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archived-doc-en/reference/filter/constants.xml
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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- Generated by xml_proto.php v2.4. Found in /scripts directory of phpdoc. -->
<appendix xml:id="filter.constants" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
&reftitle.constants;
&extension.constants;
<variablelist>
<title>Input Constants</title>
<simpara>
These constants are used by
<function>filter_input</function> and
<function>filter_input_array</function>.
</simpara>
<varlistentry xml:id="constant.input-post">
<term>
<constant>INPUT_POST</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.post">POST</link> variables.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-get">
<term>
<constant>INPUT_GET</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.get">GET</link> variables.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-cookie">
<term>
<constant>INPUT_COOKIE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.cookies">COOKIE</link> variables.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-env">
<term>
<constant>INPUT_ENV</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.environment">ENV</link> variables.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-server">
<term>
<constant>INPUT_SERVER</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.server">SERVER</link> variables.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-session">
<term>
<constant>INPUT_SESSION</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.session">SESSION</link> variables.
(Removed as of PHP 8.0.0; was not implemented previously)
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.input-request">
<term>
<constant>INPUT_REQUEST</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<link linkend="reserved.variables.request">REQUEST</link> variables.
(Removed as of PHP 8.0.0; was not implemented previously)
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.flags.generic">
<title>Generic Filter Flags</title>
<varlistentry xml:id="constant.filter-flag-none">
<term>
<constant>FILTER_FLAG_NONE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
No flags.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-require-scalar">
<term>
<constant>FILTER_REQUIRE_SCALAR</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Flag used to require the input of the filter to be a scalar.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-require-array">
<term>
<constant>FILTER_REQUIRE_ARRAY</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Flag used to require the input of the filter to be an <type>array</type>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-force-array">
<term>
<constant>FILTER_FORCE_ARRAY</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This flag wraps scalar inputs into a one element <type>array</type>
for filters which operate on arrays.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-null-on-failure">
<term>
<constant>FILTER_NULL_ON_FAILURE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Use &null; instead of &false; on failure.
</simpara>
<simpara>
Usable with any validation
<constant>FILTER_VALIDATE_<replaceable>*</replaceable></constant>
filter.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.flags.sanitization">
<title>Sanitization Filter Flags</title>
<varlistentry xml:id="constant.filter-flag-strip-low">
<term>
<constant>FILTER_FLAG_STRIP_LOW</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Strip characters with ASCII value less than 32.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-strip-high">
<term>
<constant>FILTER_FLAG_STRIP_HIGH</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Strip characters with ASCII value greater than 127.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-strip-backtick">
<term>
<constant>FILTER_FLAG_STRIP_BACKTICK</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Strips backtick (<literal>`</literal>) characters.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-encode-low">
<term>
<constant>FILTER_FLAG_ENCODE_LOW</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Encode characters with ASCII value less than 32.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-encode-high">
<term>
<constant>FILTER_FLAG_ENCODE_HIGH</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Encode characters with ASCII value greater than 127.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-encode-amp">
<term>
<constant>FILTER_FLAG_ENCODE_AMP</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Encode <literal>&amp;</literal>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-no-encode-quotes">
<term>
<constant>FILTER_FLAG_NO_ENCODE_QUOTES</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Singe and double quotes (<literal>'</literal> and <literal>"</literal>)
will not be encoded.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-empty-string-null">
<term>
<constant>FILTER_FLAG_EMPTY_STRING_NULL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<!-- TODO Document/check which filters accept this flag (FILTER_UNSAFE_RAW and FILTER_SANITIZE_STRING only) -->
If sanitizing a string results in an empty string,
convert the value to &null;
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation">
<title>Validation Filters</title>
<varlistentry xml:id="constant.filter-validate-bool">
<term>
<constant>FILTER_VALIDATE_BOOL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Returns &true; for <literal>"1"</literal>,
<literal>1</literal> including binary, octal and hexadecimal notations, <literal>1.0</literal>,
<literal>"true"</literal>, <literal>true</literal>,
<literal>"on"</literal>,
and <literal>"yes"</literal>.
</simpara>
<simpara>
Returns &false; for <literal>"0"</literal>,
<literal>0</literal> including binary, octal and hexadecimal notations, <literal>0.0</literal>,
<literal>"false"</literal>, <literal>false</literal>,
<literal>"off"</literal>,
<literal>"no"</literal>, and
<literal>""</literal>.
</simpara>
<simpara>
String values are compared case-insensitively.
The return value for non-boolean values depends on the
<constant>FILTER_NULL_ON_FAILURE</constant>.
