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What Does the “supplied argument is not a valid Zip directory resource” Error Mean When Using zip_read()? How to Fix It?

M66 2025-07-10

When using PHP's zip_read() function to handle ZIP files, it’s quite common to encounter the error message “supplied argument is not a valid Zip directory resource.” This article provides a detailed analysis of the reasons behind this error and explains how to correctly use zip_read(), as well as how to avoid and fix this issue.

What Is the zip_read() Function?

zip_read() is a function provided by PHP’s Zip extension, used to read entries (files or directories) from a ZIP archive. The typical usage process involves:

  1. Using zip_open() to open a ZIP file, which returns a resource handle.

  2. Using zip_read() to read the next entry from that resource.

  3. Processing the entry, such as retrieving the filename, size, etc.

Example function usage:

$zip = zip_open('example.zip');
if (is_resource($zip)) {
    while ($entry = zip_read($zip)) {
        echo zip_entry_name($entry) . "\n";
    }
    zip_close($zip);
}

What Does the Error “supplied argument is not a valid Zip directory resource” Mean?

This error indicates that the argument passed to the zip_read() function is not a valid ZIP directory resource. This usually means:

  • zip_open() returned false because the ZIP file couldn’t be opened successfully.

  • The argument passed to zip_read() is not the actual resource returned by zip_open().

  • The resource has already been closed or corrupted.

In short, zip_read() requires a valid ZIP resource handle as its argument—otherwise, this error will occur.

Common Causes and Solutions for the Error

1. Incorrect File Path or File Does Not Exist

If the file path passed to zip_open() is incorrect or the file does not exist, zip_open() will return false instead of a resource.

Solution: Ensure that the file path is correct and that the file exists and is readable.

Example:

$zipFile = 'path/to/file.zip';
if (!file_exists($zipFile)) {
    die("File does not exist!");
}
$zip = zip_open($zipFile);
if (!is_resource($zip)) {
    die("Failed to open ZIP file!");
}

2. Passing a Non-Resource to zip_read()

This might happen due to a logic error in the code, where a non-resource value is passed to zip_read().

Solution: Always check whether the return value of zip_open() is a resource before calling zip_read().

if (is_resource($zip)) {
    while ($entry = zip_read($zip)) {
        // Process entry
    }
} else {
    echo "Failed to open ZIP file.";
}

3. Resource Closed or Misused Order

If zip_close() is called before zip_read(), the resource is already closed, causing the error.

Solution: Ensure the function calls are in the correct order. Do not call zip_read() after the resource has been closed.

4. PHP Extension Not Installed or Misconfigured

If the PHP Zip extension is not enabled, related functions may fail.

Solution: Check your PHP configuration to ensure the Zip extension is installed and enabled.

php -m | grep zip

If zip is not listed, enable it in php.ini or install the extension.


Complete Example: Correct Usage of zip_read()

<?php
$zipFile = 'm66.net/files/test.zip'; // Make sure to replace with actual file path
<p>// Open the ZIP file<br>
$zip = zip_open($zipFile);</p>
<p>if (!is_resource($zip)) {<br>
die("Failed to open ZIP file or the file format is incorrect.");<br>
}</p>
<p>while (($entry = zip_read($zip)) !== false) {<br>
echo "Filename: " . zip_entry_name($entry) . "\n";<br>
}</p>
<p>zip_close($zip);<br>
?><br>

Conclusion

The error “supplied argument is not a valid Zip directory resource” usually occurs because the provided argument is not a valid ZIP resource. To avoid this issue, you should:

  • Ensure the ZIP file exists and the path is correct.

  • Verify that zip_open() returns a resource, not false.

  • Use the resource correctly and avoid closing it prematurely.

  • Make sure the PHP Zip extension is installed and enabled.

By carefully troubleshooting and addressing these issues, you can effectively prevent this error. We hope this article helps you resolve any confusion when using zip_read().