When I'm connecting to MySQL using the mysqli class constructor I get an echoed error message from PHP when I don't provide the correct connection details. However, there is an appropriate way to deal with errors, like connect_errno and connect_error, but PHP always seems to echo the fact that a connection was unsuccessful whereas I want to deal with any errors manually.
ini_set('display_errors', FALSE);
Related
What I was trying to do is inserting all query errors into a database, but, it doesnt work. I wanted to do this:
<?php
include('db_settings.php');
$query = $conn->query("mysql_query here");
if (!query) {
$error = $conn->error;
$log_error = $conn->query("INSERT INTO tab (log) VALUES ('$error')");
}
?>
However, this does not work, the error is not being submitted into the db.
Does any of you know some workaround for this?
(before someone asks, all parameters of DB and variables are correct).
You simply shouldn't do that.
Do not try to use a medium that failed you that very instant!
Let's take one of your recent questions: The very error message that troubled you here, Mysqli Commands out of sync will prevent your wunderlogging from functioning! Your database won't get back to sync by magic! And thus will effectively prevent you from logging its own error. And so you simply will never have an idea it occurred.
Let errors to be logged, and then you'll be able find them all.
add these three lines at the top of your code,
ini_set('log_errors',1);
error_reporting(E_ALL);
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
and then check the server error log.
This is how everyone is doing it and there is no reason to devise such an awkward and illogical device.
I have some code that allows a user to input details for their database on their server. After they submit the details, the code checks a connection to the database to see if valid details were entered. I want it to give outcomes of variables being true if the connection either works or does, like this:
$mysqli = new mysqli($_POST['dbHost'],$_POST['dbUser'],$_POST['dbPassword'],$_POST['dbName']);
if ($mysqli->connect_errno) { $badDetails = true; }
else { goodDetails = true; }
Problem is, if the details are indeed incorrect, it shows a PHP warning from the first line of the code above giving 'Unknown MySQL server host'.
What is the way around this? I don't want PHP throwing it's own visible error for this, I want to deal with the error myself.
You should not worry about visual errors. In a production environment, these should be turned off in the ini, and all errors should go to a log on the server instead of just to the screen.
This is configured with the display_errors setting and error_reporting()
Many frameworks override the PHP error handler with a custom implementation to display error in a pretty way, depending on their severity.
To achieve this, you can override the PHP error handler
As seen in the manual one can register custom handlers for regular errors and exceptions. And it is also possible to trigger an user defined error.
Just use a die()
$mysqli = new mysqli($_POST['dbHost'],$_POST['dbUser'],$_POST['dbPassword'],$_POST['dbName']) or die("Database Connection Failed");
A quick, dirty method would be error supression:
$con = #mysqli_connect( /* info */ );
Note that you should not keep this there, as this will suppress all errors, and mysqli can have multiple errors that you might need to know about.
Though I would check the host variable first, to see why the error is caused. You can also use die.
$con = mysqli_connect(/* info */) or die ("SQL Error!");
As far as where to look, try seeing that the host var is actually set and check it's value:
if (!isset($_POST['dbHost'])) {
echo "Host var not set!";
} else {
echo "Host var set: " . $_POST['dbHost']
}
I'm moving a php application to a new web server.
In the origin server, the following code is working, but it is not in the new server.
$request=$connexion->prepare("SELECT * FROM access_control ");
$request->execute();
$request2=$connexion->prepare("SELECT * FROM tplmail ");
$request2->execute();`
The first request always works. I tried to reverse the two requests, but the script always stop at the second execute. In the others scripts, there is the same problem, I can't do two executes in the same page.
Your problem #1 is lack of error reporting. Without seeing an error message you will be unable to do anything
To be able to see database errors, one have to set PDO errmode to exceptions. Exceptions are better than regular errors in many ways: they always contains a stack trace, they can be caught using try..catch or handled using dedicated error handler. And even unhandled, they act as regular PHP errors providing all the important information, following site-wide error reporting settings.
Note that setting this mode as a connection option will let PDO throw exceptions on connection errors too, which is very important.
So, here is an example for creating a PDO connection right way:
$dsn = "mysql:host=$host;dbname=$db;charset=utf8";
$opt = array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
// other options
);
$pdo = new PDO($dsn, $user, $pass, $opt);
Connecting this way, you will be always notified of all database errors, occurred during query execution. Note that you have to be able to see PHP errors in general. On a live site you have to peek into error logs, so, settings have to be
error_reporting(E_ALL);
ini_set('display_errors',0);
ini_set('log_errors',1);
while on a local development server it's ok to make errors on screen:
error_reporting(E_ALL);
ini_set('display_errors',1);
and of course you should never ever use error suppression operator (#) in front of your PDO statements.
