I have no luck when the subject is reading text files. I have a small script to read a log file (real time updated) but I want to send some data to DB.
And the problem is, if I don't stat reading from the end of the files, I will get duplicated entries in database. Wich can't happen!
// Keep alive
for (;;)
{
$handle = fopen("data.log", "r");
if (!$handle) die("Open error - data.log");
while (!feof($handle))
{
$line = fgets($handle, 4096);
// If match with, I output the result
if (strpos($line, ':gshop_trade:') > 0)
{
if (!preg_match('/([\d-: ]+)\s*.*\sformatlog:gshop_trade:userid=(\d+):(.*)item_id=(\d+):expire=(\d+):item_count=(\d+):cash_need=(\d+):cash_left=(\d+).*$/', $line, $data))
{
echo "Parsing error on line: {$line}";
}
// show the data
}
}
sleep(5);
}
This script is working, but as I mentioned above, I need to send the data to BD. But also, I need to leave script running, with this current code, the script match the wanted string, and instead of wait for new entries on data.log he starting reading the whole file again.
I see this question here and I tested but doesn't work. I'll start the script when I start the service that generates "data.log" but to prevent duplicate entries in database, I need to read the last lines.
How can I do that?
Keep a track of the file offset from the previous reading using ftell() and keeping that result in a variable, and jump to that offset in the file when you re-open it for the next reading using fseek()
$lastPos = 0;
for (;;)
{
$handle = fopen("data.log", "r");
if (!$handle) die("Open error - data.log");
fseek($handle, $lastPos); // <--- jump to last read position
while (!feof($handle))
{
$line = fgets($handle, 4096);
$lastPos = ftell($handle); // <--- maintain last read position
// If match with, I output the result
if (strpos($line, ':gshop_trade:') > 0)
{
if (!preg_match('/([\d-: ]+)\s*.*\sformatlog:gshop_trade:userid=(\d+):(.*)item_id=(\d+):expire=(\d+):item_count=(\d+):cash_need=(\d+):cash_left=(\d+).*$/', $line, $data))
{
echo "Parsing error on line: {$line}";
}
// show the data
}
}
sleep(5);
}
Maybe you can use file_get_contents, explode and read the array backwards?
$arr = explode(PHP_EOL, file_get_contents("data.log")); // or file("data.log");
$arr = array_reverse($arr);
foreach($arr as $line){
// do stuff here in reverse order
}
From comments above I suggest this method to only use the new data in your code.
It will read your log and a text file with what has been read last time.
Remove what was read last time and use the new data in the code.
$logfile = file_get_contents("data.log");
$ReadData = file_get_contents("readdata.txt");
$newdata = str_replace($ReadData, "", $logfile); // this is what is new since last run.
file_put_contents("readdata.txt", $logfile); // save what has been read.
$arr = explode(PHP_EOL, $newdata);
foreach($arr as $line){
// do your stuff here with the new data.
}
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="refresh" content="5"> <!-- This will run the page every five seconds.
</head>
</html>
Related
When I run this function on multiple scripts one script generated warning:
fread(): Length parameter must be greater than 0
function test($n){
echo "<h4>$n at ".time()."</h4>";
for ($i = 0; $i<50; $i++ ){
$fp = fopen("$n.txt", "r");
$s = fread($fp, filesize("$n.txt") );
fclose($fp);
$fp = fopen("$n.txt", "w");
$s = $_SERVER['HTTP_USER_AGENT'].' '.time();
if (flock($fp, LOCK_EX)) { // acquire an exclusive lock
fwrite($fp, $s);
// fflush($fp);// flush output before releasing the lock
flock($fp, LOCK_UN); // release the lock
} else {
echo "Couldn't get the lock!";
}
}
}
I try to write reading of the file for multiple users, but only one user can write the file. I know that when I use fwrite with flock - LOC_EX, next scripts must wait till the write is finished. But here it seems like filesize doesn't wait till the write operation is finished. My opinion is that it tries to reach the file when the file size is 0, and as a result this produces the problem: 0 bytes will be read from the file, when it is written by original script.
Is it possible to fix this for fread function?
