gradle-master/subprojects/resources-http/src/main/java/org/gradle/internal/resource/transport/http/HttpResourceAccessor.java
/*
 * Copyright 2012 the original author or authors.
 *
 * 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.gradle.internal.resource.transport.http;

import org.gradle.internal.IoActions;
import org.gradle.internal.resource.ExternalResourceName;
import org.gradle.internal.resource.metadata.ExternalResourceMetaData;
import org.gradle.internal.resource.transfer.AbstractExternalResourceAccessor;
import org.gradle.internal.resource.transfer.ExternalResourceAccessor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nullable;
import java.net.URI;

public class HttpResourceAccessor extends AbstractExternalResourceAccessor implements ExternalResourceAccessor {

    private static final Logger LOGGER = LoggerFactory.getLogger(HttpResourceAccessor.class);
    private final HttpClientHelper http;

    public HttpResourceAccessor(HttpClientHelper http) {
        this.http = http;
    }

    @Override
    @Nullable
    public HttpResponseResource openResource(final ExternalResourceName location, boolean revalidate) {
        String uri = location.getUri().toString();
        LOGGER.debug("Constructing external resource: {}", location);

        HttpClientResponse response = http.performGet(uri, revalidate);
        return wrapResponse(location.getUri(), response);
    }

    /**
     * Same as #getResource except that it always gives access to the response body,
     * irrespective of the returned HTTP status code. Never returns {@code null}.
     */
    public HttpResponseResource getRawResource(final URI uri, boolean revalidate) {
        String location = uri.toString();
        LOGGER.debug("Constructing external resource: {}", location);
        HttpClientResponse response = http.performRawGet(location, revalidate);
        return wrapResponse(uri, response);
    }

    @Override
    public ExternalResourceMetaData getMetaData(ExternalResourceName location, boolean revalidate) {
        String uri = location.getUri().toString();
        LOGGER.debug("Constructing external resource metadata: {}", location);
        HttpClientResponse response = http.performHead(uri, revalidate);

        if (response == null || response.wasMissing()) {
            return null;
        }

        HttpResponseResource resource = new HttpResponseResource("HEAD", location.getUri(), response);
        try {
            return resource.getMetaData();
        } finally {
            IoActions.closeQuietly(resource);
        }
    }

    private HttpResponseResource wrapResponse(URI uri, HttpClientResponse response) {
        return new HttpResponseResource("GET", uri, response);
    }

}
