ob_implicit_flush - PHP code example

PHP Function Ob-Implicit-Flush

php function ob_implicit_flush is used to enable or disable implicit flushing of the output buffer. Implicit flushing means that the output buffer will be flushed after every output call. This is very useful if you need to capture the output of certain functions such as phpinfo () and then process it for gzip compression, simple string substitution or for generating static files. It also helps to prevent browsers from displaying cached content, which can cause 504 Gateway Time-out errors.

A very important thing to note is that ob_implicit_flush() only effects the system output buffer of PHP and not the web server itself. This is why you still need to use a buffer control in your scripts. It also doesn't override any buffering done at a higher level than PHP such as by antivirus software or the Apache mod_deflate gzip compression module.

The ob_implicit_flush() function can be used with an integer parameter called chunk_size, which is the size of the internal buffer that will be flushed after each output call. This value can be modified by using the PHP_OUTPUT_HANDLER_FLUSHABLE | PHP_OUTPUT_HANDLER_CLEANABLE | PHP_OUTPUT_HANDLER_REMOVABLE constants. The third parameter of ob_implicit_flush() has been changed from a boolean value to an integer parameter called flags, which may cause some compatibility issues with code written prior to PHP 5.4.0. This change allows custom error handlers to catch ob_implicit_flush() failures. The default value of the flags parameter is FALSE. ob_implicit_flush() returns TRUE if successful and FALSE otherwise.

ob_implicit_flush example

            return call_user_func_array($callback, $parameters);
        }

        $id = $this->_makeId($callback, $parameters);
        if ( ($rs = $this->load($id)) && isset($rs[0], $rs[1])) {
            // A cache is available             $output = $rs[0];
            $return = $rs[1];
        } else {
            // A cache is not available (or not valid for this frontend)             ob_start();
            ob_implicit_flush(false);
            $return = call_user_func_array($callback, $parameters);
            $output = ob_get_clean();
            $data = array($output, $return);
            $this->save($data, $id, $tags, $specificLifetime, $priority);
        }

        echo $output;
        return $return;
    }

    /** * ZF-9970 * * @deprecated */

/** * Start the cache * * @param string $id Cache id * @return mixed True if the cache is hit (false else) with $echoData=true (default) ; string else (datas) */
    public function start($id, array $tags, $extension = null)
    {
        $this->_tags = $tags;
        $this->_extension = $extension;
        ob_start(array($this, '_flush'));
        ob_implicit_flush(false);
        $this->_idStack[] = $id;
        return false;
    }

    /** * callback for output buffering * (shouldn't really be called manually) * * @param string $data Buffered output * @return string Data to send to browser */

            if ($this->_specificOptions['debug_header']) {
                echo 'DEBUG HEADER : This is a cached page !';
            }
            echo $data;
            if ($doNotDie) {
                return true;
            }
            die();
        }
        ob_start(array($this, '_flush'));
        ob_implicit_flush(false);
        return false;
    }

    /** * Cancel the current caching process */
    public function cancel()
    {
        $this->_cancel = true;
    }

        $data = $this->load($id, $doNotTestCacheValidity);
        if ($data !== false) {
            if ( $echoData ) {
                echo($data);
                return true;
            } else {
                return $data;
            }
        }
        ob_start();
        ob_implicit_flush(false);
        $this->_idStack[] = $id;
        return false;
    }

    /** * Stop the cache * * @param array $tags Tags array * @param int $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime) * @param string $forcedDatas If not null, force written datas with this * @param boolean $echoData If set to true, datas are sent to the browser * @param int $priority integer between 0 (very low priority) and 10 (maximum priority) used by some particular backends * @return void */

            return call_user_func_array($callback, $parameters);
        }

        $id = $this->_makeId($name, $parameters);
        if ( ($rs = $this->load($id)) && isset($rs[0], $rs[1]) ) {
            // A cache is available             $output = $rs[0];
            $return = $rs[1];
        } else {
            // A cache is not available (or not valid for this frontend)             ob_start();
            ob_implicit_flush(false);

            try {
                $return = call_user_func_array($callback, $parameters);
                $output = ob_get_clean();
                $data = array($output, $return);
                $this->save($data, $id, $this->_tags, $this->_specificLifetime, $this->_priority);
            } catch (Exception $e) {
                ob_end_clean();
                throw $e;
            }
        }

    public function start(string $name)
    {
        if (\in_array($name, $this->openSlots)) {
            throw new \InvalidArgumentException(sprintf('A slot named "%s" is already started.', $name));
        }

        $this->openSlots[] = $name;
        $this->slots[$name] = '';

        ob_start();
        ob_implicit_flush(0);
    }

    /** * Stops a slot. * * @return void * * @throws \LogicException if no slot has been started */
    public function stop()
    {