com.centurylink.mdw.service.rest.Rules Maven / Gradle / Ivy

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MDW is a workflow framework specializing in microservice orchestration
There is a newer version: 6.1.39
/*
 * Copyright (C) 2017 CenturyLink, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.centurylink.mdw.service.rest;

import java.io.IOException;
import java.util.List;
import java.util.Map;

import javax.ws.rs.Path;

import org.json.JSONException;
import org.json.JSONObject;

import com.centurylink.mdw.cache.asset.AssetCache;
import com.centurylink.mdw.common.service.Query;
import com.centurylink.mdw.common.service.ServiceException;
import com.centurylink.mdw.model.Jsonable;
import com.centurylink.mdw.model.Status;
import com.centurylink.mdw.model.asset.Asset;
import com.centurylink.mdw.model.listener.Listener;
import com.centurylink.mdw.model.user.Role;
import com.centurylink.mdw.model.user.UserAction.Entity;
import com.centurylink.mdw.model.workflow.RuntimeContext;
import com.centurylink.mdw.model.workflow.RuntimeContextAdapter;
import com.centurylink.mdw.rules.Operand;
import com.centurylink.mdw.services.ServiceLocator;
import com.centurylink.mdw.services.rest.JsonRestService;
import com.centurylink.mdw.services.rules.RulesServicesImpl;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;

@Path("/Rules")
@Api("Asset-driven rules service")
public class Rules extends JsonRestService {

    @Override
    public List getRoles(String path, String method) {
        List roles = super.getRoles(path);
        roles.add(Role.PROCESS_EXECUTION);
        return roles;
    }

    @Override
    protected Entity getEntity(String path, Object content, Map headers) {
        return Entity.Rule;
    }

    /**
     * Apply rules designated in asset path against incoming request parameters.
     */
    @Override
    public JSONObject get(String path, Map headers)
            throws ServiceException, JSONException {
        Asset rules = getRulesAsset(path);

        Operand input = new Operand();
        input.setContext(getContext(path));
        Query query = getQuery(path, headers);
        input.setParams(query.getFilters());
        input.setMeta(headers);

        JSONObject response = invokeRules(rules, input, getExecutor(headers));

        Status status = input.getStatus();
        if (status != null) {
            headers.put(Listener.METAINFO_HTTP_STATUS_CODE, String.valueOf(status.getCode()));
            if (response == null)
                return status.getJson();
        }

        return response;
    }

    /**
     * Apply rules designated in asset path against incoming JSONObject.
     */
    @Override
    @Path("/{assetPath}")
    @ApiOperation(value="Apply rules identified by assetPath.", notes="Query may contain runtime values")
    @ApiImplicitParams({
        @ApiImplicitParam(name="FactsObject", paramType="body", required=true, value="Input to apply rules against"),
        @ApiImplicitParam(name="assetPath", paramType="path", required=true, value="Identifies a .drl or .xlsx asset"),
        @ApiImplicitParam(name="rules-executor", paramType="header", required=false, value="Default is Drools")})
    public JSONObject post(String path, JSONObject content, Map headers)
            throws ServiceException, JSONException {

        Asset rules = getRulesAsset(path);

        Operand input = new Operand(content);
        input.setContext(getContext(path));
        Query query = getQuery(path, headers);
        input.setParams(query.getFilters());
        input.setMeta(headers);

        JSONObject response = invokeRules(rules, input, getExecutor(headers));

        Status status = input.getStatus();
        if (status != null) {
            headers.put(Listener.METAINFO_HTTP_STATUS_CODE, String.valueOf(status.getCode()));
            if (response == null)
                return status.getJson();
        }

        return response;
    }

    protected Asset getRulesAsset(String path) throws ServiceException {
        String[] pathSegments = getSegments(path);
        if (pathSegments.length != 3)
            throw new ServiceException(ServiceException.BAD_REQUEST, "Invalid path: " + path);
        String assetPath = pathSegments[1] + "/" + pathSegments[2];
        Asset asset;
        try {
            if (assetPath.endsWith(".drl") || assetPath.endsWith(".xlsx")) {
                asset = AssetCache.getAsset(assetPath);
            } else {
                asset = AssetCache.getAsset(assetPath + ".drl");
                if (asset == null)
                    asset = AssetCache.getAsset(assetPath + ".xlsx");
            }
        } catch (IOException ex) {
            throw new ServiceException(ServiceException.INTERNAL_ERROR, "Error loading " + assetPath, ex);
        }

        if (asset == null)
            throw new ServiceException(ServiceException.NOT_FOUND, "Rules asset not found: " + assetPath);

        return asset;
    }

    /**
     * Override to specify runtime context.
     */
    protected RuntimeContext getContext(String path)
            throws ServiceException {
        return new RuntimeContextAdapter();
    }

    protected String getExecutor(Map headers) {
        String executor = headers.get("rules-executor");
        if (executor == null)
            executor = RulesServicesImpl.DROOLS_EXECUTOR;

        return executor;
    }

    protected JSONObject invokeRules(Asset rules, Operand input, String executor) throws ServiceException {
        Object result = ServiceLocator.getRulesServices().applyRules(rules, input, executor);

        if (result instanceof Jsonable) {
            return ((Jsonable)result).getJson();
        }
        else if (result instanceof JSONObject) {
            return (JSONObject)result;
        }
        else if (result == null) {
            return null; // default response
        }
        else {
            throw new ServiceException(ServiceException.INTERNAL_ERROR, "Invalid result type: " + result.getClass());
        }
    }

}