ServiceArgumentsParser.java

/*
** Module   : ServiceArgumentsParser.java
** Abstract : Base class to interpret input arguments for a web service (REST or SOAP).
**
** Copyright (c) 2020-2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
** 001 CA  20200514 First version.
**     CA  20200528 Added APIs for REST extent arguments (not implemented yet). 
** 002 CA  20211112 Refactored to allow transfer of the DATASET or TABLE via XML, for SOAP.
**     CA  20220329 Added support for REST services written directly in Java.
*/

/*
** 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.
** 
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** 
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**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
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*/

package com.goldencode.p2j.rest;

import java.io.*;

import javax.servlet.http.*;

import com.goldencode.p2j.main.*;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.util.*;

/**
 * Base class for parsing the input arguments for a web service call (REST or SOAP).
 */
public abstract class ServiceArgumentsParser
{
   /**
    * Parse an extent argument.
    * 
    * @param    body
    *           The HTTP body.
    * @param    request
    *           The request payload.
    * @param    idx
    *           The argument's index.
    * @param    source
    *           The arguments's source.
    * @param    type
    *           The arguments's type.
    * @param    extent
    *           The arguments's length.
    * 
    * @return   An array with the argument's values.
    */
   protected abstract Object[] parseExtentArgument(String             body, 
                                                   HttpServletRequest request,
                                                   int                idx,
                                                   String             source,
                                                   String             type,
                                                   int                extent)
   throws RequestArgumentError;
   
   /**
    * Assign the given argument to the specified value.
    * 
    * @param    idx
    *           The argument's index.
    * @param    bdt
    *           The argument's {@link BaseDataType} instance (may be <code>null</code>).
    * @param    sval
    *           The string representation of this argument.
    */
   protected abstract void assignArgument(int idx, BaseDataType bdt, String sval)
   throws RequestArgumentError;
   
   /**
    * Parse the argument, by interpreting the request.
    * 
    * @param    body
    *           The request body.
    * @param    source
    *           The parameter's encoded source.
    * @param    request
    *           The request payload.
    *           
    * @return   The resolved argument.
    */
   protected abstract String parseArgumentInt(String body, String source, HttpServletRequest request)
   throws IOException;
   
   /**
    * Load the specified table.
    * 
    * @param    content
    *           The table definition.
    *           
    * @return   A {@link TableWrapper} instance to be passed as argument to the remote call.
    */
   protected abstract TableWrapper loadTable(String content)
   throws IOException,
          RequestArgumentError;

   
   /**
    * Load the specified dataset.
    * 
    * @param    content
    *           The dataset definition.
    *           
    * @return   A {@link DatasetWrapper} instance to be passed as argument to the remote call.
    */
   protected abstract DatasetWrapper loadDataSet(String content)
   throws IOException,
          RequestArgumentError;

   /**
    * Create a new {@link DatasetWrapper}.  This implementation by default returns <code>null</code>.
    * 
    * @param    name
    *           The dataset name.
    * @param    input
    *           The INPUT mode.
    * @param    output
    *           The OUTPUT mode.
    * @param    asHandle
    *           Flag indicating if this is a DATASET-HANDLE parameter.
    *           
    * @return   <code>null</code> by default.
    */
   protected DatasetWrapper createDataset(String name, boolean input, boolean output, boolean asHandle)
   {
      return null;
   }
   
   /**
    * Create a new {@link TableWrapper}.  This implementation by default returns <code>null</code>.
    * 
    * @param    name
    *           The table name.
    * @param    input
    *           The INPUT mode.
    * @param    output
    *           The OUTPUT mode.
    * @param    asHandle
    *           Flag indicating if this is a DATASET-HANDLE parameter.
    *           
    * @return   <code>null</code> by default.
    */
   protected TableWrapper createTable(String name, boolean input, boolean output, boolean asHandle)
   {
      return null;
   }
   