If it is set, &null; is returned, otherwise &false; is returned.
</simpara>
<variablelist xml:id="filter.constants.validation.bool.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<simpara>
Available as of PHP 8.0.0.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-boolean">
<term>
<constant>FILTER_VALIDATE_BOOLEAN</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
&Alias; <constant>FILTER_VALIDATE_BOOL</constant>.
The alias was available prior to the introduction of its canonical
name in PHP 8.0.0.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-int">
<term>
<constant>FILTER_VALIDATE_INT</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the value is an integer,
on success it is converted to type <type>int</type>.
</simpara>
<note>
<simpara>
String values are trimmed using <function>trim</function>
before validation.
</simpara>
</note>
<variablelist xml:id="filter.constants.validation.int.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>min_range</literal></term>
<listitem>
<simpara>
Value is only valid if it is greater than or equal to the provided value.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>max_range</literal></term>
<listitem>
<simpara>
Value is only valid if it is less than or equal to the provided value.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.int.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-allow-octal">
<term>
<constant>FILTER_FLAG_ALLOW_OCTAL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
<!-- TODO: Check that explicit octal prefix 0o and 0O are allowed -->
Allow integers in octal notation
(<literal>0[0-7]+</literal>).
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-allow-hex">
<term>
<constant>FILTER_FLAG_ALLOW_HEX</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Allow integers in hexadecimal notation
(<literal>0x[0-9a-fA-F]+</literal>).
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-float">
<term>
<constant>FILTER_VALIDATE_FLOAT</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the value is a float,
on success it is converted to type <type>float</type>.
</simpara>
<note>
<simpara>
String values are trimmed using <function>trim</function>
before validation.
</simpara>
</note>
<variablelist xml:id="filter.constants.validation.float.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>decimal</literal></term>
<listitem>
<simpara>
<!-- TODO -->
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>min_range</literal></term>
<listitem>
<simpara>
Value is only valid if it is greater than or equal to the provided value.
Available as of PHP 7.4.0.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>max_range</literal></term>
<listitem>
<simpara>
Value is only valid if it is less than or equal to the provided value.
Available as of PHP 7.4.0.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.float.flags">
<title>Optional Flags</title>
<varlistentry>
<term>
<constant>FILTER_FLAG_ALLOW_THOUSAND</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Accept commas (<literal>,</literal>),
which usually represent the thousand separator.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-regexp">
<term>
<constant>FILTER_VALIDATE_REGEXP</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates value against the regular expression provided by the
<literal>regexp</literal> option.
</simpara>
<variablelist xml:id="filter.constants.validation.regex.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>regexp</literal></term>
<listitem>
<simpara>
<link linkend="book.pcre">Perl-compatible</link> regular expression.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-url">
<term>
<constant>FILTER_VALIDATE_URL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the <acronym>URL</acronym> is valid according to
<link xlink:href="&url.rfc;2396">RFC 2396</link>.
</simpara>
<variablelist xml:id="filter.constants.validation.url.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.url.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-scheme-required">
<term>
<constant>FILTER_FLAG_SCHEME_REQUIRED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Requires the <acronym>URL</acronym> to contain a scheme part.
</simpara>
<warning>
<simpara>
<emphasis>DEPRECATED</emphasis> as of PHP 7.3.0 and
<emphasis>REMOVED</emphasis> as of PHP 8.0.0.
This is because it is always implied by the
<constant>FILTER_VALIDATE_URL</constant> filter.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-host-required">
<term>
<constant>FILTER_FLAG_HOST_REQUIRED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Requires the <acronym>URL</acronym> to contain a host part.
</simpara>
<warning>
<simpara>
<emphasis>DEPRECATED</emphasis> as of PHP 7.3.0 and
<emphasis>REMOVED</emphasis> as of PHP 8.0.0.
This is because it is always implied by the
<constant>FILTER_VALIDATE_URL</constant> filter.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-path-required">
<term>
<constant>FILTER_FLAG_PATH_REQUIRED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Requires the <acronym>URL</acronym> to contain a path part.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-query-required">
<term>
<constant>FILTER_FLAG_QUERY_REQUIRED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Requires the <acronym>URL</acronym> to contain a query part.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<warning>
<simpara>
A valid <acronym>URL</acronym> may not specify the
<acronym>HTTP</acronym> protocol (<literal>http://</literal>).
Therefore, further validation may be required to determine if the
<acronym>URL</acronym> uses an expected protocol,
e.g. <literal>ssh://</literal> or <literal>mailto:</literal>.
