LegacyServiceHandler.java

/*
** Module   : LegacyServiceHandler.java
** Abstract : Handler for legacy service calls.
**
** Copyright (c) 2019-2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
** 001 CA  20190701 Extracted from RestHandler.
** 002 CA  20190710 Moved the HTTP body read APIs from RequestArguments.
** 003 CA  20191003 If an external store is specified, we need the entry password, too.
** 004 CA  20200514 Added support for SOAP web services.
**                  Mark this context as 'headless'.
** 005 CA  20200910 Fixed path splitting in case of multiple '//' chars. 
**     CA  20210304 The cookies must follow RFC2965.
**     CA  20211012 Fixed generated WSDL and reworked SOAP support to rely on namespace, when resolving an
**                  operation.
**     CA  20211112 The worker must be aware if the appserver is in MSA mode (for error processing and other
**                  differences between classic and multisession).
**     CA  20211214 Extracted the worker pool to AppServerConnectionPool, to be used by the legacy java client,
**                  too.
**     CA  20211216 Any request while the worker pool has not yet initialized will return a 404/NOT-FOUND
**                  status code.
**     CA  20220104 Added custom web response headers to be specified in the directory via the 
**                  'web-response-headers' node: 'web-response-headers/default' is added first, and 
**                  'web-response-headers/[type]' is merged next
**     CA  20220208 Mark pools which are used for the web services managed by FWD.
**     CA  20220405 Added authentication and authorization for web requests.  When this is enabled, the target
**                  API call will be executed under the authenticated FWD context, and not the agent's context.
**     CA  20220509 Fixed 'getInputStream', in some cases the stream is not read properly (if is chunked).
** 006 GBB 20240610 LegacyAppServerWork replaced by Consumer<LegacyServiceWorker>. 
** 007 SBI 20231206 Added getMask.
** 008 GBB 20250403 Added ServiceType enum.
** 009 RB2 20250530 Added a request parameter to all handle methods (except the authentication one). Also 
**                  added a request parameter to the prepareResponse method and modified it to handle multiple
**                  URLs in the Access-Control-Allow-Origin field. The syntax is <URL>, <URL>, <URL> etc.
** 010 LS  20250606 Changed 'handle' to bypass OPTIONS requests. Added 'handleCorsPreflight'.
*/

/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
**   0. Attribution Requirement.
** 
**     You must preserve all legal notices or author attributions in the covered
**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
** 
**   1. No License To Use Trademarks.
** 
**     This license does not grant any license or rights to use the trademarks
**     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
**     of Golden Code Development Corporation. You are not authorized to use the
**     name Golden Code, FWD, or the names of any author or contributor, for
**     publicity purposes without written authorization.
** 
**   2. No Misrepresentation of Affiliation.
** 
**     You may not represent yourself as Golden Code Development Corporation or FWD.
** 
**     You may not represent yourself for publicity purposes as associated with
**     Golden Code Development Corporation, FWD, or any author or contributor to
**     the covered work, without written authorization.
** 
**   3. No Misrepresentation of Source or Origin.
** 
**     You may not represent the covered work as solely your work.  All modified
**     versions of the covered work must be marked in a reasonable way to make it
**     clear that the modified work is not originating from Golden Code Development
**     Corporation or FWD.  All modified versions must contain the notices of
**     attribution required in this license.
*/

package com.goldencode.p2j.main;

import java.io.*;
import java.util.*;
import java.util.BitSet;
import java.util.stream.*;
import java.util.zip.*;

import javax.servlet.*;
import javax.servlet.http.*;

import org.eclipse.jetty.http.*;
import org.eclipse.jetty.server.*;
import org.eclipse.jetty.server.handler.*;

import com.goldencode.p2j.security.*;
import com.goldencode.p2j.security.SecurityManager;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.Utils.DirScope;

