ImgScroll/src/main/java/de/gurkengewuerz/ripmewrapper/handler/APIHandler.java

package de.gurkengewuerz.ripmewrapper.handler;

import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;
import org.json.JSONArray;
import org.json.JSONObject;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Created by gurkengewuerz.de on 09.10.2018.
 */
public class APIHandler extends AbstractHandler {

    @Override
    public void handle(String s, Request request, HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws IOException {
        try {
            Connection connection = DriverManager.getConnection("jdbc:sqlite:reddit_meta.db");
            Statement statement = connection.createStatement();
            statement.setQueryTimeout(30);  // set timeout to 30 sec.


            JSONObject returnObject = null;
            JSONArray returnArray = null;

            request.setCharacterEncoding("UTF-8");
            httpServletResponse.setCharacterEncoding("UTF-8");

            if (s.equals("/get")) {
                httpServletResponse.setStatus(HttpServletResponse.SC_OK);
                returnArray = new JSONArray();

                if (request.getParameter("subreddits") != null) {
                    String[] subreddits = request.getParameter("subreddits").split(",");

                    int offset = request.getParameter("offset") == null ? -1 : Integer.valueOf(request.getParameter("offset"));

                    StringBuilder builder = new StringBuilder();
                    for (int i = 0; i < subreddits.length; i++) {
                        builder.append("?,");
                    }

                    String builderString = builder.deleteCharAt(builder.length() - 1).toString();

                    int limit = 0;
                    int index = 1;


                    if (offset != -1) {
                        PreparedStatement psPre = connection.prepareStatement(
                                "SELECT iid FROM filelist LEFT JOIN metalist ON filelist.id = metalist.id WHERE subreddit IN (" + builderString + ") ORDER BY created DESC, iid DESC"
                        );

                        for (String o : subreddits) {
                            psPre.setString(index++, o);
                        }

                        ResultSet rsPre = psPre.executeQuery();
                        while (rsPre.next()) {
                            limit++;
                            if (rsPre.getInt("iid") == offset) {
                                break;
                            }
                        }
                        rsPre.close();
                        psPre.close();
                    }

                    // ----------------

                    PreparedStatement ps = connection.prepareStatement(
                            "SELECT iid, metalist.id, subreddit, created, path FROM filelist LEFT JOIN metalist ON filelist.id = metalist.id WHERE subreddit IN (" + builderString + ") ORDER BY created DESC, iid DESC LIMIT 10 OFFSET ?"
                    );

                    index = 1;
                    for (String o : subreddits) {
                        ps.setString(index++, o);
                    }

                    ps.setInt(index, limit);


                    ResultSet rs = ps.executeQuery();
                    while (rs.next()) {
                        JSONObject data = new JSONObject();
                        data.put("iid", rs.getInt("iid"));
                        data.put("id", rs.getString("id"));
                        data.put("subreddit", rs.getString("subreddit"));
                        data.put("created", rs.getInt("created"));
                        data.put("webm", rs.getString("path").endsWith(".webm"));
                        data.put("mp4", rs.getString("path").endsWith(".mp4"));
                        returnArray.put(data);
                    }
                    rs.close();
                }
            } else if (s.equals("/img")) {
                httpServletResponse.setStatus(HttpServletResponse.SC_OK);

                PreparedStatement ps = connection.prepareStatement("SELECT path FROM filelist WHERE iid = ? AND id = ?");

                ps.setString(1, request.getParameter("iid"));
                ps.setString(2, request.getParameter("id"));

                ResultSet rs = ps.executeQuery();


                if (rs.next()) {
                    String path = rs.getString("path");


                    byte[] encoded = Files.readAllBytes(Paths.get(path));
                    httpServletResponse.setContentType(Files.probeContentType(Paths.get(path)));// or png or gif, etc
                    httpServletResponse.setContentLength(encoded.length);
                    httpServletResponse.getOutputStream().write(encoded);
                }

                request.setHandled(true);
                return;
            } else if (s.equals("/info")) {
                httpServletResponse.setStatus(HttpServletResponse.SC_OK);
                returnObject = new JSONObject();

                ResultSet rs = statement.executeQuery("SELECT DISTINCT subreddit FROM metalist;");
                JSONArray ja = new JSONArray();
                while (rs.next()) {
                    ja.put(rs.getString("subreddit"));
                }
                returnObject.put("subreddits", ja);
                returnObject.put("subreddits_count", ja.length());

                rs = statement.executeQuery("SELECT COUNT(*) c_all FROM filelist;");
                if (rs.next()) {
                    returnObject.put("files", rs.getInt("c_all"));
                }


                if (request.getParameter("subreddits") != null) {
                    String[] subreddits = request.getParameter("subreddits").split(",");
                    StringBuilder builder = new StringBuilder();
                    for (int i = 0; i < subreddits.length; i++) {
                        builder.append("?,");
                    }

                    PreparedStatement ps = connection.prepareStatement(
                            "SELECT COUNT(*) c FROM filelist LEFT JOIN metalist ON filelist.id = metalist.id WHERE subreddit IN (" + builder.deleteCharAt(builder.length() - 1).toString() + ")"
                    );

                    int index = 1;
                    for (String o : subreddits) {
                        ps.setString(index++, o);
                    }

                    rs = ps.executeQuery();
                    if (rs.next()) {
                        returnObject.put("files_subreddits", rs.getInt("c"));
                    }
                }
            } else {
                httpServletResponse.setStatus(HttpServletResponse.SC_FORBIDDEN);
            }

            httpServletResponse.setContentType("application/json; charset=utf-8");

            PrintWriter out = httpServletResponse.getWriter();
            if (returnObject != null) {
                out.write(returnObject.toString());
            } else if (returnArray != null) {
                out.write(returnArray.toString());
            } else {
                returnObject = new JSONObject();
                returnObject.put("error", "not found");
                out.write(returnObject.toString());
            }

            request.setHandled(true);

            connection.close();
        } catch (SQLException e) {
            Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, e);
        }
    }

}