Purpose of this script is to test fread with some limit and to check the data which I read later, if the data are really written when I did not used fflush.
function test($n){
echo "<h4>$n at ".time()."</h4>";
for ($i = 0; $i<50; $i++ ){
$start = microtime(true);
$fp = fopen("$n.txt", "r");
if(filesize($n.txt) > 0)
{
$s = fread($fp, filesize($n.txt) );
fclose($fp);
$fp = fopen("$n.txt", "w");
$s = $_SERVER['HTTP_USER_AGENT'].' '.time();
if (flock($fp, LOCK_EX)) { // acquire an exclusive lock
fwrite($fp, $s);
// fflush($fp);// flush output before releasing the lock
flock($fp, LOCK_UN); // release the lock
} else {
echo "Couldn't get the lock!";
}
}
else
{
echo "Filesize must be greater than 0";
}
}
}
please change $s variables name its use same things two time
$fp = fopen("$n.txt", "r");
$s = fread($fp, filesize("$n.txt") );
fclose($fp);
The error occurs in the middle line of the above three lines.
Firstly, these three lines could be rewritten into a single line as follows:
$s = file_get_contents("$n.txt");
However, these isn't necessary, as these three lines are entirely redundant in your code. They don't do anything useful.
What they do is open a file, store its contents to $s and then close it.
But you are then immediately setting $s to a different value, thus throwing away the previous value, and making it pointless to have read it from the file in the first place.
If you need to keep the original contents of the file, then use file_get_contents() and make sure you don't overwrite the contents of the variable.
If you don't need the original contents of the file, then just delete those three lines from your code.
Incidentally, this error highlights a couple of good coding practices that you should take on board: Firstly, never re-use a variable for two different things, and secondly always give your variables (and functions) good names. $s is not a good name; $previousFileContents would be a better name; it would have made the error much more obvious.
I am having this strange issue and can't figure it out.
On some websites I have this script works perfect... same code, same server settings...
With php, there is a simple page view hit counter that stores locally in a txt file.
Then I echo out the value on the footer copyright area of my websites to give the client a quick statistic... its pretty cool how fast it grows.
Anyway.. i have a client corner grill ny . com (seo purposes I added spaces )
On that website.. its been working great for years.
Now another website and a bunch more.. for example... savianos . com
This breaks.. and the text value is blank.
This is the counter.php code
<?php
session_start();
$counter_name = "counter/hits.txt";
//Check if a text file exists. If not create one and initialize it to zero.
if (!file_exists($counter_name)) {
$f = fopen($counter_name, "w");
fwrite($f,"0");
fclose($f);
}
// Read the current value of our counter file
$f = fopen($counter_name,"r");
$counterVal = fread($f, filesize($counter_name));
fclose($f);
// Has visitor been counted in this session?
// If not, increase counter value by one
if(!isset($_SESSION['hasVisited'])){
$_SESSION['hasVisited']="yes";
$counterVal++;
$f = fopen($counter_name, "w");
fwrite($f, $counterVal);
fclose($f);
}
?>
Now, if I add a value in the txt file.. like 1040... and go to the website it starts to work... then after a week or so I check it .. its blank again.
Any ideas?
I am thinking that this may be happening because the website might get a TON of views during dinner time friday night.. and the simple script can't handle it so.. while its trying to write a added a number it just breaks and go to blank.. and never starts back up again.
The structure is this.
/counter/ folder has
counter.php and a hits.txt file
Every page of the website the very first thing is
<?php include ('counter/counter.php'); ?>
and in the footer of the website we have
<?php echo $counterVal; ?>
Your code looks perfect, but let's understand the situation. You have a file which can be accessed concurrently for many users, because page visit can be done by multiple users on same time. This does't seem right you have to lock the file manipulation for another user while someone is modifying it, right?. Please have a look
Visits counter without database with PHP
It is most likely because you have two concurrent scripts that tried to open the file at one and one of them fail. You have to use flock() when there are multiple instances of the script that could operate at the same time. Counter are some of the heaviest things if you going to use file reading and writing. I wrote this wrapper to easily implement file locking.
If you want to check out one of my counters that in operation try http://ozlu.org. That dynamic counter image was self-built. The fileReadAll will read the entire file in one shot. The file writer only has two modes, write or append. You can pass the fileWriter an array or a string and it will write it to the file. The function will not add any \n to format your text so you would have to add that. The default mode for the fileWriteAll is w if you do not set the third argument.