/**
 * Common APIs for processing legacy services (REST, WebHandler, etc).
 */
public abstract class LegacyServiceHandler
extends AbstractHandler
{
   /** The type of the legacy service. */
   public enum ServiceType
   {
      REST("rest"),
      SOAP("soap"),
      WEB("WebHandler");
      
      /** The name of the type. */
      private String typeName;

      /**
       * Enum constructor.
       *
       * @param   typeName
       *          The name of the legacy service type.
       */
      ServiceType(String typeName)
      {
         this.typeName = typeName;
      }

      /**
       * Returns the string representation.
       *
       * @return   See above.
       */
      @Override
      public String toString()
      {
         return typeName;
      }
   }
   
   /** The base path for the service handler. */
   protected String basePath;

   /** The service type. */
   private final ServiceType type;
   
   /** The appserver connection pool of worker threads. */
   private final AppServerConnectionPool pool;
   
   /** 
    * Additional response headers to add.  Configured in the <code>web-response-headers</code> directory node.
    */
   private Map<String, String> responseHeaders = null;

   /** The authentication handler, if enabled in the directory, for this web service type. */
   private WebAuthHandler authHandler;
   
   /**
    * Initialize this handler with the given base path.
    * 
    * @param    type
    *           The service type, also name of node to get the configuration from the directory.
    * @param    basePath
    *           The implicit basepath.
    */
   public LegacyServiceHandler(ServiceType type, String basePath)
   {
      this.type = type;
      this.pool = new AppServerConnectionPool(type);
      this.basePath = basePath;
      
      readResponseHeaders();
   }

   /**
    * Code to process web requests.
    * 
    * @param    instance
    *           The legacy service instance.
    * @param    work
    *           The work to perform the request.
    * @param    target
    *           The target path.
    * @param    response
    *           The HTTP response.
    * @param    request
    *           The HTTP request.
    */
   public static void handle(LegacyServiceHandler          instance,
                             LegacyAppServerWork           work,
                             String                        target,
                             HttpServletResponse           response,
                             HttpServletRequest            request) 
   throws IOException
   {
      handle(instance, null, work, target, response, request);
   }
   
   /**
    * Code to process web requests.
    * 
    * @param    instance
    *           The legacy service instance.
    * @param    connectionID
    *           When not-null, force to use the worker with the specified connection ID.
    * @param    work
    *           The work to perform the request.
    * @param    target
    *           The target path.
    * @param    response
    *           The HTTP response.
    * @param    request
    *           The HTTP request.
    */
   public static void handle(LegacyServiceHandler          instance,
                             String                        connectionID,
                             LegacyAppServerWork           work,
                             String                        target,
                             HttpServletResponse           response,
                             HttpServletRequest            request) 
   throws IOException
   {
      instance.prepareResponse(response, request);
      
      if (!instance.pool.isInitialized())
      {
         response.setStatus(HttpStatus.NOT_FOUND_404);
         return;
      }

      try
      {
         boolean ran = instance.pool.dispatch(connectionID, work, target);
         if (!ran)
         {
            response.setStatus(HttpStatus.GATEWAY_TIMEOUT_504);
         }
      }
      catch (Throwable t)
      {
         if (t instanceof IOException)
         {
            throw (IOException) t;
         }
         else if (t.getCause() instanceof IOException)
         {
            throw (IOException) t.getCause();
         }
         else
         {
            throw new IOException(t);
         }
      }
   }

   /**
    * Get the individual path entries from this path.
    * 
    * @param    path
    *           The '/' separated path.
    * 
    * @return   The paths.
    */
   public static String[] getPaths(String path)
   {
      if (path.startsWith("/"))
      {
         path = path.substring(1);
      }
      if (path.endsWith("/"))
      {
         path = path.substring(0, path.length() - 1);
      }
      
      String[] paths = path.split("/");
      paths = Arrays.asList(paths)
                    .stream()
                    .filter(s -> !s.isEmpty())
                    .collect(Collectors.toList())
                    .toArray(new String[0]);
      return paths;
   }

