Catcher is a Throwable catcher and error handling library for PHP. Error handling is accomplished using a stack-based approach.
Catcher uses classes called _handlers_ to handle throwables sent its way. PHP is currently in a state of flux when it comes to errors. There are traditional PHP errors which are triggered in userland by using `trigger_error()` which can't be caught using `try`/`catch` and are generally a pain to work with. PHP has begun to remedy this problem by introducing the `\Error` class and its various child classes. However, a lot of functions and core aspects of the language itself continue to use legacy errors. This class does away with this pain point in PHP by turning all errors into throwables. Non user-level fatal errors are picked up by Catcher using its shutdown handler. This means that simply by invoking Catcher one may now catch (almost) any error PHP then handles.
## Requirements
* PHP 8.1 or newer with the following _optional_ extensions:
* [dom][a] extension (for HTMLHandler)
## Installation
```shell
composer require mensbeam/catcher
```
## Usage
For most use cases this library requires no configuration and little effort to integrate into non-complex environments:
```php
use MensBeam\Foundation\Catcher;
$catcher = new Catcher();
```
That's it. It will automatically register Catcher as an exception, error, and shutdown handler and use `PlainTextHandler` as its sole handler. Catcher can be configured to use one or multiple _handlers_. Imagine a situation where it is necessary to both output text for logging and JSON for an API endpoint. This is easily done using Catcher:
```php
use MensBeam\Foundation\Catcher,
Monolog\Logger;
use MensBeam\Foundation\Catcher\{
JSONHandler,
PlainTextHandler
};
$catcher = new Catcher(
new PlainTextHandler([
'logger' => new Logger('log'),
'silent' => true
]),
new JSONHandler()
);
```
The example above uses [Monolog][b] for its logger, but any PSR-3-compatible logger will work. The `PlainTextHandler` is configured to use a logger where then it will send any and all errors to the logger to do with as it pleases. It is also configured to be otherwise silent. `JSONHandler` is then configured using its default configuration. Handlers are placed within a stack and executed in the order by which they are fed to Catcher, so in this case `PlainTextHandler` will go first, logging the error. `JSONHandler` will follow afterwards and print the JSON.
Catcher comes built-in with the following handlers:
*`HTMLHandler`– Outputs errors in a clean HTML document; uses DOM to assemble the document.
*`JSONHandler`– Outputs errors in a JSON format mostly representative of how errors are stored internally by Catcher handlers; it is provided as an example. The decision to make it like this was made because errors often need to be represented according to a particular specification, and we cannot possibly support them all. `JSONHandler`, however, can be easily extended to suit individual project needs.
*`PlainTextHandler`– Outputs errors in plain text and provides for logging
### MensBeam\Foundation\Catcher
```php
namespace MensBeam\Foundation;
use Mensbeam\Foundation\Catcher\Handler;
class Catcher {
public bool $preventExit = false;
public bool $throwErrors = true;
public function __construct(Handler ...$handlers);
public function getHandlers(): array;
public function getLastThrowable(): ?\Throwable;
public function isRegistered(): bool;
public function popHandler(): Handler;
public function pushHandler(Handler ...$handlers): void;
public function register(): bool;
public function setHandlers(Handler ...$handlers): void;
public function shiftHandler(): Handler;
public function unregister(): bool;
public function unshiftHandler(Handler ...$handlers): void;
}
```
#### Properties
_preventExit_: When set to true Catcher won't exit at all even after fatal errors or exceptions
_throwErrors_: When set to true Catcher will convert errors to throwables
#### MensBeam\Foundation\Catcher::getHandlers
Returns an array of the handlers defined for use in the Catcher instance
Returns the last throwable that this instance of Catcher has handled
#### MensBeam\Foundation\Catcher::isRegistered
Returns whether the Catcher still is registered as a error, exception, and shutdown handler
#### MensBeam\Foundation\Catcher::popHandler
Pops the last handler off the stack and returns it
#### MensBeam\Foundation\Catcher::pushHandler
Pushes the specified handler(s) onto the stack
#### MensBeam\Foundation\Catcher::register
Registers the Catcher instance as an error, exception, and shutdown handler. By default the constructor does this automatically, but this method exists in case `unregister` has been called.
#### MensBeam\Foundation\Catcher::setHandlers
Replaces the stack of handlers with those specified as parameters.
Shifts the first handler off the stack of handlers and returns it.
#### MensBeam\Foundation\Catcher::unregister
Unregisters the Catcher instance as an error, exception and shutdown handler.
#### MensBeam\Foundation\Catcher::unshiftHandler
Unshifts the specified handler(s) onto the beginning of the stack
### MensBeam\Foundation\Handler
All handlers inherit from this abstract class. Since it is an abstract class meant for constructing handlers protected methods and properties will be documented as well.
Properties which begin with an underscore all are options. They can be set either through the constructor or via `setHandler` by name, removing the underscore at the beginning. All handlers inherit these options.
"Cleans" an output throwable -- an individual item in the output array -- by removing information that's unnecessary in the output; useful for structured data output such as JSON.
