Add filter to extract a torrent state from an HTML state.

diff --git a/src/main/java/net/pterodactylus/reactor/filters/KickAssTorrentsFilter.java b/src/main/java/net/pterodactylus/reactor/filters/KickAssTorrentsFilter.java
new file mode 100644 (file)
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+++ b/src/main/java/net/pterodactylus/reactor/filters/KickAssTorrentsFilter.java
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+/*
+ * Reactor - KickAssTorrentsFilter.java - Copyright © 2013 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.reactor.filters;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import net.pterodactylus.reactor.Filter;
+import net.pterodactylus.reactor.State;
+import net.pterodactylus.reactor.queries.HttpQuery;
+import net.pterodactylus.reactor.states.FailedState;
+import net.pterodactylus.reactor.states.HtmlState;
+import net.pterodactylus.reactor.states.TorrentState;
+import net.pterodactylus.reactor.states.TorrentState.TorrentFile;
+
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
+import org.jsoup.select.Elements;
+
+/**
+ * {@link Filter} implementation that parses a {@link TorrentState} from an
+ * {@link HtmlState} which was generated by a {@link HttpQuery} to
+ * {@code kickasstorrents.ph}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class KickAssTorrentsFilter implements Filter {
+
+       /**
+        * {@inheritDoc}
+        */
+       @Override
+       public State filter(State state) {
+               if (!state.success()) {
+                       return FailedState.from(state);
+               }
+               checkState(state instanceof HtmlState, "state is not an HtmlState but a %s", state.getClass().getName());
+
+               /* get result table. */
+               Document document = ((HtmlState) state).document();
+               Elements mainTable = document.select("table.data");
+               if (mainTable.isEmpty()) {
+                       /* no main table? */
+                       return new FailedState();
+               }
+
+               /* iterate over all rows. */
+               TorrentState torrentState = new TorrentState();
+               Elements dataRows = mainTable.select("tr:gt(0)");
+               for (Element dataRow : dataRows) {
+                       String name = extractName(dataRow);
+                       String size = extractSize(dataRow);
+                       String magnetUri = extractMagnetUri(dataRow);
+                       String downloadUri;
+                       try {
+                               downloadUri = new URI(((HtmlState) state).uri()).resolve(extractDownloadUri(dataRow)).toString();
+                               TorrentFile torrentFile = new TorrentFile(name, size, magnetUri, downloadUri);
+                               torrentState.addTorrentFile(torrentFile);
+                       } catch (URISyntaxException use1) {
+                               /* ignore; if uri was wrong, we wouldn’t be here. */
+                       }
+               }
+
+               return torrentState;
+       }
+
+       //
+       // STATIC METHODS
+       //
+
+       /**
+        * Extracts the name from the given row.
+        *
+        * @param dataRow
+        *            The row to extract the name from
+        * @return The extracted name
+        */
+       private static String extractName(Element dataRow) {
+               return dataRow.select("div.torrentname a.normalgrey").text();
+       }
+
+       /**
+        * Extracts the size from the given row.
+        *
+        * @param dataRow
+        *            The row to extract the size from
+        * @return The extracted size
+        */
+       private static String extractSize(Element dataRow) {
+               return dataRow.select("td:eq(1)").text();
+       }
+
+       /**
+        * Extracts the magnet URI from the given row.
+        *
+        * @param dataRow
+        *            The row to extract the magnet URI from
+        * @return The extracted magnet URI
+        */
+       private static String extractMagnetUri(Element dataRow) {
+               return dataRow.select("a.imagnet").attr("href");
+       }
+
+       /**
+        * Extracts the download URI from the given row.
+        *
+        * @param dataRow
+        *            The row to extract the download URI from
+        * @return The extracted download URI
+        */
+       private static String extractDownloadUri(Element dataRow) {
+               return dataRow.select("a.idownload:not(.partner1Button)").attr("href");
+       }
+
+}