Php basic manual

A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. Note : For our purposes here, a letter is a-z, A-Z, and the bytes from through 0xxff. Prior to PHP 7. See also the Userland Naming Guide. For information on variable related functions, see the Variable Functions Reference.

By default, variables are always assigned by value. That is to say, when you assign an expression to a variable, the entire value of the original expression is copied into the destination variable. This means, for instance, that after assigning one variable's value to another, changing one of those variables will have no effect on the other.

For more information on this kind of assignment, see the chapter on Expressions. PHP also offers another way to assign values to variables: assign by reference. This means that the new variable simply references in other words, "becomes an alias for" or "points to" the original variable. This behaviour is the same when passing instances to a function. A copy of an already created object can be made by cloning it.

It is possible to access a member of a newly created object in a single expression:. Note : Prior to PHP 7. Class properties and methods live in separate "namespaces", so it is possible to have a property and a method with the same name. Referring to both a property and a method has the same notation, and whether a property will be accessed or a method will be called, solely depends on the context, i.

That means that calling an anonymous function which has been assigned to a property is not directly possible. Instead the property has to be assigned to a variable first, for instance. It is possible to call such a property directly by enclosing it in parentheses. A class can inherit the constants, methods, and properties of another class by using the keyword extends in the class declaration.

It is not possible to extend multiple classes; a class can only inherit from one base class. The inherited constants, methods, and properties can be overridden by redeclaring them with the same name defined in the parent class.

However, if the parent class has defined a method or constant as final , they may not be overridden. It is possible to access the overridden methods or static properties by referencing them with parent Note : As of PHP 8. When overriding a method, its signature must be compatible with the parent method. Otherwise, a fatal error is emitted, or, prior to PHP 8. A signature is compatible if it respects the variance rules, makes a mandatory parameter optional, and if any new parameters are optional.

The constructor , and private methods are exempt from these signature compatibility rules, and thus won't emit a fatal error in case of a signature mismatch. The following examples demonstrate that a child method which removes a parameter, or makes an optional parameter mandatory, is not compatible with the parent method. Example 13 Fatal error when a child method makes an optional parameter mandatory. Renaming a method's parameter in a child class is not a signature incompatibility.

However, this is discouraged as it will result in a runtime Error if named arguments are used. Example 14 Error when using named arguments and parameters were renamed in a child class. The class keyword is also used for class name resolution.

To obtain the fully qualified name of a class ClassName use ClassName::class. This is particularly useful with namespaced classes. Example 15 Class name resolution.

Note : The class name resolution using ::class is a compile time transformation. That means at the time the class name string is created no autoloading has happened yet. As a consequence, class names are expanded even if the class does not exist. Some people use this to "time out" logins, or provide a "log-out" button. This behavior is not required by the HTTP Basic authentication standard, so you should never depend on this.

Testing with Lynx has shown that Lynx does not clear the authentication credentials with a server response, so pressing back and then forward again will open the resource as long as the credential requirements haven't changed.

Click on " Edit " and only check " Anonymous Access ", all other fields should be left unchecked. Cookies ». Submit a Pull Request Report a Bug. This is the simplest form I found to do a Basic authorization with retries. It also can contain link relations to CSS. So you need to "fetch" request headers and pass them to your script somehow.

Following construction in. It will make ZF work transparently with you solution and I believe any other framework should work also.

I came up with another approach to work around the problem of browsers caching WWW authentication credentials and creating logout problems.

While most browsers have some kind of way to wipe this information, I prefer having my website to take care of the task instead of relying on the user's sanity. Even with Lalit's method of creating a random realm name, it was still possible to get back into the protected area using the back button in Firefox, so that didn't work.

Note that using a random, unrestricted number will still allow the user to hit the back button to get back into the page. You should keep track of this number in a server-side file or database and regenerate it upon each successful login, so that the last number s become invalid.

Using an invalid number might result in a response or, depending on how you feel that day, a to a nasty website. Care should be taken when linking from the page generated in this case, since relative links will be relative to the virtual and non-existant directory rather than the true script directory. Good day. Sorry for my english.

This script must use in the protected pages. Be careful using http digest authentication see above, example IMHO, I suggest you not to use setlocale before having your authentication completed PS : Here's a non-compatible setlocale declaration ISO' ;.

Here is my attempt to create a digest authentication class that will log the user in and out without using a cookie,session,db,or file. At the core is this simple code to parse the digest string into variables works for several browsers.

Go to page two for links to the code. Comments, ideas, suggestions, or critique welcome. You could also use print to print something which essentially is the same thing as echo. Echo could print multiple values while print can not. No space and no special character are allowed. Variables in php are by default assign by value.