JettyWebServer

web-WebService

This service encapsulates access to the HTTP server as well as the servlet infrastructure used to expose custom applications over HTTP. Only one WebService is supported in a station.

BWebServer

BWebServer serves as the base for any class wishing to provide web server capabilities. A web server must reside as a child of a BWebService.

public abstract class BWebServer extends BComponent implements BIService
{
  protected abstract void doStartWebServer() throws Exception;
  protected abstract void doStopWebServer() throws Exception;

  /**
   * Schedule a restart for 500ms from now. Any pending restart is cancelled and a new one is scheduled.
   */
  protected final synchronized void scheduleRestart()
  {
    scheduleRestart(BRelTime.make(500));
  }

  protected synchronized void scheduleRestart(BRelTime delay)
  {
    restartTicket.cancel();
    restartTicket = Clock.schedule(this, delay, restart, null);
  }

  @Override
  public IFuture post(Action action, BValue argument, Context cx)
  {
    if(restart==action && isRunning())
    {
      post(new Invocation(BWebServer.this, action, argument, cx));
      return null
    }
    else
    {
      return super.post(action,argument, cx);
    }
  }

 /**
   * Post some work to the Web Server Config Thread.
   *
   * @param r The work to be done.
   */
  public final Future<?> post(Runnable r)
  {
    if (executorService == null)
    {
      throw new IllegalStateException("Cannot post to Web Server Config " +
          "Thread. Thread not running: " + r.toString());
    }

    return executorService.submit(r);
  }

  ...
    executorService = ExecutorUtil.newSingleThreadBackgroundExecutor("webServerConfig", 1, TimeUnit.MINUTES);
  ...
}

BJettyWebServer

Eclipse Jetty provides a Web server and javax.servlet container, plus support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations.

基于Jetty的BWebServer实现，创建Server，加载Connectors，加载Handlers，加载Servlets等，最后启动服务start。

public final class BJettyWebServer extends BWebServer {

  public void doStartWebServer() throws Exception {
    ...
  }

  private void configureNiagaraWebApp(ServletContextHandler context) {
    ...
    context.addFilter(AddSubjectFilter.class, "/*", (EnumSet)null);
    context.addFilter(TridiumSecurityFilter.class, "/*", (EnumSet)null);
    context.addFilter(LocaleFilter.class, "/*", (EnumSet)null);
    context.addFilter(ContextFilter.class, "/*", (EnumSet)null);
    AccessController.doPrivileged(() -> {
      context.addServlet(new ServletHolder(new PreloginServlet()), "/prelogin");
      context.addServlet(new ServletHolder(new LoginServlet()), "/login");
      context.addServlet(new ServletHolder(new LoginFileServlet()), "/login/*");
      context.addServlet(new ServletHolder(new LogoutServlet()), "/logout");
      return null;
    });
    context.addServlet(new ServletHolder(new WebStartServlet()), "/webstart/*");
    context.setSessionHandler(new NiagaraSessionHandler());
    context.getSessionHandler().setSessionManager(this.sessManager);
  }
}

Jetty限制可以从浏览器或其他客户端回发到服务器的数据量，允许的默认最大值是200000 bytes和1000 keys，可以通过修改system.properties来调整它们的大小：

org.eclipse.jetty.server.Request.maxFormContentSize=250000
org.eclipse.jetty.server.Request.maxFormKeys=2000

NiagaraLoginService

public UserIdentity login(String username, Object credentials, ServletRequest request) {
  if (username == null) {
    return null;
  } else {
    BUserService userService = (BUserService)Sys.getService(BUserService.TYPE);
    NiagaraHttpSession session = (NiagaraHttpSession)credentials;
    CallbackHandler handler = (CallbackHandler)session.getAttribute("callbackHandler");
    BAuthenticationScheme scheme = (BAuthenticationScheme)session.getAttribute("authenticationScheme");
    BUser user = userService.getUser(username);

    try {
      BAuthenticationService authnService = (BAuthenticationService)Sys.getService(BAuthenticationService.TYPE);
      user = authnService.authenticate(session, user, handler, scheme);
    } catch (AuthenticationException ex) {
      if (ex.getLoginFailureCause() != null) {
        session.setAttribute("loginFailureCause", ex.getLoginFailureCause());
      }

      log.info(ex.toString() + ": most likely a username/password mismatch");
      return null;
    }

    return new NiagaraUserIdentity(user);
  }
}

LoginService

The Login service provides an abstract mechanism for an Authenticator to check credentials and to create a UserIdentity using the set IdentityService.

ServletContextHandler

This extension to the ContextHandler allows for simple construction of a context with ServletHandler and optionally session and security handlers, etc.

WebAppContext

The WebAppContext handler is an extension of ContextHandler that coordinates the construction and configuration of nested handlers: ConstraintSecurityHandler, SessionHandler and ServletHandler. The handlers are configured by pluggable configuration classes, with the default being WebXmlConfiguration and JettyWebXmlConfiguration.

ConstraintSecurityHandler

Handler to enforce SecurityConstraints. This implementation is servlet spec 3.1 compliant and pre-computes the constraint combinations for runtime efficiency.

ContextHandlerCollection

This HandlerCollection is creates a Map of contexts to it’s contained handlers based on the context path and virtual hosts of any contained ContextHandlers. The contexts do not need to be directly contained, only children of the contained handlers. Multiple contexts may have the same context path and they are called in order until one handles the request.

NCSA Log

The Common Log Format, also known as the NCSA Common log format, is a standardized text file format used by web servers when generating server log files.

Field	Description
Remote host address	The IP address of the client that made the request.
Remote log name	Not used. This value is always a hyphen.
User name	The name of the authenticated user that accessed the server. Anonymous users are indicated by a hyphen. The best practice is for the application always to provide the user name.
Date, time, and Greenwich mean time (GMT) offset	The local date and time at which the activity occurred. The offset from Greenwich mean time is also indicated.
Request and Protocol version	The HTTP protocol version that the client used.
Service status code	The HTTP status code.
Bytes sent	The number of bytes sent by the server.

如果在JettyWebServer -> NCSA Log里配置Extended Format为true，那么会增加下面两个字段：

Field	Description
Referer	This identifies the address of the webpage (i.e. the URI or IRI) that linked to the resource being requested.
User agent	Most Web browsers use a User-Agent string value as follows: Mozilla/[version] ([system and browser information]) [platform] ([platform details]) [extensions].

启用NCSA Log后默认会在站点的webLogs目录下生成yyyy_mm_dd.request.log文件，参看下面的Log示例：

10.78.148.251 - Admin [04/Jul/2018:10:48:16 +0800] "POST https://10.78.148.251/vrf/SearchStationCascade HTTP/1.1" 200 24 "https://10.78.148.251/vrf/web/machine-mgr.html" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36"
10.78.148.251 - Admin [04/Jul/2018:10:48:16 +0800] "POST https://10.78.148.251/vrf/SearchUserInfo HTTP/1.1" 200 60 "https://10.78.148.251/vrf/web/machine-mgr.html" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36"