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Posted by Jerry Stuckle on 09/02/06 14:05
lawrence k wrote:
> I've made it habit to check all returns in my code, and usually, on
> most projects, I'll have an error function that reports error messages
> to some central location. I recently worked on a project where someone
> suggested to me I was spending too much time writing error messages,
> and that I was therefore missing the benefit of using a scripting
> language. The idea, apparently, is that the PHP interpreter writes all
> the error messages that are needed, and that I shouldn't write such
> code myself. I was given the impression that if I needed extensive
> error checking, or strict typing, then I should use a real language,
> like Java, but if I'm going to use a scripting language like PHP or
> Ruby, then I should leave errors to the interpreter, since the whole
> point of using scripting languages is speed of development. Has anyone
> else heard this argument, and do you agree with it? I'm wondering how
> other PHP programmers handle error messages. Check everything or leave
> it to the PHP interpreter to tell you when there is an error?
>
Obviously either someone who was entirely clueless or a very sloppy
programmer. In either case there is no way I would want to work with
anyone with that attitude.
> Which of these two functions is better, the one with error checking or
> the one without?
>
> function getWeblogEntries() {
> $query = "SELECT * FROM weblogs";
> $result = mysql_query($query);
> $howManyWeblogEntries = mysql_num_rows($result);
> for ($i=0; $i < $howManyWeblogEntries; $i++) {
> $row = getRow($result);
> extract($row);
> echo "<h1>$headline</h1>";
> echo "<h7>$date</h7>";
> echo "<div class=\"mainContent\">$mainContent</div>";
> }
> }
>
>
>
> function getWeblogEntries() {
> $query = "SELECT * FROM weblogs";
> $result = mysql_query($query);
> if ($result) {
> $howManyWeblogEntries = mysql_num_rows($result);
> for ($i=0; $i < $howManyWeblogEntries; $i++) {
> $row = getRow($result);
> if (is_array($row)) {
> extract($row);
> echo "<h1>$headline</h1>";
> echo "<h7>$date</h7>";
> echo "<div class=\"mainContent\">$mainContent</div>";
> } else {
> reportError("In getWeblogEntries, the function getRow
> failed to return an array on the $i iteration.");
> }
> }
> } else {
> reportError("In getWeblogEntries, the query to the database
> failed.");
> }
> }
>
>
Definitely the second one is better. Additionally, you've taken the
extra step of hiding the MySQL error message itself - which is a good thing.
Those messages are meant for you, the programmer, and can contain
information useful to hackers. It's much better to keep that
information private.
Although I do generally take the extra step of writing the MySQL message
to an error log.
>
> My own feeling, obviously, is that it is better to error check
> everything, and to write extensive comments everywhere. I've taken over
> PHP projects, started by other programmers, that had no error checking
> and no comments, and such projects are always a big pain in the neck. I
> lose time playing Sherlock Holmes, trying to track down where a
> function's parameter first originates and why it's in use. I'd rather
> have a comment on it, and error message for when the wrong thing is
> passed in. Obviously this slows development. Is there any concensus
> among developers about what is the best approach? I think whatever is
> cheapest for the client should be considered the best approach, but it
> seems to me cheapest-in-the-short-term is quite different from
> cheapest-in-the-long-term.
>
Yes. Do all of your own error checking, write messages you aren't
afraid of your client or a website user seeing, and log more sensitive
information to a file for later reference.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
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