   /**
    * Get the mask for the given path entries.
    * 
    * @param    paths
    *           The given path entries.
    * 
    * @return   The bit set that has the i-th 1 bit if the i-th path is not a wildcard parameter.
    */
   public static BitSet getMask(String[] paths)
   {
      int nbits = paths.length;
      BitSet mask = new BitSet(nbits);
      for(int i = 0; i < nbits; i++)
      {
         if (!paths[i].startsWith("{"))
         {
            mask.set(i);
         }
      }
      
      return mask;
   }
  
   /**
    * Red the body from a HTTP request.
    * 
    * @param    request
    *           The HTTP request payload.
    * 
    * @return   The body, as a byte array.
    */
   public static byte[] readBody(HttpServletRequest request)
   throws IOException
   {
      InputStream input = getInputStream(request);

      ByteArrayOutputStream baos = new ByteArrayOutputStream();
      byte[] b = new byte[32];
      while (input.available() > 0)
      {
         int len = input.read(b);
         if (len == -1)
         {
            break;
         }
         
         baos.write(b, 0, len);
      }
      return baos.toByteArray();
   }

   /**
    * Get the {@link #basePath}.
    * 
    * @return   See above.
    */
   public String getBasePath()
   {
      return basePath;
   }
   
   /**
    * Get the {@link AppServerConnectionPool#timeout}.
    * 
    * @return   See above.
    */
   public int getTimeout()
   {
      return pool.getTimeout();
   }
   
   /**
    * Terminate the service worker threads.
    */
   public void terminateWorkers()
   {
      pool.terminateWorkers();
   }
   
   /**
    * Initialize the worker(s) and start them.
    */
   public void initializeHandler()
   {
      this.basePath = resolveBasePath(this.basePath);

      // read the authentication details
      SecurityManager mgr = SecurityManager.getInstance();
      boolean authEnabled = Utils.getDirectoryNodeBoolean(null, type + "/authentication/enabled", false, false);
      WebServiceResource wsr = (WebServiceResource) mgr.getPluginInstance("webservice");
      
      authHandler = null;
      if (authEnabled)
      {
         if (wsr == null)
         {
            throw new IllegalStateException("The authentication for " + type + 
                                            " is enabled, but no WebServiceResource plugin is registered.");
         }
         
         String authType = Utils.getDirectoryNodeString(null, type + "/authentication/type", "basic", false);
         int timeout = Utils.getDirectoryNodeInt(null, type + "/authentication/timeout", 0, false);
         String loginPath = Utils.getDirectoryNodeString(null, type + "/authentication/login_path", 
                                                         null, false);
         String logoutPath = null;
         if (loginPath != null)
         {
            logoutPath = Utils.getDirectoryNodeString(null, type + "/authentication/logout_path", 
                                                      "/fwdlogout", false);
         }
         else if (timeout != 0)
         {
            throw new IllegalStateException("For " + type + ", if the login path is not set, then timeout " +
                                            "must be set to zero, and authentication will be performed for " +
                                            "each API call.");
         }
         
         // filters can be registered only with webapp's (WebAppContext).  for legacy services, we are using
         // ContextHandler; for this reason, an auth handler is used.
         authHandler = new WebAuthHandler(type.toString(), authType, loginPath, logoutPath, timeout);
      }
      
      pool.initialize();
   }
   
   /**
    * Process web requests:
    * <ul>
    *    <li>
    *       If it is an {@link HttpMethod#OPTIONS OPTIONS} request, handle it accordingly.
    *    </li>
    *    <li>
    *       Otherwise, if {@link #authHandler authorization} is enabled, this will authenicate the
    *       request.  The {@link #authorize authorization} will be responsible of creating the FWD context and
    *       returning the token for this web request.
    *    </li>
    * 
    * @param    target
    *           The target path.
    * @param    baseRequest
    *           The base request.
    * @param    request
    *           The HTTP request.
    * @param    response
    *           The HTTP response.
    */
   @Override
   public void handle(String              target, 
                      Request             baseRequest,
                      HttpServletRequest  request,
                      HttpServletResponse response) 
   throws IOException
   {
      // respond to CORS preflight OPTIONS requests without authentication or further processing
      if (request.getMethod().equals(HttpMethod.OPTIONS.name()))
      {
         handleCorsPreflight(baseRequest, request, response);
      }
      else if (authHandler != null)
      {
         // this part handles only the authentication; the authorization is done later in the process
         authHandler.handle(target, baseRequest, request, response);
      }
   }
   
