php脚本编写的两个文本文件之间的区别

Question

I have build this script that should save only unique lines, in this case url's. One url per line into a .txt file.

On my form I have only one value which is "url" from input name="url".

Script works, get's the value, checks if unique or not, writes into constant file , then I applied sorting from A to Z and writes sorted output into a new temp file. Here are my 3 things that I would like to ask for, any help appreciated:

1. I'm not sure if this is correct approach to write sorting into new file or is it possible to re-write the original file

2. Temp file is written with empty lines in between lines with values. Can't figure it out from where empty lines are coming from.

3. Last bit is that temp file is always one line less than constant file.

   <?php
   
   // config
   $url = $_GET['url'];
   $n = "
   ";
   $data = $url . $n;
   $file = "datatest.txt"; // constant file
   $file2 = "datatest2.txt"; // temp file
   
   // check for duplicates & add new value if unique
   $unique_data = file_get_contents($file);
   if(strpos($unique_data, $data) === false){
   $fh = fopen($file, 'a') or die("Can't open the file");
   
   // chmod (optional)
   chmod($file,0666);
   chmod($file2,0666);
   
   // sort
   $lines = file($file);
   sort($lines);
   
   // write to original
   $record = file_put_contents($file, $data, FILE_APPEND | LOCK_EX);
   
   // write to temp
   $record2 = file_put_contents("$file2", implode("
   ", $lines));
   
   }
   
   // testing echo the results
   if (empty($record)){
   echo "data already exists </br></br>";
   }else{
   echo $record . " bytes written to file </br></br>";
   echo $record2 . " bytes written to file2 </br></br>";
   }
   
   // display all (change file if needed)
   $fh = fopen($file, 'r');
   $pageText = fread($fh, 25000);
   
   echo nl2br($pageText);
   
   ?>
   

Any input appreciated.

edit:

With @Barmar help I managed to eliminate points 2 & 3.

<?php

// config
$url = $_GET['url'];
$n = "
";
$data = $url . $n;
$file = "temp.txt"; // temp file in local folder
$file2 = "constant.txt"; // constant counterpart file

// check for duplicates & add new value if unique
$unique_data = file_get_contents($file);
if(strpos($unique_data, $data) === false){

$fh = fopen($file, 'a') or die("Can't open the file");

// chmod (optional)
chmod($file,0666);
chmod($file2,0666);

// write to original
$record = file_put_contents($file, $data, FILE_APPEND | LOCK_EX);

// sort
$lines = file($file, FILE_IGNORE_NEW_LINES);
sort($lines);

// write to temp
$record2 = file_put_contents($file2, implode("
", $lines), LOCK_EX);

}

// testing echo the results
if (empty($record)){
echo "data already exists </br></br>";
}else{
echo $record . " bytes written to file </br></br>";
echo $record2 . " bytes written to file2 </br></br>";
}

// display all (change file if needed)
$fh = fopen($file2, 'r');
$pageText = fread($fh, 25000);

echo nl2br($pageText);

?>

Still can't figure it out how to use only one file instead. @Barmar, I've tried to use your "in_array" but it's giving me an error.

Answer 1

1. Yes, it's possible to rewrite the original file. Just use a single file that's always sorted:

   $lines = file($file, FILE_IGNORE_NEW_LINES);
   if (in_array($url, $lines)) {
       $lines[] = $url;
       sort($lines);
       file_put_contents($file, implode("
   ", $lines) . "
   ");
   }
   

2. The empty lines are from implode(" ", $lines), because the strings in $lines already end with newline. So you're adding a second newline between them. In my code above I used FILE_IGNORE_NEW_LINES to prevent it from including them in the strings.

3. I suspect this has something to do with the newlines, but I'm not quite sure.