A common use for gzdecode is processing data without rebuilding the operation manually. Decompresses a gzip-format string, returning false for invalid compressed data.
What Is gzdecode in PHP?
Decompresses a gzip-format string, returning false for invalid compressed data.
Syntax:
gzdecode(?string $data, ?int $max_length = ...) : string|false
Parameters and Return Value
$data— A required string input for this operation. Verify the allowed values in the examples and context below.$max_length— An optional int input for this operation. Verify the allowed values in the examples and context below.
Declared return type: string|false. Distinguish false, an empty result, and exceptions where the API permits them.
Example 1: Basic Usage
This example demonstrates the main operation with a small, controlled input.
<?php
echo gzdecode(gzencode("Hello"));
The example focuses on the value produced or the state changed by this API. Review the return value and validate input before using this pattern in production.
Example 2: Another Input
This example changes the input or surrounding setup to illustrate another behavior.
<?php
var_dump(@gzdecode("not-gzip"));
The example focuses on the value produced or the state changed by this API. Review the return value and validate input before using this pattern in production.
Practical Example
This application-style example shows a self-contained usage pattern and checks its result.
<?php
$compressedReport = gzencode("First line\nSecond line");
$restoredReport = gzdecode($compressedReport);
if ($restoredReport === false) { throw new RuntimeException("Invalid gzip content"); }
echo $restoredReport;
The example focuses on the value produced or the state changed by this API. Review the return value and validate input before using this pattern in production.
Important Behavior and Edge Cases
- Never decompress untrusted data without limiting its maximum expanded size.
- Use the intended input type and handle empty or malformed values explicitly.
- Where this API requires an extension, version, or file, document that dependency before using it in a real application.
Comparison With Related Functions
| Function or Method | When to Use It |
|---|---|
gzdecode | Decompresses a gzip-format string, returning false for invalid compressed data. |
gzencode | Compresses a string into the gzip file format, including gzip headers and trailer. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using this API without checking the required input or extension | Never decompress untrusted data without limiting its maximum expanded size. |
| Treating malformed input as a successful result | Handle invalid values and documented failure results explicitly. |
| Using this operation for the wrong data representation | Choose the matching data format and compare its result to the required output. |
Key Takeaways
- Decompresses a gzip-format string, returning false for invalid compressed data.
- Never decompress untrusted data without limiting its maximum expanded size.
- Test both the expected case and at least one failure or empty-input case before deployment.
Decompresses a gzip-format string, returning false for invalid compressed data. Use it when the operation fits your input, output and validation requirements.