W3Schools offers free online tutorials, references and exercises in all the major languages of the web. You are entirely right kijin, I edited a bit before your comment. ob_get_clean() return the buffer and empty it. Thank you very much for your help. Tiện ích lọc dữ liệu: Bạn có thể sử dụng ob_start để lọc. If you want, use output buffering with ob_start() and ob_get_clean() to get the output contents into a string which you can then use to fill out Content-Length. – Cain Nuke Jun 25, 2019 at 23:37Off the top of my head, ob_flush() basically outputs the current buffer to PHP's internal buffer, then cleans the ob buffer. Parameters. For text-logfile/debugging needs, I want all , , multiple spaces and so on to be cleared. answered Oct 8. ob_get_clean() essentially executes both ob_get_contents() and ob_end_clean(). No examples exist of running ob_get_clean within a while loop, and for my purpose there is no alternative. Here I’ve just added style: float=right. Taking ob_start() out of my code seems to make no difference to how it works. Send content immediately to the browser on every statement which produces output: <?php. Best you can do is:. flush is different in that it asks the web server to output PHP's current internal buffer to the client (browser), but to wait for further output (i. This is fine in contexts where you're outputting stuff directly, but sometimes you want to use that workflow, but capture the output instead of sending it to the browser. El búfer de salida debe estar iniciado por ob_start () con el indicador PHP_OUTPUT_HANDLER_CLEANABLE . –W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Of course, I was overlooking the fact that the only reason to use the callback on ob_start() was because I wanted to run Obfuscate() on the content before it was flushed, but if I'm getting that content back I don't need to run a callback! So, not using a callback and just running ob_get_clean()'s results through Obfuscate() does what I wanted. @BartHuis. Please I need an explanation on. Collectives™ on Stack Overflow. 2. そうすると、出力. This function will send the contents of the topmost output buffer (if any) and turn this output buffer off. It's showing two because you have a 2nd layer of output buffering active. I need to use ob_get_contents() because I am going to implement a simple caching mechanism that saves the the output to a file. This function discards the contents of the output buffer. Im novice so i dont understand what this doing. Learn more about TeamsWith ob_start and ob_get_clean you redirect the echo from the standard outputbuffer to a variable. I also want to be able to show the user the XML before hand. We can take the previous example to learn how to subsequent buffers into a stack. 2. ob_get_length() Get the size of the buffer, in bytes. joson_encode however does just fine, when wp_debug is disabled. ob_get_length — Return the length of the output buffer. I also tried v5. A callback function can be passed in to do processing on the contents of the buffer before it gets flushed from the buffer. you have to use the new aliases instead of using the PHP 7. I'm trying to find a catch-all filter that gives me one last crack at modifying the final markup in its entirety before output. There are two other functions you typically pair it with: ob_get_contents (), which basically gives you whatever has been "saved" to the buffer since it was turned on. The definition should mention that the function also "turns off output buffering", not just cleans it. The output buffer must be started by ob_start () with PHP_OUTPUT_HANDLER_FLUSHABLE flag. For the OP's purposes, it's probably fine, but ob_get_clean() ends output buffering while ob_get_contents() and ob_clean() do not. ob_get_clean(); Technical Details. Place the buffer start before your output begins and the buffer content capture and clean after the output is complete and then save the content to a cache file… Buffering also allows headers() to be implemented after output has began. Definition and Usage. 0, PHP 5, PHP 7) ob_get_clean — Get current buffer contents and delete current output buffer Description ob_get_clean ( ) : string Gets the current buffer contents and delete current output buffer. 43. First, you can't call a PHP page like that using include_once - the query string will be ignored. My main template file which would have the page layout (header, body, sidebar, footer) is included into the page. flush (); // Display the rest of the content three seconds later. This function discards the contents of the topmost output buffer and turns off this output buffering. If output buffering is turned on, then an echo. php on line 946. In this case, since the 2 statements follow each other, you're not intercepting anything at all. April 3, 2012. ob_start (); $ attributes = shortcode_atts (array ( 'id' = > 'value', ), $ atts); // your desired code return ob_get_clean. Descripción ¶. I have used ob_start and ob_get_clean function to clear the buffer and it starts working. When ob_end_clean is called, it turns off buffering. Gets the current buffer contents and delete current output buffer. 