具有 Angular URL 重写功能的嵌入式 Jetty

Question

我正在使用 Jetty 部署 WebSocket 和 Angular 应用程序。在开发中，一切正常，但在生产中，我遇到了一个问题，当刷新前端或输入 url 时，我从服务器收到 404 消息，指出给定的资源不存在。现在我正在尝试创建重写规则以将请求重定向到我的index.html。初始化我的服务器如下所示：server = new Server();ServerConnector connector = new ServerConnector(server);connector.setPort(config.getServer().getPort());server.addConnector(connector);RewriteHandler rewriteHandler = new RewriteHandler();rewriteHandler.setRewriteRequestURI(true);rewriteHandler.setRewritePathInfo(false);rewriteHandler.setOriginalPathAttribute("requestedPath");/* RedirectRegexRule rule1 = new RedirectRegexRule();rule1.setRegex("/(.+)");rule1.setLocation("/index.html");rewriteHandler.addRule(rule1);*/URL webRootLocation = this.getClass().getResource("/frontend/index.html");if (webRootLocation == null)    throw new IllegalStateException("Unable to determine webroot URL location");URI webRootUri = URI.create(webRootLocation.toURI().toASCIIString().replaceFirst("/index.html$","/"));logger.debug("Web Root URI: {}",webRootUri);ServletContextHandler contextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);contextHandler.setContextPath("/");contextHandler.setBaseResource(Resource.newResource(webRootUri));contextHandler.setWelcomeFiles(new String[]{ "index.html" });rewriteHandler.setHandler(contextHandler);ServerContainer container = WebSocketServerContainerInitializer.initialize(contextHandler);List<Class<? extends Encoder>> encoders = new ArrayList<>();encoders.add(MessageEncoder.class);List<Class<? extends Decoder>> decoders = new ArrayList<>();decoders.add(MessageDecoder.class);我的 Angular 前端编译在应用程序的资源文件夹中，该文件夹由服务器提供服务 - 例如：localhost:8080/。如果我的应用程序路由到localhost:8080/some/path一切都很好，但刷新页面时我会收到some/path未知的 404。使用重写规则（注释掉）我ERR_TOO_MANY_REDIRECTIONS也得到了延迟加载的资源/模块未找到。关于如何对 Angular 应用程序使用 Jetty 重写的任何建议，因为我不知道如何继续这里，或者 Jetty 不支持Angular 部署建议的 apache 重写之类的东西

Answer 1

对于任何正在寻找解决方案的人，我让它与 Jettys 一起工作RewriteHandler。我的服务器设置现在如下所示：

server = new Server(config.getServer().getPort());

RewriteHandler rewriteHandler = new RewriteHandler();

rewriteHandler.setRewriteRequestURI(true);

rewriteHandler.setRewritePathInfo(false);

rewriteHandler.setOriginalPathAttribute("requestedPath");

RewriteRegexRule rule1 = new RewriteRegexRule();

rule1.setRegex("^((?!"+wsPath+"|\\.js|\\.css|\\.jpe?g|\\.png).)*$");

rule1.setReplacement("/index.html");

rewriteHandler.addRule(rule1);

URL webRootLocation = this.getClass().getResource("/frontend/index.html");

if (webRootLocation == null)

    throw new IllegalStateException("Unable to determine Web-Root URL location");

URI webRootUri = URI.create(webRootLocation.toURI().toASCIIString().replaceFirst("/index.html$","/"));

logger.debug("Web-Root URI: {}",webRootUri);

ServletContextHandler contextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);

contextHandler.setContextPath("/");

contextHandler.setBaseResource(Resource.newResource(webRootUri));

contextHandler.setWelcomeFiles(new String[]{ "index.html" });

rewriteHandler.setHandler(contextHandler);

// Initialize WebSocket

ServerContainer container = WebSocketServerContainerInitializer.initialize(contextHandler);

List<Class<? extends Encoder>> encoders = new ArrayList<>();

encoders.add(MessageEncoder.class);

List<Class<? extends Decoder>> decoders = new ArrayList<>();

decoders.add(MessageDecoder.class);

ServerEndpointConfig endpointConfig = ServerEndpointConfig.Builder

        .create(AppEndpoint.class, "/" + wsPath)

        .encoders(encoders)

        .decoders(decoders)

        .configurator(new AppEndpointConfig(config, factory))

        .build();

container.addEndpoint(endpointConfig);

server.setHandler(rewriteHandler);

contextHandler.addServlet(DefaultServlet.class, "/");

server.start();

server.join();

这并不理想，因为只有特定的文件结尾与正则表达式匹配，但它确实可以与 Jetty 内构建和部署的 Angular 应用程序配合使用。如果使用 RESTful API，则必须定义一些正则表达式来匹配 API 的路径，如wsPath我的示例中的（一个简单的字符串）。

Answer 2

在 Servlet 世界中实现此目的的唯一方法是让错误页面处理 404 状态代码并自行发出重定向。

这只能在特定的 Web 应用程序中完成，而不能从通用重写处理例程中完成。

为什么？

那么，“如果请求的资源不存在，则使用index.html”是关键。

会发生什么。

1. 输入了 web 应用程序，但没有匹配的 url-pattern，因此使用默认的 url-pattern (of )。"/"

