com.ltasks.BaseClient.java Source code

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Here is the source code for com.ltasks.BaseClient.java

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/*
 *  Copyright 2011 LTasks
 *
 *  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.ltasks;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.zip.GZIPInputStream;

import javax.xml.parsers.ParserConfigurationException;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.NameValuePair;
import org.xml.sax.SAXException;

import com.ltasks.htmlfilteroptions.HtmlFilterOptions;
import com.ltasks.htmlfilteroptions.SimpleXPath;

/**
 * BaseClient implements common methods that should be used by different tasks.
 */
public abstract class BaseClient {

    /** The user API KEY */
    private final String mApiKey;

    /** The http client */
    private HttpClient client;

    private boolean mIsIncludeSource;

    private boolean mIsGZipContentEncoding;

    /**
     * Creates a new BaseClient. By default will not include text source, and
     * communication not gzipped.
     * 
     * @param aApiKey
     *            the user api key
     * @throws IllegalArgumentException
     *             the api key does not conform with the standard
     *             representation.
     */
    public BaseClient(String aApiKey) throws IllegalArgumentException {
        this(aApiKey, true, true);
    }

    /**
     * Creates a new BaseClient.
     * 
     * @param aApiKey
     *            the user api key
     * @param aIsIncludeSource
     *            if to include the source text (default is true)
     * @param aIsGZipContentEncoding
     *            if true will gzip contents to communicate with server (default
     *            is true)
     * @throws IllegalArgumentException
     *             the api key does not conform with the standard
     *             representation.
     */
    public BaseClient(String aApiKey, boolean aIsIncludeSource, boolean aIsGZipContentEncoding)
            throws IllegalArgumentException {
        validateApiKey(aApiKey);
        mApiKey = aApiKey;
        client = new HttpClient();
        client.getParams().setParameter("http.useragent", "ltasks4j/0.0.3");
        mIsIncludeSource = aIsIncludeSource;
        mIsGZipContentEncoding = aIsGZipContentEncoding;
    }

    /**
     * This method validates the api key by trying to parse it using
     * {@link UUID#fromString(String)}. If it fails it throws an exception.
     * 
     * @param aApiKey
     *            the user api key
     * @throws IllegalArgumentException
     *             the api key does not conform with the standard
     *             representation.
     */
    private void validateApiKey(String aApiKey) throws IllegalArgumentException {
        UUID.fromString(aApiKey);
    }

    /**
     * The resource URL.
     */
    protected abstract String getResourceUrl();

    /**
     * Post the data to the remote resource.
     * 
     * @param data
     *            the data to post
     * @return the returned object
     * @throws HttpException
     *             Got a protocol error.
     * @throws IOException
     *             Failed to communicate or to read the result.
     * @throws IllegalArgumentException
     *             The data received from server was invalid.
     */
    protected LtasksObject post(List<NameValuePair> data)
            throws HttpException, IOException, IllegalArgumentException {
        GZipPostMethod method = new GZipPostMethod(getResourceUrl(), mIsGZipContentEncoding);

        // Set input content type
        method.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=utf-8");

        // Set response/output format
        method.setRequestHeader("Accept", "application/xml");

        method.setRequestHeader("Accept-Charset", "utf-8");

        List<NameValuePair> body = new ArrayList<NameValuePair>(data.size() + 2);
        body.addAll(data);
        body.add(new NameValuePair("apikey", mApiKey));
        body.add(new NameValuePair("includeSourceText", Boolean.toString(mIsIncludeSource)));

        method.setRequestBody(body.toArray(new NameValuePair[body.size()]));
        method.setContentChunked(true);

        if (mIsGZipContentEncoding) {
            method.setRequestHeader("Accept-Encoding", "gzip");
            method.setRequestHeader("Content-Encoding", "gzip");
        }

        boolean processedOk = false;
        int code = client.executeMethod(method);
        if (code == 200) {
            processedOk = true;
        }
        InputStream is;
        if (method.getResponseHeader("Content-Encoding") != null
                && method.getResponseHeader("Content-Encoding").getValue().contains("gzip")) {
            is = new GZIPInputStream(method.getResponseBodyAsStream());
        } else {
            is = method.getResponseBodyAsStream();
        }

        LtasksObject result = null;
        if (is != null) {
            try {
                result = ResultParser.parse(is, processedOk);
            } catch (ParserConfigurationException e) {
                throw new IllegalArgumentException("Got an invalid response from server.", e);
            } catch (SAXException e) {
                throw new IllegalArgumentException("Got an invalid response from server.", e);
            }
        } else {
            result = new LtasksObject(null, "Failed to process request. Code: " + code, false, null);
        }
        is.close();
        method.releaseConnection();
        return result;
    }

    protected List<NameValuePair> createNameValuePairs(NameValuePair data, HtmlFilterOptions filterOptions) {
        List<NameValuePair> list = new ArrayList<NameValuePair>(4);

        list.add(data);
        if (filterOptions.getInclude() != null) {
            list.add(new NameValuePair("include", SimpleXPath.toString(filterOptions.getInclude())));
        }
        if (filterOptions.getExclude() != null) {
            list.add(new NameValuePair("exclude", SimpleXPath.toString(filterOptions.getExclude())));
        }
        if (filterOptions.getFilter() != null) {
            list.add(new NameValuePair("filter", filterOptions.getFilter().toString()));
        }

        return list;
    }
}