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From: Matthew Carter <m@ahungry.com>
Newsgroups: comp.lang.php
Subject: Re: PHP Warning: extract() expects parameter 1 to be array
Date: Tue, 23 Aug 2016 01:26:34 -0400
Organization: Ahungry (http://ahungry.com)
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Jerry Stuckle <jstucklex@attglobal.net> writes:

> On 8/22/2016 3:34 PM, the troll Thomas 'Pointed Head' Lahn wrote:
>> Ben Bacarisse wrote:
>> 
>>> […] I prefer the "more structured" version:
>>>
>>> if ($argc < 2)
>>>     echo "Please, provide a path to a file\n";
>>> else if (!file_exists($file))
>>>     echo "Sorry, there is no such file $file\n";
>>> else if (!is_readable($file))
>>>     echo "$file is not readable\n";
>>> ...
>>> else if (($open_file = fopen($file, "r")) === false)
>>>     echo "Sorry, couldn't open $file\n";
>>> else {
>>>     // All ok.  Let's get on with it...
>>>
>>>     while (...)
>>>     {
>>>     // Main work is here
>>>     }
>>> }
>> 
>> This code style is a maintenance nightmare (the missing blocks and the 
>> assignment in the “if” statement doubly so).  Do you know what the condition 
>> on line 50 was because of which you wrote “else” on line 100?
>>
>
> Yes - if the code is properly indented and commented (something you
> wouldn't understand).
>
>> Also, PHP is influenced by C, but it is _not_ C.  The function should throw 
>> (PHP Standard Library) exceptions like \InvalidArgumentException instead of 
>> echo-ing error conditions without regard to the user’s locale.  This will 
>> also get them a stack trace (even better if the Xdebug extension is 
>> installed and enabled) if they do not catch the exception.  As a result, the 
>> then-unnecessary “else” statements would vanish in a puff of program logic.
>> 
>
> Which would display to a user internal details of your code - a huge
> security exposure.  But you don't understand security, either, do you?
>
> In addition, it will immediately stop processing of the page - resulting
> in invalid HTML being sent to the browser.  Something else you don't
> care about, either.
>
>> <http://php.net/manual/en/language.exceptions.php>
>> 
>
> Glad you can cut/paste a URL.  Too bad you don't understand how write
> good PHP code.

Details of stack traces are only exposed if the environment
(production?) is configured to match that of a developer environment
(such as showing errors vs logging them).

It is also quite easy to wrap your outer-most layer of code input/output
in a try/catch block and handle:

- Rendering a generic or descriptive error message for the user in the
  catch block

- Manually logging the stack trace (part of the \Exception object) to a
  file or sending as part of an email to the webmaster (if this is not
  configurable in the php.ini of the server for some reason)

- Ensuring the HTML the user receives is still valid

This also allows for easier to extend code in the future, as you end up
with a single exit point.

-- 
Matthew Carter (m@ahungry.com)
http://ahungry.com