function fileWriteAll($file, $content, $mode = "w"){
$mode = $mode === "w" || $mode === "a"? $mode : "w";
$FILE = fopen($file, $mode);
while (!flock($FILE, LOCK_EX)) { usleep(1); }
if( is_array($content) ){
for ($i = 0; $i < count($content); $i++){
fwrite($FILE, $content[$i]);
}
} else {
fwrite($FILE, $content);
}
flock($FILE, LOCK_UN);
fclose($FILE);
}
function fileReadAll($file){
$FILE = fopen($file, 'r');
while (!flock($FILE, LOCK_SH)) { usleep(1); }
$content = fread($FILE, filesize($file));
flock($FILE, LOCK_UN);
fclose($FILE);
return $content;
}
Your modified code:
session_start();
$counterName = './views.txt';
if (!file_exists($counterName)) {
$file = fopen($counterName, 'w');
fwrite($file, '0');
fclose($file);
}
$file = fopen($counterName, 'r');
$value = fread($file, filesize($counterName));
fclose($file);
if (! isset($_SESSION['visited'])) {
$_SESSION['visited'] = 'yes';
$value++;
$file = fopen($counterName, 'w');
fwrite($file, $value);
fclose($file);
}
session_unset();
echo $value;
I'm trying to read a specific line from a text file using php.
Here's the text file:
foo
foo2
How would I get the content of the second line using php?
This returns the first line:
<?php
$myFile = "4-24-11.txt";
$fh = fopen($myFile, 'r');
$theData = fgets($fh);
fclose($fh);
echo $theData;
?>
..but I need the second.
Any help would be greatly appreciated
$myFile = "4-24-11.txt";
$lines = file($myFile);//file in to an array
echo $lines[1]; //line 2
file — Reads entire file into an array
omg I'm lacking 7 rep to make comments. This is #Raptor's & #Tomm's comment, since this question still shows up way high in google serps.
He's exactly right. For small files file($file); is perfectly fine. For large files it's total overkill b/c php arrays eat memory like crazy.
I just ran a tiny test with a *.csv with a file size of ~67mb (1,000,000 lines):
$t = -microtime(1);
$file = '../data/1000k.csv';
$lines = file($file);
echo $lines[999999]
."\n".(memory_get_peak_usage(1)/1024/1024)
."\n".($t+microtime(1));
//227.5
//0.22701287269592
//Process finished with exit code 0
And since noone mentioned it yet, I gave the SplFileObject a try, which I actually just recently discovered for myself.
$t = -microtime(1);
$file = '../data/1000k.csv';
$spl = new SplFileObject($file);
$spl->seek(999999);
echo $spl->current()
."\n".(memory_get_peak_usage(1)/1024/1024)
."\n".($t+microtime(1));
//0.5
//0.11500692367554
//Process finished with exit code 0
This was on my Win7 desktop so it's not representative for production environment, but still ... quite the difference.
If you wanted to do it that way...
$line = 0;
while (($buffer = fgets($fh)) !== FALSE) {
if ($line == 1) {
// This is the second line.
break;
}
$line++;
}
Alternatively, open it with file() and subscript the line with [1].
I would use the SplFileObject class...
$file = new SplFileObject("filename");
if (!$file->eof()) {
$file->seek($lineNumber);
$contents = $file->current(); // $contents would hold the data from line x
}
you can use the following to get all the lines in the file
$handle = #fopen('test.txt', "r");
if ($handle) {
while (!feof($handle)) {
$lines[] = fgets($handle, 4096);
}
fclose($handle);
}
print_r($lines);
and $lines[1] for your second line
$myFile = "4-21-11.txt";
$fh = fopen($myFile, 'r');
while(!feof($fh))
{
$data[] = fgets($fh);
//Do whatever you want with the data in here
//This feeds the file into an array line by line
}
fclose($fh);
This question is quite old by now, but for anyone dealing with very large files, here is a solution that does not involve reading every preceding line. This was also the only solution that worked in my case for a file with ~160 million lines.
<?php
function rand_line($fileName) {
do{
$fileSize=filesize($fileName);
$fp = fopen($fileName, 'r');
fseek($fp, rand(0, $fileSize));
$data = fread($fp, 4096); // assumes lines are < 4096 characters
fclose($fp);
$a = explode("\n",$data);
}while(count($a)<2);
return $a[1];
}
echo rand_line("file.txt"); // change file name
?>
It works by opening the file without reading anything, then moving the pointer instantly to a random position, reading up to 4096 characters from that point, then grabbing the first complete line from that data.
If you use PHP on Linux, you may try the following to read text for example between 74th and 159th lines:
$text = shell_exec("sed -n '74,159p' path/to/file.log");
This solution is good if your file is large.
You have to loop the file till end of file.
while(!feof($file))
{
echo fgets($file). "<br />";
}
fclose($file);
Use stream_get_line: stream_get_line — Gets line from stream resource up to a given delimiter
Source: http://php.net/manual/en/function.stream-get-line.php
You could try looping until the line you want, not the EOF, and resetting the variable to the line each time (not adding to it). In your case, the 2nd line is the EOF. (A for loop is probably more appropriate in my code below).