2. 默认 url 模式映射到所谓的“默认 Servlet”

3. 默认 Servlet 负责在 Web 应用程序的基础资源中查找匹配的资源，并将该内容作为静态资源请求返回。

4. 如果静态资源不存在，并且请求是针对目录（例如：/js/然后使用欢迎文件列表来查找欢迎文件。（此列表在 中配置WEB-INF/web.xml）

<welcome-file-list>

    <welcome-file>index.html</welcome-file>

    <welcome-file>index.htm</welcome-file>

    <welcome-file>index.jsp</welcome-file>

</welcome-file-list>

如果静态资源仍然不存在，则将其作为 404 响应进行处理。

同时，servlet 规范的错误页面处理例程启动。这将导致在您的WEB-INF/web.xml.

<servlet>

  <servletname>404Handler</servlet-name>

  <servlet-class>com.acme.My404Servlet</servlet-class>

</servlet>

<servlet-mapping>

  <servlet-name>404Handler</servlet-name>

  <url-pattern>/404status</url-pattern>

</servlet-mapping>

<!-- ... then later ... -->

<error-page>

    <error-code>404</error-code>

    <location>/404status</location>

</error-page>

该路径可以是 servlet、静态资源、jsp 等。几乎可以是任何可以通过路径引用的内容。

如果它是 servlet（或 jsp），您可以通过请求属性询问原始请求，以了解处理此错误的原因。

嵌入式码头中的一个例子是......

package jetty.errors;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import javax.servlet.DispatcherType;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Server;

import org.eclipse.jetty.server.handler.DefaultHandler;

import org.eclipse.jetty.server.handler.HandlerList;

import org.eclipse.jetty.servlet.DefaultServlet;

import org.eclipse.jetty.servlet.ErrorPageErrorHandler;

import org.eclipse.jetty.servlet.ServletContextHandler;

import org.eclipse.jetty.servlet.ServletHolder;

import org.eclipse.jetty.util.resource.PathResource;

public class EmbeddedWelcomeErrorDemo

{

    public static void main(String[] args) throws Exception

    {

        Server server = new Server(8080);

        String baseDir = System.getProperty("user.home");

        if (args.length > 0)

            baseDir = args[0];

        Path basePath = Paths.get(baseDir);

        if (!Files.exists(basePath) || !Files.isDirectory(basePath))

        {

            throw new IOException("Not a valid directory: " + basePath);

        }

        ServletContextHandler context = new ServletContextHandler();

        context.setContextPath("/");

        context.setBaseResource(new PathResource(basePath));

        context.setWelcomeFiles(new String[]{

            "index.html"

        });

        // Add error page mapping for context

        context.addServlet(ErrorHandling.class, "/errorpage");

        ErrorPageErrorHandler errorMapper = new ErrorPageErrorHandler();

        errorMapper.addErrorPage(404, "/errorpage");

        context.setErrorHandler(errorMapper);

        // to handle static resources against base resource (always last)

        // always named "default" (per spec)

        ServletHolder defaultHolder = new ServletHolder("default", DefaultServlet.class);

        // assigned to default url-pattern of "/" (per spec)

        context.addServlet(defaultHolder, "/");

        HandlerList handlers = new HandlerList();

        handlers.addHandler(context);

        handlers.addHandler(new DefaultHandler()); // for non-context errors

        server.setHandler(handlers);

        server.start();

        server.join();

    }

    public static class ErrorHandling extends HttpServlet

    {

        @Override

        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException

        {

            if (req.getDispatcherType() != DispatcherType.ERROR)

            {

                // we didn't get here from a error dispatch.

                // somebody attempted to use this servlet directly.

                resp.setStatus(404);

                return;

            }

            String requestedResource = (String)req.getAttribute(RequestDispatcher.ERROR_REQUEST_URI);

            log("[ErrorHandling] Requested resource was " + requestedResource);

            int statusCode = (int)req.getAttribute(RequestDispatcher.ERROR_STATUS_CODE);

            switch (statusCode)

            {

                case 404:

                    // let handle it by a redirect

                    resp.sendRedirect("/");

                    break;

                default:

                    // pass the other errors through

                    resp.setStatus(statusCode);

                    break;

            }

        }

    }

}

发生的情况的一些例子。

$ mkdir $HOME/tmp-base

$ mdkir css

$ echo "this is the index.html" > index.html

$ echo "this is my other html" > myother.html

$ echo "this is my fancy css" > css/main.css

然后使用命令行运行服务器示例到该目录

$ java ... jetty.errors.EmbeddedWelcomeErrorDemo $HOME/tmp-base

2019-09-24 14:17:55.540:INFO::main: Logging initialized @190ms to org.eclipse.jetty.util.log.StdErrLog

2019-09-24 14:17:55.621:INFO:oejs.Server:main: jetty-9.4.20.v20190813; built: 2019-08-13T21:28:18.144Z; git: 84700530e645e812b336747464d6fbbf370c9a20; jvm 1.8.0_202-b08

2019-09-24 14:17:55.661:INFO:oejsh.ContextHandler:main: Started o.e.j.s.ServletContextHandler@7921b0a2{/,file:///home/joakim/tmp-base/,AVAILABLE}

2019-09-24 14:17:55.674:INFO:oejs.AbstractConnector:main: Started ServerConnector@7cef4e59{HTTP/1.1,[http/1.1]}{0.0.0.0:8080}

2019-09-24 14:17:55.674:INFO:oejs.Server:main: Started @325ms

然后提出一些要求...

