What's New In PHP.docx

7/22/2019 What's New In PHP.docx

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for ($i = $start; $i < $end; $i += $step) {// yield one result at a timeyield $i;

}}

foreach (generateRange(0, 1000000) as $number) {echo $number;

}This code produces exactly the same result as the first example, but without

producing a large array to store all the values. According to the manual, thisreduces the memory footprint to less than a single kilobyte – a huge savingcompared with the original example.

Password Hashing

The new password hashing API is one of the most important and useful featuresadded in PHP 5.5. In the past, developers have had to rely on the somewhatconfusing crypt() function, which is poorly documented in the PHP manual. Theintroduction of a simplified set of functions to handle password hashing will makeit much easier for developers to understand and implement secure passwordhashing for their sites.

The new API introduces two new

functions, password_hash() and password_verify().Calling password_hash($password, PASSWORD_DEFAULT) will return a stronghash using bcrypt, with salting handled automatically. Verifying the password lateris as easy as checking the result of password_verify($password, $hash).

The API uses bcrypt by default, but in the future new algorithms may beintroduced to provide even more secure methods of hashing. Developers canspecify their own bcrypt work factor to adjust the strength of the hashes produced,and can also use their own salts instead of the automatic salt generation (although

the manual discourages this).

finally

PHP 5.5 adds support for the finally keyword, a much-requested feature found inmany other languages with exception handling. finally allows developers to specify

http://www.php.net/manual/en/book.password.php



http://www.sitepoint.com/why-you-should-use-bcrypt-to-hash-stored-passwords/







code to be run at the end of try and catch blocks, regardless of whether an exceptionwas thrown or not, before the normal execution flow resumes.

Without the finally keyword, developers were sometimes be forced to repeat codewithin both thetry and catch blocks to handle cleanup tasks. For example, in thefollowing example the call toreleaseResource() must be made in two places:

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<?phpfunction doSomething() {

$resource = createResource();try {

$result = useResource($resource);}catch (Exception $e) {

releaseResource($resource);log($e->getMessage());throw $e;

}releaseResource($resource);return $result;

}With the addition of finally, we can eliminate the duplicate code:

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<?php

function doSomething() {$resource = createResource();try {

$result = useResource($resource);return $result;

}catch (Exception $e) {

log($e->getMessage());throw $e;

}finally {

releaseResource($resource);}

}In the modified version, we call the cleanup function releaseResource() inthe finally block where we know it will always be called. Note that even though



the try block returns a value, the finally block will still be called beforethe return statement is executed and normal execution continues.

Array and String Literal Dereferencing

Array and string literals can now be dereferenced using array access syntax:

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<?php// array dereferencing - returns 3echo [1, 3, 5, 7][1];

// string dereferencing - returns "l"echo "hello"[3];

This feature was added primarily to improve the consistency of the language, and

probably won’t revolutionize the way we write PHP. However, there are someinteresting applications to consider, such as the following:

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<?php$randomChar = "abcdefg0123456789"[mt_rand(0, 16)];

Using empty() with Function Calls and Expressions

The empty() construct can now be used with function calls and other expressions.For example,empty($object->getProperty()) is valid code in PHP 5.5. This makes it

possible to use empty() on the return value of functions without capturing the valuein a variable first.

Class Name Resolution

Since the introduction of namespaces in PHP 5.3, it has become common practiceto use extensive namespacing to organize classes in PHP projects. However, untilnow it has been difficult to retrieve a fully-qualified class name as a string.Consider the following code:

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<?phpuse NamespacedClassFoo;

$reflection = new ReflectionClass("Foo");

http://php.net/manual/en/function.empty.php




http://www.sitepoint.com/php-namespaces/







This will fail as PHP will attempt to use the global Foo class instead of thenamespaced class. In PHP 5.5, it is now possible to retrieve the full namespacedclass name as a string using the classkeyword:

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<?phpuse NamespacedClassFoo;

$reflection = new ReflectionClass(Foo::class);This will now work as intended, as Foo:class will resolveto Namespaced\Class\Foo.

Changes to foreach

The list() construct in PHP allows the values of an array to be easily assigned to

variables. For example:

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<?php$values = ["sea", "blue"];

list($object, $description) = $values;

// returns "The sea is blue"echo "The $object is $description";

It’s now possible to use list() with multidimensional arrays within foreach loops.

For example:

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<?php$data = [

["sea", "blue"],["grass", "green"]

];

foreach ($data as list($object, $description)) {

echo "The $object is $descriptionn";}

/* Outputs:The sea is blueThe grass is green*/

http://php.net/manual/en/function.list.php







This is a powerful new feature that has the potential to make iterating throughnested arrays much easier and cleaner.

foreach loops can now also handle non-scalar values as iterator keys, which meansthat element keys may have values that are not strings or integers.

Conclusion

PHP 5.5 offers many improvements to facilitate PHP development. In addition tonew features, a long list of bugs have been resolved in this release (see thechangelog for details), and various optimizations and enhancements have beenmade to improve performance and stability.

Will you be upgrading to PHP 5.5? Let us know in the comments.

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What's New In PHP.docx