org.mar9000.space2latex.utils.ConfluenceRESTUtils.java Source code

Introduction

Here is the source code for org.mar9000.space2latex.utils.ConfluenceRESTUtils.java

Source

/*
 * Copyright 2016 Marco Lombardo
 * https://github.com/mar9000
 * 
 * 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.mar9000.space2latex.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import org.json.JSONArray;
import org.json.JSONObject;
import org.mar9000.space2latex.WikiPage;

public class ConfluenceRESTUtils {

    public static final int LIMIT_FOR_REQUEST = 25;
    public static final int MAX_REQUEST_TRY = 3;

    public static void getPages(String urlString, int start, int limit, File destDir) throws MalformedURLException {
        int count = 0;
        int currentLimit = limit < LIMIT_FOR_REQUEST ? limit : LIMIT_FOR_REQUEST;
        while (true) {
            System.out.println("Request pages: start=" + start + ", limit=" + currentLimit);
            JSONObject json = getURLResponse(urlString, start, currentLimit);
            String type = json.optString(WikiPage.JSON_TYPE_ATTR);
            if (WikiPage.JSON_TYPE_VALUE_PAGE.equals(type)) {
                // Single page query,
                WikiPage page = WikiPage.getWikiPage(json);
                try {
                    page.save(destDir);
                } catch (IOException e) {
                    e.printStackTrace();
                    throw new RuntimeException("Error saving page " + page.title + "(" + page.id + ")");
                }
                return;
            } else if (json.optJSONObject(WikiPage.JSON_PAGE_ATTR) != null) {
                // A space query.
                JSONObject pageArray = json.getJSONObject(WikiPage.JSON_PAGE_ATTR);
                JSONArray results = pageArray.getJSONArray(WikiPage.JSON_RESULTS_ATTR);
                if (results.length() == 0)
                    return;
                // Save pages returned by last REST request.
                for (int p = 0; p < results.length(); p++) {
                    WikiPage page = WikiPage.getWikiPage((JSONObject) results.get(p));
                    try {
                        page.save(destDir);
                    } catch (IOException e) {
                        e.printStackTrace();
                        throw new RuntimeException("Error saving page " + page.title + "(" + page.id + ")");
                    }
                }
                // Finish?
                // Less records than requested.
                if (results.length() < currentLimit) {
                    return;
                }
                // Download next chunk.
                count += results.length();
                if (count >= limit) // Greater than should never happen.
                    return;
                start += results.length();
                currentLimit = (limit - count) < LIMIT_FOR_REQUEST ? limit - count : LIMIT_FOR_REQUEST;
            } else {
                throw new RuntimeException("Unknown response from server:" + json.toString());
            }
        }
    }

    public static JSONObject getURLResponse(String urlString) throws MalformedURLException {
        return getURLResponse(urlString, 0, LIMIT_FOR_REQUEST);
    }

    public static JSONObject getURLResponse(String urlString, int start, int limit) throws MalformedURLException {
        StringBuffer buffer = new StringBuffer();
        // Always add limit.
        URL receivedURL = new URL(urlString);
        if (receivedURL.getQuery() == null)
            urlString += "?";
        else
            urlString += "&";
        urlString += "limit=" + limit;
        if (start != 0) {
            urlString += "&start=" + start;
        }
        URL requestURL = new URL(urlString);
        URLConnection urlConn = null;
        int count = MAX_REQUEST_TRY;
        while (urlConn == null && count > 0) {
            try {
                urlConn = requestURL.openConnection();
            } catch (IOException e) {
                try {
                    Thread.sleep(1000 * 5);
                } catch (InterruptedException e1) {
                }
                count--;
                urlConn = null;
            }
        }
        if (urlConn == null)
            throw new RuntimeException("Max retry count reached for open URL: " + urlString);
        //
        BufferedReader reader = null;
        count = MAX_REQUEST_TRY;
        while (reader == null && count > 0) {
            try {
                reader = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
            } catch (IOException e) {
                reader = null;
                count--;
                try {
                    Thread.sleep(1000 * 5);
                } catch (InterruptedException e1) {
                }
            }
        }
        if (reader == null)
            throw new RuntimeException("Max retry count reached for open InputStream: " + urlString);
        //
        try {
            String inputLine;
            while ((inputLine = reader.readLine()) != null) {
                buffer.append(inputLine);
            }
            reader.close();
        } catch (IOException e) {
            throw new RuntimeException("Error reading line from URL: " + urlString);
        }
        // Return.
        return new JSONObject(buffer.toString());
    }

}