All web programming language is stateless – i.e, you cannot save state variables within the programming of the pages. As they work with requests, every time a page is fully loaded, all variables used are “erased” and with it, its further use is not possible.
In some cases, however, it is necessary that certain information navigate between pages. This requirement is vital in certain cases, such as when it needs to retrieve information in the database. A unique registration code may be necessary on several screens and therefore we need to keep this information, so that, when required, it is available – optimizing thus the productivity and time. In order to assist on this point, PHP provides the calls sessions.
Briefly, session is an array of variables that can be stored on the server and retrieved by the application later. Following, it will be shown how to create, change and delete sessions in PHP.
CREATING SESSIONS IN PHP
Creating a session in PHP takes place in two steps: First you must call the session_start () method, which creates and instantiates the array $ _SESSION used to store variables. Then we create the position in the array indicating the name and the value to be stored.
RECOVERING DATA SESSION
Once the value is stored, any application page can work with the stored value or manipulate the session already created.
$var 1 = $_SESSION[“new”];
In the above, we have two examples of use mentioned above. To modify the session value, it is not necessary to call any other method of support; just perform the default assignment.
EXCLUDING ONE SESSION
The use of session consumes server processing resources – thus it needs to be used carefully. Once a routine is finished and there is no more need for session usage, it must be finalized, as the following example:
GENERAL TIPS OF SESSION USE IN PHP
Below are listed some tips that help in optimizing a session:
- • Avoid using many sessions in the application;
- • In case of simple traffic information, evaluate other possibilities such as using Storage or Querystrings;
- • At the end of the process, always delete the session;
- • Each system user opens a new session instance. Therefore, in the logout routine of users, you need to validate the sessions used and delete them.