How to debug a file that doesn't output

[OM2]

If I have a file that is full of functions that do 'things',  I assume if I wanted to debug or test that it would necessarily work if I try to echo from inside of a function?

 

In that case, what do I do if I want to test or debug?

The only thing I can think of is creating a file and writing to it

But is this the only way

Could I write to a log file - without going to the bother of opening and closing a file or something?

 

Thanks

 

 

OM

[xyph]

What?

 

You can echo inside of a function in order to debug or trace

[OM2]

Maybe, I'm doing something wrong

Are you saying that if I echo ANYWHERE, as long as that part of code is run, and echo will ALWAYS output to the screen?

Are there no circumstances where this won't be true?

 

I have a Flash file that uploads files and then runs a php script

In this php script, I have put echo statements next to code that I know 100% it runs - but I get no output

 

Am I doing something wrong?

 

Thanks

 

[xyph]

Perhaps a header redirect before the echo gets a chance to run?

 

Is the file being called by the flash application rather than the browser? Similar to an AJAX call? If so, you'll have to find a way to get the flash application to give you the text returned by the script.

[OM2]

Perhaps a header redirect before the echo gets a chance to run?

 

Is the file being called by the flash application rather than the browser? Similar to an AJAX call? If so, you'll have to find a way to get the flash application to give you the text returned by the script.

yes being called by flash file

forgetting flash for a second, if an echo is done, will it ALWAYS output to the browser?

thanks

[xyph]

Assuming the browser is executing the script, it should output to the browser (though client-side configurations can affect this - plugins like adblock will hide pre-defined lists of images etc.)

 

There are functions that can prevent this however, like ob_start() and ob_end_clean(). If you haven't coded any output buffering into your script though, I really wouldn't be worried.

[OM2]

thanks

that's really helpful

 

i was going through some code a freelancer coded for me and they used ob_start()

i looked up on php.net, but couldn't get my head round what it was supposed to do and why one might use it?

[xyph]

Here's a read that tells you everything you need to know about how PHP handles outputs

 

http://phpadvent.org/2010/output-buffering-by-nicholas-sloan

 

I don't really like using output buffering. I don't ever see a need for it myself with the rare exception of a pesky function that outputs directly rather than returning a value. Just my personal opinion - some good programmers use it, other good programmers don't. Just about anything you can do with output buffering can be done without it.

[OM2]

hey: that's a great article

i have a good understanding now

and can see the benefits of using

it's really annoying creating a damn string and continually concatinating to

 

i've book marked the site as well - its got a lot of useful articles

 

thanks!