</simpara>
</warning>
<warning>
<simpara>
This filter only works on <acronym>ASCII</acronym> <acronym>URL</acronym>s.
This means that Internationalized Domain Names (IDN) will always be rejected.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-domain">
<term>
<constant>FILTER_VALIDATE_DOMAIN</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the domain name is valid according to
<link xlink:href="&url.rfc;952">RFC 952</link>,
<link xlink:href="&url.rfc;1034">RFC 1034</link>,
<link xlink:href="&url.rfc;1035">RFC 1035</link>,
<link xlink:href="&url.rfc;1034">RFC 1123</link>,
<link xlink:href="&url.rfc;1034">RFC 2732</link>,
and
<link xlink:href="&url.rfc;2181">RFC 2181</link>.
</simpara>
<variablelist xml:id="filter.constants.validation.domain.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.domain.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-hostname">
<term>
<constant>FILTER_FLAG_HOSTNAME</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Require hostnames to start with an alphanumeric character and contain
only alphanumerics or hyphens.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-email">
<term>
<constant>FILTER_VALIDATE_EMAIL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the value is a "valid" e-mail address.
</simpara>
<simpara>
The validation is performed against the <literal>addr-spec</literal>
syntax in
<link xlink:href="&url.rfc;822">RFC 822</link>.
However, comments, whitespace folding, and dotless domain names
are not supported, and thus will be rejected.
</simpara>
<variablelist xml:id="filter.constants.validation.email.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.email.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-email-unicode">
<term>
<constant>FILTER_FLAG_EMAIL_UNICODE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Accepts Unicode characters in the local part.
Available as of PHP 7.1.0.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<warning>
<simpara>
Email validation is complex and the only true way to confirm an email
is valid and exists is to send an email to the address.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-ip">
<term>
<constant>FILTER_VALIDATE_IP</constant>
(<type>int</type>)
</term>
<listitem>
<para>
Validates value as IP address.
</para>
<variablelist xml:id="filter.constants.validation.ip.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.validation.ip.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-ipv4">
<term>
<constant>FILTER_FLAG_IPV4</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Allow IPv4 address.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-ipv6">
<term>
<constant>FILTER_FLAG_IPV6</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Allow IPv6 address.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-no-res-range">
<term>
<constant>FILTER_FLAG_NO_RES_RANGE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Deny reserved addresses.
</simpara>
<simpara>
These are the ranges that are marked as
<literal>Reserved-By-Protocol</literal> in
<link xlink:href="&url.rfc;6890">RFC 6890</link>.
</simpara>
<para>
Which for IPv4 corresponds to the following ranges:
<simplelist type="inline">
<member><literal>0.0.0.0/8</literal></member>
<member><literal>169.254.0.0/16</literal></member>
<member><literal>127.0.0.0/8</literal></member>
<member><literal>240.0.0.0/4</literal></member>
</simplelist>.
</para>
<para>
And for IPv6 corresponds to the following ranges:
<simplelist type="inline">
<member><literal>::1/128</literal></member>
<member><literal>::/128</literal></member>
<member><literal>::FFFF:0:0/96</literal></member>
<member><literal>FE80::/10</literal></member>
</simplelist>.
</para>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-no-priv-range">
<term>
<constant>FILTER_FLAG_NO_PRIV_RANGE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Deny private addresses.
</simpara>
<para>
These are IPv4 addresses which are in the following ranges:
<simplelist type="inline">
<member><literal>10.0.0.0/8</literal></member>
<member><literal>172.16.0.0/12</literal></member>
<member><literal>192.168.0.0/16</literal></member>
</simplelist>.
</para>
<simpara>
These are IPv6 addresses starting with
<literal>FD</literal> or <literal>FC</literal>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-global-range">
<term>
<constant>FILTER_FLAG_GLOBAL_RANGE</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Only allow global addresses.
These can be found in
<link xlink:href="&url.rfc;6890">RFC 6890</link>
where the <literal>Global</literal> attribute is <literal>True</literal>.
Available as of PHP 8.2.0.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-validate-mac">
<term>
<constant>FILTER_VALIDATE_MAC</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Validates whether the value is a MAC address.
</simpara>
<variablelist xml:id="filter.constants.validation.mac.options">
<title>Available options</title>
<varlistentry>
<term><literal>default</literal></term>
<listitem>
<simpara>
Value to return in case the filter fails.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
<variablelist xml:id="filter.constants.sanitization">
<title>Sanitizing Filters</title>
<varlistentry xml:id="constant.filter-unsafe-raw">
<term>
<constant>FILTER_UNSAFE_RAW</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This filter does nothing.