   /**
    * Contains any post {@link #handle} code to be executed after the service request has been invoked.
    * 
    * @param    token
    *           When set, the web service token used to authenticate and authorize this request.
    */
   protected void postHandle(String token)
   {
      if (authHandler != null)
      {
         // if the login API path is not used, perform the logout
         authHandler.postHandle(token);
      }
   }
   
   /**
    * Check if the authentication and authorization is enabled for this web service type.
    * 
    * @return   <code>true</code> if {@link #authHandler} exists.
    */
   protected boolean useAuthorization()
   {
      return authHandler != null;
   }
   
   /**
    * If {@link #useAuthorization() authorization is enabled}, perform the 
    * {@link WebAuthHandler#authorize authorization} to check if the request configuration is allowed to
    * access this API.
    * 
    * @param    target
    *           The target path.
    * @param    request
    *           The HTTP request.
    * @param    response
    *           The HTTP response.
    *           
    * @return   If authorization is enabled, it will return the token associated with this service request.
    */
   protected String authorize(String target, HttpServletRequest request, HttpServletResponse response)
   {
      if (authHandler != null)
      {
         // this will return the token used for this API request
         return authHandler.authorize(target, request, response);
      }
      
      return null;
   }

   /**
    * Resolve the configured basepath for this handler.
    * 
    * @param    basePath
    *           The default base path.
    *           
    * @return   The configured base path from the directory.
    */
   protected String resolveBasePath(String basePath)
   {
      basePath = Utils.getDirectoryNodeString(null, type + "/basepath", basePath, false);
      if (basePath.isEmpty() || basePath.equals("/"))
      {
         throw new RuntimeException("Invalid " + type + " base path: [" + basePath + "]");
      }
      
      if (!basePath.startsWith("/"))
      {
         basePath = "/" + basePath;
      }
      if (!basePath.endsWith("/"))
      {
         basePath = basePath + "/";
      }
      
      return basePath;
   }
   
   /**
    * Get the service handler's {@link #type}.
    *  
    * @return   The service type.
    */
   protected String getType()
   {
      return type.toString();
   }

   /**
    * Handles a CORS preflight (HTTP OPTIONS) request by validating the request origin
    * against the configured CORS policy and setting the appropriate HTTP response status.
    * <p>
    * If the request origin matches the value set in the {@code Access-Control-Allow-Origin}
    * response header, a {@code 204 No Content} status is returned.
    * Otherwise, a {@code 403 Forbidden} status is returned to deny the request.
    * </p>
    *
    * @param    baseRequest
    *           The base request.
    * @param    request
    *           The HTTP request.
    * @param    response
    *           The HTTP response.
    */
   private void handleCorsPreflight(Request baseRequest,
                                    HttpServletRequest request,
                                    HttpServletResponse response)
   {
      prepareResponse(response, request);

      String requestOrigin = request.getHeader("Origin");
      String responseOrigin = response.getHeader("Access-Control-Allow-Origin");
      if (requestOrigin != null && requestOrigin.equals(responseOrigin))
      {
         response.setStatus(HttpStatus.NO_CONTENT_204);
      }
      else
      {
         response.setStatus(HttpStatus.FORBIDDEN_403);
      }
      baseRequest.setHandled(true);
   }

   /**
    * Read any custom response headers configured in the directory.  The building is done by first reading
    * from the <code>web-response-headers/default</code>, and after that overwriting/merging the ones from
    * <code>web-response-headers/{@link #type}</code>.
    */
   private void readResponseHeaders()
   {
      List<String> defaults = Utils.getDirectoryNodeStrings(null, "web-response-headers/default", 
                                                            DirScope.BOTH, null);
      List<String> custom = Utils.getDirectoryNodeStrings(null, "web-response-headers/" + type, 
                                                          DirScope.BOTH, null);
      
      if (defaults.isEmpty() && custom.isEmpty())
      {
         return;
      }
      
      responseHeaders = new HashMap<>();
      for (String h : defaults)
      {
         String[] pair = parseHeader(h);
         responseHeaders.put(pair[0], pair[1]);
      }
      for (String h: custom)
      {
         String[] pair = parseHeader(h);
         responseHeaders.put(pair[0], pair[1]);
      }
   }
   
   /**
    * Parse a header string, in the <code>name: value</code> format, and return its header name and value.
    * 
    * @param    h
    *           The string to parse.
    *           
    * @return   See above.
    */
   private String[] parseHeader(String h)
   {
      String split = ": ";
      int idx = h.indexOf(split);
      if (idx == -1)
      {
         throw new IllegalArgumentException("Web response header " + h + " can't be parsed!");
      }
      
      String name = h.substring(0, idx);
      String value = h.substring(idx + split.length());
      
      return new String[] { name, value };
   }

   /**
    * Prepare the HTTP response with any custom settings or headers.
    * 
    * @param    response
    *           The HTTP response.
    * @param    request
    *           The HTTP request.
    */
   private void prepareResponse(HttpServletResponse response,
                                HttpServletRequest  request)
   {
      ((Response) response).getHttpChannel()
                           .getHttpConfiguration()
                           .setResponseCookieCompliance(CookieCompliance.RFC2965);
      
      if (responseHeaders != null)
      {
         String origin = request.getHeader("Origin");
         for (Map.Entry<String, String> header : responseHeaders.entrySet())
         {
            // The Access-Control-Allow-Origin header is documented to be case-insensitive
            if ("Access-Control-Allow-Origin".equalsIgnoreCase(header.getKey()))
            {
               if (header.getValue().equals("null"))
               {
                  continue;
               }
               else if (header.getValue().equals(origin))
               {
                  response.addHeader(header.getKey(), header.getValue());
                  continue;
               }
               else
               {
                  if (header.getValue().equals("*"))
                  {
                     response.addHeader(header.getKey(), origin);
                  }
                  else if (origin != null)
                  {
                     String[] allowedOrigins = header.getValue().split(",\\s+");
                     for (String allowed : allowedOrigins) 
                     {
                        if (origin.equals(allowed.trim())) 
                        {
                           response.addHeader(header.getKey(), origin);
                           break;
                        }
                     }
                  }
               }
            }
            else
            {
               response.addHeader(header.getKey(), header.getValue());
            }
         }
      }
   }
   
   /**
    * Get the input stream to read the request's body.
    * <p>
    * Depending on the 'Content-Encoding', a different stream will read it.
    * 
    * @param    request
    *           The HTTP request.
    *           
    * @return   The request body's input stream.
    */
   private static InputStream getInputStream(HttpServletRequest request)
   throws IOException
   {
      String encoding = request.getHeader("Content-Encoding");
      if (encoding == null || encoding.isEmpty())
      {
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         
         ServletInputStream input = request.getInputStream();
         byte[] b = new byte[32];
         while (!input.isFinished())
         {
            int len = input.read(b);
            if (len == -1)
            {
               break;
            }
            
            baos.write(b, 0, len);
         }
         
         return new ByteArrayInputStream(baos.toByteArray());
      }
      else if (encoding.equals("gzip,deflate") || encoding.equals("gzip"))
      {
         return new GZIPInputStream(request.getInputStream());
      }
      
      throw new IOException("Unknown encoding: " + encoding);
   }
}