I'm creating a client for protocol running over TCP/IP sockets,the protocol is request/respond but unlike HTTP, any party can initiate the request and get back respond.
The protocol is session oriented and passes state between requests in its header fields. So I would like to build upon PHP native sessions management to manage sessions and avoid having to re-invent the wheel.
But PHP sessions were build with http protocol in mind and assumes client capabilities related to sessions handling. For example
session_start();
The above line sends a session cookie to the browser or in case session.use_cookies='0' is set sends url parameter.
The question is now, is there way PHP can be forced to use session id given in the code at run time or retrieved from other storage locations to get current session data.
something like this.
//start session in index.php
session_start();
// somewhere in other pages
set_active_session_id('47f6ac750'); // magical function
$name = $_SESSION['name'] // works as normal
So, in other words, I want to use php sessions outside HTTP protocol.To be precise, on the CLI.
session_id() can be used to set the session ID. And it does it before the session is started, which will save you a ton of headaches.
I just hope you're only doing this for educational purposes, because it sounds horrible.
Related
We want to use sessions instead of cookies for keeping track of a few things. However, when I close my browser, and I reopen a page to echo a session var, it doesn't exist (which is how it is suppose to be). Is it possible to prevent this from happening with some magic or anything?
This is not a duplicate question, all I see are people wanting to destroy sessions, I want to do the opposite and retain the session for as long as possible.
Any knowledge would be appreciated.
The right way of doing this is with a database, you can mimic or control php sessions and store them in a database instead of in a file ( as normal ). Then once you have control of the data you can base renewing session via the ip address or better yet by login.
So say a user logs in and then you need to store some data, you store that in the session but php will store it in your database table ( when configured correctly ). Latter the user comes back, initially any visitor would get a fresh session, however once they login you would be able to retrieve the past session they had. You generally don't have much control on if or when a client will delete expired cookies.
This topic is too extensive to put just a few pieces of example code but I did find this small article on the topic.
http://culttt.com/2013/02/04/how-to-save-php-sessions-to-a-database/
The guts of it is to use this function, session_set_save_handler
http://php.net/manual/en/function.session-set-save-handler.php
Once you have control of the data you can do whatever you want, however I would caution you about relying only on the IP address and it would be preferable to use a login system for something like this to prevent serving the session up to the wrong visitor.
You cannot reliably control what happens on the client side, even using a separate cookie would not be reliable and would have the disadvantage of storing data on the client where it could be accessed instead of keeping it on your server. Sessions are controlled by cookies but the data in them remains on your server, the cookie just identifies the client.
As a side note, I personally dislike using sessions at all. It may be possible to store what you need in the url, then it can be bookmarked. The classic example would be input for a search form ( via $_GET ) or for paging purposes. There is nothing wrong with doing this if it's not secure data. The problem with sessions is if the data is for a page such as my "classic example" or for paging you get only one session, so you would only be able to have one set of search data at a time, in the url you could have several sets of search data open at once. That said it does largely depend on what you need to save or persist.
Reset the session cookie manually.
$lifetime=60*60; // duration in seconds
session_start();
setcookie(session_name(),session_id(),time()+$lifetime);
You can use session.gc_maxlifetime and session_set_cookie_params, i.e.:
// server should keep session data for AT LEAST 1 Year
ini_set('session.gc_maxlifetime', 3600 * 24 * 365);
// each client should remember their session id for EXACTLY 1 Year
session_set_cookie_params(3600 * 24 * 365);
session_start();
Note:
You can also change the session options globally by editing php.ini -
Session configuration options
PHP sessions use session cookies. Browsers have their own ways of dealing with them but they all consider them to be trash if you close the browser.
Session cookies are not and can not be made persistent. If you need persistent cookies, just use a regular cookie to save a user identification code that your server would recognize, and save their session information in a database or flat file indexed on that id code.
Note that accumulating sessions on the server progressively causes important performance and security concerns.
Note on other answers: All of them mention ways to extend the session cookie expiration which will not overcome the regular behavior when you close your browser window.
i am working on PHP and i know how to manage the session. But my question is, session is related to language or web server. Who is responsible to execute the session?
You are responsible for session execute by starting the session with session_start().