</simpara>
<simpara>
However, it can strip or encode special characters if used together with
the <constant>FILTER_FLAG_STRIP_<replaceable>*</replaceable></constant>
and <constant>FILTER_FLAG_ENCODE_<replaceable>*</replaceable></constant>
filter sanitization flags.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-default">
<term>
<constant>FILTER_DEFAULT</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
&Alias; <constant>FILTER_UNSAFE_RAW</constant>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-string">
<term>
<constant>FILTER_SANITIZE_STRING</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This filter strips tags and HTML-encodes double and single quotes.
</simpara>
<simpara>
Optionally it can strip or encode specified characters if used together with
the <constant>FILTER_FLAG_STRIP_<replaceable>*</replaceable></constant>
and <constant>FILTER_FLAG_ENCODE_<replaceable>*</replaceable></constant>
filter sanitization flags.
</simpara>
<simpara>
The behaviour of encoding quotes can be disabled by using the
<constant>FILTER_FLAG_NO_ENCODE_QUOTES</constant> filter flag.
</simpara>
<warning>
<simpara>
<emphasis>Deprecated</emphasis> as of PHP 8.1.0,
use <function>htmlspecialchars</function> instead.
</simpara>
</warning>
<warning>
<simpara>
The way this filter strips tags is not equivalent to
<function>strip_tags</function>.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-stripped">
<term>
<constant>FILTER_SANITIZE_STRIPPED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
&Alias; <constant>FILTER_SANITIZE_STRING</constant>.
</simpara>
<warning>
<simpara>
<emphasis>Deprecated</emphasis> as of PHP 8.1.0,
use <function>htmlspecialchars</function> instead.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-encoded">
<term>
<constant>FILTER_SANITIZE_ENCODED</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This filter URL-encodes a string.
</simpara>
<simpara>
Optionally it can strip or encode specified characters if used together with
the <constant>FILTER_FLAG_STRIP_<replaceable>*</replaceable></constant>
and <constant>FILTER_FLAG_ENCODE_<replaceable>*</replaceable></constant>
filter sanitization flags.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-special-chars">
<term>
<constant>FILTER_SANITIZE_SPECIAL_CHARS</constant>
(<type>int</type>)
</term>
<listitem>
<para>
This filter HTML-encodes
<simplelist type="inline">
<member><literal>'</literal></member>
<member><literal>"</literal></member>
<member><literal>&lt;</literal></member>
<member><literal>&gt;</literal></member>
<member><literal>&amp;</literal></member>
</simplelist>
and characters with an ASCII value less than 32.
Unlike the <constant>FILTER_SANITIZE_FULL_SPECIAL_CHARS</constant> filter, the
<constant>FILTER_SANITIZE_SPECIAL_CHARS</constant> filter ignores the
<constant>FILTER_FLAG_NO_ENCODE_QUOTES</constant> flag.
</para>
<simpara>
Optionally it can strip specified characters if used together with
the <constant>FILTER_FLAG_STRIP_<replaceable>*</replaceable></constant>
filter sanitization flags, and it can encode characters with ASCII value
greater than 127 using <constant>FILTER_FLAG_ENCODE_HIGH</constant>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-full-special-chars">
<term>
<constant>FILTER_SANITIZE_FULL_SPECIAL_CHARS</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This filter is equivalent to calling <function>htmlspecialchars</function>
with <constant>ENT_QUOTES</constant> set.
</simpara>
<simpara>
The behaviour of encoding quotes can be disabled by using the
<constant>FILTER_FLAG_NO_ENCODE_QUOTES</constant> filter flag.
</simpara>
<warning>
<simpara>
Like <function>htmlspecialchars</function>, this filter is aware of the
<link linkend="ini.default-charset">default_charset</link> INI setting.
If a sequence of bytes is detected that makes up an invalid character
in the current character set then the entire string is rejected
resulting in a empty string being returned.
</simpara>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-email">
<term>
<constant>FILTER_SANITIZE_EMAIL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Sanitize the string by removing all characters except
latin letters (<literal>[a-zA-Z]</literal>),
digits (<literal>[0-9]</literal>),
and the special characters
<literal>!#$%&amp;'*+-=?^_`{|}~@.[]</literal>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-url">
<term>
<constant>FILTER_SANITIZE_URL</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Sanitize the string by removing all characters except
latin letters (<literal>[a-zA-Z]</literal>),
digits (<literal>[0-9]</literal>),
and the special characters
<literal>$-_.+!*'(),{}|\\^~[]`&lt;&gt;#%";/?:@&amp;=</literal>.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-number-int">
<term>
<constant>FILTER_SANITIZE_NUMBER_INT</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Sanitize the string by removing all characters except digits
(<literal>[0-9]</literal>), plus sign (<literal>+</literal>),
and minus sign (<literal>-</literal>).
