JsonRequestsParser.java

/*
** Module   : JsonRequestsParser.java
** Abstract : APIs to read the INPUT arguments from the HTTP servlet request, as JSON.
**
** Copyright (c) 2019-2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- -----------------------------------------Description--------------------------------------
** 001 CA  20190614 First version.
** 002 CA  20190628 Fixed parsing request JSON arguments (from the HTTP body).
** 003 CA  20200427 Fixed TABLE and added DATASET support; misc improvements.
**     CA  20200514 Refactoring to allow common code for SOAP services support.
**     CA  20220110 Refactored the temp-table's row-meta state to use constants for the indexes in the array 
**                  used for serialization.
**     CA  20220329 Added support for REST services written directly in Java.
**     OM  20221103 Fixed parsing of tables from JSON string in loadTable().
**     OM  20221205 Boolean values are not parsed but the original string value returned.
*/

/*
** 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
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**     name Golden Code, FWD, or the names of any author or contributor, for
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*/

package com.goldencode.p2j.rest;

import java.io.*;
import java.util.*;
import javax.servlet.http.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.node.*;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.util.*;

/**
 * Helper class to parse a parameter's value, JSON-style.
 */
class JsonRequestsParser
extends RequestArguments
{
   /** Used to parse the HTTP body as a JSON object. */
   private final ThreadLocal<ObjectMapper> mapper = ThreadLocal.withInitial(ObjectMapper::new);

   /**
    * Parse the argument, by interpreting the request.
    * 
    * @param    body
    *           The request body.
    * @param    src
    *           The parameter's encoded source.
    * @param    request
    *           The request payload.
    *
    * @return   The resolved argument.
    */
   @Override
   protected String parseArgumentInt(String body, String src, HttpServletRequest request)
   throws IOException
   {
      String sval = super.parseArgumentInt(body, src, request);
      if (sval != null)
      {
         return sval;
      }
      
      if (src.startsWith("${"))
      {
         src = src.substring(2);
      }
      if (src.endsWith("}"))
      {
         src = src.substring(0, src.length() - 1);
      }

      if (src.startsWith("json.object['request']."))
      {
         String jsonMode = src.substring("json.object['request'].".length());
         String attr = RestHandler.extractVal(jsonMode);
         jsonMode = jsonMode.substring(0, jsonMode.indexOf('['));
         
         JsonNode rootNode = mapper.get().readTree(body);
         
         JsonNode jsonReq = rootNode.path("request");
         if (!jsonReq.isMissingNode())
         {
            jsonReq = jsonReq.path(attr);
            if (!jsonReq.isMissingNode())
            {
               if (jsonReq.isNull())
               {
                  return null;
               }
               
               if ("".equals(jsonMode))
               {
                  switch (jsonReq.getNodeType())
                  {
                     case BOOLEAN:
                        jsonMode = "boolean";
                        break;
                     case STRING:
                     case NUMBER:
                     case BINARY:
                        jsonMode = "string";
                        break;
                     case ARRAY:
                     case NULL:
                     case OBJECT:
                     case POJO:
                        jsonMode = "object";
                        break;
                  }
               }
               
               // the values seem to be simply returned as its original string representation, not sure if
               // there is any validation performed on the node's content
               switch (jsonMode.toLowerCase())
               {
                  case "boolean":
                     return jsonReq.asText();
                  case "integervalue":
                     return Integer.toString(jsonReq.asInt());
                  case "longvalue":
                     return Long.toString(jsonReq.asLong());
                  case "decimalvalue":
                     return Double.toString(jsonReq.asDouble());
                  case "string":
                     return jsonReq.asText();
                  case "object":
                  default:
                     return jsonReq.toString();
               }
            }
            else
            {
               return null;
            }
         }
         else
         {
            return null;
         }
      }
      
      return null;
   }
   
   /**
    * Load the specified dataset.
    * 
    * @param    content
    *           The dataset definition.
    *
    * @return   A {@link DatasetWrapper} instance to be passed as argument to the remote call.
    */
   @Override
   protected DatasetWrapper loadDataSet(String content)
   throws IOException
   {
      DataSetContainer dataset = new DataSetContainer(true, false, false);
      
      ObjectNode root = (ObjectNode) mapper.get().readTree(content);
      String dsName = root.fieldNames().next();
      dataset.setStructureName(dsName);
      
      List<DsTableDefinition> tableDefinitions = new ArrayList<>();
      root = (ObjectNode) root.get(dsName);
      Iterator<String> tables = root.fieldNames();
      for (int i = 0; i < root.size(); i++)
      {
         String table = tables.next();
         
         List<PropertyDefinition> props = new ArrayList<>();
         List<Object[]> rows = new ArrayList<>();
         
         JsonNode tableRoot = root.get(table);
         if (tableRoot.isArray())
         {
            for (int j = 0; j < tableRoot.size(); j++)
            {
               JsonNode jrow = tableRoot.get(j);
               
               rows.add(readRow(props, jrow));
            }
         }
         else
         {
            rows.add(readRow(props, tableRoot));
         }
         
