Invalid argument in foreach

[Gandalf]

I’ve written a script to enable me to edit a simple TSV file and it seems to work except that having updated the file I get a PHP warning when it displays the data for editing.

First time through there is no warning; second and subsequent times I get the warning. If I press update without making any changes the “before” and “after” versions of the TSV file look identical in Notepad++ - but there is clearly some difference.

Here is my code:

function readtsvfile($file) {
  // Read tsv file into array
  $handle = fopen($file, 'r');
  while ( !feof($handle) )
    $array[] = fgetcsv($handle, 1024, "\t");
  fclose($handle);
  return $array;
}

$file = '../accounts-copy.tsv';

// values may have been modified - write updated file
if ( $_SERVER['REQUEST_METHOD'] == 'POST' ) {
  $data = readtsvfile($file);
  $handle = fopen($file, 'w');
  foreach ( $_POST['cell'] as $k1 => $row ) {
    $line = $data[$k1][0] . "\t";
    foreach ( $row as $k2 => $val )
      $line .= $val . "\t";
    fwrite($handle, rtrim($line).PHP_EOL);
  }
  fclose($handle);
  echo 'File updated', "\n";
}

// display file contents for editing
$data = readtsvfile($file);
echo '<form method="post">', "\n";
echo '<table>', "\n";
foreach ( $data as $k1 => $row ) {
  echo '  <tr>', "\n"; # line 34
  foreach ( $row as $k2 => $val ) {
    if ( $k2 == 0 )
      $val = htmlentities($val);
    if ( $k2>0 )
      echo '    <td><input type="text" name="cell[', $k1, '][', $k2, ']" value="', $val, '"></td>', "\n";
    else
      echo '    <td>', $val, '</td>', "\n";
  }
  echo '  </tr>', "\n";
}
echo '</table>', "\n";
echo '<input type="submit" value="Update">', "\n";
echo '</form>', "\n";

The warning is: Warning: Invalid argument supplied for foreach() in editcsv.php on line 34.

My unadulterated TSV file is attached (although I have had to change the extension to csv to upload).

accounts-copy.csv (490 Bytes)

[Dormilich]

Well, the obvious thing to do is logging (resp. looking, if you have remote debugging) what the variable in question actually contains.

[Gandalf]

Thanks @Dormilich. I had been var_dumping $data and noticed no difference between “before” and “after”. Now when I var_dump $row AND look in the right place I see my edited file has an end of line at the end which the original doesn’t have.

[John_Betong]

The problem was an extra blank line being added to the end of the CSV file when it was updated

Try this:

<?php 
# ERRORS VERBOSE
  declare(strict_types=1);

  $tmp = 'ERROR_LOG.php';
  ini_set('error_log', $tmp );
  ini_set('log_errors', 'true');
  ini_set('html_errors', 'true');
  ini_set('track_errors', 'true');
  ini_set('display_errors', 'true');
  ini_set('display_startup_errors', 'true');
  error_reporting(-1);

# File Name
	$file = 'accounts-copy.tsv';
	$file = 'accounts-copy.csv'; // 

# values may have been modified - write updated file
	if ( $_SERVER['REQUEST_METHOD'] == 'POST' )
	{
		# fred($_POST, 'Just Posted');

	  $data 	= readtsvfile($file);
	  $handle = fopen($file, 'w');
	  foreach ( $_POST['cell'] as $k1 => $row )
	  {
	    $line = $data[$k1][0] . "\t";
	    foreach ( $row as $k2 => $val )
	    {	
	      $line .= $val . "\t";
	    }  

	    fwrite($handle, rtrim($line).PHP_EOL);
	  }
	  fclose($handle);
	  echo 'File updated', "\n";
	}

# display file contents for editing
	$data = readtsvfile($file);
	echo '<form method="post">', "\n";
	echo '<table>', "\n";
		foreach ( $data as $k1 => $row )
		{
		  echo '  <tr>', "\n"; # line 34
			  foreach ( $row as $k2 => $val )
			  {
			    if ( $k2 === 0 )
			    {
			      $val = htmlentities($val);
			      echo '<td>', $val, '</td>', "\n";
			    }else{  
			      echo '<td><input type="text" name="cell[', $k1, '][', $k2, ']" value="', $val, '"></td>', "\n";
			    }  
			  }#endif
		  echo '  </tr>', "\n";
		}#endforeach
	echo '</table>', "\n";
echo '<input type="submit" value="Update">', "\n";
echo '</form>', "\n";


//===============================================
function readtsvfile($file)
{
	$array = [];

  // Read tsv file into array
  $handle = fopen($file, 'r');
  while ( !feof($handle) )
  {	
  	$tmp = fgetcsv($handle, 1024, "\t");
  	if( $tmp ):
    	$array[] 	= $tmp;
    else:
    	echo '<h1> Yes we have NO fgetcsv(...) <br>' ; // fred($tmp)';
    		echo 'line: ' .__line__;
    		echo '<br>';
    	echo '</h1>';
    endif;
  }
    
  fclose($handle);
  return $array;
}

//===============================================
function fred($val, $title='')
{
	echo '<pre>'; echo $title .'<br>';
  	print_r($val); 
  echo '</pre>';
}