php - Who creates a session and how does cookie and any role in it? -
who creates session , how cookie , role in it? asked question in company's interview process , didn't know answer. to know side creates sessions i.e whether client side or server side , cookie has role in it.
also how server understands session provided client , user of client if multiple users logged in?
what’s difference between cookie , session in php?
php sessions improve upon cookies because allow web applications store , retrieve more info cookies. php sessions utilize cookies, add together more functionality , security.
sessions store info on server, not on browser cookies
the main difference between session , cookie session info stored on server, whereas cookies store info in visitor’s browser. sessions utilize session identifier locate particular user’s session data. session identifier stored in user’s web browser in cookie, sensitive info needs more secure — user’s id, name, etc. — remain on server.
sessions more secure cookies
so, why should utilize sessions when cookies work fine? well, mentioned, sessions more secure because relevant info stored on server , not sent , forth between client , server. sec reason users either turn off cookies or reject them. in scenario, sessions, while designed work cookie, can work without cookies workaround, can read here: can php sessions work without cookies?.
sessions need space, unlike cookies
php sessions, unlike cookies stored on user’s browser, need temporary directory on server php can store session data. servers running unix isn’t problem @ all, because /tmp directory meant used things this. but, if server running windows , version of php before 4.3.6, server need configured – here do: create new folder on windows server – can phone call c:\temp. want sure every user can read , write folder. then, need edit php.ini
file, , set value of session.save_path point folder created on windows server (in case, folder under c:\temp). , finally, need restart web server changes in php.ini
file take effect.
sessions must utilize session_start function
a of import thing remember when using sessions each page utilize session must begin calling session_start()
function. session_start()
function tells php either start brand new session or access existing one.
how session_start in php uses cookies
the first time session_start()
function used, seek send cookie name of phpsessid , value of looks a30f8670baa8e10a44c878df89a2044b
– session identifier contains 32 hexadecimal letters. because cookies must sent before info sent browser, means session_start must called before info sent web browser.
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php session cookies