         Iterator<Object[]> iterRows = rows.iterator();
         Iterator<PropertyDefinition> iterProps = props.iterator();
         
         DsTableDefinition dsTable = new DsTableDefinition(new TableResultSet(true, false, false)
         {
            @Override
            public Object[] nextRow()
            {
               return iterRows.next();
            }
            
            @Override
            public PropertyDefinition nextProperty()
            {
               return iterProps.next();
            }
            
            @Override
            public boolean hasMoreRows()
            {
               return iterRows.hasNext();
            }
            
            @Override
            public boolean hasMoreProperties()
            {
               return iterProps.hasNext();
            }

            @Override
            public Object[] nextRowMeta()
            {
               // nothing is kept here...
               return new Object[TempRecord._META_PROPERTIES_LENGTH];
            }
         });
         
         dsTable.setName(table);
         tableDefinitions.add(dsTable);
      }
      
      dataset.setTableDefinitions(tableDefinitions);
      DatasetWrapper ds = new DatasetWrapper(true, dataset);
      ds.setDatasetName(dsName);
      
      return ds;
   }
   
   /**
    * Load the specified table.
    * 
    * @param    content
    *           The table definition.
    *
    * @return   A {@link TableWrapper} instance to be passed as argument to the remote call.
    */
   @Override
   protected TableWrapper loadTable(String content)
   throws IOException
   {
      List<PropertyDefinition> props = new ArrayList<>();
      List<Object[]> rows = new ArrayList<>();
      String tableName = "";
      
      JsonNode root = mapper.get().readTree(content);
      if (root.isArray()) 
      {
         // the table is directly serialized with multiple arrays rows
         // (4) table name is not specified, request.tInfieldvalue is an array:
         //    "tInfieldvalue": [ { "t-infieldvalue": "some-value" } ]
         for (int i = 0; i < root.size(); i++)
         {
            rows.add(readRow(props, root.get(i)));
         }
      }
      else if (root.size() == 1)
      {
         // should be only one child
         Iterator<String> it = root.fieldNames();
         tableName = it.next(); // legacy name ?
         JsonNode firstAndOnlyChild = root.get(tableName);
         
         if (firstAndOnlyChild.isArray())
         {
            // (1) table name is specified, rows as array:
            //    "tInfieldvalue": { "t-infieldvalue": [] }
            for (int i = 0; i < firstAndOnlyChild.size(); i++)
            {
               rows.add(readRow(props, firstAndOnlyChild.get(i)));
            }
         }
         else if (firstAndOnlyChild.size() != 0)
         {
            // (2) table name is specified, single row as object
            //    "tInfieldvalue": { "t-infieldvalue": { field assignments }}
            rows.add(readRow(props, firstAndOnlyChild)); // firstAndOnlyChild is a normal object
         }
         else
         {
            // (3) table name is not specified, request.tInfieldvalue is an object and there is a field with
            // the same name as the table (the child is not an object or an array):
            //    "tInfieldvalue": { "t-infieldvalue": "some-value" }
            props.add(new PropertyDefinition(tableName, unknown.class, tableName));
            rows.add( new Object[] { firstAndOnlyChild.textValue() });
         }
      }
      else
      {
         // (5) table name is not specified, rows are an object with more than one field:
         //    "tInfieldvalue": { "t-infieldvalue": "some-value", "t-outfieldvalue": "other-value" }
         rows.add(readRow(props, root));
      }
      
      Iterator<Object[]> iterRows = rows.iterator();
      Iterator<PropertyDefinition> iterProps = props.iterator();
      TableWrapper tw = new TableWrapper(true, new TableResultSet(true, false, false)
      {
         @Override
         public Object[] nextRow()
         {
            return iterRows.next();
         }
         
         @Override
         public PropertyDefinition nextProperty()
         {
            return iterProps.next();
         }
         
         @Override
         public boolean hasMoreRows()
         {
            return iterRows.hasNext();
         }
         
         @Override
         public boolean hasMoreProperties()
         {
            return iterProps.hasNext();
         }
         
         @Override
         public Object[] nextRowMeta()
         {
            // nothing is kept here...
            return new Object[TempRecord._META_PROPERTIES_LENGTH];
         }
      });
      tw.setTableName(tableName);
      return tw;
   }
   
   /**
    * Read a row from the specified JSON node.
    * 
    * @param    props
    *           The table properties.
    * @param    root
    *           The JSON row.
    *
    * @return   The de-serialized row, based on each property type.
    */
   protected Object[] readRow(List<PropertyDefinition> props, JsonNode root)
   {
      Object[] vals = new Object[root.size()];
      ObjectNode node = (ObjectNode) root;
      Iterator<String> itrFields = node.fieldNames();
      boolean addProps = props.isEmpty();
      for (int i = 0; i < root.size(); i++)
      {
         String field = itrFields.next();
         vals[i] = node.get(field).asText(null);
         
         if (addProps)
         {
            props.add(new PropertyDefinition(field, unknown.class, field));
         }
      }
      
      return vals;
   }
}