Also, due to many bad examples telling you to wrap every PDO statement into try..catch block, I have to make a distinct note:
DO NOT use try..catch operator just to echo an error message. Uncaught exception is already excellent for this purpose, as it will act just the same way as other PHP errors - so, you can define the behavior using site-wide settings - so, you will have your error message without this useless code. While unconditionally echoed error message may reveal some sensitive information to a potential attacker, yet confuse a honest visitor.
A custom exception handler could be added later, but not required. Especially for new users, it is recommended to use unhandled exceptions, as they are extremely informative, helpful and secure.
Use try..catch only if you are going to handle the error itself - say, to rollback a transaction.
Your problem #2 is a buffering state which prevent second query from execution.
Adding
PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
to the init array should solve the problem
Or you can just fetch all the data from the first query before firing the second
How would I go about getting PDO statements to generate a safe error message? I don't want the user to see the error message. I want them to get directed to a page that says a clean message, "Whoops something unexpected happened!". I would also like to log the errors in a database to review and catch errors others are generating.
I'm using PHP and MySQL.
I found that when you make your connection you can set your error handling like this.
$dbh = new PDO($dsn, $user, $password);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
Anyone do anything like this before?
So this is just a suggestion as I have never tried this but after thinking about it a bit I think it would be an interesting option to explore. As I am fairly new to PHP & PDO I'm sure there are other and better ways.
Perhaps you could try using the try function of PHP and then instead of echo'ing (if failed) the PDOException you could run another function that prints it to a text file. Something like.
<?php
try {
$dbh = new PDO('mysql:host=localhost;dbname=test', $user, $pass);
foreach($dbh->query('SELECT * from FOO') as $row) {
print_r($row);
}
$dbh = null;
} catch (PDOException $e) {
$strFileName = 'whatever.txt';
if(!is_writable($strFileName))
die('Change permisions to ' . $strFileName);
$handle = fopen($strFileName, 'a+');
fwrite($handle, "\r" . $e->getMessage() . "\r");
fclose($handle);
}
?>
This way you would avoid a DB connection (which is the problem I guess) but still save the error.
You would perhaps want to omit the echo'd text after die within the if statement.
I think it is better to write your logs to a file, instead of a database. Especially since you want to log PDO errors, which indicate something is wrong with your database connection.
You can show the user a nice error page by catching your errors. You can redirect your users to your error page then, in case something went wrong.
You have to understand that PDO do not generate a "safe" or "unsafe" error message. It does generate an error message. That's all. The rest is is the responsibility of site-wide PHP settings.
PDO is not the only source of errors. Why care of PDO errors only? Why not to handle ALL errors the same way?
Want errors logged? It's a matter of one PHP ini setting.
Want errors not to be displayed? It's a matter of one PHP ini setting.
Want generic error page to be shown? It's a matter of simple function that will handle all errors at once.
Everything can be done proper and straight way, without wrapping every statement into try catch. Without writing into log manually. Without even single additional line of code.
You need to set up PHP error handling, not PDO.
And of course, it makes absolutely no sense in trying to store a database error in the same database that failed you right now. Errors have to go into error log on a live server and on screen - on a local development PC.
Anyone do anything like this before?
Sure. Every single one of 1000000s sites in the world. The way described above.
How do i get a detailed error description during a php-mysql script run?
I have the following statements where the script fails and displays the custom error message - the contents of the "or die".
I want to get the actual error from MySQL (instead of the custom error i have mentioned), which would give better idea about the scenario - whether its a database issue or server connectivity issue etc..
this is the code i have where i need to enhance the error reporting
$query = "SELECT * FROM table_name";
$result = mysqli_query($db_conn, $query)
or die('Connected to database, but querying failed');
thanks!
Check out mysql_error function.
Have a look at the manual page for mysqli_error. In the section "Procedural style" you'll find a complete example that shows how to set up the database connection and querying the database, both steps with error handling.
If you want detailed error information from your scripts you can put the lines
error_reporting( E_ALL );
ini_set('log_errors', true);
ini_set('error_log', '/tmp/php-errors.log');
at the start of your code. That way all errors coming from PHP will be written into the log file. Make sure that the path to the log file exists (/tmp is only an example) and is writable by the web server, otherwise the errors will be silently discarded.
As a side note: While the "or die()" pattern is good for small examples, you should not use it in production code.
I prefer using PDO, and having PDO throw an exception.
you could insert the query into the query page on phpmyadmin that is if you are using it. But this wont tell you if the errors are with the variables