com.google.step2.http.DefaultHttpFetcher.java Source code

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Here is the source code for com.google.step2.http.DefaultHttpFetcher.java

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/**
 * Copyright 2009 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.step2.http;

import org.apache.commons.io.IOUtils;
import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.ProxySelectorRoutePlanner;

import java.io.IOException;
import java.io.InputStream;

/**
 * Default implementations of HttpFetcher and FetchResponse. Based on
 * Apache http client. We use the {@link ProxySelectorRoutePlanner}, which means
 * that we pick up the default proxy set in the VM (can be set through
 * {@link java.net.ProxySelector}.setDefault(), or by specifying system
 * properties http.proxyHost, http.proxyPort, etc.).
 */
public class DefaultHttpFetcher implements HttpFetcher {

    private final DefaultHttpClient httpClient;

    public DefaultHttpFetcher() {
        // this follows redirects by default
        this.httpClient = new DefaultHttpClient();

        // this means you can set a proxy through
        // java.net.ProxySelector.setDefault(), or by simply starting the
        // jvm with -Dhttp.proxyHost=foo.com -Dhttp.proxyPort=8080
        httpClient.setRoutePlanner(
                new ProxySelectorRoutePlanner(httpClient.getConnectionManager().getSchemeRegistry(), null));
    }

    public FetchResponse fetch(FetchRequest request) throws FetchException {

        HttpUriRequest uriRequest;

        switch (request.getMethod()) {
        case GET:
            uriRequest = new HttpGet(request.getUri());
            break;
        case POST:
            uriRequest = new HttpPost(request.getUri());
            break;
        case HEAD:
            uriRequest = new HttpHead(request.getUri());
            break;
        default:
            throw new FetchException("unsupported HTTP method: " + request.getMethod());
        }

        try {
            return new DefaultFetchResponse(httpClient.execute(uriRequest));
        } catch (ClientProtocolException e) {
            throw new FetchException(request, e);
        } catch (IOException e) {
            throw new FetchException(request, e);
        }
    }

    private static class DefaultFetchResponse implements FetchResponse {

        private final HttpResponse response;

        public DefaultFetchResponse(HttpResponse response) {
            this.response = response;
        }

        public int getStatusCode() {
            return response.getStatusLine().getStatusCode();
        }

        public InputStream getContentAsStream() throws FetchException {
            try {
                return response.getEntity().getContent();
            } catch (IllegalStateException e) {
                throw new FetchException(e);
            } catch (IOException e) {
                throw new FetchException(e);
            }
        }

        public byte[] getContentAsBytes() throws FetchException {
            try {
                return IOUtils.toByteArray(getContentAsStream());
            } catch (IOException e) {
                throw new FetchException(e);
            }
        }

        public String getFirstHeader(String name) {
            Header header = response.getFirstHeader(name);
            if (header == null) {
                return null;
            }
            return header.getValue();
        }
    }
}