Databases
StackOverflow2013
Postsdbo
POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
    primarykey
    data
    text
    <p>I am wondering if there is any real benefit to using this...</p> <pre><code>function getSomeContent() { ob_start(function($content) { // ... modify content ... return $content; } // ... output stuff ... return ob_get_clean(); } </code></pre> <p>...as opposed to this...</p> <pre><code>function getSomeContent() { ob_start(); // ... output stuff ... $result = ob_get_clean(); // ... modify content ... return $result; } </code></pre> <p>...?</p> <p>Assume the "output stuff" and "modify content" parts are the same in each case. The key point is that the "modify content" has changed its location, being in a callback in the first case, and being "inline" in the second case.</p> <p>Is there a performance benefit of one over the other? For example, does the second form make two copies of the buffer contents when the first uses only one? Or is it purely a coding style decision? Why would <em>you</em> choose one form over the other?</p> <p>I can see there are differences in scope access, because any variables in the enclosing scope will be available in the "modify content" part of the second example, where they would have to be "passed in" with a <code>use</code> clause in the first example. In fact this is exactly why I would normally choose the second form.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USleftclickben
    1. USleftclickben
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. This table or related slice is empty.
      1. VTModeratorReview
    3. VO
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. This table or related slice is empty.
      1. VTDownMod
    1. COIn the first case, you don't need to do `$result = ob_get_clean();`, you'll do `ob_end_clean();` (calls the callback before cleaning too). Else the second case is yours. If you want to use the first case this way (modifying 2 times result), you'll just add complexity to your app.
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. USAlain Tiemblo
    2. COThanks @Ninsuo, but I think maybe you didn't understand my code samples properly (I wasn't clear enough in my question), so I have added a bit more context by making them into method calls with identical signatures. The first case isn't modifying the result twice, I don't understand what you mean there, can you clarify how that is the case? Of course I want to use `ob_get_clean()` and not `ob_end_clean()` as that simply discards the contents of the buffer, which I want to keep. I'm asking about using the callback in `ob_start()` vs processing the result "inline" so to speak.
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. USleftclickben
    3. COWhile I think that all of this is just a matter of coding style (with Ninsuo correctly pointing out that the callback style can get you a little cleaner code), you should re-evaluate if it is really necessary to fall back to using output buffering for capturing the output. What are you doing in between `ob_start` and `ob_get_clean`? Wouldn't you be able to append the output to a variable in the first place?
      singulars
      1. POWhat is the benefit of passing a callback to ob_start compared to just processing the result of ob_get_clean()?
      1. USakirk
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload