im developing my PHP framework and at the moment im stuck with a strange behaviour in my error-dispatching page.
The page itself is beautiful, it catches and lists all error using a custom error-handler registered with "set_error_handler()" and can print the line, file, invoked variables and such. It even triggers multiple errors perfectly (except for fatal or syntax-errors which causes the script to hold) but still the dispatches the fatal or even syntax error in this case and even shows me, even when its a null-pointer in a template where the error is located which is beautiful and works awesome.
This system works "using set_error_handler"! The entire output (rendering html /php templates) is realised using "ob_start" and "ob_get_clean" - outputbuffer context.
Next I check if the error-handler catched any errors (will be written in an array in the error-handler's class) and if there are errors and error-display is enabled (developer mode = on) the error-dispatcher page will be displayed instead of the page's content.
However since I implemented that I have one strange behaviour which I do not want:
Whenever I use die() inside of outputbuffer context ((ob_start() ... ob_get_clean()) ) The registered error-handler method is called with an empty error-list displayed and even error_get_last() is empty, but still he triggers that damn function.
This is very disturbing as you cant use die to hold the script to test the output of certain variables which is disturbing in development and seems to be an unusual behaviour to me.
I think posting my entire code is making the thing a little bit too complicated for you to understand thatswhy I leave a little draft explaining the situation, its basically same as it looks in my classes:
//index.php
$errorList = array();
function myErrorHandler($errorType, $errorString, $errorFile, $errorLine, array $errorContext) {
global $errorList;
$errorList[] = $errorString;
}
set_error_handler("myErrorHandler");
//Here my classses and entire rest of framework is loaded...()
//Initialise output
$output = "";
//This method parses templates, it remotely close works like that...
function includeTemplate($templatePath) {
global $output;
ob_start("myErrorHandler");
include($templatePath);
$output .= ob_get_clean(); //Attach to output
}
//This method is called at the very end, it flushes the output, wether by displaying error-dispatcher or page content to be shown.
function flush() {
global $output;
if(count($errorList) > 0) {
echo implode("<br />", $errorList);
} else {
echo $output;
}
}
//Template file: registerTemplate.php
<div class="container">
<Some template output here, doesnt matter if an error occured...>
<?php die($var); ?> //<- Error rised -> Entering "myErrorHandler()" -> but why????
</div>
-> This die() above would rise an error because registerTemplate.php was somewhen parsed using includeTemplate("reigsterTemplate"); which is as located within an ob_start() context. It does not matter if an error occured before or not or even if I just place die("!"); without any invoked variable, it will riase an error.
If I put the die() before or after the include_template context, in upper scope it works as usual and the error_handler does not trigger, as it should work.
Can anyone tell me why this is happening? Thanks alot!
(Important: again this code is not realistic I know its just a draft from how the things look like very barely, dont bother with that giving me hints that this is a bad way to do things. The entire thing is perfectly object oriented and very well structured. I just made this little draft to make you guys understand in what order the methods are called and how my problem comes up because posting my code would waste me and you alot of time as it would be too huge and complex here).
Related
while using Codacy to analyze my PHP code I found a number of errors caused by the exit(); function. here's one function,
public function saveCssForm(){
$data = $_POST;
if(!$data){
// is a direct acess
$this->index();exit();
}
// update the data
$this->csssettingmodel->updateCSS($data);
// save the notifications
$this->notify_update($data['site_id'],$data['lang_key']);
// set the success message
$this->session->set_flashdata('edit_item', 'edited');
// redirect to the view page
$baseUrl = $this->config->item('base_url');
redirect($baseUrl.'index.php/cssSettings/view/'.$this->session->userdata("languageabbr"));
}
public function index()
{
// Denay Direct Access
echo "<hr><h1><center>NO DIRECT ACCESS</h1> </center>";
echo "<center>You are not permitted to access this page </center>";
}
and the codacy result shows this...
any alternatives or suggestions to avoid this would be helpful.
Codacy is not displaying errors, in the sense of problems you need to fix; it is analysing the quality of your code, and suggesting that the exit appearing in this position is not a good practice, so you might want to fix it.
Firstly, application frameworks are often designed to have a single point of entry, process some logic, and then return a result to the entry point which will output and clean up. Exiting from different points in the code makes it harder to predict the flow, because whole sections of the code may look reachable but actually come after the program has exited.
Secondly, such code might be used for debugging, to interrupt the flow of execution at a particular point to display some intermediate data or simulate a particular failure. In this case, it appearing in the analysed code would suggest that you had left the debugging code in accidentally.
I am actually trying to monitor a PHP variable (may be as a separate thread but not possible in PHP) and fire a PHP function whenever the value of the variable changes.
eg: lets take a variable $_GLOBALS['foo']=1;
if at any point in the code, the value of $_GLOBALS['foo'] changes to something else, i want to fire a PHP function immediately.
The variable can be anywhere inside a loop or in a function,etc.
Why i want this: I have a variable which stores the last error occured as a text. If the value of the variable changes from "" to something else, i want to trigger an error. My LOGIC may seem a bit strange but this is what i would like to do.
Thanx in advance.
Edit: I tried: How to use monitors in PHP? and How can one use multi threading in PHP applications but does not seem to solve the problem.
The Code (Thought this could solve some of your doubts on my question):
public function addtag($tagarray,$uid,$tagtype="1")
{
$dbobj=new dboperations();
$uiobj=new uifriend();
$tagid=$uiobj->randomstring(30,DB_SOCIAL,SOCIAL_TAG,tag_tagid);
$c=0;
foreach($tagarray as $tags)
{
$c++;
$tagname=$tags["tagname"];
$taguid=$tags["tagid"];
$dbobj->dbinsert("INSERT INTO ".SOCIAL_TAG." (".tag_tagid.",".tag_fuid.",".tag_tuid.",".tag_tagname.",".tag_tagtype.") VALUES
('$tagid','$uid','$taguid','$tagname','$tagtype')",DB_SOCIAL);
}
if($c==0)
{
$lasterror="No tags were added";return "";
}
else
{
return $tagid;
}
}
Here, if i call a error handling function instead of monitoring the variable, it wont be advisable in my case since the error handling function may do any operation like give alert and redirect to a page or any similar operation.
I asked this question cause, i thought what if the script does not reach the line
return "";
It would affect the project's workflow. Thats what i am worried about.
And the variable i was talking about is $lasterror and i have many functions like this where $lasterror is used.
I saw this, so I built this:
https://github.com/leedavis81/vent
Should solve your problem.
There is no built-in way to do this in PHP, and there's no easy way to add it. It doesn't really feel right for the way the language works anyway.
Instead of setting a variable, you could build a custom function that handles the error - or use PHP's built-in error handling functionality using a custom error handler.
Another error handling method which comes close to what you want to do (I think) is exceptions.
I am reading the No frills magento layout book written by Alan Storm. I have come across the following code:
public function handleAction()
{
$this ->loadLayout();
$handles = Mage::getSingleton('core/layout')->getUpdate()->getHandles();
var_dump($handles);
exit;
}
What is the need of that exit in this code ? That code works perfectly without that exit.
It stops the rest of the code from executing, looking at that script it seems like the purpose of it is to debug something. Having the rest of your page render won't make that debugging any easier since CSS styles will be applied that could make the var_dump() less readable.
Also there could be a redirect involved or such which could cause your var_dump() to disappear immediately, using exit you prevent the redirect from happening.
Bottom line, it's just not needed to have the rest of the code render.
This is a bit of an oddity for me. PHP is my forte, and I can normally figure out any issue I encounter.
I have a custom framework that I have been using for years. I have taken it upon myself to rewrite it, and I'm doing everything essentially the same that I was before. The problem lies in the following construct:
function ModPages_GetPage() {
$page = ModPages_GetPageByName($_GET['page_name']);
if($page != false) {
include(TPL_DIR.'pages/pages.view.php');
} else {
ErrorMessage('Invalid Page', 'The selected page could not be found.');
}
}
function ModPages_GetPageByName($page_name = null) {
$db = new Database;
$query = '
SELECT *
FROM pages
WHERE page_name = "'.CleanStr($page_name).'"
AND page_enabled = "yes"
LIMIT 1
';
$page = $db->GetRow($query);
return $page;
}
This code is being called with 'home' for the value of $_GET['page_name']. The call to ModPages_GetPageByName() is working fine, but the value of $page in ModPages_GetPage() isn't getting set. Matter of fact, any debugging statements thrown in after that call are failing to display anything.
I have display_errors set to on, and error_reporting set to E_ALL. I get a couple notices from my Database class, but that's it.
Running the script at a shell fails to produce any errors. When using strace, I do see the process spits out an 'exit_group(255)'.
This one has me quite baffled. I could sure use some direction on this.
I would think it's your query, shouldn't you just return the page name instead of star? as star (*) would return an array which is probably being passed back as the value? just my guess.
$query = '
SELECT *
FROM pages
WHERE page_name = "'.CleanStr($page_name).'"
AND page_enabled = "yes"
LIMIT 1
';
if you do a print_r on the $page return I would think it should be an array
$page = $db->GetRow($query);
echo "Page:<pre>".print_r($page,true)."</pre><br />\n";
Then maybe return something like this
return $page['page_name_field'];
ok before we get to a solution can we first make sure that before setting the $page variable, first just echo $_GET['page_name'] to see if there is a value being received.
PK
Does your script stop right after your database call, or just doesn't display any output?
If the first is true, then it looks like a fatal error. With E_ALL, it should be displayed, are you sure both display_errors and error_reporting are as you say at that point, and that the GetRow function doesn't alter them in any way? If so, maybe there's something in the Apache error log (PHP errors are sometimes logged there).
If the latter is true I'm thinking about an exception being thrown in a method that is being called, and caught in a higher level function. To check this you can put the database call (ie: the point where things go wrong) inside a try/catch block and see if you reach the catch block.
I would try following:
replace $_GET with $_REQUEST (maybe your form is using POST?)
do a print_r to check contents of your variables.
use mysql_error to view any errors, or print your mysql query in your browser, copy/paste it in phpmyadmin, is it returning anything? error.. data?
something similar happend to me once, my framework was encoded in ANSI and my calling php file was UTF8+BOM... I changed everything to UTF8+BOM and it worked.
try also different browser, I know it might not be a browser problem, but it might be that your script is cached somewhere.
are you using some caching? like eaccelerator?
Are those functions in a class? If so, you will need $page = $this->ModPages_GetPageByName().
Also I would echo out the argument and the sql statment in ModPages_GetPageByName(). This way you can verify that it isn't a SQL error.
I can't say for sure why your code isn't working, but I can make some suggestions that might help in locating the error.
The first thing I notice is you don't check that $db actually contains a valid database. I don't know the details of your Database object but I'm assuming there's some mechanism in there for checking if it's actually connected to the database. You should use that to determine if the database is connected before running queries on it.
$db = new Database ();
if ($db -> isConnected ())
{
$query = 'SELECT * (etc etc etc)';
// ...
}
else
{
// Put some kind of DB connection error notification or throw an exception here
}
Just on a stylistic note, you don't need to store the results of your DB lookup before returning it, unless you're planning on doing some processing on the result before returning it. You can just return the lookup directly. Of course that's just a stylistic choice, but it saves a line or two :)
return ($db->GetRow($query));
After you run your getpage function, I'd strongly recommend var_dump()ing the result. Even if your function returned NULL, you'll still see this in the var_dump. If in doubt, dump it out :). I'd also recommend installing xdebug to make the var_dump output more readable.
$page = ModPages_GetPageByName($_GET['page_name']);
var_dump ($page);
I would also strongly recommending var_dumping your query before you execute just to make absolutely sure that you're running the query you think you're running. Copy and paste the outputted query into sqlyog or phpmyadmin or whatever you use for interactive access to your database and make sure it returns what you think it should return.
Other things to check, is the page you're trying to return actually set page_enabled='yes'? Does the page_enabled column actually store the value as 'yes', or is it a bool or an integer or something else? Is magic quotes enabled or disabled? If they're in one state when you think they're in the other they can cause confusion. Are errors actually being reported to the browser? Add a line at the top of your script that's guaranteed to fail just to make sure, like an attempted foreach on an integer. If you don't see an error, then maybe error reporting isn't configured properly. I know those are obvious questions but I also know how easy it is to overlook the obvious if you're not getting what you expect out of a query.
Are you sure $page is not set, or is it just that your debug instructions don't print anything? Try logging to a file or a database instead; maybe your code triggered output buffering or something like that.
Also, you are calling ModPages_GetPageByName before declaring it. That is usually okay, but might not be in special circumstances (e.g. when the code is wrapped in an if block). Try swapping the two.
Also, check your environment and disable opcode caching and other possible error sources. APC for example can call the old version of the script long after you changed the PHP file.
While some of you have put extra effort into responding to this, nobody has been able to see the full picture, even given the details I have provided. I have been unable to trace the issue back to its source, but have moved on to a different project.
I created a few mediawiki custom tags, using the guide found here
http://www.mediawiki.org/wiki/Manual:Tag_extensions
I will post my code below, but the problem is after it hits the first custom tag in the page, it calls it, and prints the response, but does not get anything that comes after it in the wikitext. It seems it just stops parsing the page.
Any Ideas?
if ( defined( 'MW_SUPPORTS_PARSERFIRSTCALLINIT' ) ) {
$wgHooks['ParserFirstCallInit'][] = 'tagregister';
} else { // Otherwise do things the old fashioned way
$wgExtensionFunctions[] = 'tagregister';
}
function tagregister(){
global $wgParser;
$wgParser->setHook('tag1','tag1func');
$wgParser->setHook('tag2','tag2func');
return true;
}
function tag1func($input,$params)
{
return "It called me";
}
function tag2func($input,$params)
{
return "It called me -- 2";
}
Update: #George Mauer -- I have seen that as well, but this does not stop the page from rendering, just the Mediawiki engine from parsing the rest of the wikitext. Its as if hitting the custom function is signaling mediawiki that processing is done. I am in the process of diving into the rabbit hole but was hoping someone else has seen this behavior.
Never used Mediawiki but that sort of problem in my experience is indicative of a PHP error that occurred but was suppressed either with the # operator or because PHP error output to screen is turned off.
I hate to resort to this debugging method but when absolutely and utterly frustrated in PHP I will just start putting echo statements every few lines (always with a marker so I remember to remove them later), to figure out exactly where the error is coming from. Eventually, you'll get to the bottom of the rabbit hole and figure out exactly what the problematic line of code is.
Silly me.
Had to close the tags.
Instead of<tag1> I had to change it to <tag1 /> or <tag1></tag1>
Now all works!