This way the entire file is not in the memory; the drawback is it takes time to go through the file up to the point you want.
<?php
$myFile = "4-24-11.txt";
$fh = fopen($myFile, 'r');
$i = 0;
while ($i < 2)
{
$theData = fgets($fh);
$i++
}
fclose($fh);
echo $theData;
?>
I like daggett answer but there is another solution you can get try if your file is not big enough.
$file = __FILE__; // Let's take the current file just as an example.
$start_line = __LINE__ -1; // The same with the line what we look for. Take the line number where $line variable is declared as the start.
$lines_to_display = 5; // The number of lines to display. Displays only the $start_line if set to 1. If $lines_to_display argument is omitted displays all lines starting from the $start_line.
echo implode('', array_slice(file($file), $start_line, lines_to_display));
I searched for a one line solution to read specific line from a file.
Here my solution:
echo file('dayInt.txt')[1]
I have a txt file that has a change-log.I'm trying to display the new changes only for the current version.
I wrote a function to read the file and check every line if it has the wanted words, if it finds those words it starts to get the content and push it to an array.
I searched to see if there is an example but everyone was talking about how to stop at a specified line, not to start from one.
Here is the code I use:
public function load($theFile, $beginPosition, $doubleCheck) {
// Open file (read-only)
$file = fopen($_SERVER['DOCUMENT_ROOT'] . '/home/' . $theFile, 'r');
// Exit the function if the the file can't be opened
if (!$file) {
return;
}
$changes = Array();
// While not at the End Of File
while (!feof($file)) {
// Read current line only
$line = fgets($file);
// This will check if the current line has the word we look for to start loading
$findBeginning = strpos($line, $beginPosition);
// Double check for the beginning
$beginningCheck = strpos($line, $doubleCheck);
// Once you find the beginning
if ($findBeginning !== false && $beginningCheck !== false) {
// Start storing the data to an array
while (!feof($file)) {
$line = fgets($file);
// Remove space and the first 2 charecters ('-' + one space)
$line = trim(substr($line, 2));
if (!empty($line)) { // Don't add empty lines
array_push($changes, $line);
}
}
}
}
// Close the file to save resourses
fclose($file);
return $changes;
}
It's working currently, but as you can see it's nested loops and that's not good and in case the txt file grows it will take more time!
I'm trying to improve the performance, so does is there any better way to do this ?
much simpler than you think
$found = false;
$changes = array();
foreach(file($fileName) as $line)
if($found)
$changes[] = $line;
else
$found = strpos($line, $whatever) !== false;
That nested loop will not degrade performance, cause it's not really a nested loop in the sense that it is a combinatorially-growing loop over multiple variables. It isn't necessary to write it like that though. Here's another way that avoids it. Try this (pseudocode here):
// skim through the beginning of the file, break upon finding the start
// of the portion I care about.
while (!feof($file)) {
if $line matches beginning marker, break;
}
// now read and process until the endmarker (or eof...)
while (!feof($file)) {
if $line matches endmarker, break;
filter/process/store line here.
}
Also, doublechecking is absolutely not necessary. Why is that there?
I have a script which, each time is called, gets the first line of a file. Each line is known to be exactly of the same length (32 alphanumeric chars) and terminates with "\r\n".
After getting the first line, the script removes it.
This is done in this way:
$contents = file_get_contents($file));
$first_line = substr($contents, 0, 32);
file_put_contents($file, substr($contents, 32 + 2)); //+2 because we remove also the \r\n
Obviously it works, but I was wondering whether there is a smarter (or more efficient) way to do this?
In my simple solution I basically read and rewrite the entire file just to take and remove the first line.
I came up with this idea yesterday:
function read_and_delete_first_line($filename) {
$file = file($filename);
$output = $file[0];
unset($file[0]);
file_put_contents($filename, $file);
return $output;
}
There is no more efficient way to do this other than rewriting the file.
