# Document Usage
The `Document` class in the provided code is a container used to store and manage data, typically used by a controller or response in a web application. It implements `ArrayAccess` and `LinkProviderInterface`, allowing it to be used like an array and to manage links.
This example demonstrates creating a `Document`, adding content and metadata, logging events, rendering the document, accessing data, adding links, and importing files.
### Purpose
1. **Data Storage**: It stores data in the `$body` property, which can be accessed and modified using array-like syntax.
2. **Serialization**: It can be serialized to JSON, including metadata, links, data, and logs.
3. **Logging**: It can log events and store them in the `$logs` property.
4. **Rendering**: It can render its content to a string using a specified printer.
5. **Link Management**: It can manage links, providing methods to add and retrieve links.
6. **Importing**: It supports importing files and capturing their output.
### Example Usage
```php
'value']);
// Add more content to the document
$document->addContent(['newKey' => 'newValue']);
// Set metadata
$document->addMeta(['metaKey' => 'metaValue']);
// Log an event
$document->logEvent(new \stdClass());
// Render the document to a string
echo $document->render();
// Access data using array-like syntax
echo $document['key']; // Outputs: value
// Add a link
$link = new \MMO\core\server\Link(['rel' => 'example', 'href' => '/example.jpg']);
$document->addLink($link);
// Prints the links in the document
print_r($document->getLinks());
// Import a file and capture its output
$output = $document->import('path/to/file.php', ['var1' => 'value1']);
echo $output;
```
### Templates read `$_VARS`, not bare variables
`import()` does not `extract()` anything. Inside the imported file, the variables are in the `$_VARS` array
(merged with the document's own `getVars()`), and `$this` is the document:
```php
```
The filename is looked up literally in the document's import paths: pass `'welcome.phtml'`, not `'welcome'`.
### Options
A document takes options when it is built: its own (`raw`, `charset`, `printer`, `vars`) and those of the printer
that renders its values. Pass them typed, with <@\MMO\core\documents\DocumentOptions> and
<@\MMO\core\printers\PrintOptions>:
```php
use MMO\core\documents\{DocumentOptions, HtmlDocument};
use MMO\core\printers\PrintOptions;
//every value the page's templates print with $this->renderValue() is HTML-escaped
$page = new HtmlDocument(null, new DocumentOptions(print: new PrintOptions(escape: true)));
//or one value
echo $page->renderValue('user input', new PrintOptions(escape: true));
```
An array still works (`['raw' => true]`), but a misspelled key is silently ignored: `['escpae' => true]` prints the
value unescaped, where `new PrintOptions(escpae: true)` fails with "Unknown named parameter $escpae".