org.apache.shindig.gadgets.http.HttpResponseMetadataHelper.java Source code

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Here is the source code for org.apache.shindig.gadgets.http.HttpResponseMetadataHelper.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 org.apache.shindig.gadgets.http;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;

import org.apache.shindig.common.util.Base32;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Map;
import java.util.logging.Logger;

/**
 * Helper class to update HttpResponse metadata value.
 *
 * @since 2.0.0
 */
public class HttpResponseMetadataHelper {
    public static final String DATA_HASH = "DataHash";
    public static final String IMAGE_HEIGHT = "ImageHeight";
    public static final String IMAGE_WIDTH = "ImageWidth";

    private static final Logger LOG = Logger.getLogger(HttpResponseMetadataHelper.class.getName());

    /**
     * Return a copy of input response with additional metadata values.
     * @param response source response
     * @param values added metadata values
     * @return copy of source response with updated metadata
     */
    public static HttpResponse updateMetadata(HttpResponse response, Map<String, String> values) {
        Map<String, String> metadata = Maps.newHashMap(response.getMetadata());
        // metadata.putAll(values);
        for (Map.Entry<String, String> val : values.entrySet()) {
            metadata.put(val.getKey(), val.getValue());
        }
        return new HttpResponseBuilder(response).setMetadata(metadata).create();
    }

    /**
     * Calculate hash value for response and update metadata value (DATA_HASH)
     * @return hash value
     */
    public String getHash(HttpResponse response) {
        try {
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            md5.update(response.getResponseAsBytes());
            byte[] md5val = md5.digest();
            return new String(Base32.encodeBase32(md5val), "UTF-8");
        } catch (NoSuchAlgorithmException e) {
            // Should not happen
            LOG.info("Error getting MD5 digest, ignored");
        } catch (UnsupportedEncodingException e) {
            // Should not happen
            LOG.info("Error parsing MD5 string as UTF8");
        }
        return null;
    }

    public static HttpResponse updateHash(HttpResponse response, HttpResponseMetadataHelper helper) {
        if (helper != null) {
            String hash = helper.getHash(response);
            if (hash != null) {
                return updateMetadata(response, ImmutableMap.<String, String>of(DATA_HASH, hash));
            }
        }
        return response;
    }
}