No need to create a second temporary file, nor put the whole file in memory:
if ($handle = fopen("file", "c+")) { // open the file in reading and editing mode
if (flock($handle, LOCK_EX)) { // lock the file, so no one can read or edit this file
while (($line = fgets($handle, 4096)) !== FALSE) {
if (!isset($write_position)) { // move the line to previous position, except the first line
$write_position = 0;
} else {
$read_position = ftell($handle); // get actual line
fseek($handle, $write_position); // move to previous position
fputs($handle, $line); // put actual line in previous position
fseek($handle, $read_position); // return to actual position
$write_position += strlen($line); // set write position to the next loop
}
}
fflush($handle); // write any pending change to file
ftruncate($handle, $write_position); // drop the repeated last line
flock($handle, LOCK_UN); // unlock the file
}
fclose($handle);
}
This will shift the first line of a file, you dont need to load the entire file in memory like you do using the 'file' function. Maybe for small files is a bit more slow than with 'file' (maybe but i bet is not) but is able to manage largest files without problems.
$firstline = false;
if($handle = fopen($logFile,'c+')){
if(!flock($handle,LOCK_EX)){fclose($handle);}
$offset = 0;
$len = filesize($logFile);
while(($line = fgets($handle,4096)) !== false){
if(!$firstline){$firstline = $line;$offset = strlen($firstline);continue;}
$pos = ftell($handle);
fseek($handle,$pos-strlen($line)-$offset);
fputs($handle,$line);
fseek($handle,$pos);
}
fflush($handle);
ftruncate($handle,($len-$offset));
flock($handle,LOCK_UN);
fclose($handle);
}
you can iterate the file , instead of putting them all in memory
$handle = fopen("file", "r");
$first = fgets($handle,2048); #get first line.
$outfile="temp";
$o = fopen($outfile,"w");
while (!feof($handle)) {
$buffer = fgets($handle,2048);
fwrite($o,$buffer);
}
fclose($handle);
fclose($o);
rename($outfile,$file);
I wouldn't usually recommend opening up a shell for this sort of thing, but if you're doing this infrequently on really large files, there's probably something to be said for:
$lines = `wc -l myfile` - 1;
`tail -n $lines myfile > newfile`;
It's simple, and it doesn't involve reading the whole file into memory.
I wouldn't recommend this for small files, or extremely frequent use though. The overhead's too high.
You could store positional info into the file itself. For example, the first 8 bytes of the file could store an integer. This integer is the byte offset of the first real line in the file.
So, you never delete lines anymore. Instead, deleting a line means altering the start position. fseek() to it and then read lines as normal.
The file will grow big eventually. You could periodically clean up the orphaned lines to reduce the file size.
But seriously, just use a database and don't do stuff like this.
Here's one way:
$contents = file($file, FILE_IGNORE_NEW_LINES);
$first_line = array_shift($contents);
file_put_contents($file, implode("\r\n", $contents));
There's countless other ways to do that also, but all the methods would involve separating the first line somehow and saving the rest. You cannot avoid rewriting the whole file. An alternative take:
list($first_line, $contents) = explode("\r\n", file_get_contents($file), 2);
file_put_contents($file, implode("\r\n", $contents));
My problem was large files. I just needed to edit, or remove the first line. This was a solution I used. Didn't require to load the complete file in a variable. Currently echos, but you could always save the contents.
$fh = fopen($local_file, 'rb');
echo "add\tfirst\tline\n"; // add your new first line.
fgets($fh); // moves the file pointer to the next line.
echo stream_get_contents($fh); // flushes the remaining file.
fclose($fh);
I think this is best for any file size
$myfile = fopen("yourfile.txt", "r") or die("Unable to open file!");
$ch=1;
while(!feof($myfile)) {
$dataline= fgets($myfile) . "<br>";
if($ch == 2){
echo str_replace(' ', ' ', $dataline)."\n";
}
$ch = 2;
}
fclose($myfile);
The solutions here didn't work performantly for me.
My solution grabs the last line (not the first line, in my case it was not relevant to get the first or last line) from the file and removes that from that file.
This is very quickly even with very large files (>150000000 lines).
function file_pop($file)
{
if ($fp = #fopen($file, "c+")) {
if (!flock($fp, LOCK_EX)) {
fclose($fp);
}
$pos = -1;
$found = 0;
while ($found < 2) {
if (fseek($fp, $pos--, SEEK_END) < 0) { // can not seek to position
rewind($fp); // rewind to the beginnung of the file
break;
};
if (ord(fgetc($fp)) == 10) { // newline
$found++;
}
}
$lastpos = ftell($fp); // get current position of file
$lastline = fgets($fp); // get current line
ftruncate($fp, $lastpos); // truncate file to last position
flock($fp, LOCK_UN); // unlock
fclose($fp); // close the file
return trim($lastline);
}
}
You could use file() method.
Gets the first line
$content = file('myfile.txt');
echo $content[0];