io.wcm.config.core.override.impl.RequestHeaderOverrideProvider.java Source code

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Here is the source code for io.wcm.config.core.override.impl.RequestHeaderOverrideProvider.java

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/*
 * #%L
 * wcm.io
 * %%
 * Copyright (C) 2014 wcm.io
 * %%
 * 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.
 * #L%
 */
package io.wcm.config.core.override.impl;

import io.wcm.config.spi.ParameterOverrideProvider;
import io.wcm.sling.commons.request.RequestContext;

import java.util.Dictionary;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.commons.osgi.PropertiesUtil;
import org.osgi.framework.Constants;
import org.osgi.service.component.ComponentContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.ImmutableMap;

/**
 * Provides parameter override map from current request header.
 */
@Component(immediate = true, metatype = true, label = "wcm.io Configuration Property Override Provider: Request Header", description = "Allows to define configuration property default values or overrides from inconming request headers.")
@Service(ParameterOverrideProvider.class)
public final class RequestHeaderOverrideProvider implements ParameterOverrideProvider {

    /**
     * Prefix for override request header
     */
    public static final String REQUEST_HEADER_PREFIX = "config.override.";

    @Property(label = "Enabled", boolValue = RequestHeaderOverrideProvider.DEFAULT_ENABLED, description = "Enable parameter override provider")
    static final String PROPERTY_ENABLED = "enabled";
    static final boolean DEFAULT_ENABLED = false;

    @Property(label = "Service Ranking", intValue = RequestHeaderOverrideProvider.DEFAULT_RANKING, description = "Priority of parameter override providers (lower = higher priority)", propertyPrivate = false)
    static final String PROPERTY_RANKING = Constants.SERVICE_RANKING;
    static final int DEFAULT_RANKING = 1000;

    private static final Logger log = LoggerFactory.getLogger(RequestHeaderOverrideProvider.class);

    private boolean enabled;

    @Reference
    private RequestContext requestContext;

    @Override
    public Map<String, String> getOverrideMap() {
        if (this.enabled) {
            if (requestContext != null) {
                SlingHttpServletRequest request = requestContext.getThreadRequest();
                if (request != null) {
                    return buildMapFromHeaders(request);
                }
            } else {
                log.warn("RequestContext service not running - unable to inspect current request.");
            }
        }
        return ImmutableMap.<String, String>of();
    }

    private Map<String, String> buildMapFromHeaders(SlingHttpServletRequest request) {
        Map<String, String> map = new HashMap<>();
        Enumeration keys = request.getHeaderNames();
        while (keys.hasMoreElements()) {
            Object keyObject = keys.nextElement();
            if (keyObject instanceof String) {
                String key = (String) keyObject;
                if (StringUtils.startsWith(key, REQUEST_HEADER_PREFIX)) {
                    map.put(StringUtils.substringAfter(key, REQUEST_HEADER_PREFIX), request.getHeader(key));
                }
            }
        }
        return map;
    }

    @Activate
    void activate(final ComponentContext ctx) {
        Dictionary config = ctx.getProperties();
        this.enabled = PropertiesUtil.toBoolean(config.get(PROPERTY_ENABLED), DEFAULT_ENABLED);
    }

}