By default session is stored in /tmp on a Linux/Unix system. You can change it with session_save_path() method.
Also take a look in php.ini for [Session] part, it should look like this
; Handler used to store/retrieve data.
; http://www.php.net/manual/en/session.configuration.php#ini.session.save-handler
session.save_handler = files
As You can see by default it is stored as file storage, it's recommended to move session to cache i.e. memcache.
EDIT:
Maybe this post can help You: https://security.stackexchange.com/a/19054
A session token is a unique identifier that is generated and sent from a server to a client to identify the current interaction session. The client usually stores and sends the token as an HTTP cookie and/or sends it as a parameter in GET or POST queries. The reason to use session tokens is that the client only has to handle the identifier—all session data is stored on the server (usually in a database, to which the client does not have direct access) linked to that identifier. Examples of the names that some programming languages use when naming their HTTP cookie include JSESSIONID (JSP), PHPSESSID (PHP), CGISESSID (CGI), and ASPSESSIONID (ASP).
Sessions are a combination of two components, namely, a client-side session ID and server-side session data. well, practically it behaves like a cookie, 2 cookies which reply on each other. The Client-side can send a session ID to the server-side as a URL param, cookie, or even HTTP headers. The server then uses this session ID to find the matching session data to return to the requesting client.
so to answer your question straight up, a session is part of both the server and the client, which you maybe refer to as language. But PHP handles the execution.
additionally, You can tweak session behavior via the various session functions.
Session is generated by server but it is coupled with the language. So if you look into your browser resource you'll find your session id prefixed with the language you are using.
Is it possible start Session with out using any server side scripting like PHP.
I want start SESSION with pure HTML/HTML5./Javascript.. ?
Thanks Advance. :)
The usual meaning of the term "session" in web development is "A bucket of information stored on the server that is linked to a specific user via a token". Since the definition requires a server to be involved, no you cannot achieve that without a server.
You can store the data in a session cookie (one without an explicit expiry time that will die when the browser is closed).
In modern browsers, you can store larger amounts of data using sessionStorage.
You could set a COOKIE with Javascript (http://www.w3schools.com/js/js_cookies.asp).
If you really want a PHP Session without PHP, that's impossible. A Cookie is the closest you'll get.
On the topic of Cookies, these are stored locally on the users system and can be edited. I do not reccomend using this method if you need good security. See this blog post explaining more on this matter:
http://www.nczonline.net/blog/2009/05/12/cookies-and-security/
No its not possible. What you use in PHP is the PHP session handler.
In javascript you can use cookies to store some small data.
does any body have any info/links as to how to integrate a cookie based session system? i've used file/mysql, and am currently using memcached. i wanted to play with apc sessions, but thought i'd give a go at cookies, only i don't know much about it.
i imagine i'd have to write my own session handler class?
In PHP session data is usually stored in a file. The only thing stored in the cookie is a session identifier. When sessions are enabled and a valid session cookie is found, PHP loads the users session data from the file into a super global called funnily enough SESSION.
Basic sessions are started using session_start(); called before any text is sent to the browser. then items are added to or removed from the session object using simple array indexing eg.
$_SESSION['favcolour'] = 'blue';
later...
$favcolour = $_SESSION['favcolour'];
basic cookie only sessions (no local storage) can be created with a call to
set_cookie('favcolour','blue'[,other params]);
before any text is sent to the browser, then retrieved from the cookie superglobal
$favcolour = $_COOKIE['favcolour'];
you don't need to call session_start() if doing cookie only sessions.
the optional [,other params] are more advanced and can be read about here http://www.php.net/manual/en/function.setcookie.php
Sessions can become a very complex discussion, I'd suggest doing some light work in them and then expand your knowledge.
DC
all you ever wanted to know about PHP sessions
http://www.php.net/manual/en/book.session.php
DC
To reuse PHP's session handling code you will need to add a write handler using session_set_save_handler and then do exactly nothing in that handler. That's because its called after the output to the browser is closed therefore you cannot send anything to the browser.
Before writing non header data to the browser use the set_cookie functions and store the contents of the $_SESSION array (after serialising and encrypting) into a cookie. when the applications start you can read the cookie unserialise it and put it into the $_SESSION array.
