Php ob start what is it

To fix, remove the flush. Spent several hours discovering this. Apache 1. Some web hosting servers mine do, at least have in their php. Since I spent a lot of time scouring the net searching for a work-around. It seems to me that rewriting occurs in the very same buffering envelope where the session gets started, not at the final output stage. Careful with while using functions that change headers of a page; that change will not be undone when ending output buffering. If you for instance have a class that generates an image and sets the appropriate headers, they will still be in place after the end of ob.

Though the image will not be sent to the client, the png header is still in place; if you do html output here, the browser will most likely display "image error, cannot be viewed", at least firefox does. When used in constructor part of class it have to be prefixed by "self::" or by classname, else PHP fails to create buffer. Following clement dot ayme at st dot com 's remark : In my experience it seems that the output IS buffered, but ALSO sent to the standard output!

In extension to the compress function posted below, here's a nifty little class that improves the idea a bit. Basically, running that compress function for all your CSS for every single page load is clearly far less than optimal, especially since the styles will change only infrequently at the very worst. The contents of each file are saved in compress 'd form in a cache file that is only recreated when the corresponding source CSS changes. I think it's worth noting that while you can't call any output functions such as echo or print from within a callback function, you can still send headers presumably including cookies, haven't checked.

This can be handy if you want to avoid replacing header values that are uncertain. For example if your code may return an image, but you don't want to set content type until you're sure that the image can be sent successfully, you can use the callback to leave the decision right until the very last moment, by which point you're hopefully sure of what's being sent in the HTTP body.

When a fatal error is thrown, PHP will output the current buffer of Output-Control without postprocessing before printing the error message. If you are working with several output control levels, this might not result in the desired behavior. You can use an output callback handler to handle this and discard the output.

If anyone has 5. The page you are trying to view cannot be shown because it uses an invalid or unsupported form of compression. Here's a nifty function I use daily. Learn more. Asked 5 years, 6 months ago. Active 2 years, 1 month ago. Viewed 15k times. I'm learning how to build a WordPress plugin. Improve this question. I read that it prevents the HTML from outputting..

Im trying to bypass the "headers already sent" warning so I can write HTML inside the plugin file itself — cpcdev. Better to solve the headers error rather than resorting to output buffering, but either way, it doesn't look like you're using it right - if you want to buffer the output in that function, you should start buffering within the function. Also, I assume you're ending buffering somewhere and doing something with the output.

Warning Some web servers e. Changelog Version Description 7. See the flags example for an example of how to handle this with code that needs to be compatible with both. A chunk size of 1 now results in chunks of 1 byte being sent to the output buffer.

You output the image and the buffer becomes the image raw data. Make the edits. This is especially handy when your Server is not configured to compress output. Some servers are configured to compress on file extension rather than Content type.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 6 years, 10 months ago. Active 6 years, 10 months ago.