Recursive function file_put_contents file header issue

[jarvis]

Hi All,

I've a function that pulls data from a paginated API. The function is called recursively in order to work through each page and get the data.

Within the function, I use file_put_contents to write the information to a CSV file.

What I'd like to do, is add a first row/header to the CSV file with column names. 

I'm probably being daft but if I add the header information in, it gets repeated on each iteration of the loop.

Here's my code:

function get_from_api() {
	
	#$page_report 	= get_stylesheet_directory() . '/page-report.txt';
	
	$filename = 'products.csv';	
	
	$product_data	= get_stylesheet_directory() . '/'.$filename;
		
	$current_page = ( ! empty( $_POST['current_page'] ) ) ? $_POST['current_page'] : 1;
	$products = [];

	// Should return an array of objects
	$results = wp_remote_retrieve_body( wp_remote_get('www.domain.com/batch.php?page=' . $current_page . '&per_page=10') );	
	
	// create a file to test the output
	$data = 'Current Page: '.$current_page;
	#file_put_contents( $page_report, $data . "\n\n", FILE_APPEND );	

	// turn it into a PHP array from JSON string
	$results = json_decode( $results );   
  
	// Either the API is down or something else spooky happened. Just be done.
	if( ! is_array( $results ) || empty( $results ) ){
	    return false;
	}
	#print_r($results);
	$products[] = $results;	
	
	foreach( $products[0] as $product ){    		
				
			$result .= $product->id. ',';
			$result .= $product->name;
					
			file_put_contents( $product_data, $result . "\n", FILE_APPEND );

	}
	
	$current_page = $current_page + 1;
	wp_remote_post( admin_url('admin-ajax.php?action=get_from_api'), [
		'blocking' => false,
		'sslverify' => false, // we are sending this to ourselves, so trust it.
		'body' => [
			'current_page' => $current_page
		]
	]);
  
}

Any help would be great

Thanks

[requinix]

So in other words, you only want to write the header line if you've started writing to this file from scratch?

[jarvis]

Yes that's right. So the first iteration adds the header

[requinix]

No no, forget "iteration". Focus only on the "if you've started writing to this file from scratch" part.

What, exactly, would "from scratch" mean? Is there any way you could tell when that's the case?

[jarvis]

Would it be when you declare the file?

I'm clearly missing something because surely being recursive, it will just keep adding to the file

[requinix]

"Declare the file"?

A much bigger hint so I can go to bed: the first time you run this code, will the file exist?

[jarvis]

No, the file doesn't exist - which I get.

I can't see how to add something to the file without it being repeated, as this is the issue I keep getting.

I switched from file_put_contents to fopen and have achieved what I need.

Why it doesn't work using file_put_contents I don't know

	$products[] = $results;	
	
	$data = array();
	
	if( $current_page == 1 ){
		$data[] = array(
				'id',
				'name'
		);	
	}
	
	foreach( $products[0] as $product ){    

		$result .= $product->id. ',';
		$result .= '"'.$product->name.'"';
		
		$data[] = array(
				'id' => $product->id,
				'name' => $product->name
		);
					
		file_put_contents( $product_data, $result . "\n", FILE_APPEND | LOCK_EX );
		$i++;
	}
	
	
	$file = fopen($product_data2,"a");

	foreach ($data as $line) {
		fputcsv($file, $line);
	}

	fclose($file);	

 

Edited August 13, 2021 by jarvis
typo in code

[Phi11W]

2 hours ago, jarvis said:

I can't see how to add something to the file without it being repeated, as this is the issue I keep getting.

At the point in your function where you're about to append some data into the file, test whether the file exists. 

If the file does not exist, then write the column headers into the file. 

Then, append the data into the file, regardless of whether you just wrote the headers or not. 

In the second and subsequent calls (recursive or not), the file will exist and so the headers will not be repeated. 

Regards, 
   Phill  W.

 

[jarvis]

Ah! Penny drops - many thanks @Phi11W