That's a quick hint at what to do as I have never done it, I prefer to write all my own cookie code. There may be some gotcha's but its not hard a few tests should find any gotcha's.
DC
I have an API that is dependent on certain state information between requests. As an easy first version of the code, I am simply using PHP session's to store the state information instead of something more advanced (APC, memcache, DB). Throughout my initial testing in a web browser, everything worked perfectly. However, it seems that when clients try to connect through non-browser methods such as Curl or wget, the state information is not being preserved.
Will a PHP session only be created if a browser is requesting the page? I am explicitly starting the session with session_start() as well as naming it before hand with session_name().
An added note. I learned that one of the major problems I was having was that I was naming the session instead of setting the session id via session_id($id); My intention in using session_name() was to retrieve the same session that was previously created, and the correct way to do this is by setting the session_id not the session_name.
It seems that session information will be persisted on the server as noted below (THANK YOU). But to keep this you must pass the session id, or, as in my case, any other id that would uniquely identify the user. Use this id as the session_id and your sessions will function as expected.
Session Cookies
Remember that HTTP is stateless, so sessions are tracked on your server, but the client has to identify itself with each request. When you declare session_start(), your browser is usually setting a cookie (the "PHP Session Id"), and then identifying itself by sending the cookie value with each request. When a script is called using a request with a session value, then the session_start() function will try to look up the session. To prove this to yourself, notice that sessions die when you clear your cookies.. many will die even as soon as you quit the browser, if the cookie is a "session" cookie (a temporary one). You mentioned that you're naming the session.. take a look in your browser cookies and see if you can find a cookie with the same name.
All of this is to say that cookies are playing an active role in your sessions, so if the client doesn't support cookies, then you can't do a session the way you're currently doing it.. at least not for those alternative clients. A session will be created on the server; the question is whether or not the client is participating.
If cookies aren't an option for your client, you're going to have to find another way to pass a session id to the server. This can be done in the query string, for example, although it's a considered a bit less private to send a session id in this way.
mysite.com?PHPSESSID=10alksdjfq9e
How do to this specifically may vary with your version of PHP, but it's basically just a configuration. If the proper runtime options are set, PHP will transparently add the session id as a query parameter to links on the page (same-source only, of course). You can find the specifics for setting that up on the PHP website.
Sidenote: Years ago, this was a common problem when attempting to implement a session. Cookies were newer and many people were turning off the cookie support in their browsers because of purported security concerns.
Sidenote: #Uberfuzzy makes a good point- Using sessions with curl or wget is actually possible. The problem is that it's less automatic. A user might dump header values into a file and use the values on future requests. curl has some "cookie awareness" flags, which allow you to handle this more easily, but you still must explicitly do it. Then again, you could use this to your advantage. If curl is available on your alternative client, then you can plausibly make the call yourself, using the cookie awareness flags. Refer to the curl manual.
If you call session_start(), then a session will be created if the client isn't in an existing one. If the client doesn't support (or is configured to ignore) the cookies or querystring mechanism used to maintain the session, a new session will be created on every request.
This may bloat your session storage mechanism with unused sessions.
It might be a better idea to only call session_start() when you have something to store in the session (e.g. user login, or something else that robots aren't likely to do), if you feel this is likely to be a problem.
Will a PHP session only be created if a browser is requesting the page?
Short answer: Yes. Sessions were created specifically to solve the HTTP stateless problem by leveraging browser features. APC, memcached, DB, etc. don't matter. Those are just storage methods for the session, and will suffer from the same problem.
Longer answer: The concept of sessions were created to account for the fact that HTTP is a stateless protocol, and it turns out that state's pretty important for a wide variety of software applications.
The most common way of implementing sessions is with cookies. PHP sends the session ID in a cookie, and the browser sends the cookie with the session ID back. This ID is used on the server to find whatever information you've stored in the session. PHP has the capacity to include and read a session ID at the end of a URLs, but this assumes that users will navigate to pages on your site/application by clicking links that include a generated session ID.
In your specific case, it is possible to use cookies with curl (and possibly wget). Curl is a web browser, just one without a GUI. If it's the command line curl program you're using (as opposed to the C library, PHP extension,etc.) read up on the following options
-b/--cookie
-c/--cookie-jar
-j/--junk-session-cookies