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-number-float">
<term>
<constant>FILTER_SANITIZE_NUMBER_FLOAT</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Sanitize the string by removing all characters except digits
(<literal>[0-9]</literal>), plus sign (<literal>+</literal>),
and minus sign (<literal>-</literal>).
</simpara>
<variablelist xml:id="filter.constants.sanitization.float.flags">
<title>Optional Flags</title>
<varlistentry xml:id="constant.filter-flag-allow-fraction">
<term>
<constant>FILTER_FLAG_ALLOW_FRACTION</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Accept dot (<literal>.</literal>) character,
which usually represents the separator between the integer and
fractional parts.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-allow-thousand">
<term>
<constant>FILTER_FLAG_ALLOW_THOUSAND</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Accept commas (<literal>,</literal>) character,
which usually represents the thousand separator.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-flag-allow-scientific">
<term>
<constant>FILTER_FLAG_ALLOW_SCIENTIFIC</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Accept numbers in scientific notation by allowing the
<literal>e</literal> and <literal>E</literal> characters.
</simpara>
</listitem>
</varlistentry>
</variablelist>
<warning>
<simpara>
If the <constant>FILTER_FLAG_ALLOW_FRACTION</constant> flag is not used,
then the decimal separator is removed, altering the value received.
</simpara>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
$number = '12.34';
var_dump(filter_var($number, FILTER_SANITIZE_NUMBER_FLOAT));
var_dump(filter_var($number, FILTER_SANITIZE_NUMBER_FLOAT, FILTER_FLAG_ALLOW_FRACTION));
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
string(4) "1234"
string(5) "12.34"
]]>
</screen>
</informalexample>
</warning>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-add-slashes">
<term>
<constant>FILTER_SANITIZE_ADD_SLASHES</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
Apply <function>addslashes</function> to the input.
Available as of PHP 7.3.0.
</simpara>
</listitem>
</varlistentry>
<varlistentry xml:id="constant.filter-sanitize-magic-quotes">
<term>
<constant>FILTER_SANITIZE_MAGIC_QUOTES</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
&Alias; <constant>FILTER_SANITIZE_ADD_SLASHES</constant>.
</simpara>
<warning>
<simpara>
<emphasis>DEPRECATED</emphasis> as of PHP 7.3.0 and
<emphasis>REMOVED</emphasis> as of PHP 8.0.0.
</simpara>
</warning>
</listitem>
</varlistentry>
</variablelist>
<variablelist>
<title>User Defined Filter</title>
<varlistentry xml:id="constant.filter-callback">
<term>
<constant>FILTER_CALLBACK</constant>
(<type>int</type>)
</term>
<listitem>
<simpara>
This filter delegates the filtering to a user defined function.
The <type>callable</type> is passed via the
<parameter>options</parameter> parameter as the value associated to
the <literal>'options'</literal> key.
</simpara>
<para>
The callback should have the following signature:
<methodsynopsis>
<type>mixed</type><methodname><replaceable>callback</replaceable></methodname>
<methodparam><type>string</type><parameter>value</parameter></methodparam>
</methodsynopsis>
<variablelist role="function_parameters">
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<simpara>
The value that is being filtered.
</simpara>
</listitem>
</varlistentry>
</variablelist>
</para>
<note>
<simpara>
The value returned by the callback will be the value returned by
the invoked filter function.
</simpara>
</note>
<example>
<title>
Example of using <constant>FILTER_CALLBACK</constant> to validate
a login name
</title>
<programlisting role="php">
<![CDATA[
<?php
function validate_login(string $value): ?string
{
if (strlen($value) >= 5 && ctype_alnum($value)) {
return $value;
}
return null;
}
$login = "val1dL0gin";
$filtered_login = filter_var($login, FILTER_CALLBACK, ['options' => 'validate_login']);
var_dump($filtered_login);
$login = "f&ke login";
$filtered_login = filter_var($login, FILTER_CALLBACK, ['options' => 'validate_login']);
var_dump($filtered_login);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
string(10) "val1dL0gin"
NULL
]]>
</screen>
</example>
<warning>
<simpara>
This filter cannot be used with any other filter flags, e.g.
<constant>FILTER_NULL_ON_FAILURE</constant>.
</simpara>
</warning>
</listitem>
</varlistentry>
</variablelist>
</appendix>
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