Question

CORS规范规定，如果HTTP请求被认为是“简单”，则不需要CORS和/或预检。

我正在尝试执行似乎具有以下条件的HTTP请求：

我没有设置自定义HTTP标头。
我正在使用POST方法。
我正在使用application/x-www-form-urlencoded。

代码示例：

$.ajax({
  type: 'POST',
  url: 'http://example.org/',
  data: {foo: 'bar'}
});

但是，在运行此请求时，请求仍以OPTIONS预检（失败）。有什么明显的东西我不见了吗？

对简单请求的一些引用：

Answer 1

CORS限制会影响从一个域到另一个域的所有请求。示例：localhost - ＆gt; example.com。我最终只是转到我的example.com服务器端代码，并确保我从myotherexample.com启用我正在拨打电话的请求。在本地开发时使用CORS标头执行此操作

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.ClassCastException: org.phan.message.Response cannot be cast to java.lang.String] with root cause

java.lang.ClassCastException: org.phan.message.Response cannot be cast to java.lang.String
    at org.springframework.http.converter.StringHttpMessageConverter.getContentLength(StringHttpMessageConverter.java:41) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.http.converter.AbstractHttpMessageConverter.addDefaultHeaders(AbstractHttpMessageConverter.java:260) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:205) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:247) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:174) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:81) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:113) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55) ~[spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:110) ~[spring-boot-actuator-1.5.3.RELEASE.jar:1.5.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:106) ~[spring-boot-actuator-1.5.3.RELEASE.jar:1.5.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.8.RELEASE.jar:4.3.8.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.14.jar:8.5.14]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]

准备生产时的另一个例子

Access-Control-Allow-Origin: *

Answer 2

重新阅读文档时，我意识到自己的错误。

我正在做的确实是简单的请求。该请求实际上是在没有OPTIONS请求的情况下发送到服务器并且成功了！

但是，当它回来时，我不允许读取响应。因此，简单和非简单CORS请求之间的真正区别是：

对于简单请求，不需要预检，但服务器仍需要使用CORS标头进行响应。

所以我的选择如下：

我忽略了错误。毕竟请求成功了，我只是无法阅读回复。
无论如何我实现了CORS服务器端。就我而言，我无法做到，因为我无法控制目标服务器。
我使用html表单提交数据，在其上调用.submit()并定位隐藏的iFrame。
我通过我控制的服务器代理请求。

未来：

我想，但我不确定，新的Fetch API还允许一种模式，您可以在这种模式下跨域进行HTTP请求，选择退出CORS并简单地被拒绝访问HTTP响应。如果这是正确的，那么这将是理想的方式（对我来说）。但我不确定100％确定这是否确实如此。

使用jQuery发送“简单”的POST请求，但无论如何都要获得CORS

2 个答案: