AngularJS .get Method Causing Internal Error 500 - php

Question

I've got a working version of the code on my local machine using xampp but when I uploaded it to my Raspberry Pi it seems to go haywire.
Basically I've got an angularjs script calling a file called dbConn.php which is in the same directory and works on a local machine but doesn't when uploaded to a Pi.
function raspberryController($scope, $http, $timeout) {
var poll = function() {
$timeout(function() {
try{
$http.get("dbConn.php")
.success(function(response) {$scope.names = response;})
.error(function(data, status, header, config) {
console.log(alert, status, header, config);
});
} catch (e) {
console.log("Got an error!",e);
throw e;
// rethrow to not marked as handled
}
poll();
}, 1000);
}
poll();
}
dbConn.php
<?php
//$db = new SQLite3('system/modules/test.db');
header("Access-Control-Allow-Origin: *");
try{
$dbh = new PDO('sqlite:system/test.db') or die("cannot open db");
} catch(Exception $e) {
echo $e->getMessage();
}
$query = 'SELECT * FROM connected;';
$results = $dbh->query($query);
$outp = '[';
foreach($dbh->query($query) as $row){
if ($outp != "[") {
$outp .= ",";
}
$outp .= ' { "ID":"' . $row[0] .'",';
$outp .= '"IP":"' . $row[1] .'",';
$outp .= '"CONNECTED":"' . $row[2] .'",';
$outp .= '"LEASE_TIME":"' .$row[3] .'" } ';
}
$outp .= ']';
echo($outp);
?>

Answer 1

You have:
try { $dbh = new PDO('sqlite:system/test.db') or die("cannot open db"); } catch(Exception $e) { echo $e->getMessage(); }
You're trying to call the query() function on the $dbh object outside of the try.
Here's a link to variable scoping in PHP: http://php.net/manual/en/language.variables.scope.php
To solve your problem either have an empty $dbh variable outside the try block and then initialise it within the try eg:
$dbh = null;
try {
$dbh = new PDO('sqlite:system/test.db') or die('cannot open db');
} catch (Exception $e) {
//some code to handle it in here
exit(); //to stop anything else from executing
}
$result = $dbh->query();
The other way to solve the problem would be to put the rest of your code in the try/catch block you've created for the initialisation of the $dbh variable.
try {
$dbh = new PDO('sqlite:system/test.db') or die('cannot open db');
$query = 'SELECT * FROM connected;';
$results = $dbh->query($query);
$outp = '[';
foreach($results as $row){
if ($outp != "[") {
$outp .= ",";
}
$outp .= ' { "ID":"' . $row[0] .'",';
$outp .= '"IP":"' . $row[1] .'",';
$outp .= '"CONNECTED":"' . $row[2] .'",';
$outp .= '"LEASE_TIME":"' .$row[3] .'" } ';
}
$outp .= ']';
echo $outp;
} catch (Exception $e) {
echo $e->getMessage();
}
You'd be better off abstracting DB logic into a separate class and using it like a Singleton or a static class as detailed in this other post: Best practices for a PDO class?.
Oh and for future reference, the easiest way to find out what's going wrong if you're met with a unhelpful err 500 is to use tail -f /var/log/apache2/error.log from your terminal if you're using a Debian distro such as Raspbian.