Error on PHP fgets() reading a line of CSV - php

Question

I am working on this snippet. Why am I getting fgets() error on line 6?
Warning: fgets() expects parameter 1 to be resource, string given in
D:\wamp64\www\WP\wp-content\plugins\test.php on line 6
Code:
<?php
$file = "http://localhost:8080/WP/Data.csv";
function wdm_validate_csv($csv_file)
{
$requiredHeaders = array('title', 'price','color');
$firstLine = fgets($csv_file); //get first line of the CSV file
$fileHeader = str_getcsv(trim($firstLine), ',', "'"); //parse the contents to an array
//check the headers of the file
if ($foundHeaders !== $requiredHeaders) {
// report an error
return false;
}
return true;
}
wdm_validate_csv($file);
As you can see I have a CSV file at this $file = "http://localhost:8080/WP/Data.csv" directory and trying to read it

Answer 1

if you read a file with Url you can use the function file_get_contents(), but if you need to read in the local server change this http://localhost:8080/WP/Data.csv for "./WP/Data.csv" if the php file is in the root directory.
`
<?php
// Create a stream
$opts = array(
'http'=>array(
'method'=>"GET",
'header'=>"Accept-language: en\r\n" .
"Cookie: foo=bar\r\n"
)
);
$context = stream_context_create($opts);
// Open the file using the HTTP headers set above
$file = file_get_contents('http://www.example.com/', false, $context);
?>
`

Answer 2

Using file()[0] will give you the first line of a file.
file() returns a file as an array line by line, and [0] means give me the first line only.
Then I assume it's a typo $fileheaders and $foundheaders?
$file = "http://localhost:8080/WP/Data.csv";
function wdm_validate_csv($csv_file)
{
$requiredHeaders = array('title', 'price','color');
$firstLine = file($csv_file)[0]; //get first line of the CSV file
$fileHeader = str_getcsv(trim($firstLine), ',', "'"); //parse the contents to an array
//check the headers of the file
if ($fileHeader !== $requiredHeaders) {
// report an error
return false;
}
return true;
}
wdm_validate_csv($file);

Answer 3

Assuming you're going to do other stuff with the file after validating its headers, I think it makes sense to open it and pass the resource handle to the function instead of just the path.
$file = fopen("http://localhost:8080/WP/Data.csv");
$valid_headers = wdm_validate_csv($file);
If your CSV is valid, you can combine fgets and str_getcsv into one operation with fgetcsv.
function wdm_validate_csv($csv_file)
{
$requiredHeaders = array('title', 'price','color');
$fileHeader = fgetcsv($csv_file); //get first line of the CSV file
return $fileHeader == $requiredHeaders;
}
file_get_contents and file are great, but they're both going to read the entire file in, which is a bit heavy if you just need to check the first line.

Answer 4

As the error suggests, fgets requires a resource, not a string. Try using file_get_contents instead:
<?php
$file = "http://localhost:8080/WP/Data.csv";
function wdm_validate_csv($csv_file)
{
$requiredHeaders = array('title', 'price','color');
$firstLine = file_get_contents($csv_file); //get first line of the CSV file
$data = str_getcsv(trim($firstLine), ',', "'"); //parse the contents to an array
$foundHeaders = array_key_exists($data[0]) ? $data[0] : null;
//check the headers of the file
if ($foundHeaders !== $requiredHeaders) {
// report an error
return false;
}
return true;
}
wdm_validate_csv($file);