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| public boolean processRequest(@Nullable CorsConfiguration config, HttpServletRequest request,
HttpServletResponse response) throws IOException {
//非cors请求的直接返回true
if (!CorsUtils.isCorsRequest(request)) {
return true;
}
//设过Access-Control-Allow-Origin的直接返回true,如果此filter前面还有其他filter处理过了,就会有Access-Control-Allow-Origin头了
ServletServerHttpResponse serverResponse = new ServletServerHttpResponse(response);
if (responseHasCors(serverResponse)) {
logger.trace("Skip: response already contains \"Access-Control-Allow-Origin\"");
return true;
}
//是同源的直接返回true,同源的请求满足cors,允许放行
ServletServerHttpRequest serverRequest = new ServletServerHttpRequest(request);
if (WebUtils.isSameOrigin(serverRequest)) {
logger.trace("Skip: request is from same origin");
return true;
}
//得到是否是预检请求
boolean preFlightRequest = CorsUtils.isPreFlightRequest(request);
//如果config为空,则没有配置文件,然后判断如果是预检请求则拒绝,如果不是预检请求则放行。
if (config == null) {
if (preFlightRequest) {
rejectRequest(serverResponse);
return false;
}
else {
return true;
}
}
//真实检测逻辑,获取各种请求头和配置文件进行对比
return handleInternal(serverRequest, serverResponse, config, preFlightRequest);
}
protected boolean handleInternal(ServerHttpRequest request, ServerHttpResponse response,
CorsConfiguration config, boolean preFlightRequest) throws IOException {
//获取origin头
String requestOrigin = request.getHeaders().getOrigin();
//与配置的AllowedOrigins进行比较,得到匹配的
String allowOrigin = checkOrigin(config, requestOrigin);
HttpHeaders responseHeaders = response.getHeaders();
responseHeaders.addAll(HttpHeaders.VARY, Arrays.asList(HttpHeaders.ORIGIN,
HttpHeaders.ACCESS_CONTROL_REQUEST_METHOD, HttpHeaders.ACCESS_CONTROL_REQUEST_HEADERS));
//如果origin都不匹配,返回false
if (allowOrigin == null) {
logger.debug("Reject: '" + requestOrigin + "' origin is not allowed");
rejectRequest(response);
return false;
}
//获取请求method,如果是预检请求则获取Access-Control-Request-Method里的method
HttpMethod requestMethod = getMethodToUse(request, preFlightRequest);
//检查请求头是否是AllowedMethods里配置的
List<HttpMethod> allowMethods = checkMethods(config, requestMethod);
if (allowMethods == null) {
logger.debug("Reject: HTTP '" + requestMethod + "' is not allowed");
rejectRequest(response);
return false;
}
//获取请求header,如果是预检请求则获取Access-Control-Request-Headers里配置的
List<String> requestHeaders = getHeadersToUse(request, preFlightRequest);
//请求头与AllowedHeader里的进行匹配
List<String> allowHeaders = checkHeaders(config, requestHeaders);
if (preFlightRequest && allowHeaders == null) {
logger.debug("Reject: headers '" + requestHeaders + "' are not allowed");
rejectRequest(response);
return false;
}
//上面的method,origin,head 三个检测都通过的话,则说明请求是自己人请求的,放行设置响应头
responseHeaders.setAccessControlAllowOrigin(allowOrigin);
if (preFlightRequest) {
responseHeaders.setAccessControlAllowMethods(allowMethods);
}
if (preFlightRequest && !allowHeaders.isEmpty()) {
responseHeaders.setAccessControlAllowHeaders(allowHeaders);
}
if (!CollectionUtils.isEmpty(config.getExposedHeaders())) {
responseHeaders.setAccessControlExposeHeaders(config.getExposedHeaders());
}
if (Boolean.TRUE.equals(config.getAllowCredentials())) {
responseHeaders.setAccessControlAllowCredentials(true);
}
if (preFlightRequest && config.getMaxAge() != null) {
responseHeaders.setAccessControlMaxAge(config.getMaxAge());
}
response.flush();
return true;
}
|