In PHP, stream_wrapper_restore() is useful when your application needs a specific operation rather than manually reproducing it. Restores a built-in stream wrapper previously unregistered or replaced.
Stream functions work with PHP stream resources, wrappers, contexts or custom filters. Not every wrapper supports every operation.
What Is stream_wrapper_restore() in PHP?
Restores a built-in stream wrapper previously unregistered or replaced.
Signature:
stream_wrapper_restore(string $protocol): boolParameters:
$protocol— Wrapper protocol or socket transport identifier.
Return value: bool.
Example 1: Basic Usage
This first example shows the method or function in a minimal context. For environment-dependent operations, adapt the required path, stream or connection before running it.
<?php
class ExampleStreamWrapper {
public $context;
private string $contents = "Sample text";
private int $position = 0;
public function stream_open(string $path, string $mode, int $options, ?string &$openedPath): bool { return true; }
public function stream_read(int $count): string {
$chunk = substr($this->contents, $this->position, $count);
$this->position += strlen($chunk);
return $chunk;
}
public function stream_eof(): bool { return $this->position >= strlen($this->contents); }
public function stream_stat(): array { return []; }
public function stream_tell(): int { return $this->position; }
}
if (!stream_wrapper_unregister("file")) { throw new RuntimeException("Cannot unregister file wrapper"); }
try {
// Perform a short, tightly controlled wrapper replacement operation.
} finally {
stream_wrapper_restore("file");
}
The important operation is stream_wrapper_restore(). Restores a built-in stream wrapper previously unregistered or replaced.
Example 2: Another Input or Scenario
The next example changes the input or surrounding context to show how the operation behaves in a second situation.
<?php
class ExampleStreamWrapper {
public $context;
private string $contents = "Sample text";
private int $position = 0;
public function stream_open(string $path, string $mode, int $options, ?string &$openedPath): bool { return true; }
public function stream_read(int $count): string {
$chunk = substr($this->contents, $this->position, $count);
$this->position += strlen($chunk);
return $chunk;
}
public function stream_eof(): bool { return $this->position >= strlen($this->contents); }
public function stream_stat(): array { return []; }
public function stream_tell(): int { return $this->position; }
}
// Always restore the built-in file wrapper using a finally block.
stream_wrapper_unregister("file");
try { echo "Temporarily unregistered"; }
finally { stream_wrapper_restore("file"); }
Compare the inputs and the handling of the return value with the first example. Avoid assuming that filesystem paths, resource states or binary bytes are interchangeable.
Practical Example: Applying the Operation
This example illustrates how the operation fits into a small application workflow. Paths, streams and secrets must be created or provided securely by the calling application.
<?php
class ExampleStreamWrapper {
public $context;
private string $contents = "Sample text";
private int $position = 0;
public function stream_open(string $path, string $mode, int $options, ?string &$openedPath): bool { return true; }
public function stream_read(int $count): string {
$chunk = substr($this->contents, $this->position, $count);
$this->position += strlen($chunk);
return $chunk;
}
public function stream_eof(): bool { return $this->position >= strlen($this->contents); }
public function stream_stat(): array { return []; }
public function stream_tell(): int { return $this->position; }
}
$wasRemoved = stream_wrapper_unregister("file");
if ($wasRemoved) {
try { echo "Perform controlled replacement"; }
finally { stream_wrapper_restore("file"); }
}
Practical note: Restores a built-in stream wrapper previously unregistered or replaced.
Important Behavior and Edge Cases
- Restores a built-in stream wrapper previously unregistered or replaced.
- Check failure values and exceptions; do not assume every environment supports the same stream wrapper, extension or filesystem capability.
- When handling paths, streams or external input, validate inputs before using results and release resources after use.
Comparison With Related Functions
| Function or Method | Behavior |
|---|---|
stream_wrapper_restore() | restores a built-in scheme after replacement. |
stream_wrapper_unregister() | removes a wrapper registration. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Assuming stream_wrapper_restore() can be used without its required setup | Provide the correct file, stream, state, key or object before calling it; Restores a built-in stream wrapper previously unregistered or replaced. |
| Assuming a resource result is always successful | Check false returns, actual byte counts, and resource state before using the result. |
| Confusing local and remote stream behavior | Read the wrapper capabilities and handle unsupported operations explicitly. |
Key Takeaways
stream_wrapper_restore()restores a built-in stream wrapper previously unregistered or replaced.- Use appropriate input types and verify results before continuing.
- Prefer specialized, safer APIs when the operation concerns untrusted input, encryption or network traffic.
In summary: Restores a built-in stream wrapper previously unregistered or replaced. Build in error handling and use this function where its specific behavior matches the application requirements.