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    用户贡献的备注 8 notes

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    17
    jgeewax a t gmail
    17 years ago
    It seems that while using output buffering, an included file which calls die() before the output buffer is closed is flushed rather than cleaned. That is, ob_end_flush() is called by default.

    <?php
    // a.php (this file should never display anything)
    ob_start();
    include(    'b.php');
    ob_end_clean();
    ?>

    <?php
    // b.php
    print "b";
    die();
    ?>

    This ends up printing "b" rather than nothing as ob_end_flush() is called instead of ob_end_clean(). That is, die() flushes the buffer rather than cleans it. This took me a while to determine what was causing the flush, so I thought I'd share.
    up
    6
    Anonymous
    15 years ago
    You possibly also want to end your benchmark after the output is flushed.

    <?php
    your_benchmark_start_function    ();

    ob_start ();
    for (    $i = 0; $i < 5000; $i++)
    echo     str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

    <----------
    echo     your_benchmark_end_function(); |
    ob_end_flush (); ------------------------
    ?>
    up
    3
    gruik at libertysurf dot fr
    20 years ago
    For those who are looking for optimization, try using buffered output.

    I noticed that an output function call (i.e echo()) is somehow time expensive. When using buffered output, only one output function call is made and it seems to be much faster.
    Try this :

    <?php
    your_benchmark_start_function    ();

    for (    $i = 0; $i < 5000; $i++)
    echo     str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

    echo     your_benchmark_end_function();
    ?>

    And then :

    <?php
    your_benchmark_start_function    ();

    ob_start ();
    for (    $i = 0; $i < 5000; $i++)
    echo     str_repeat ("your string blablabla bla bla", (rand() % 4) + 1)."<br>\n";

    echo     your_benchmark_end_function();
    ob_end_flush ();
    ?>
    up
    -1
    Attila Houtkooper
    9 years ago
    Take care to take exceptions in the code in mind when using ob_start and ob_get_contents. If you do not do this, the number of calls to ob_start will not match those to ob_end and you're not gonna have a good time.

    <?php
    public function requireIntoVariable($path) {
    ob_start();

    try {
    require     $path;
    } catch (    Exception $e) {
    ob_end_clean();
    throw     $e;
    }

    $output = ob_get_contents();
    ob_end_clean();
    return     $output;
    }
    ?>
    up
    -2
    basicartsstudios at hotmail dot com
    17 years ago
    Sometimes you might not want to include a php-file under the specifications defined in the functions include() or require(), but you might want to have in return the string that the script in the file "echoes".

    Include() and require() both directly put out the evaluated code.

    For avoiding this, try output-buffering:
    <?php
    ob_start    ();
    eval(    file_get_contents($file));
    $result = ob_get_contents();
    ob_end_clean();
    ?>
    or
    <?php
    ob_start    ();
    include(    $file);
    $result = ob_get_contents();
    ob_end_clean();
    ?>
    which i consider the same, correct me if I'm wrong.

    Best regards, BasicArtsStudios
    up
    -3
    kend52 at verizon dot net
    19 years ago
    I ran out of memory, while output buffering and drawing text on imported images. Only the top portion of the 5MP image was displayed by the browser. Try increasing the memory limit in either the php.ini file( memory_limit = 16M; ) or in the .htaccess file( php_value memory_limit "16M" ). Also see function memory_get_usage() .
    up
    -2
    kamermans at teratechnologies dot net
    18 years ago
    Output buffering is set to '4096' instead of 'Off' or '0' by default in the php-5.0.4-10.5 RPM for Fedora Core release 4 (Stentz). This has cost me much time!
    up
    -5
    della at sun dot com
    16 years ago
    Sometimes users are blaming about slow pages ... not being aware that mostly this is due to network issues.
    So I've decided to add some statistics at the end of my pages:

    At beginning I start the counters:

    <?php
    function microtime_float() {
    if (    version_compare(PHP_VERSION, '5.0.0', '>')) return microtime(true);
    list(    $u,$s)=explode(' ',microtime()); return ((float)$u+(float)$s);
    }
    $initime=microtime_float();
    ob_start();
    ob_implicit_flush();
    ?>

    And at the end I show the statistics:

    <?php
    echo "PHP Time: ".round((microtime_float()-$initime)*1000)." msecs. ";
    echo     "Size: ".round_byte(strlen(ob_get_contents()));
    ob_end_flush();
    ?>

    (round_byte is my function to print byte sizes)
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