com.google.cloud.runtime.jetty.util.HttpUrlUtil.java Source code

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Here is the source code for com.google.cloud.runtime.jetty.util.HttpUrlUtil.java

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/*
 * Copyright (C) 2016 Google 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.google.cloud.runtime.jetty.util;

import org.apache.commons.io.IOUtils;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URI;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

public final class HttpUrlUtil {
    private static final Logger log = Logger.getLogger(HttpUrlUtil.class.getName());

    /**
     * Wait for a server to be "up" by requesting a specific GET resource
     * that should be returned in status code 200.
     * <p>
     * This will attempt a check for server up.
     * If any result other then response code 200 occurs, then
     * a 2s delay is performed until the next test.
     * Up to the duration/timeunit specified.
     * </p>
     *
     * @param uri      the URI to request
     * @param duration the time duration to wait for server up
     * @param unit     the time unit to wait for server up
     */
    public static void waitForServerUp(URI uri, int duration, TimeUnit unit) {
        System.err.println("Waiting for server up: " + uri);
        boolean waiting = true;
        long expiration = System.currentTimeMillis() + unit.toMillis(duration);
        while (waiting && System.currentTimeMillis() < expiration) {
            try {
                System.out.print(".");
                HttpURLConnection http = openTo(uri);
                int statusCode = http.getResponseCode();
                if (statusCode != HttpURLConnection.HTTP_OK) {
                    log.log(Level.FINER, "Waiting 2s for next attempt");
                    TimeUnit.SECONDS.sleep(2);
                } else {
                    waiting = false;
                }
            } catch (MalformedURLException e) {
                throw new IllegalArgumentException("Invalid URI: " + uri.toString());
            } catch (IOException e) {
                log.log(Level.FINEST, "Ignoring IOException", e);
            } catch (InterruptedException ignore) {
                // ignore
            }
        }
        System.err.println();
        System.err.println("Server seems to be up.");
    }

    /**
     * Open a new {@link HttpURLConnection} to the provided URI.
     * <p>
     * Note: will also set the 'User-Agent' to {@code jetty-runtime/gcloud-util-core}
     * </p>
     *
     * @param uri the URI to open to
     * @return the open HttpURLConnection
     * @throws IOException if unable to open the connection
     */
    public static HttpURLConnection openTo(URI uri) throws IOException {
        log.info("HttpUrlUtil.openTo(" + uri + ")");
        HttpURLConnection http = (HttpURLConnection) uri.toURL().openConnection();
        http.setRequestProperty("User-Agent", "jetty-runtime/gcloud-util-core");
        return http;
    }

    /**
     * Obtain the text (non-binary) response body from an {@link HttpURLConnection},
     * using the response provided charset.
     * <p>
     * Note: Normal HttpURLConnection doesn't use the provided charset properly.
     * </p>
     *
     * @param http the {@link HttpURLConnection} to obtain the response body from
     * @return the text of the response body
     * @throws IOException if unable to get the text of the response body
     */
    public static String getResponseBody(HttpURLConnection http) throws IOException {
        Charset responseEncoding = StandardCharsets.UTF_8;
        if (http.getContentEncoding() != null) {
            responseEncoding = Charset.forName(http.getContentEncoding());
        }

        return IOUtils.toString(http.getInputStream(), responseEncoding);
    }
}