In session how to#
In session password#

Otherwise, you’ll encounter the infamous Headers are already sent error. The important thing is that the session_start function must be called at the beginning of the script, before any output is sent to the browser. This is the method that you'll see most often, where a session is started by the session_start function. There are a couple of ways you can start a session in PHP. Whenever you want to deal with session variables, you need to make sure that a session is already started.

In session how to#

In this section, we’ll discuss how to start a session in PHP.

Now that you've seen a brief introduction to how sessions work, we'll create a few practical examples to demonstrate how to create and manipulate session variables. The following diagram depicts how the HTTP protocol works with sessions. In this way, the user data is preserved across multiple requests, and the user is kept logged in throughout a session. It will then initialize the super-global array variable $_SESSION with the data stored in the session file. It does so by loading the session file which was created earlier, during session initialization. When the server comes across the PHPSESSID cookie, it will try to initialize a session with that session id.

For subsequent requests, the PHPSESSID cookie is passed back to the server.

If cookies are allowed by the browser, it will save this PHPSESSID cookie, which stores the session id passed by the server.

When the browser receives the response from the server, it comes across the PHPSESSID cookie header.

Behind the scenes, this session id is sent in the PHPSESSID cookie in the response header.

Next, a session id is passed back to the user, along with whatever resource was requested.

It also creates a new file on the server which is used to store the session-specific information.

The server generates a unique random number, which is called a session id. If the credentials entered by the user are valid, the server creates a new session.After submitting the login form, a server on the other end authenticates the request by validating the credentials that were entered.A user opens the login page of a website.

Let's quickly go through a common login flow for a website to understand what happens behind the scenes. This lets the server know that all requests originate from the same user, thus allowing the site to display user-specific information and preferences.

In session password#

Imagine if you had to type your username and password on every page that displayed your profile information! Yes, it would be cumbersome and not practical at all, and that's where sessions come into the picture.Ī session allows you to share information across different pages of a single site or app-thus it helps maintain state. In this model, if you wanted to display user-specific information, you'd have to authenticate a user in each request. The following diagram depicts the HTTP protocol in a nutshell. There's no way for the server to know that each request originated from the same user. So when you access other pages of the same website, the web server interprets each and every request separately, as if they were unrelated to one another. For example, when you access a web page, the server is just responsible for providing the contents of the requested page. The HTTP protocol is a stateless protocol, which means that there's no way a server can remember a specific user between multiple requests. Are you wondering why sessions are needed for a website? To see why sessions are necessary, we have to go back and see how the HTTP protocol is designed to work. A session is a mechanism to persist information across different web pages to identify users as they navigate a site or app.