PHP - Output Buffer

About

An output buffer is a mechanism to capture all input of output function

Basic

• You create a capture session of the buffer with ob_start

ob_start();

• The php script generates output

echo "My output"
print "Whatever"

• You get the content with with ob_get_contents

ob_get_contents();

• You clean and end the actual capture session with ob_end_clean

ob_end_clean();

Nested / Level

This is a nested feature meaning that a sub-function may also create and end a capture session (ob_start, ob_end) to capture the output of its own instructions

ie:

• A root function can start to capture the output with ob_start (making the level of ob_get_level to 1)
• A sub-function of function can also start to capture the output with ob_start (making the level of ob_get_level to 2)
• The sub-function can get and the capture with ob_end (making the level of ob_get_level back to 1)
• The root function can get and the capture with ob_end (making the level of ob_get_level back to 0)

Support

phpunit: Test code or tested code did not (only) close its own output buffers

See the dedicated page: How to solve Test code or tested code did not (only) close its own output buffers