0, PHP 5, PHP 7) ob_get_clean — Get current buffer contents and delete current output buffer Description ob_get_clean ( ) : string Gets the current. ob_get_flush — Flush the output buffer, return it as a string and turn off output buffering. ob_flush ( void ) : void. Sorted by: 1. To review, open the file in an editor that reveals hidden Unicode characters. –I am assuming the data displays properly on the site itself and the browser shows your pages are UTF-8. ob_end_flush () Deletes the topmost output buffer and outputs its contents. La función ob_get_clean() es la combinación de ob_get_contents() y ob_end_clean(). ob_implicit_flush (1); // Some browsers will not display the content if it is too short. 5. ob_clean () Also be aware that nothing is already being flushed with functions like echo, print_r, etc. e. ob_end_clean () Deletes the topmost output buffer and all of its contents. We hope this article has been informative and useful in understanding the ob_clean () function in PHP. See full list on w3docs. it uses flush() and ob_flush() functions. Q&A for work. Actually, we can use type regulation - intval (ob_get_contents ()), for cheking On/Off output buffering, but it lays the possible problems in the future. But in genereal this code is strange, why there is a return? how do you access this code? why is there even. 2 Answers. From PHP 5. I'm facing a weird problem when using the Elementor Wordpress Page Builder. I think I'll better send the output in an HTML file using the code you provided me. Otherwise this function will not work. 0, PHP 5, PHP 7) ob_clean — Clean (erase) the output buffer Description ob_clean ( ) : void This function discards the contents of the output buffer. 5. Code Examples. When the component writes it's output directly to the stream you need to code to accommodate that behavior unless you want to rewrite the. Follow edited Oct 8, 2014 at 1:22. Kakou347 opened this issue on Apr 27, 2019 · 1 comment. ob_get_clean() gets the buffer content, cleans the buffer and ends the buffering. Edson's code works because the output buffer did not automatically get flushed because it doesn't exceed the buffer size (and the script isn't terminated obviously before the. 2. Capture php output of function call. Output Control 함수 목록. 14. ob_end_clean (): bool. Since `ob_get_clean()` accumulates the entire output in memory, dealing with large amounts of data might affect performance and memory usage. php: SFWD_CPT_Instance::template_content () Generate output for courses, lessons, topics, quizzes Filter callback for ‘the_content’ (wp core filter)In this article, we will take an in-depth look at the ob_get_level() function and its usage. I have a script that echo out content in a php script and resulting in a very large file, e. Some parameters will be different depending on the include. Hot Network Questions Voltage change on Resistor change (TinkerCad) Does the escape velocity formula take into account how a gravitationally bound object's distance to its primary increases before coming back down?. I am including HTML template in my shortcode by using ob_start & ob_get_clean. I don't see here why you would use them to pass data from PHP to js. Improve this answer. The output may be caught by another output buffer, or, if there are no other output buffers, sent directly to the browser. Here are the functions that invoke callback function immediately: ob_clean. The ob_clean () function is a useful tool for clearing the output buffer in your PHP web application. However, instead of repeatedly starting a new buffer, you could just erase the current buffer with ob_clean() in between calls of ob_get_contents()now what i want here is to remove the newlines from the stored output of the ob_get_clean(). I need to re-populate mini-cart when product added via ajax add to cart. So as i'm only using ob_get_clean to stop junk being passed back is there any implications to not using ob_start? Test Code:PHP - ob_flush - clean old text and print new text in loop Hot Network Questions A stranger messaged me “please put 10 dollars on my card”, followed by a card number. ob_end_clean (): bool. - To make peace with devel, we use drupal_set_header() to set the headers. Learn how to use the ob_get_clean () function to get the contents of an output buffer and delete it from the buffer. That wasn't the central point of my comment. Otherwise ob_get_clean() will not work. The browser should then only get gz-encoded data as it was the output buffer at the topmost level. Note: This function is similar to ob_end_flush (), except that this function also returns the. 3. When I run in terminal php artisan migrate this results in 'Nothing to migrate' when indeed there is nothing to migrate. The reason I'm not voting for ob_get_clean is because I've had times when other developers get confused regarding what is really going on, the function name doesn't really state that the output buffering will end after it's call. output buffering ob_get_clean not working. Milo Milo. Follow answered Feb 29, 2016 at 15:54. