org.xwiki.formula.internal.MathTranFormulaRenderer.java Source code

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Here is the source code for org.xwiki.formula.internal.MathTranFormulaRenderer.java

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/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.formula.internal;

import java.io.IOException;
import java.net.URLEncoder;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.GetMethod;
import org.xwiki.component.annotation.Component;
import org.xwiki.component.phase.Initializable;
import org.xwiki.component.phase.InitializationException;
import org.xwiki.formula.AbstractFormulaRenderer;
import org.xwiki.formula.FormulaRenderer;
import org.xwiki.formula.ImageData;

/**
 * Implementation of the {@link FormulaRenderer} component, which uses the <a
 * href="http://www.mathtran.org/">MathTran</a> remote service for rendering mathematical formulae. Results as good as
 * those obtained from the native TeX system, with the advantage that it doesn't require the presence of a local TeX
 * installation, but with the disadvantage that it requires fast, continuous access to an external server.
 * <p>
 * Performance tip: MathTran is free software. You can install and run it on a local server, or even on the same
 * machine, since on most systems the batch/daemon mode of MathTran might give better performance than using the native
 * TeX command.
 * </p>
 * 
 * @version $Id: 80ccb5434ab669029dd5783f650327a8d1eef345 $
 * @since 2.0M3
 */
@Component("mathtran")
public final class MathTranFormulaRenderer extends AbstractFormulaRenderer implements Initializable {
    /** The base URL of the mathematical formula transformation service. */
    private static final String MATHTRAN_BASE_URL = "http://www.mathtran.org/cgi-bin/mathtran?";

    /** Handles requests to the mathematical formula transformation service. */
    private final HttpClient client = new HttpClient();

    /**
     * {@inheritDoc}
     */
    public void initialize() throws InitializationException {
        this.client.getHttpConnectionManager().getParams().setConnectionTimeout(10000);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected ImageData renderImage(String formula, boolean inline, FormulaRenderer.FontSize size,
            FormulaRenderer.Type type) throws IllegalArgumentException, IOException {
        String encodedFormula = URLEncoder.encode((inline ? "" : "\\displaystyle") + formula, "UTF-8");
        GetMethod method = new GetMethod(
                MATHTRAN_BASE_URL + "D=" + Math.max(size.ordinal() - 3, 0) + "&tex=" + encodedFormula);
        method.setRequestHeader("accept", type.getMimetype());
        method.setFollowRedirects(true);

        // Execute the GET method
        int statusCode = this.client.executeMethod(method);
        if (statusCode >= HttpStatus.SC_OK && statusCode < HttpStatus.SC_BAD_REQUEST) {
            byte[] b = method.getResponseBody();
            method.releaseConnection();
            return new ImageData(b, type);
        }

        throw new IOException("Can't load image from MathTran server");
    }
}