Detailed explanation of functions that come with PHP to verify whether email, URL, and IP are legal

In the past, I used PHP to verify whether the email, URL, and IP were legal by writing regular rules myself. However, sometimes I was confused and might write a regular rule that was not completely correct, causing verification errors. Today I discovered that PHP itself automatically With functions to verify whether the email, URL, and IP are legal

The filter_var function is mainly used.

Syntax

filter_var(variable, filter, options)

Parameter description

variable Required. Specifies the variables to filter.

filter Optional. Specifies the ID of the filter to use.

options Specifies an array containing flags/options. Check the possible flags and options for each filter.

PHP Filters

HTML escape characters ‘”& and characters with ASCII values ​​less than 32.Delete all characters , except numbers and -Remove all characters except numbers, - and.,eE.Apply addslashes().

ID Name	Description
FILTER_CALLBACK	Call user-defined function to filter data.
FILTER_SANITIZE_STRING	Remove tags, remove or encode special characters.
FILTER_SANITIZE_STRIPPED	"string" Alias ​​for the filter.
FILTER_SANITIZE_ENCODED	URL-encode string, remove or encode special characters.
##FILTER_SANITIZE_SPECIAL_CHARS
FILTER_SANITIZE_EMAIL	Remove all characters except letters, numbers and !#$%&'* -/=?^_`{| }~@.[]
FILTER_SANITIZE_URL	Remove all characters except letters, numbers and $-_. !*'(), {}|\\^~[]`#%”;/?:@&=
#FILTER_SANITIZE_NUMBER_INT
FILTER_SANITIZE_NUMBER_FLOAT
FILTER_SANITIZE_MAGIC_QUOTES
FILTER_UNSAFE_RAW	Does not do any filtering, stripping or encoding of special characters.
FILTER_VALIDATE_INT	Validates values ​​as integers in the specified range.
FILTER_VALIDATE_BOOLEAN	If it is "1", "true", "on" and "yes", then return true, if it is " 0″, “false”, “off”, “no” and “”, then false is returned. Otherwise NULL is returned.
FILTER_VALIDATE_FLOAT	Validate the value as a floating point number.
FILTER_VALIDATE_REGEXP	Validates values ​​based on regexp, a Perl-compatible regular expression.
FILTER_VALIDATE_URL	Validate the value as a URL.
FILTER_VALIDATE_EMAIL	Validate the value as an e-mail.
FILTER_VALIDATE_IP	Validate the value as an IP address.

Example #1 A filter_var() example

<?php
var_dump(filter_var(&#39;bob@example.com&#39;, FILTER_VALIDATE_EMAIL));
var_dump(filter_var(&#39;http://example.com&#39;, FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
?>

The above routine will output:

string(15) "bob@example.com"
bool(false)

The above is the content of this article All content, I hope it will be helpful to everyone's study.

Related recommendations:

PHP email verification example tutorial, php email example

PHP comes with its own method to verify whether the email exists , php comes with verification email

PHP email verification example tutorial, php email example_PHP tutorial

The above is the detailed content of Detailed explanation of functions that come with PHP to verify whether email, URL, and IP are legal. For more information, please follow other related articles on the PHP Chinese website!