前文讲到当收到请求后,swoft将swoole原生的Request及Response对象封装成适合swoft框架内部调用的Swoft\Http\Message\Request以及Swoft\Http\Message\Response.
接下来,本章将跟随方法$this->dispatcher->dispatch($psrRequest, $psrResponse)逐步分析请求到来后的框架的调度过程.
先看Swoft\Http\Server\HttpDispatcher的实现:
public function dispatch(...$params): void
{
/**
* @var Request $request
* @var Response $response
*/ [$request, $response] = $params;
$response = $this->configResponse($response);
/* @var RequestHandler $requestHandler */
$requestHandler = Swoft::getBean(RequestHandler::class);
try {
//初始化中间件
$requestHandler->initialize($this->requestMiddlewares, $this->defaultMiddleware);
// 创建新的HttpContext并设置到Context中
// 在业务逻辑中获取到的Context就是这里设置的HttpContext
// 后面附上此方法的源码调用
// Before request
$this->beforeRequest($request, $response);
// 触发BEFORE_REQUEST事件
// Trigger before handle event
Swoft::trigger(HttpServerEvent::BEFORE_REQUEST, null, $request, $response);
// 匹配路由,将路由信息绑定在新的Request对象上,返回
// Match router and handle
$request = $this->matchRouter($request);
// 调用handle处理请求,实际上就是处理中间件
// 控制器的执行也是放在中间件中执行的
// Swoft\Http\Server\Middleware\DefaultMiddleware
$response = $requestHandler->handle($request);
} catch (Throwable $e) {
// 在处理请求时若发送异常会被系统在此处捕获
// 然后调用HttpErrorDispatcher去处理对应的异常
// 我们在业务中注册的异常处理类就是在此处得到执行
/** @var HttpErrorDispatcher $errDispatcher */
$errDispatcher = Swoft::getSingleton(HttpErrorDispatcher::class);
// Handle request error
$response = $errDispatcher->run($e, $response);
}
try {
// 调用格式化处理对象来格式化得到的response
// Format response content type
$response = $this->acceptFormatter->format($response);
// 触发AFTER_REQUEST事件
// Trigger after request
Swoft::trigger(HttpServerEvent::AFTER_REQUEST, null, $response);
// 返回内容给客户端
// 触发协程COROUTINE_DEFER和COROUTINE_COMPLETE事件,后面附代码
// After request
$this->afterRequest($response);
} catch (Throwable $e) {
// 此步骤出现错误,则表示未能将内容正常返回给客户端
// 需要写入error级别的错误,控制台会有error内容打印
// 如果是协程环境(request周期内就是协程环境)
// 还会写入日志
Error::log('response error=%s(%d) at %s:%d', $e->getMessage(), $e->getCode(), $e->getFile(), $e->getLine());
}
}方法使用的是php中的动态参数传递方式,前文说过,此方法当前获取的request及response变量是Swoft\Http\Message\Request以及Swoft\Http\Message\Response的实例.
beforeRequest源码(创建HttpContext):
private function beforeRequest(Request $request, Response $response): void
{
$httpContext = HttpContext::new($request, $response);
// Add log data
if ($this->logger->isEnable()) {
$data = [
'event' => SwooleEvent::REQUEST,
'uri' => $request->getRequestTarget(),
'requestTime' => $request->getRequestTime(),
];
$httpContext->setMulti($data);
}
Context::set($httpContext);
}HttpContext::new源码(self::__instance()实际上是获取的bean对象,bean的注解是@Bean(scope=Bean::PROTOTYPE)):
public static function new(Request $request, Response $response): self
{
$instance = self::__instance();
$instance->request = $request;
$instance->response = $response;
return $instance;
}路由匹配代码:
private function matchRouter(Request $request): Request
{
$method = $request->getMethod();
$uriPath = $request->getUriPath();
/** @var Router $router */
$router = Swoft::getSingleton('httpRouter');
$result = $router->match($uriPath, $method);
// Save matched route data to request
$request = $request->withAttribute(Request::ROUTER_ATTRIBUTE, $result);
context()->setRequest($request);
return $request;
}afterRequest代码:
private function afterRequest(Response $response): void
{
// 后附代码
$response->send();
// Defer
Swoft::trigger(SwoftEvent::COROUTINE_DEFER);
// Destroy
Swoft::trigger(SwoftEvent::COROUTINE_COMPLETE);
}send代码:
public function send(): void
{
// 是否发送文件
// Is send file
if ($this->filePath) {
// 修改发送状态为true
$this->sent = true;
// 写入header
// Write Headers to co response
foreach ($this->getHeaders() as $key => $value) {
$headerLine = implode(';', $value);
if ($key !== ContentType::KEY) {
$this->coResponse->header($key, $headerLine);
}
}
// Do send file
$this->coResponse->header(ContentType::KEY, $this->fileType);
// 发送文件
$this->coResponse->sendfile($this->filePath);
return;
}
// 格式化返回内容,并发送
// Prepare and send
$this->quickSend($this->prepare());
}quickSend代码,此方法主要功能是将Swoft的Response对象通过请求处理完成获得的业务数据重新设置回swoole原生的Response对象,并调用原生Response对象的end方法返回数据给客户端:
public function quickSend(Response $response = null): void
{
$response = $response ?: $this;
// 获取swoole原生Response对象
// 后续的设置和返回都是通过原生Response对象完成
// Ensure coResponse is right
$coResponse = $response->getCoResponse();
// 设置返回的headers
// Write Headers to co response
foreach ($response->getHeaders() as $key => $value) {
$headerLine = implode(';', $value);
if ($key === ContentType::KEY) {
$headerLine .= '; charset=' . $response->getCharset();
$coResponse->header($key, $headerLine, $this->headerUcWords);
} else {
$coResponse->header($key, $headerLine, $this->headerUcWords);
}
}
// 设置返回的COOKIES
// Write cookies
foreach ($response->cookies as $n => $c) {
$coResponse->cookie($n, $c['value'], $c['expires'], $c['path'], $c['domain'], $c['secure'], $c['httpOnly']);
}
// 设置返回的状态码
// Set status code
$coResponse->status($response->getStatusCode());
// 获取返回的body
// Set body
$content = $response->getBody()->getContents();
// 调用swoole的Response对象的end方法,发送数据给客户端
$coResponse->end($content);
// 修改发送状态为true
// 此属性是在创建Response对象是初始化为false的
// Ensure sent
$this->sent = true;
}总结:
1.请求的业务逻辑是在系统注册的Swoft\Http\Server\Middleware\DefaultMiddleware中间件中得到执行的.
2.请求的业务逻辑是包裹在try/catch块中执行的,出现异常会调用系统和用户注册的异常处理handler.
该handler会返回一个Response对象,正常执行的中间件返回的Response对象将会被丢弃.
这也是swoft业务逻辑中出现异常后,跨域中间件无法正常设置header的原因.
关于此点的处理方式请参考本人之前的文章[swoft中跨域设置的问题](https://segmentfault.com/a/1190000038411563)
3.swoft返回数据的方式是将业务返回的Swoft\Http\Message\Response上携带的像headers,cookies,body等内容重新设置回swoole原生Response对象上,然后调用原生Response对象返回业务数据.
4.在执行完发送动作后,swoft会触发协程的deffer和finish事件,之后本次请求正式结束,当前请求协程的生命周期也结束了.