How could one write a new line to a file in php without erasing all the other contents of the file?
<?php
if(isset($_POST['songName'])){
$newLine = "\n";
$songName = $_POST['songName'];
$filename = fopen('song_name.txt', "wb");
fwrite($filename, $songName.$newLine);
fclose($filename);
};
?>
This is what the file looks like
Current view
This is what is should look like Ideal View
Simply:
file_put_contents($filename,$songName.$newLine,FILE_APPEND);
Takes care of opening, writing to, and closing the file. It will even create the file if needed! (see docs)
If your new lines aren't working, the issue is with your $newLine variable, not the file append operations. One of the following will work:
$newLine = PHP_EOL; << or >> $newLine = "\r\n";
You have it set for writing with the option w which erases the data.
You need to "append" the data like this:
$filename = fopen('song_name.txt', "a");
For a complete explanation of what all options do, read here.
To add a new line to a file and append it, do the following
$songName = $_POST['songName'];
$filename = fopen('song_name.txt', "a+");
fwrite($filename, $songName.PHP_EOL);
fclose($filename);
PHP_EOL will add a new line to the file
Im trying to update a text file using the code below:
$filename = "flat-file-data.txt"; // File which holds all data
$rowToUpdate = $_REQUEST['number']; // This is line need to be updated
$newString = $_REQUEST['line'].'\r\n'; // This is what you want to replace it with
$arrFp = file( $filename ); // Open the data file as an array
// Replace the current element in array which needs to be updated with new string
$arrFp[$rowToUpdate-1] = $newString;
$numLines = count( $arrFp ); // Count the elements in the array
$fp = fopen( $filename, "w" ); // Open the file for writing
for($i=0; $i < $numLines; $i++)
{
fwrite($fp, $arrFp[$i]);
}
fclose( $fp ); // Close the file
as you can see from the above codes, it will update the line 1 with the data from $newString and it should be able to create a new line after each line with this '\r\n'.
Unfortunately, it doesnt create a new line, it just goes along with the same line or in the current line like for example 'this is the firstline\r\nthis is the second line'. Is there any accurate way that I could make it in a new line like
this is the firstline
this is the secondline
and so on and so forth?
You have to put \r\n in double quotes:
$newString = $_REQUEST['line']."\r\n";
I'm writing some code that can read in from a .txt file a display it on a webpage.
I had problems in my initial code, in that it would read in any text and it would erase whatever was in the document.
My original code:
function readIn(){
$input = fopen("input.txt", "r"); //Open the file, save opened file in input
$line = fgets($input);
fclose($input);
return $line
}
It only started working once I put in a While loop to go through EVERY LINE
function readIn(){
$input = fopen("input.txt", "r"); //Open the file, save opened file in input
$fullText = ""; //Variable full text
while(!feof($input)){
$line = fgets($input);
$fullText = $fullText . $line;
}
fclose($input);
return $fullText;
}
echo readIn();
Use "file_get_contents" to read an entire file into a variable, and then output in whatever fashion you choose.
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];
I have:
<?php
$file=fopen(date("Y-m-d").".txt","r+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
?>
but it overwrites the beginning of the file. How do I make it insert?
I'm not entirely sure of your question - do you want to write data and not have it over-write the beginning of an existing file, or write new data to the start of an existing file, keeping the existing content after it?
To insert text without over-writing the beginning of the file, you'll have to open it for appending (a+ rather than r+)
$file=fopen(date("Y-m-d").".txt","a+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
If you're trying to write to the start of the file, you'll have to read in the file contents (see file_get_contents) first, then write your new string followed by file contents to the output file.
$old_content = file_get_contents($file);
fwrite($file, $new_content."\n".$old_content);
The above approach will work with small files, but you may run into memory limits trying to read a large file in using file_get_conents. In this case, consider using rewind($file), which sets the file position indicator for handle to the beginning of the file stream.
Note when using rewind(), not to open the file with the a (or a+) options, as:
If you have opened the file in append ("a" or "a+") mode, any data you write to the file will always be appended, regardless of the file position.
A working example for inserting in the middle of a file stream without overwriting, and without having to load the whole thing into a variable/memory:
function finsert($handle, $string, $bufferSize = 16384) {
$insertionPoint = ftell($handle);
// Create a temp file to stream into
$tempPath = tempnam(sys_get_temp_dir(), "file-chainer");
$lastPartHandle = fopen($tempPath, "w+");
// Read in everything from the insertion point and forward
while (!feof($handle)) {
fwrite($lastPartHandle, fread($handle, $bufferSize), $bufferSize);
}
// Rewind to the insertion point
fseek($handle, $insertionPoint);
// Rewind the temporary stream
rewind($lastPartHandle);
// Write back everything starting with the string to insert
fwrite($handle, $string);
while (!feof($lastPartHandle)) {
fwrite($handle, fread($lastPartHandle, $bufferSize), $bufferSize);
}
// Close the last part handle and delete it
fclose($lastPartHandle);
unlink($tempPath);
// Re-set pointer
fseek($handle, $insertionPoint + strlen($string));
}
$handle = fopen("file.txt", "w+");
fwrite($handle, "foobar");
rewind($handle);
finsert($handle, "baz");
// File stream is now: bazfoobar
Composer lib for it can be found here
You get the same opening the file for appending
<?php
$file=fopen(date("Y-m-d").".txt","a+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
fwrite($file,$_POST["lastname"]."\n");
}
fclose($file);
?>
If you want to put your text at the beginning of the file, you'd have to read the file contents first like:
<?php
$file=fopen(date("Y-m-d").".txt","r+") or exit("Unable to open file!");
if ($_POST["lastname"] <> "")
{
$existingText = file_get_contents($file);
fwrite($file, $existingText . $_POST["lastname"]."\n");
}
fclose($file);
?>