$ curl -L -vv http://localhost:8080/

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET / HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:26:28 GMT

< Last-Modified: Tue, 24 Sep 2019 19:12:21 GMT

< Content-Type: text/html

< Accept-Ranges: bytes

< Content-Length: 23

< Server: Jetty(9.4.20.v20190813)

< 

this is the index.html

* Connection #0 to host localhost left intact

这是受欢迎的文件处理

$ curl -L -vv http://localhost:8080/myother.html

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET /myother.html HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:21:10 GMT

< Last-Modified: Tue, 24 Sep 2019 19:13:46 GMT

< Content-Type: text/html

< Accept-Ranges: bytes

< Content-Length: 22

< Server: Jetty(9.4.20.v20190813)

< 

This is my other html

* Connection #0 to host localhost left intact

这是正常的静态文件服务

$ curl -L -vv http://localhost:8080/css/main.css

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET /css/main.css HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:22:22 GMT

< Last-Modified: Tue, 24 Sep 2019 19:22:16 GMT

< Content-Type: text/css

< Accept-Ranges: bytes

< Content-Length: 21

< Server: Jetty(9.4.20.v20190813)

< 

this is my fancy css

* Connection #0 to host localhost left intact

这是正常的静态文件服务

如果我向不存在的资源或目录发出一些请求......

$ curl -L -vv http://localhost:8080/css/bogus.css

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET /css/bogus.css HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 302 Found

< Date: Tue, 24 Sep 2019 19:22:46 GMT

< Location: http://localhost:8080/

< Content-Length: 0

< Server: Jetty(9.4.20.v20190813)

< 

* Connection #0 to host localhost left intact

* Issue another request to this URL: 'http://localhost:8080/'

* Found bundle for host localhost: 0x5647e1581a50 [can pipeline]

* Re-using existing connection! (#0) with host localhost

* Connected to localhost (::1) port 8080 (#0)

> GET / HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:22:46 GMT

< Last-Modified: Tue, 24 Sep 2019 19:12:21 GMT

< Content-Type: text/html

< Accept-Ranges: bytes

< Content-Length: 23

< Server: Jetty(9.4.20.v20190813)

< 

this is the index.html

* Connection #0 to host localhost left intact

这是由ErrorHandlingservlet处理的

$ curl -L -vv http://localhost:8080/this/directory/does/not/exist

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET /this/directory/does/not/exist HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 302 Found

< Date: Tue, 24 Sep 2019 19:23:02 GMT

< Location: http://localhost:8080/

< Content-Length: 0

< Server: Jetty(9.4.20.v20190813)

< 

* Connection #0 to host localhost left intact

* Issue another request to this URL: 'http://localhost:8080/'

* Found bundle for host localhost: 0x561eefa8b020 [can pipeline]

* Re-using existing connection! (#0) with host localhost

* Connected to localhost (::1) port 8080 (#0)

> GET / HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:23:02 GMT

< Last-Modified: Tue, 24 Sep 2019 19:12:21 GMT

< Content-Type: text/html

< Accept-Ranges: bytes

< Content-Length: 23

< Server: Jetty(9.4.20.v20190813)

< 

this is the index.html

* Connection #0 to host localhost left intact

这是由ErrorHandlingservlet处理的

[joakim@hyperion tmp]$ curl -L -vv http://localhost:8080/non-existant.jpeg

*   Trying ::1...

* TCP_NODELAY set

* Connected to localhost (::1) port 8080 (#0)

> GET /non-existant.jpeg HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 302 Found

< Date: Tue, 24 Sep 2019 19:21:18 GMT

< Location: http://localhost:8080/

< Content-Length: 0

< Server: Jetty(9.4.20.v20190813)

< 

* Connection #0 to host localhost left intact

* Issue another request to this URL: 'http://localhost:8080/'

* Found bundle for host localhost: 0x563f476b6a50 [can pipeline]

* Re-using existing connection! (#0) with host localhost

* Connected to localhost (::1) port 8080 (#0)

> GET / HTTP/1.1

> Host: localhost:8080

> User-Agent: curl/7.58.0

> Accept: */*

> 

< HTTP/1.1 200 OK

< Date: Tue, 24 Sep 2019 19:21:18 GMT

< Last-Modified: Tue, 24 Sep 2019 19:12:21 GMT

< Content-Type: text/html

< Accept-Ranges: bytes

< Content-Length: 23

< Server: Jetty(9.4.20.v20190813)

< 

this is the index.html

* Connection #0 to host localhost left intact