   /**
    * Parse the arguments, by interpreting the request.
    * <p>
    * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
    * the request.
    * 
    * @param    service
    *           The service definition.
    * @param    request
    *           The request payload.
    *           
    * @return   The resolved arguments.
    */
   public final Object[] parseArguments(RestService service, HttpServletRequest request)
   throws IOException,
          RequestArgumentError
   {
      LegacyServiceParameter[] serviceParameters = service.ls.parameters();
      LegacyServiceParameter[] original = service.getDefinitionParameters();
      ArgumentsParser parser = service.getParser(this);
      
      return parseArguments(parser, serviceParameters, original, request);
   }
   
   
   /**
    * Parse the arguments, by interpreting the request.
    * <p>
    * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
    * the request.
    * 
    * @param    serviceParameters
    *           The legacy service definition parameters.
    * @param    original
    *           The definition parameters.
    * @param    request
    *           The request payload.
    *           
    * @return   The resolved arguments.
    */
   public final Object[] parseArguments(LegacyServiceParameter[] serviceParameters, 
                                        LegacyServiceParameter[] original, 
                                        HttpServletRequest       request)
   throws IOException,
          RequestArgumentError
   {
      return parseArguments(new LegacyArgumentsParser(this), serviceParameters, original, request);
   }
   
   /**
    * Parse the arguments, by interpreting the request.
    * <p>
    * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
    * the request.
    * 
    * @param    parser
    *           The parser to be used for parsing the arguments
    * @param    serviceParameters
    *           The legacy service definition parameters.
    * @param    original
    *           The definition parameters.
    * @param    request
    *           The request payload.
    *           
    * @return   The resolved arguments.
    */
   public final Object[] parseArguments(ArgumentsParser          parser,
                                        LegacyServiceParameter[] serviceParameters, 
                                        LegacyServiceParameter[] original, 
                                        HttpServletRequest       request)
   throws IOException,
          RequestArgumentError
   {
      byte[] bbody = LegacyServiceHandler.readBody(request);
      String body = new String(bbody);
      
      Object[] args = new Object[original.length];
      for (int i = 0; i < args.length; i++)
      {
         LegacyServiceParameter lsp = original[i];
         
         args[i] = parser.initArgument(lsp, serviceParameters, i);
      }
      
      for (int i = 0; i < serviceParameters.length; i++)
      {
         LegacyServiceParameter lsp = serviceParameters[i];
         if (lsp.returnValue())
         {
            continue;
         }
         
         if (lsp.input())
         {
            int idx = lsp.ordinal() - 1;
            Object arg = parser.parseArgument(lsp, original, args[idx], i, body, request);
            args[idx] = arg;
         }
      }
      
      return args;
   }

   /**
    * Raises an error so that the request stops with a 5xx internal server error.
    * 
    * @param    bdt
    *           The BDT for which the value could not be parsed.
    * @param    val
    *           The attempted value to assign.
    */
   protected void notAValue(BaseDataType bdt, String val)
   throws RequestArgumentError
   {
      String msg = "The value was not a " + bdt.getTypeName();
      switch (bdt.getClass().getSimpleName())
      {
         case "decimal":
            msg = "Unable to convert from java.lang.String to java.math.BigDecimal - The value was not a DECIMAL";
            break;
         case "integer":
            msg = "Unable to convert from java.lang.String to java.lang.Integer - The value was not an INTEGER";
            break;
         case "int64":
            msg = "Unable to convert from java.lang.String to java.lang.Long - The value was not a LONG";
            break;
         case "date":
         case "datetime":
         case "datetimetz":
            msg = "Unable to convert from java.lang.String to java.util.GregorianCalendar - The value was not a DATE, DATETIME or DATETIME-TZ";
            break;
         case "rowid":
            // TODO: what is the correct message?
            msg = "The value was not a Rowid";
            break;
         case "memptr":
            // TODO: what is the correct message?
            msg = "The value was not a Memptr";
            break;
      }

      throw new RequestArgumentError(msg);
   }

   /**
    * Generate an unknown instance for the given type.
    * 
    * @param    type
    *           The parameter's type.
    *           
    * @return   The unknown instance.
    */
   BaseDataType unknownInstance(String type)
   {
      return BaseDataType.generateUnknown(BaseDataType.fromTypeName(type));
   }
}