File manupulation search and replace csv php - php

Question

I need a script that is finding and then replacing a sertain line in a CSV like file.
The file looks like this:
18:110327,98414,127500,114185,121701,89379,89385,89382,92223,89388,89366,89362,89372,89369
21:82297,79292,89359,89382,83486,99100
98:110327,98414,127500,114185,121701
24:82297,79292,89359,89382,83486,99100
Now i need to change the line 21.
This is wat i got so far.
The first 2 to 4 digits folowed by : ar a catergory number. Every number after this(followed by a ,) is a id of a page.
I acces te id's i want (i.e. 82297 and so on) from database.
//test 2
$sQry = "SELECT * FROM artikelen WHERE adviesprijs <>''";
$rQuery = mysql_query ($sQry);
if ( $rQuery === false )
{
echo mysql_error ();
exit ;
}
$aResult = array ();
while ( $r = mysql_fetch_assoc ($rQuery) )
{
$aResult[] = $r['artikelid'];
}
$replace_val_dirty = join(",",$aResult);
$replace_val= "21:".$replace_val_dirty;
// file location
$file='../../data/articles/index.lst';
// read the file index.lst
$file1 = file_get_contents($file);
//strip eerde artikel id van index.lst
$file3='../../data/articles/index_grp21.lst';
$file3_contents = file_get_contents($file3);
$file2 = str_replace($file3_contents, $replace_val, $file1);
if (file_exists($file)) {
echo "The file $filename exists";
} else {
echo "The file $filename does not exist";
}
if (file_exists($file3)) {
echo "The file $filename exists";
} else {
echo "The file $filename does not exist";
}
// replace the data
$file_val = $file2;
// write the file
file_put_contents($file, $file_val);
//write index_grp98.lst
file_put_contents($file3, $replace_val);
mail('info#', 'Aanbieding catergorie geupdate', 'Aanbieding catergorie geupdate');
Can anyone point me in the right direction to do this?
Any help would be appreciated.

Answer 1

You need to open the original file and go through each line. When you find the line to be changed, change that line.
As you can not edit the file while you do that, you write a temporary file while doing this, so you copy over line-by-line and in case the line needs a change, you change that line.
When you're done with the whole file, you copy over the temporary file to the original file.
Example Code:
$path = 'file';
$category = 21;
$articles = [111182297, 79292, 89359, 89382, 83486, 99100];
$prefix = $category . ':';
$prefixLen = strlen($prefix);
$newLine = $prefix . implode(',', $articles);
This part is just setting up the basics: The category, the IDs of the articles and then building the related strings.
Now opening the file to change the line in:
$file = new SplFileObject($path, 'r+');
$file->setFlags(SplFileObject::DROP_NEW_LINE | SplFileObject::SKIP_EMPTY);
$file->flock(LOCK_EX);
The file is locked so that no other process can edit the file while it gets changed. Next to that file, the temporary file is needed, too:
$temp = new SplTempFileObject(4096);
After setting up the two files, let's go over each line in $file and compare if it needs to be replaced:
foreach ($file as $line) {
$isCategoryLine = substr($line, 0, $prefixLen) === $prefix;
if ($isCategoryLine) {
$line = $newLine;
}
$temp->fwrite($line."\n");
}
Now the $temporary file contains already the changed line. Take note that I used UNIX type of EOF (End Of Line) character (\n), depending on your concrete file-type this may vary.
So now, the temporary file needs to be copied over to the original file. Let's rewind the file, truncate it and then write all lines again:
$file->seek(0);
$file->ftruncate(0);
foreach ($temp as $line) {
$file->fwrite($line);
}
And finally you need to lift the lock:
$file->flock(LOCK_UN);
And that's it, in $file, the line has been replaced.
Example at once:
$path = 'file';
$category = 21;
$articles = [111182297, 79292, 89359, 89382, 83486, 99100];
$prefix = $category . ':';
$prefixLen = strlen($prefix);
$newLine = $prefix . implode(',', $articles);
$file = new SplFileObject($path, 'r+');
$file->setFlags(SplFileObject::DROP_NEW_LINE | SplFileObject::SKIP_EMPTY);
$file->flock(LOCK_EX);
$temp = new SplTempFileObject(4096);
foreach ($file as $line) {
$isCategoryLine = substr($line, 0, $prefixLen) === $prefix;
if ($isCategoryLine) {
$line = $newLine;
}
$temp->fwrite($line."\n");
}
$file->seek(0);
$file->ftruncate(0);
foreach ($temp as $line) {
$file->fwrite($line);
}
$file->flock(LOCK_UN);
Should work with PHP 5.2 and above, I use PHP 5.4 array syntax, you can replace [111182297, ...] with array(111182297, ...) in case you're using PHP 5.2 / 5.3.