访问 docker 容器内的 Tomcat 时出现 CORS 错误

Question

我正在构建一个 Angular 4 应用程序，它使用 REST API 与 Camunda 进程交互。正在尝试登录，遇到 CORS 错误。

Docker 文件：

FROM camunda/camunda-bpm-platform:tomcat-latest

ADD sample.war /camunda/webapps/sample.war

COPY ./web.xml /camunda/webapps/engine-rest/WEB-INF

运行喜欢：

docker build -t camunda-eval .
docker run -d --name camunda -p 8080:8080 <image>

控制台错误：

Failed to load http://localhost:8080/camunda/api/admin/auth/user/default/login/tasklist: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access.

我的 web.xml 看起来像这样：

<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

  <filter>
    <filter-name>EmptyBodyFilter</filter-name>
    <filter-class>org.camunda.bpm.engine.rest.filter.EmptyBodyFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>EmptyBodyFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <filter>
    <filter-name>CacheControlFilter</filter-name>
    <filter-class>org.camunda.bpm.engine.rest.filter.CacheControlFilter</filter-class>    
  </filter>
  <filter-mapping>
    <filter-name>CacheControlFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <!-- Http Basic Authentication Filter -->
  <!-- <filter>
    <filter-name>camunda-auth</filter-name>
    <filter-class>
      org.camunda.bpm.engine.rest.security.auth.ProcessEngineAuthenticationFilter
    </filter-class>
    <init-param>
      <param-name>authentication-provider</param-name>
      <param-value>org.camunda.bpm.engine.rest.security.auth.impl.HttpBasicAuthenticationProvider</param-value>
    </init-param>
    <init-param>
        <param-name>rest-url-pattern-prefix</param-name>
        <param-value></param-value>
      </init-param> 
  </filter>

  <filter-mapping>
    <filter-name>camunda-auth</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping> -->

  <filter>
      <filter-name>Resteasy</filter-name>
      <filter-class>
          org.jboss.resteasy.plugins.server.servlet.FilterDispatcher
      </filter-class>
      <init-param>
          <param-name>javax.ws.rs.Application</param-name>
          <param-value>org.camunda.bpm.engine.rest.impl.application.DefaultApplication</param-value>
      </init-param>
  </filter>

  <filter-mapping>
      <filter-name>Resteasy</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>
 <filter>
  <filter-name>CorsFilter</filter-name>
  <filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
  <init-param>
    <param-name>cors.allowed.origins</param-name>
    <param-value>*</param-value>
  </init-param>
  <init-param>
    <param-name>cors.allowed.methods</param-name>
    <param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
  </init-param>
  <init-param>
    <param-name>cors.allowed.headers</param-name>
    <param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
  </init-param>
  <init-param>
    <param-name>cors.exposed.headers</param-name>
    <param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
  </init-param>
  <init-param>
    <param-name>cors.support.credentials</param-name>
    <param-value>true</param-value>
  </init-param>
  <init-param>
    <param-name>cors.preflight.maxage</param-name>
    <param-value>10</param-value>
  </init-param>
</filter>
  <filter-mapping>
    <filter-name>CorsFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

关于如何解决这个问题有什么想法吗？

Answer 1

您收到此错误是因为 "localhost:4200" 和 "localhost:8080" 在 CORS 方面不是同一台机器。

一般来说，您有 3 种方法可以避免这种情况：

只需告诉您的浏览器忽略 CORS（例如 chromium-browser --disable-web-security --user-data-dir）- 如果您只是想玩玩，这是最快的，但当然没有生产解决方案
在 8080 上设置 CORS headers 以允许从 4200 访问...此处不适用（很简单，因为您无法控制 camunda-app）
使用内部 re-routes 通过 reverse-proxying 请求的 "edge"（或 "gateway"）服务器。意思是：你的浏览器只与网关（比如说端口 80）对话，这会将请求路由到你的任务列表（4200）或 camunda（8080）。这是解决这个问题的标准方法，如果你寻找 nginx 或 zuul，你会找到很好的文档。不过，它将需要一个额外的服务组件。

访问 docker 容器内的 Tomcat 时出现 CORS 错误

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