Full array evaluating as empty and null - php

Question

I have a very strange problem that I have been unable to find an answer to. I have a PHP function that reads CSV data into an array then returns true if the data was successfully read and passes the array back by reference variable
function ReadCsvDataIntoArray($path, &$headers, &$array, $idFilter = NULL){
if(file_exists($path)){
$fh = fopen($path, 'r');
if($fh){
$headers = fgetcsv($fh);
$rowIdx = 0;
while($row = fgetcsv($fh)){
$addRow = true;
if($idFilter != NULL){
if(isset($row[0])){
if(!in_array($row[0], $idFilter)){
$addRow = false;
}
}
}
if($addRow){
$colIdx = 0;
foreach($row as $val){
$array[$rowIdx][$headers[$colIdx]] = $val;
$colIdx++;
}
$rowIdx++;
}
}
fclose($fh);
return true;
} else {
echo "Unable to open file: ".$path;
}
} else {
echo "CSV doesn't exist: ".$path;
}
return false;
}
If the function returns as true I then check to make sure the array wasn't passed back as null or empty, then sort the data.
if($this->ReadCsvDataIntoArray($client_library_path, $headers, $CSVdata, $log)){
if($CSVData != NULL){
usort($CSVdata, create_function('$a, $b', 'return $a["engagement"] < $b["engagement"];'));
// Do stuff with the sorted array
} else {
echo "CSV data is NULL.\n";
}
I keep getting "CSV data is NULL" from this. If I change the logic to if($CSVData == NULL) or even if(empty($CSVData)) it enters the if statement, attempts to sort the array (which is full, even though the if statement says it's empty) and does stuff with the data.
This is where my second issue comes in. This usort works on my localhost:
usort($CSVdata, function($a, $b) { return $a["scheduled"] < $b["scheduled"]; });
but it doesn't work on the server because of its php version, so I have changed it to:
usort($CSVData, create_function('$a, $b', 'return $a["scheduled"] < $b["scheduled"];'));
But with the create_function version of the usort I get this error message
Warning: usort(): The argument should be an array
I am guessing this has something to do with the fact that my full array is somehow being evaluated as empty and null even when it isn't.

Answer 1

You say this:
…and passes the array back by reference variable…
And this:
If the function returns as true I then check to make sure the array
wasn't passed back as null or empty, then sort the data.
Why are you doing this? If you are checking true or false then checking if it is null or empty what is the value of that? Just check if it is null or empty by doing this instead:
// return true;
return $array;
} else {
echo "Unable to open file: ".$path;
}
} else {
echo "CSV doesn't exist: ".$path;
}
// return false;
return $array;
And then get rid of the return by reference for $array in the interface:
function ReadCsvDataIntoArray($path, &$headers, $array, $idFilter = NULL){
Your true or false logic is probably broken & not worth dealing with correctly at all. But why spend time reinventing the wheel if the value returns null or empty and that is what you are acting on.
Also you can then adjust this $CSVData logic to fit the new structure:
$CSVData = $this->ReadCsvDataIntoArray($client_library_path, $headers, $CSVdata, $log);
if(!empty($CSVData)){
usort($CSVdata, create_function('$a, $b', 'return $a["engagement"] < $b["engagement"];'));
// Do stuff with the sorted array
} else {
echo "CSV data is empty.\n";
}
Also, your whole return true logic is based strictly on the file itself can be opened:
$fh = fopen($path, 'r');
if($fh){
// Code removed for structural illustration purposes.
// ...
// ...
fclose($fh);
return true;
} else {
But you say this; empahsis mine:
I have a PHP function that reads CSV data into an array then returns
true if the data was successfully read…
No. Your logic does not check if the data was read successfully. Your logic simply returns true if the file itself can be read. Which does not mean the contents of the file itself is valid. Have you checked the file itself? Or did you check if this line:
while($row = fgetcsv($fh)){
Actually has values in $row by doing something like this?
echo '<pre>';
print_r($row);
echo '</pre>';
I think that maybe your CSV has line formatting issues. Like it was saved on a Windows machine but is now being read on a Mac OS X or Linux machine or the other way around. Look at this in the documentation for fgetcsv:
Note: If PHP is not properly recognizing the line endings when reading
files either on or created by a Macintosh computer, enabling the
auto_detect_line_endings run-time configuration option may help
resolve the problem.
So perhaps add this line enabling auto_detect_line_endings to your function like this:
function ReadCsvDataIntoArray($path, &$headers, &$array, $idFilter = NULL){
ini_set("auto_detect_line_endings", true);