如何将HTML中的表单数据保存到txt文件中。

Question

My program uses PHP to open a list of configuration settings from a txt file called "configurationSettings.txt" and puts the data from it onto a form.

What I'm trying to figure out is how to enable my program to update the data on the original txt file if the user changes anything through the form.

Here is an example of the txt file data:

Channel 7
4.0000
6.0000

Here is my code that reads the data and fills my form:

<?php
$configFile = fopen("configurationSettings.txt", "r");
$title1 = fgets($configFile);
$gain1 = fgets($configFile);
$offset1 = fgets($configFile);
fclose($configFile);
?> 

<form action="program.php" method="post">
Channel 8 Title:<br>
<input type="text" name="channel0Title" value="<?php echo $title1 ?>">
<br>
Gain:<br>
<input type="text" name="channel0Gain" value="<?php echo $gain1 ?>">
<br>
Offset:<br>
<input type="text" name="Channel0Offset" value= "<?php echo $offset1 ?>">
<br>
<input type="submit" id ="submitButton" value="Submit">
</div>
</form>

And heres a picture of what it looks like:

What do I do to update the original txt file by pressing the submit button?

Answer 1

Tested, works 100%. You don't have to create .txt. Gets created automatically if not present.

index.html

<form action="program.php" method="post">
    Channel 8 Title:<br><input type="text" name="channel0Title" value="Channel 7"><br>
    Gain:<br><input type="text" name="channel0Gain" value="4.000"><br>
    Offset:<br><input type="text" name="channel0Offset" value= "6.000"><br>
    <input type="submit" id ="submitButton" value="Submit">
</form>

program.php

<?php
    $title = $_POST["channel0Title"]; //You have to get the form data
    $gain = $_POST["channel0Gain"];
    $offset = $_POST["channel0Offset"];
    $file = fopen('configurationSettings.txt', 'w+'); //Open your .txt file
    ftruncate($file, 0); //Clear the file to 0bit
    $content = $title. PHP_EOL .$gain. PHP_EOL .$offset;
    fwrite($file , $content); //Now lets write it in there
    fclose($file ); //Finally close our .txt
    die(header("Location: ".$_SERVER["HTTP_REFERER"]));
?>

Answer 2

if(isset($_POST['field1']) && isset($_POST['field2'])) {
$data = $_POST['field1'] . '-' . $_POST['field2'] . "\n";
$ret = file_put_contents('/tmp/mydata.txt', $data, FILE_APPEND | LOCK_EX);
if($ret === false) {
    die("There was an error writing this file");
}
else {
    echo "$ret bytes written to file";
}}