---
title: 渲染页面
---
## 渲染页面
```php
$response = $kernel->handle(
    $request = Request::capture()
)->send();
```
这里只需要分析这一行代码，它将请求对象`Request::capture()`捕获，并将其传递给内核对象`$kernel->handle()`，然后将响应对象返回。
在`Laravel`中，`Request::capture()`方法会捕获当前的请求对象

### send()方法
`$response`是类`Symfony\Component\HttpFoundation\Response`实例，在该类中可以找到`send()`方法。
```php
public function send()
{
    // 发送http响应头
    $this->sendHeaders();
    // 发送http响应内容
    $this->sendContent();

    if (\function_exists('fastcgi_finish_request')) {
        fastcgi_finish_request();
    } elseif (\function_exists('litespeed_finish_request')) {
        litespeed_finish_request();
    } elseif (!\in_array(\PHP_SAPI, ['cli', 'phpdbg'], true)) {
        static::closeOutputBuffers(0, true);
        flush();
    }

    return $this;
}
```

#### sendHeaders()方法
当类`Symfony\Component\HttpFoundation\Response`实例化时，构造函数详细
```php
public function __construct(?string $content = '', int $status = 200, array $headers = [])
{
    $this->headers = new ResponseHeaderBag($headers);
    $this->setContent($content);
    $this->setStatusCode($status);
    $this->setProtocolVersion('1.0');
}

public function sendHeaders()
{
    // headers have already been sent by the developer
    if (headers_sent()) {
        return $this;
    }

    // 这里设置返回的响应头
    foreach ($this->headers->allPreserveCaseWithoutCookies() as $name => $values) {
        $replace = 0 === strcasecmp($name, 'Content-Type');
        foreach ($values as $value) {
            header($name.': '.$value, $replace, $this->statusCode);
        }
    }

    // cookies
    foreach ($this->headers->getCookies() as $cookie) {
        header('Set-Cookie: '.$cookie, false, $this->statusCode);
    }

    // status
    header(sprintf('HTTP/%s %s %s', $this->version, $this->statusCode, $this->statusText), true, $this->statusCode);

    return $this;
}
```
#### sendContent()方法
```php
public function sendContent()
{
    echo $this->content;

    return $this;
}
```