basedefense.client.version.ModificationVersionCheck.java Source code

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Here is the source code for basedefense.client.version.ModificationVersionCheck.java

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/*
 * Copyright 2015 Johannes Donath <johannesd@torchmind.com>
 * and other copyright owners as documented in the project's IP log.
 *
 * 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 basedefense.client.version;

import basedefense.BaseDefenseModification;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import org.apache.commons.io.IOUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicHeader;

import java.io.InputStreamReader;
import java.util.Optional;

/**
 * Provides a simple utility class for retrieving version information.
 *
 * @author Johannes Donath <a href="mailto:johannesd@torchmind.com">johannesd@torchmind.com</a>
 */
public class ModificationVersionCheck {
    public static final String API_URL = "https://api.github.com";
    public static final String API_PATTERN = "/repos/%s/%s/releases/latest";
    public static final String USER_AGENT_PATTERN = "BaseDefense/%s (+https://github.com/LordAkkarin/BaseDefense2)";

    private final HttpClient httpClient;
    private Optional<String> latestVersion = null;

    public ModificationVersionCheck() {
        HttpClientBuilder builder = HttpClientBuilder.create();
        builder.disableCookieManagement();
        builder.disableRedirectHandling();

        builder.setUserAgent(String.format(USER_AGENT_PATTERN, BaseDefenseModification.getInstance().getVersion()));
        builder.setDefaultHeaders(Lists.newArrayList(new BasicHeader("Accept", "application/vnd.github.v3+json")));

        this.httpClient = builder.build();
    }

    /**
     * Checks the modification version.
     *
     * @return The version.
     */
    public Optional<String> check() {
        // We will only run this check once as this check may take a lot of time to process
        if (this.latestVersion != null)
            return this.latestVersion;

        InputStreamReader inputStreamReader = null;

        try {
            HttpGet getRequest = new HttpGet(API_URL + String.format(API_PATTERN, "LordAkkarin", "BaseDefense2"));
            HttpResponse response = this.httpClient.execute(getRequest);
            Preconditions.checkState(response.getStatusLine().getStatusCode() == 200,
                    "Expected status code 200 but received %s", response.getStatusLine());

            HttpEntity entity = response.getEntity();
            inputStreamReader = new InputStreamReader(entity.getContent());

            Gson gson = new Gson();
            JsonObject object = gson.fromJson(inputStreamReader, JsonObject.class);
            Preconditions.checkState(object.has("tag_name"), "No valid version found.");

            this.latestVersion = Optional.of(object.get("tag_name").getAsString());
        } catch (Exception ex) {
            BaseDefenseModification.getInstance().getLogger()
                    .warn("Unable to retrieve version information: " + ex.getMessage(), ex);
            this.latestVersion = Optional.empty();
        } finally {
            IOUtils.closeQuietly(inputStreamReader);
        }

        return this.latestVersion;
    }
}