How to use PHP to modify the content of text files online-PHP Problem-php.cn

How to use PHP to modify the content of text files online

PHPz

Release： 2023-04-24 14:41:42

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With the continuous development of Web technology, more and more websites use PHP language as the backend development language. PHP language can easily handle text files, including reading, writing and modifying text files. In web applications, it is sometimes necessary to modify the contents of text files online, such as modifying configuration files or modifying log files. This article will introduce how to use PHP language to modify the content of text files online.

1. Read the content of the text file

First, we need to read the content of the text file in order to modify it. The following is a simple PHP code for reading the contents of a text file:

$filename = 'yourfile.txt';  
$file = fopen($filename, 'r');  
$content = fread($file, filesize($filename));  
fclose($file);

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This code first opens a text file, then uses the fread function to read the contents of the file, and finally closes the file.

2. Modify the content of the text file

With the file content, we can modify it. The following is an example of replacing a specified string in a text file:

$filename = 'yourfile.txt';  
$file = fopen($filename, 'r');  
$content = fread($file, filesize($filename));  
fclose($file);  

$newcontent = str_replace('oldstring', 'newstring', $content);  
$file = fopen($filename, 'w');  
fwrite($file, $newcontent);  
fclose($file);

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This code first reads the file content using the previously mentioned method, and then uses PHP's str_replace function to replace the old string with the new one. String, and finally use the fwrite function to write the modified content to the text file.

3. Use HTML forms to modify online

Next, we will use HTML forms to modify the content of text files online. We first need to create a form in the HTML page that contains the text file path and the text content to be modified. The following is a simple HTML code:

<html>  
<head>  
<title>Modify Your File</title>  
</head>  
<body>  
<form action="modify_file.php" method="post">  
    Filepath: <input type="text" name="filepath"><br>  
    Content: <textarea name="content" rows="10" cols="30"></textarea><br>  
    <input type="submit" value="Submit">  
</form>  
</body>  
</html>

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This form contains two input boxes for entering the file path and modified content, as well as a submit button.

4. Implement the PHP script

Next, we need to implement the PHP script to write the data in the form to the specified text file. The following is a simple PHP script:

<?php  
$filepath = $_POST[&#39;filepath&#39;];  
$content = $_POST[&#39;content&#39;];  
$file = fopen($filename, &#39;w&#39;);  
fwrite($file, $content);  
fclose($file);  
?>  
<html>  
<head>  
<title>Modify Result</title>  
</head>  
<body>  
<h1>Modify Result</h1>  
<p>Your file has been modified!</p>  
</body>  
</html>

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This code first obtains the file path and new content submitted by the form, and then uses the fwrite function to write the new content to the specified text file.

5. Implement file upload

Finally, if we need to implement the function of uploading files and modifying file contents in a web application, we need to use PHP's file upload function. The following is an example of a PHP script that implements file upload and file content modification:

<?php  
$filename = $_FILES[&#39;file&#39;][&#39;name&#39;];  
$tmpname = $_FILES[&#39;file&#39;][&#39;tmp_name&#39;];  
$content = $_POST[&#39;content&#39;];  
move_uploaded_file($tmpname, $filename);  
$file = fopen($filename, &#39;w&#39;);  
fwrite($file, $content);  
fclose($file);  
?>  
<html>  
<head>  
<title>Upload Result</title>  
</head>  
<body>  
<h1>Upload Result</h1>  
<p>Your file has been uploaded and modified!</p>  
</body>  
</html>

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This PHP script uses the move_uploaded_file function to save the uploaded file to the server, and uses the fwrite function to write new content to the file.

Summary

In this article, we learned how to use PHP language to read, write and modify text files. We also introduced how to use HTML forms to modify the content of text files online, and used PHP scripts to implement file upload and text file modification functions. These technologies are very useful for web application development, and developers can use these technologies to implement more complex functions according to actual needs.

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