org.apache.ambari.view.tez.utils.ProxyHelper.java Source code

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Here is the source code for org.apache.ambari.view.tez.utils.ProxyHelper.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.ambari.view.tez.utils;

import com.google.inject.Inject;
import org.apache.ambari.view.URLConnectionProvider;
import org.apache.ambari.view.ViewContext;
import org.apache.ambari.view.tez.exceptions.ProxyException;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.util.Map;
import java.util.Set;

public class ProxyHelper {

    private ViewContext viewContext;

    private static final Logger LOG = LoggerFactory.getLogger(ProxyHelper.class);

    @Inject
    public ProxyHelper(ViewContext viewContext) {
        this.viewContext = viewContext;
    }

    public String getResponse(String url, Map<String, String> headers) {
        LOG.debug("Fetching the result from the URL: {} using proxy", url);
        InputStream inputStream = null;
        try {
            URLConnectionProvider provider = viewContext.getURLConnectionProvider();
            HttpURLConnection connection = provider.getConnectionAsCurrent(url, "GET", (String) null, headers);

            if (!(connection.getResponseCode() >= 200 && connection.getResponseCode() < 300)) {
                LOG.error("Failure in fetching results for the URL: {}. Status: {}", url,
                        connection.getResponseCode());
                String trace = "";
                inputStream = connection.getErrorStream();
                if (inputStream != null) {
                    trace = IOUtils.toString(inputStream);
                }
                throw new ProxyException("Failed to fetch results by the proxy from url: " + url,
                        connection.getResponseCode(), trace);
            }

            inputStream = connection.getInputStream();
            return IOUtils.toString(inputStream);

        } catch (IOException e) {
            LOG.error("Cannot access the url: {}", url, e);
            throw new ProxyException("Failed to fetch results by the proxy from url: " + url + ".Internal Error.",
                    Response.Status.INTERNAL_SERVER_ERROR.getStatusCode(), e.getMessage());
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    /* Noting to do */ }
            }
        }
    }

    public String getQueryParamsString(MultivaluedMap<String, String> queryParameters) {
        Set<String> keySet = queryParameters.keySet();
        StringBuilder builder = new StringBuilder();
        if (keySet.size() > 0)
            builder.append("?");

        int count = 0;
        for (String key : keySet) {
            builder.append(key);
            builder.append("=");
            builder.append(queryParameters.getFirst(key));
            if (count < keySet.size() - 1) {
                builder.append("&");
            }
        }
        return builder.toString();
    }
}