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more. If multiple output callback functions are active, output is being filtered sequentially through each of them in nesting order. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this siteSorry flushblocks(); got left in there by accident, that shouldn't be in the example. What ob_flush () does is delete everything in the buffer, but keeps the buffer itself so more data can be put into it after the ob_flush () call. SpaceX's Starship launches on its second test flight from the Starbase facility in Boca Chica, Texas, on Saturday morning. WordPress uses get_ for returning almost any function inside the loop without echoing out to the browser. David thanks for your response. When the. basically, I have products displayed on a page using a while loop, each containing an 'id' based on the product id, when this button gets pressed, I use an iframe to call a script that adds the ID to an array, that array is then accessed in the basket script, which prints all items in an SQL database where the ID matches the numbers in the. Hi, we were using html_output() to get all the tags generated by the SEO Framework 4. Description ¶. x and PHP 5. This means that the output buffer is initiated and stopped with ob_end_clean(). When output buffer is ended it is sent to the client (browser). Using ob_get_clean(), there is even a double notice: "ob_get_clean(): failed to delete buffer of default output handler (1)". Có nhiều lợi ích khi sử dụng ob_start trong PHP, bao gồm: Giảm tải server: ob_start có thể giúp giảm tải server bằng cách lưu trữ toàn bộ dữ liệu đầu ra trong bộ đệm (buffer) trước khi gửi nó đến trình duyệt. Unfortunately, there is no way to do an implicit ob_flush() after each output, that I am aware of. Provide details and share your research! But avoid. ob_get_clean, only works twice. 참고 See also header() and setcookie() . We get it wordpress has a function set up to pull in the content without using a buffer. But you also need to end and retrieve the contents of the buffer as well. Example shortcodes:I found ob_start() and ob_get_clean() in php manual to achieve this. 不过只要数据还没有真正发送到浏览器（严格来说是tcp buffer），那么是可以通过内置的ob_clean函数进行清空的。. Output buffers are stackable, that is, you may call ob_start () while another ob_start () is active. ob_get_flush ( ): string|false. So the fix I’m suggesting is this:So the original code was without the action? if thats the case you have a ob_get_clean() after a return, return, well, returns the value (in this case a json string) and stops there, no other code after return is being executed. Here are references for the two functions required for basic output buffering: PHP ob_start() PHP ob_get_clean() ★ Pro Tip: ‹ PHP Get Memory Usage vs. 0, but it seems that the function is deprecated in 4. 0, default_charset value is used as default. As for the PHP_OUTPUT_HANDLER_* constants,. patch This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. 6. $image_data = ob_get_contents(); ob_end_clean(); echo $image_data; unlink($nameimage); Client (192. 首先，我們先來看看不讓 echo 之類的內容列印輸出。. Oct 30, 2010 at 20:39. It's useful in cases where you may need to filter some output, or you're using a PHP method (such as var_dump) that writes output. ob_end_clean (): bool. However ob_get_clean() retrieves the contents first, and then cleans the buffer. Want to include php file in WP content. That script will not output anything until the end, if 'output_buffering' is set to 'on' in php. The way to check for this is through ob_get_level (): echo ob_get_level (); If the result is non-zero. 0. This code adds wp_nav_menu_items wordpress hook. If you want to further process the buffer's contents you have to call ob_get_contents () before ob_end_flush () as the buffer contents are discarded after ob_end_flush () is called. Definition and Usage. 5k 3 3 gold badges 48 48 silver badges 77 77 bronze badges. Follow edited Mar 10, 2022 at 21:43. php, instead ob_start() and ob_get_clean() are ignored, and the output of links. answered Mar 10, 2022 at 19:41. , ob_get_clean() would only return the contents of style. Hi, i am using 0. I'm trying to create a way to show an image created with PHP/GD, in an OOP fashion. PHP prior. By understanding the syntax and usage of the function, you can easily start output buffering and modify your output before sending it to the client. ob_get_clean. ob_end_flush (): bool. Hooking on the wp_h. g. 0, 5, 7, 8) ob_get_clean 현재 버퍼 내용 및 삭제 출력 현재 버퍼 내용을 가져오고 기본적으로 출력 삭제 ob_get_clean () ob_get_flush. Gets the current buffer contents and delete current output buffer. Just make sure that you call ob_end_flush () the appropriate number of times. ob_get_clean(); Technical Details. The output may be caught by another output buffer or, if there are no other output buffers, sent directly to the browser. 