56 lines
1.6 KiB
Plaintext
56 lines
1.6 KiB
Plaintext
At root, ``++require++``, ``++require_once++``, ``++include++``, and ``++include_once++`` all perform the same task of including one file in another. However, the way they perform that task differs, and they should not be used interchangeably.
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``++require++`` includes a file but generates a fatal error if an error occurs in the process.
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``++include++`` also includes a file, but generates only a warning if an error occurs.
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Predictably, the difference between ``++require++`` and ``++require_once++`` is the same as the difference between ``++include++`` and ``++include_once++`` - the "_once" versions ensure that the specified file is only included once.
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Because including the same file multiple times could have unpredictable results, the "once" versions are preferred.
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Because ``++include_once++`` generates only warnings, it should be used only when the file is being included conditionally, i.e. when all possible error conditions have been checked beforehand.
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== Noncompliant Code Example
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[source,php]
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----
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include 'code.php'; //Noncompliant; not a "_once" usage and not conditional
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include $user.'_history.php'; // Noncompliant
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require 'more_code.php'; // Noncompliant; not a "_once" usage
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----
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== Compliant Solution
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[source,php]
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----
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require_once 'code.php';
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if (is_member($user)) {
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include_once $user.'_history.php';
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}
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require_once 'more_code.php';
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----
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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include::message.adoc[]
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'''
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== Comments And Links
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(visible only on this page)
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include::comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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