org.apache.zeppelin.markdown.PegdownWebSequencelPlugin.java Source code

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Here is the source code for org.apache.zeppelin.markdown.PegdownWebSequencelPlugin.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.zeppelin.markdown;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.parboiled.BaseParser;
import org.parboiled.Rule;
import org.parboiled.support.StringBuilderVar;
import org.pegdown.Parser;
import org.pegdown.ast.ExpImageNode;
import org.pegdown.ast.TextNode;
import org.pegdown.plugins.BlockPluginParser;
import org.pegdown.plugins.PegDownPlugins;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;

/**
 * Pegdown plugin for Websequence diagram
 */
public class PegdownWebSequencelPlugin extends Parser implements BlockPluginParser {

    private static final String WEBSEQ_URL = "http://www.websequencediagrams.com";

    public PegdownWebSequencelPlugin() {
        super(PegdownParser.OPTIONS, PegdownParser.PARSING_TIMEOUT_AS_MILLIS, DefaultParseRunnerProvider);
    }

    public PegdownWebSequencelPlugin(Integer opts, Long millis, ParseRunnerProvider provider,
            PegDownPlugins plugins) {
        super(opts, millis, provider, plugins);
    }

    public static final String TAG = "%%%";

    Rule StartMarker() {
        return Sequence(Spn1(), TAG, Sp(), "sequence", Sp());
    }

    String EndMarker() {
        return TAG;
    }

    Rule Body() {
        return OneOrMore(TestNot(TAG), BaseParser.ANY);
    }

    Rule BlockRule() {
        StringBuilderVar style = new StringBuilderVar();
        StringBuilderVar body = new StringBuilderVar();

        return NodeSequence(StartMarker(),
                Optional(String("style="), Sequence(OneOrMore(Letter()), style.append(match()), Spn1())),
                Sequence(Body(), body.append(match())), EndMarker(), push(new ExpImageNode("title",
                        createWebsequenceUrl(style.getString(), body.getString()), new TextNode(""))));
    }

    public static String createWebsequenceUrl(String style, String content) {

        style = StringUtils.defaultString(style, "default");

        OutputStreamWriter writer = null;
        BufferedReader reader = null;

        String webSeqUrl = "";

        try {
            String query = new StringBuilder().append("style=").append(style).append("&message=")
                    .append(URLEncoder.encode(content, "UTF-8")).append("&apiVersion=1").toString();

            URL url = new URL(WEBSEQ_URL);
            URLConnection conn = url.openConnection();
            conn.setDoOutput(true);
            writer = new OutputStreamWriter(conn.getOutputStream(), StandardCharsets.UTF_8);
            writer.write(query);
            writer.flush();

            StringBuilder response = new StringBuilder();
            reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), StandardCharsets.UTF_8));
            String line;
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }

            writer.close();
            reader.close();

            String json = response.toString();

            int start = json.indexOf("?png=");
            int end = json.indexOf("\"", start);

            if (start != -1 && end != -1) {
                webSeqUrl = WEBSEQ_URL + "/" + json.substring(start, end);
            }
        } catch (IOException e) {
            throw new RuntimeException("Failed to get proper response from websequencediagrams.com", e);
        } finally {
            IOUtils.closeQuietly(writer);
            IOUtils.closeQuietly(reader);
        }

        return webSeqUrl;
    }

    @Override
    public Rule[] blockPluginRules() {
        return new Rule[] { BlockRule() };
    }
}