parse Configuration File
    • 3.1.1 Configurations values for Server
    • 3.1.2 Configurations values for Locations
    • 3.1.3 Configurations values for Redirections
  • 3.2 Parse HTTP Request
• 4. Execution
  • 4.1 Select()
  • 4.2 Main Loop
  • 4.3 Looper Object
• 5. Response
  • 5.1 Response Object
• 6. HTTP Methods
• 7. Redirection
• 8. CGI
  • 8.1 CGI Environment
• 9. RFC Docs

Made by Bima, YvanoffP and Tyrossel

Get Started

make

./webserv configuration_file

• Go to http://localhost:2022/index.html for example, and explore it !

Resume

Parsing

Parse Configuration File

• Configuration file must be JSON like
• See how to parse JSON here

Configurations values for Server

Key	Type	Value
address	STRING	IP address on which the server is listening on
port	INT	port on which the server is listening on
server_name	STRING or ARRAY	names used to connect to the server

Configurations values for Locations

Key	Type	Value
root	STRING	Root path of the server
index	STRING or ARRAY	names of index files
cgi_bin	STRING	path to the cgi exe by default
max_client_body_size	INT	Max size of body client request
auto_index	BOOL	Set the auto_index on or off
disabled_methods	STRING or ARRAY	Set the disable methods for all server or location
error_pages	OBJECT - String:INT ARRAY	path to custom error pages:errors code
cgi_extensions	ARRAY	Files extensions where CGI will be executed
locations	ARRAY of OBJECT	each location is a mini server, where some configuration can change
location_path	STRING	Set the disable methods for all server or location

Configurations values for Redirections

Key	Type	Value
redirections	ARRAY of OBJECT	each objects contains old_url, status and can have new_url
old_url	STRING	old url you want redirect
new_url	STRING	new url who old url will be redirected on
status	INT	status link to the redirection

• First part of configuration is server by default == location by default
• Each locations are considered as little server
• Only address, port and server_names cannot be redefined in a location
• If a configuration is not present in a location, this configuration key will take the default value in default location

Parse HTTP Request

• Client request is store in Request object

• Payload body accepted in our server :
  • classic payload
  • chunked without trailer
  • chunked with trailer
• Here is some docs according to HTTP request format :
  • RFC 7230
  • RFC 7231

Execution

Select()

• allow your program to monitor multiple file descriptor (max 1024)
• will be waiting for timeout and return a value :
  • -1 : error
  • 0 : if timeout
  • > 0 : total number of bits that are set in readfds, writefds and exceptfds

Main Loop

• When select() returns a value > 0, 3 others loop are called

Looper Object

• Looper is the main object
• He stores all objects required to get the client request, parse it and build a response to him

Response

• String, must be sent to the client
• Use the socket to communicate with him
• Response should be write with strict semantic
• 3 parts :
  • Status line with HTTP Protocol and Status Code
  • Headers with some information about the requested resource
  • Body with the content of the requested resource

• Content-Length : must be sent to the client. It indicates to your browser the length exact of the requested resource

Response Object

HTTP Methods

Method	Body	Resume
GET	No	Requests a representation of the specified resource
POST	Yes	Sends data to the server, sent via an HTML form and results in a change on the server
DELETE	May	Deletes the specified resource

• RFC 7231

Redirection

Resume

• Technique to give more than one URL address to a page
• It's a special case of response : use the 30X codes
• Client send a request to the server. Server detect that the requested resource has been moved, so server respond the right 30X code. The client will send a new request with the new location to get the requested resource

Redirection codes

Code	Status	Use case
300	Multiple choice	Choices are listed in an HTML page in the body. Few use case
301	Moved Permanently	Permanent redirection. Reorganization of a Web site
302	Found	Page is temporarily unavailable
303	See Other	Used to redirect after a PUT or a POST
304	Not Modified	Sent for revalidated conditional requests. Indicates that the cached response is still fresh
307	Temporary Redirect	Page is temporarily unavailable for unforeseen reasons. Better than 302 when non-GET method is used
308	Permanent Redirect	Reorganization of a Web site, with non-GET methods

CGI

• Common Gateway Interface
• Interface that enables servers to execute an extern program
• Use to process user requests, often when user submits a web form that use CGI
• Server will transmit the request to the script, and sent back the CGI response
• Communication between server and CGI will be made using pipe

• Here is a simple resume of CGI process

CGI Environment

Header	Value
CONTENT_LENGTH	Length of the request body
CONTENT_TYPE	Value of Content-Type headers in request
FILE_UPLOADS	On or Off
GATEWAY_INTERFACE	CGI/Version(1.1)
PATH_INFO	Full path of the requested file
PATH_TRANSLATED	Full path of the requested file
QUERY_STRING	If query, part of request path after '?' / Otherwise, empty string
REDIRECT_STATUS	Should be initialize for php-cgi
REMOTE_HOST	Name of the client that sent the request
REQUEST_METHOD	Method of the request
REQUEST_URI	Full path of the requested file
SCRIPT_NAME	Name of the cgi file
SERVER_NAME	Server hostname, or IP address
SERVER_PORT	Port where the server i listening
SERVER_PROTOCOL	Name and revision of the information protcol this request came in with : Protocol/Version
SERVER_SOFTWARE	Name and version of the information server software answering the request : Name/Version

RFC Docs

• RFC are public text use to set the standards of the Internet
• Here is the most useful ones for this project
  • RFC 7230
  • RFC 7231
  • RFC 7232
  • RFC 7233
  • RFC 7234
  • RFC 7235