Python脚本仅在执行后输出到浏览器

Question

I have a script which works as expected from the command line, but when I run through a browser it gives output only after the whole script has finished executing. I'm brand new to Python and I can't work out how to modify the behavior to print when it should. Example...

print("Show this")
time.sleep(10)
print("Then this")
time.sleep(10)
print("And then this")

In a browser it'll wait 20 seconds and then display the whole output in one go.

Thanks

Answer 1

Python buffers stdout . So what you probably need to do is flush it.

from sys import stdout

print("Show this")
stdout.flush()
time.sleep(10)
print("Then this")
stdout.flush()
time.sleep(10)
print("And then this")
stdout.flush()

Answer 2

Actually it's normal.

As you are running the script on your computer (via the console for example), the output is sent to the standard output (aka stdout) and your shell is reading directly on stdout.

When you are running a script from a web server, your browser is expecting a file.
Either way, if your web server choose to send you data as soon as it is computed (so you'll get only the first print in your case), or it choose to "bufferize" the output as long as the script has not exited to be able to send you the whole result (the program's output) as a single file.

In other words, your web server is waiting your program to complete to send you your program's output.
As your program has 2 time.sleep(10) , it waits 20sec total + the time of execution (almost negligible) of the print() calls.

Your question is not python dependent but more like web-related.