1) ob_flush (), flush () in any combination with other output buffering functions; 2) changes to php. This function discards the contents of the output buffer. ob_start () use. This function does not destroy the output buffer like ob_end_clean () does. Cette fonction ne détruit pas le contenu du tampon de sortie comme peut le faire ob_end_clean () . Oct 16, 2014 at 16:02. See syntax, parameters, return value and examples of this function. Further, with json-data as response, you need to use dataType: 'json' in your ajax call:I am using ob_get_clean in a script that is called by ajax. . Connect and share knowledge within a single location that is structured and easy to search. PHP provides a set of functions that control what content is sent to the browser and when. x. ob_get_clean ( ): string|false. to wit: given: ob_start(); echo 'before'; ob_start(); echo 'second';If you want to integrate a new plugin to sell courses and include the selection option in Tutor LMS > Settings > Monetization, then you can use the tutor_monetization_options filter. I was trying to debug my code using error_log() and I discovered that ob_get_clean() also truncates the error_log() buffer right in the middle of its output, and well as the output buffer which it is supposed to truncate. ob_get_length() gets the size of the buffer, in bytes. Two problems. The ob_clean () function deletes all of the contents of the topmost output buffer, preventing them from getting sent to the browser. The ob_start () function is a useful tool for buffering your output in your PHP web application. The ob_get_flush () function outputs the contents of the topmost output buffer, returns the contents and the deletes the buffer. 2k 11 11 gold badges 115 115 silver badges 109 109 bronze badges. There's a limit to how much there can be buffered which by default is 4KB so you are hitting the maximum with your script. For this reason, in previous versions, you were able to echo some content into the HTML. It executes both ob_get_contents () and ob_end_clean () functions. In this circumstance, the view process echoes the content of site first anomalously before the response sends cookie, headers, and content. Otherwise ob_clean () will not work. ob_get_clean — 得到当前缓冲区的内容并删除当前输出缓冲区 说明 ¶ ob_get_clean (): string|false 得到当前缓冲区的内容并删除当前输出缓冲区。 ob_get_clean () 实质上是一. Teams. When the. How to Use the ob_get_length() Function. However, casting to number should ignore regular leading spaces. The W3Schools online code editor allows you to edit code and view the result in your browser1 Answer. The short answer is that yes, you have to turn on output buffering before you can use ob_clean. This thread is more than a year old. The output may be caught by another output buffer or, if there are no other output buffers, sent directly to the browser. The above code is just an example, but it should point you in the right direction. 1 Answer. . The output buffer must be started by ob_start with PHP_OUTPUT_HANDLER_FLUSHABLE flag. Tôi nhắc đến cơ chế cache vì các hàm ob_start (), ob_get_contents (), ob_clean (), ob_end_flush () sẽ hỗ trợ chúng ta trong quá trình thực hiện cơ chế. 3. ob_get_clean (): string|false. I found out that the problem can be fixed by either using return instead of echo, or by using output buffering: (ob_start () / ob_get_contents ()) Unfortunately my coding skills are not what I would like them to be. W3Schools offers free online tutorials, references and exercises in all the major languages of the web. By understanding the syntax and usage of the function, you can easily clear the output buffer to start fresh. If you make use of ob_start('ob_gzhandler') to let PHP deal with the compression and you then echo ob_get_clean(), you will create an unreliable output. You can rate examples to help us improve the quality of examples. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. Neither discarding the buffer's contents (ob_clean() ob_end_clean(), ob_get_clean()) nor retrieving the current buffer contents (ob_get_contents(), ob_get_clean()) invoke the output callback. Everything works normally but the returned HTML structure is broken. 