org.gedcomx.rt.DataURIUtil.java Source code

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Here is the source code for org.gedcomx.rt.DataURIUtil.java

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/**
 * Copyright Intellectual Reserve, 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 org.gedcomx.rt;

import org.apache.commons.codec.binary.Base64;

import javax.ws.rs.core.MediaType;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLDecoder;

/**
 * Utilities for encoding, decoding data URIs.
 *
 * @author Ryan Heaton
 * @see <a href="http://tools.ietf.org/html/rfc2397">RFC 2397</a>
 */
public class DataURIUtil {

    private DataURIUtil() {
    }

    /**
     * Get the string data from the specified URI.
     *
     * @param uri the URI.
     * @return The string form of the data, or null if the data URI doesn't contain a string.
     */
    public static String getValueAsString(URI uri) {
        if ("data".equals(uri.getScheme())) {
            String ssp;
            try {
                ssp = URLDecoder.decode(uri.getRawSchemeSpecificPart(), "utf-8");
            } catch (UnsupportedEncodingException e) {
                return null;
            }

            int commaIndex = ssp.indexOf(',');
            if (commaIndex >= 0) {
                String meta = ssp.substring(0, commaIndex);
                try {
                    boolean base64 = meta.endsWith(";base64");
                    if (base64) {
                        meta = meta.substring(0, meta.indexOf(";base64"));
                    }

                    MediaType mediaType = meta.trim().length() > 0 ? MediaType.valueOf(meta)
                            : MediaType.TEXT_PLAIN_TYPE;
                    if (MediaType.TEXT_PLAIN_TYPE.isCompatible(mediaType)) {
                        String value = ssp.substring(commaIndex + 1);
                        if (base64) {
                            byte[] decoded = Base64.decodeBase64(value);
                            String charset = mediaType.getParameters().get("charset");
                            if (charset == null) {
                                charset = "utf-8";
                            }
                            return new String(decoded, charset);
                        } else {
                            return value;
                        }
                    }
                } catch (IllegalArgumentException e) {
                    //fall through...
                } catch (UnsupportedEncodingException e) {
                    //fall through...
                }
            }
        }

        return null;
    }

    /**
     * Encode custom text as a data URI.
     *
     * @param text The text to encode.
     * @return The URI.
     */
    public static URI encodeDataURI(String text) {
        try {
            return new URI("data", "," + text, null);
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }

}