on file() and flock()
My supervisor came up with a brilliant plan to workaround the inability of the file() to work on a flock()'ed file.
We created a dummy file called lockfile.txt. We would flock() lockfile.txt. Once we had a lock on it, we used file() on the file we wanted to read, then altered the file and called fclose on both files.
file
(PHP 4, PHP 5)
file — Liest eine Datei komplett in ein Array
Beschreibung
Die Funktion file() ist identisch mit readfile(), außer dass die eingelesene Datei als Array zurückgegeben wird. Jedes Feld des Arrays korrespondiert mit einer Zeile der Datei. Der Zeilenumbruch bleibt erhalten. Im Fehlerfall gibt file() FALSE zurück.
Hinweis: Jede Zeile in dem resultierenden Array enthält das Zeilenende, weshalb Sie trim() verwenden müssen, falls der Zeilenumbruch nicht vorhanden sein soll.
Hinweis: Wenn Sie Probleme damit haben, dass PHP Zeilenendezeichen nicht erkennt, entweder beim Lesen von Dateien auf einem Macintosh oder bei Dateien die auf einem Macintosh erstellt wurden, können Sie die Option auto_detect_line_endings aktivieren.
Optional kann der Parameter use_include_path benutzt und auf '1' gesetzt werden, wenn in dem include_path ebenfalls nach der Datei gesucht werden soll.
<?php
// Liest eine Datei in ein Array. Hier gehen wir über HTTP, um die
// HTML Datei einer URL zu bekommen
$lines = file ('http://www.example.com/');
// Durchgehen des Arrays und Anzeigen des HTML Source inkl. Zeilennummern
foreach ($lines as $line_num => $line) {
echo "Line #<b>{$line_num}</b> : " . htmlspecialchars($line) . "<br>\n";
}
// Ein anderes Beispiel: Einlesen einer Webseite in einen String.
// Siehe auch file_get_contents().
$html = implode ('', file ('http://www.example.com/'));
?>
Hinweis: Ab PHP 4.3.0 können Sie file_get_contents() verwenden, um den Inhalt einer Datei als String zurückzugeben.
Mit PHP 4.3.0 ist file() "Binary Safe".
Mit dieser Funktion können Sie eine URL als Dateinamen verwenden, falls Sie fopen wrappers ermöglicht haben. Mehr Details dazu, wie Sie den Dateinamen angeben müssen finden Sie bei fopen(). Eine Liste der unterstützten URL Protokolle finden Sie unter List of Supported Protocols/Wrappers.
Siehe auch readfile(), fopen(), fsockopen(), popen(), file_get_contents(), und include().
file
21-Apr-2008 03:49
16-Apr-2008 01:03
A user suggested using rtrim always, due to the line ending conflict with files that have an EOL that differs from the server EOL.
Using rtrim with it's default character replacement is a bad solution though, as it removes all whitespace in addition to the '\r' and '\n' characters.
A good solution using rtrim follows:
<?php
$line = rtrim($line, "\r\n") . PHP_EOL;
?>
This removes only EOL characters, and replaces with the server's EOL character, thus making preg_* work fine when matching the EOL ($)
05-Apr-2008 03:45
althought it's mentioned twice in the description, it took me a whole night to figure out why i got new-lines in my array.
hence you have to put a flag on it FILE_IGNORE_NEW_LINES.
I mention, just you wouldn't miss this little anoying thing.
*you can use trim, but it's slighty different.
16-Feb-2008 01:15
If you're getting "failed to open stream: Permission denied" when trying to use either file() or fopen() to access files on another server. Check your host doesn't have any firewall restrictions in-place which prevent outbound connections. This is the case with my host Aplus.net
12-Jul-2007 02:25
This note applies to PHP 5.1.6 under Windows (although may apply to other versions).
It appears that the 'FILE_IGNORE_NEW_LINES' flag doesn't remove newlines properly when reading Windows-style text files, i.e. files whose lines end in '\r\n'.
Solution: Always use 'rtrim()' in preference to 'FILE_IGNORE_NEW_LINES'.
28-Nov-2006 12:33
Using file() for reading large text files > 10 Mb gives problems, therefore you should use this instead. It is much slower but it works fine. $lines will return an array with all the lines.
$handle = @fopen('yourfile...', "r");
if ($handle) {
while (!feof($handle)) {
$lines[] = fgets($handle, 4096);
}
fclose($handle);
}
11-Jul-2006 02:19
justin at visunet dot ie's note of 20-Mar-2003 states
"Note: Now that file() is binary safe it is 'much' slower than it used to be. If you are planning to read large files it may be worth your while using fgets() instead of file()."
I tested fgets(), file_get_contents(), and file() on PHP 4.3.2 and PHP 5 and timed each to be under a second with over 200,000 lines. I do not know if he was testing extremely long lines or what, but I could not duplicate the difference that he mentioned.
01-Feb-2006 02:52
you can use
$file = array_map('rtrim',file('myfile.txt'));
to remove annoying ending lines of the resulting array.
18-Jan-2006 03:16
WARNING ON WINDOWS:
file() function will add "\r\n" in to the end of the row, even if you use only "\n" char to make rows in the file!
On UNIX systems there is no such problem.
12-Sep-2003 02:48
Jeff's array2file function is a good start; here are a couple of improvements (no possibility of handle leak when fwrite fails, additional capability of both string2file and array2file; presumably faster performance through use of implode).
function String2File($sIn, $sFileOut) {
$rc = false;
do {
if (!($f = fopen($sFileOut, "wa+"))) {
$rc = 1; break;
}
if (!fwrite($f, $sIn)) {
$rc = 2; break;
}
$rc = true;
} while (0);
if ($f) {
fclose($f);
}
return ($rc);
}
function Array2File($aIn, $sFileOut) {
return (String2File(implode("\n", $aIn), $sFileOut));
}
If you're generating your string text using a GET or POST from a TEXTAREA (e.g., a mini-web-text-editor), remember that strip_slashes and str_replace of "/r/n" to "/n" may be necessary as well using these functions.
HTH --dir @ badblue com
20-Jul-2003 04:32
after many months of confusion and frustration, i have finally figured out something that i should have noticed the first time around.
you can't file("test.txt") when that same file has been flocked. i guess i didn't have a full understanding of what i was doing when i used flock(). all i had to do was move the flock() around, and all was well.
20-Mar-2003 09:36
Note: Now that file() is binary safe it is 'much' slower than it used to be. If you are planning to read large files it may be worth your while using fgets() instead of file() For example:
$fd = fopen ("log_file.txt", "r");
while (!feof ($fd))
{
$buffer = fgets($fd, 4096);
$lines[] = $buffer;
}
fclose ($fd);
The resulting array is $lines.
I did a test on a 200,000 line file. It took seconds with fgets() compared to minutes with file().
You can use file with https if you go to:
http://ftp.proventum.net/pub/php/win32/misc/openssl/.
This is instead of using the php_openssl.dll, so be sure to comment this extension in your php.ini.
16-Mar-2002 11:16
file() has a strange behaviour when reading file with both \n and \r as line delimitator (DOS files), since it will return an array with every single line but with just a \n in the end. It seems like \r just disappears.
This is happening with PHP 4.0.4 for OS/2. Don't know about the Windows version.
09-Feb-2002 12:56
It appears that the file() function causes file access problems for perl cgi scripts accessing the same files. I am using Perl v5.6.0 in linux with PHP/4.0.4pl1. After running a php app using the file() function, any perl cgi trying to access the same file randomly dies returning an internal server error: premature end of script headers.
The simple fix is to use fopen(), fgets() and fclose() instead of file().
