[wp-hackers] ob_start - good or bad?

[Simon Wheatley]

Thanks.


On Thu, Apr 23, 2009 at 11:44 AM, Otto <otto at ottodestruct.com> wrote:
> Well, yes, okay, I didn't know about that reason. Seems like a PHP bug to me.
>
> The general reason to avoid output buffering is that it buffers the
> output. This seems stupidly obvious, but if your output is being saved
> in a buffer until the end of the thing, then it's not being delivered
> to the browser until the end of the process, all at once. Meaning that
> your page doesn't appear to load gradually anymore, but the whole
> thing has to run first, making it seem slower.
>
> Now, if you're using it like you are, to capture only certain output
> and prevent it from displaying, then ending the buffer, you don't have
> this same problem. But output buffering in general is a poor solution.
> You're basically taking something intended as output and putting it
> into a string instead, so that you can presumably manipulate it. The
> ideal solution in such a case is to rework something to give you the
> string you want directly, not to work around it.
>
> So usually, when there's no other way to do it except output
> buffering, then you probably have a good argument for adding some new
> functionality to the core code instead.
>
> Caching plugins being a notable exception to this, of course.
>
> -Otto
>
>
>
> On Thu, Apr 23, 2009 at 4:48 AM, Donncha O Caoimh <donncha at linux.ie> wrote:
>> If you use ob_start() and wait until the end of the PHP process to collect
>> the output and do something with it (like WP Super Cache and other caching
>> plugins do) you have to be careful about using objects.
>> The latest versions of PHP5 destroy objects during shutdown before all code
>> has actually been run.
>>
>> I had to "pre cache" a few blog options earlier in the process (into global
>> variables) to get around this. What's worse, is that this destroying of
>> objects doesn't always happen, and different versions of PHP5 do different
>> things. It's head wrecking.
>>
>> Donncha
>>
>> Simon Wheatley wrote:
>>>
>>> On Thu, Apr 23, 2009 at 10:35 AM, Otto <otto at ottodestruct.com> wrote:
>>>>
>>>> Well, there's already a get_edit_post_link() function, so why not use
>>>> that instead? Okay, so it doesn't return all the a href stuff, but
>>>> that's easy to duplicate.
>>>>
>>>
>>> I hadn't spotted that when I looked at the edit_post_link function
>>> somehow, thanks.. seems so obvious now I look again. :\
>>>
>>>> In general, it's a bad idea to use output buffering unless there's no
>>>> other way to do it. In the case of the given code, there's definitely
>>>> another way to do it.
>>>>
>>>
>>> For the sake of my education (and accepting that get_edit_post_link is
>>> available for this specific case), why is ob_start, etc,  a bad idea?
>>>
>>> Thanks Otto.
>>>
>>> S
>>
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Simon Wheatley
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