Why would one omit the close tag?

Question

I keep reading it is poor practice to use the PHP close tag ?> at the end of the file. The header problem seems irrelevant in the following context (and this

Answer 1

If I understand the question correctly, it has to do with output buffering and the affect this might have on closing/ending tags. I am not sure that is an entirely valid question. The problem is that the output buffer does not mean all content is held in memory before sending it out to the client. It means some of the content is.

The programmer can purposely flush the buffer, or the output buffer so does the output buffer option in PHP really change how the closing tag affects coding? I would argue that it does not.

And maybe that is why most of the answers went back to personal style and syntax.

Answer 2

Well, I know the reason, but I can't show it:

For files that contain only PHP code, the closing tag (?>) is never permitted. It is not required by PHP, and omitting it prevents the accidental injection of trailing white space into the response.

Source: http://framework.zend.com/manual/en/coding-standard.php-file-formatting.html

Answer 3

Pros

• Would be logical to close any opened tag, like with other languages. Not only X(HT)ML tags, but as well curly braces, brackets...
• Less confusing for beginners.

Cons

• Avoids headache with adding inadvertently whitespaces after the closing tag, because it breaks the header() function behavior... Some editors or FTP clients / servers are also known to change automatically the end of files (at least, it's their default configuration)
• PHP manual says closing tag is optional, and Zend even forbids it.

Conclusion

I would say that the arguments in favor of omitting the tag look stronger (helps to avoid big headache with header() + it's PHP/Zend "recommendation"). I admit that this isn't the most "beautiful" solution I've ever seen in terms of syntax consistency, but what could be better ?

Answer 4

There are 2 possible use of php code:

1. PHP code such as class definition or function definition
2. Use PHP as a template language (i.e. in views)

in case 1. the closing tag is totally unusefull, also I would like to see just 1 (one) php open tag and NO (zero) closing tag in such a case. This is a good practice as it make code clean and separate logic from presentation. For presentation case (2.) some found it is natural to close all tags (even the PHP-processed ones), that leads to confution, as the PHP has in fact 2 separate use case, that should not be mixed: logic/calculus and presentation

Answer 5

Well, there are two ways of looking at it.

1. PHP code is nothing more than a set of XML processing instructions, and therefore any file with a .php extension is nothing more than an XML file that just so happens to be parsed for PHP code.
2. PHP just so happens to share the XML processing instruction format for its open and close tags. Based on that, files with .php extensions MAY be valid XML files, but they don't need to be.

If you believe the first route, then all PHP files require closing end tags. To omit them will create an invalid XML file. Then again, without having an opening <?xml version="1.0" charset="latin-1" ?> declaration, you won't have a valid XML file anyway... So it's not a major issue...

If you believe the second route, that opens the door for two types of .php files:

• Files that contain only code (library files for example)
• Files that contain native XML and also code (template files for example)

Based on that, code-only files are OK to end without a closing ?> tag. But the XML-code files are not OK to end without a closing ?> since it would invalidate the XML.

But I know what you're thinking. You're thinking what does it matter, you're never going to render a PHP file directly, so who cares if it's valid XML. Well, it does matter if you're designing a template. If it's valid XML/HTML, a normal browser will simply not display the PHP code (it's treated like a comment). So you can mock out the template without needing to run the PHP code within...

I'm not saying this is important. It's just a view that I don't see expressed too often, so what better place to share it...

Personally, I do not close tags in library files, but do in template files... I think it's a personal preference (and coding guideline) based more than anything hard...

Answer 6

Sending headers earlier than the normal course may have far reaching consequences. Below are just a few of them that happened to come to my mind at the moment:

1. While current PHP releases may have output buffering on, the actual production servers you will be deploying your code on are far more important than any development or testing machines. And they do not always tend to follow latest PHP trends immediately.

2. You may have headaches over inexplicable functionality loss. Say, you are implementing some kind payment gateway, and redirect user to a specific URL after successful confirmation by the payment processor. If some kind of PHP error, even a warning, or an excess line ending happens, the payment may remain unprocessed and the user may still seem unbilled. This is also one of the reasons why needless redirection is evil and if redirection is to be used, it must be used with caution.

3. You may get "Page loading canceled" type of errors in Internet Explorer, even in the most recent versions. This is because an AJAX response/json include contains something that it shouldn't contain, because of the excess line endings in some PHP files, just as I've encountered a few days ago.

4. If you have some file downloads in your app, they can break too, because of this. And you may not notice it, even after years, since the specific breaking habit of a download depends on the server, the browser, the type and content of the file (and possibly some other factors I don't want to bore you with).

5. Finally, many PHP frameworks including Symfony, Zend and Laravel (there is no mention of this in the coding guidelines but it follows the suit) and the PSR-2 standard (item 2.2) require omission of the closing tag. PHP manual itself (1,2), Wordpress, Drupal and many other PHP software I guess, advise to do so. If you simply make a habit of following the standard (and setup PHP-CS-Fixer for your code) you can forget the issue. Otherwise you will always need to keep the issue in your mind.

Bonus: a few gotchas (actually currently one) related to these 2 characters:

1. Even some well-known libraries may contain excess line endings after ?>. An example is Smarty, even the most recent versions of both 2.* and 3.* branch have this. So, as always, watch for third party code. Bonus in bonus: A regex for deleting needless PHP endings: replace (\s*\?>\s*)$ with empty text in all files that contain PHP code.