4. How to pass a callback function with parameters for ob_start in PHP? 4. Starts the output buffer, any output placed after this will be captured and not displayed: ob_get_contents() Returns all content captured by ob_start() ob_end_clean() Empties the output buffer and turns it off for the current nesting level: ob_get_clean() Triggers both ob_get_contents() and ob_end_clean() ob_get_level() ob_flush — Flush (send) the output buffer. Description ¶. So the browser doesn't receive header correctly. ob_get_clean — Get current buffer contents and delete current output buffer. It would be better to place all your output in the included file in a function that stores everything in a variable that is returned by the function. This function will send the contents of the output buffer (if any). Learn how to use the ob_get_clean () function in PHP, an in-built function that cleans or deletes the current output buffer and returns the output buffering again. ob_end_clean (): bool. the *_clean variants just empty the buffer, whereas *_flush functions print what is in the buffer (send the contents to the output buffer). Syntax. I understand, that only cleanable buffer can't be flush and delete. That's related to how the. Description ¶. 在php的默认配置下，php输出是先输出到缓冲区（output_buffering，内存区域），然后输送到浏览器。. ob_get_clean () essentially executes both ob_get_contents () and ob_end_clean () . Share. ob_get_clean() gets the buffer content, cleans the buffer and ends the buffering. The output may be caught by another output buffer or, if there are no other output buffers, sent directly to the browser. The ob_clean () function deletes all of the contents of the topmost output buffer, preventing them from getting sent to the browser. Books. Yes it is possible. También se usa para obtener el búfer de salida nuevamente después de limpiar el búfer. Description ¶. Here we are using three function ob_start() will start output buffer and ob_end_clean() will clean the output of buffer and ob_get_contents will give you output as string which is echoed till now. The output buffer must be started by ob_start() with PHP_OUTPUT_HANDLER_CLEANABLE flag. Like the_content filter, which lets you access the markup for a post before it's output to the screen. ob_start(), ob_get_clean() would be useful in case you want to include some views (~ MVC) in your shortcode, e. When placing a shortcode on a custom WordPress page the output is always displayed at the top of my page content. And for that, you can give him the content like the previous example, or give an url. Learn more. The ob_flush () function outputs the contents of the topmost output buffer and then clears the buffer of the contents. I was trying to debug my code using error_log() and I discovered that ob_get_clean() also truncates the error_log() buffer right in the middle of its output, and well as the output buffer which it is supposed to truncate. css files; whereas ob_get_flush() returns the contents of both file types. There raises a question, if we use ob_end_clean() to clean the whole output buffer then why even use output buffering. If you are using error_log(), use ob_get_contents() and ob_end_clean() instead of ob_get_clean(). Descripción ¶. That will return the content rather than echo it directly and that you have to do in the case of a WordPress shortcode. ob_start(); // This is NECESSARY for the next ob_get_clean () to work as intended. The function will be called when the output buffer is flushed (sent) or cleaned (with ob_flush (), ob_clean () or similar function) or when the output buffer is flushed to. The output buffer must be started by ob_start () with PHP_OUTPUT_HANDLER_CLEANABLE flag. Share. ob_get_flush() return the buffer and immediately output it. Since `ob_get_clean()` accumulates the entire output in memory, dealing with large amounts of data might affect performance and memory usage. Just make sure that you call ob_end_flush() the appropriate number of times. There is some things I dont get about end_clean, clean, get_clean, etc, and therefore, the answer is going to be different and nuanced from the other one. By understanding the syntax and usage of the function, you can easily start output buffering and modify your output before sending it to the client. clean) can occur simultaneously. This way when you won’t go inside that “if”, you are closing the output buffer which wasn’t started by you. If you want to use it for a larger buffer you have to edit your php. Its output is rendered to the buffer. ob_get_clean() Triggers both ob_get_contents() and ob_end_clean() ob_get_level() Returns the current nesting level of the output buffer: ob_flush() Flush the content buffer and send it to the browser without ending the buffer: ob_implicit_flush() Enables implicit flushing after every output call. Output Control 함수 목록. 5. ob_get_contents simply gets the contents of the output buffer since you called ob_start (). I actually wrote the function with with ob_get_clean(), however I switched it to ob_get_flush() as the later worked more reliably, i. ob_get_clean() essentially executes both ob_get_contents() and ob_end_clean(). In theory when I call _insert() function in test. ini and try to set it's value to "none" if possible. This function will send the contents of the output buffer (if any). output buffering ob_get_clean not working. 4 ob_* functions. fdehanne fdehanne. Using return: function foo () { return 'abc'; } echo foo (); Using ob_get_clean. Conclusion. ob_get_clean ( ): string|false. I am including HTML template in my shortcode by using ob_start & ob_get_clean. This was a "teaching an old dog new tricks" mistake. The ob_get_level () function indicates how many output buffers are currently on the stack. ob_get_clean, only works twice. ob_get_clean () is a function that gets the current output buffer contents and deletes it. 4 ob_* functions. To do this correctly you should be doing ob_start() after ob_get_clean() because ob_get_clean() gets the current buffer contents and delete the current output buffer. Unfortunately, my webhost doesn't have output_buffering. Also, there is another function ob_get_contents() that grabs all of the data gathered since we called ob_start. While this is convenient in some situations for generating documents on-the-fly it also exposes a. Hey, no it didn't work Salut, je suis encore en apprentissage de la programmation web notamment avec PHP ou je suis encore novice . もしダウンロード処理までに出力バッファがあった場合、 ob_end_flush () を使うと、そのバッファの中身が出力されます。. txt file contain a new line - " " at the end, except for the data10. Une des plus pratique est ob_get_contents qui permet de récupérer le contenu du tampon de sortie dans une. This function discards the contents of the output buffer. And by that you can put the variable content into your json data. May 23, 2015 at 9:20. This function discards the contents of the topmost output buffer and turns off this output buffering. 3. // We use str_pad () to make the output long enough. This is a bit harsh. Code Examples. mPDF is a PHP library which generates PDF files from UTF-8 encoded HTML. We hope this article has been informative and useful in understanding the ob_clean () function in PHP. ob_get_clean(): Three Birds, One Stone. Your shortcode callback is going to output content rather than return it which is why you're seeing it appear at the top of your page. After this is done you are not able to modify header. ob_get_clean() — Similarly, this will be the combination of ob_get_contents() and ob_end_flush(). output_callback. Using output buffering ( ob_start () / ob_get_contents ()) is a valid way of addressing the problem however you need to move the code. g. I am working on a CSS and JS compiler and need to find a way to list the contents of wp_head() I am trying to get a list of all CSS/JS files and inline CSS on any give page. Starting from ob_start(); to ob_end_clean(); nothing will be printed, I. Improve this question. ob_clean () Deletes all of the content from the topmost output buffer. ob_get_clean does two things: it gets the contents of the buffer as a string, and it cleans out the buffer. Esta función desecha el contenido del búfer de salida en cola y lo desactiva. . You have to give the id to report. The call to ob_get_clean will return the contents of your buffered output. 1 1 1 silver badge. Otherwise. output buffering ob_get. Other functions are all working fine e. I do not want to write different include functions for each include file. Essentially, an output buffer in PHP catches anything that would have been output to the browser (excluding headers). Im novice so i dont understand what this doing. htaccess. Esto se utiliza comúnmente para que las páginas puedan enviar cabeceras "después" de haber "enviado" algún contenido (es decir. In such case the creation of the file can fail. answered May 17, 2012 at 13:57. . Definition and Usage. The rocket booster and then the spacecraft. 5. output_compression to 0 or Off; 3) setting Apache variables such as "no-gzip" either through apache_setenv () or through entries in . 1 Answer Sorted by: 9 This will return the same as your example given : ob_start (); echo 'custom code'; echo 'another line of custom code'; echo 'more code'; return. This one uses ob_get_clean() and does not produce the correct result:Wordpress: ob_get_clean(); doesn't return $value in shortcode?Helpful? Please support me on Patreon: thanks & prai. ob_get_clean () remove value of input. You must register a filter and let parse your content. I think what @toscho tried to say isn't that you can't nest, but that if for some reason you call ob_get_clean() before the code of e. Follow edited Nov 17 at 20:42. Definition and Usage. Pippin. asked Nov 19, 2013 at 0:45. Shortcodes have to return their. ob_get_clean. ob_get_clean essentially executes both ob_get_contents and ob_end_clean (). x and PHP 5. php it should replace a string with the output of links. ) The buffer is limited in size, and can easily overrun when left to defaults. Whether the buffer-cleaning functions _should_ invoke the output callback (keeping in mind that in themselves they do not generate. it will work as you would use ob_start with no. If you want to further process the buffer's contents you have to call ob_get_contents () before ob_flush () as the buffer contents are discarded after ob_flush () is called. (Necessitating ob_clean() as a further workaround. Gets the current buffer contents and delete current output buffer.