Implement http caching (#2840)

* Implement first response parts of http caching
* Implement cached response for static resources
* Implement HTTP caching for json responses
* Fix last seen value for online players
* Implement http caching for pages (.html)
* Use placeholder cache even with async requests.

Affects issues:
- Close #2813

Plan/api/src/main/java/com/djrapitops/plan/delivery/web/resource/WebResource.java

@@ -16,11 +16,10 @@
  */
 package com.djrapitops.plan.delivery.web.resource;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
 import java.nio.charset.StandardCharsets;
+import java.util.Optional;
+import java.util.function.Supplier;
 
 /**
  * Represents a customizable resource.
@@ -61,19 +60,55 @@ static WebResource create(String utf8String) {
      * @throws IOException If the stream can not be read.
      */
     static WebResource create(InputStream in) throws IOException {
+        return create(in, null);
+    }
+
+    /**
+     * Creates a new WebResource from an InputStream.
+     *
+     * @param in           InputStream for the resource, closed after inside the method.
+     * @param lastModified Epoch millisecond the resource was last modified
+     * @return WebResource.
+     * @throws IOException If the stream can not be read.
+     */
+    static WebResource create(InputStream in, Long lastModified) throws IOException {
         try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
             int read;
             byte[] bytes = new byte[1024];
             while ((read = in.read(bytes)) != -1) {
                 out.write(bytes, 0, read);
             }
 
-            return new ByteResource(out.toByteArray());
+            return new ByteResource(out.toByteArray(), lastModified);
         } finally {
             in.close();
         }
     }
 
+    /**
+     * Create a lazy WebResource that only reads contents if necessary.
+     *
+     * @param in           Supplier for InputStream, a lazy method that reads input when necessary.
+     * @param lastModified Last modified date for the resource.
+     * @return WebResource.
+     */
+    static WebResource create(Supplier<InputStream> in, Long lastModified) {
+        return new LazyWebResource(in, () -> {
+            try (ByteArrayOutputStream out = new ByteArrayOutputStream();
+                 InputStream input = in.get()) {
+                int read;
+                byte[] bytes = new byte[1024];
+                while ((read = input.read(bytes)) != -1) {
+                    out.write(bytes, 0, read);
+                }
+
+                return out.toByteArray();
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+        }, lastModified);
+    }
+
     byte[] asBytes();
 
     /**
@@ -85,11 +120,21 @@ static WebResource create(InputStream in) throws IOException {
 
     InputStream asStream();
 
+    default Optional<Long> getLastModified() {
+        return Optional.empty();
+    }
+
     final class ByteResource implements WebResource {
         private final byte[] content;
+        private final Long lastModified;
 
         public ByteResource(byte[] content) {
+            this(content, null);
+        }
+
+        public ByteResource(byte[] content, Long lastModified) {
             this.content = content;
+            this.lastModified = lastModified;
         }
 
         @Override
@@ -106,5 +151,42 @@ public String asString() {
         public InputStream asStream() {
             return new ByteArrayInputStream(content);
         }
+
+        @Override
+        public Optional<Long> getLastModified() {
+            return Optional.ofNullable(lastModified);
+        }
+    }
+
+    final class LazyWebResource implements WebResource {
+        private final Supplier<InputStream> inputStreamSupplier;
+        private final Supplier<byte[]> contentSupplier;
+        private final Long lastModified;
+
+        public LazyWebResource(Supplier<InputStream> inputStreamSupplier, Supplier<byte[]> contentSupplier, Long lastModified) {
+            this.inputStreamSupplier = inputStreamSupplier;
+            this.contentSupplier = contentSupplier;
+            this.lastModified = lastModified;
+        }
+
+        @Override
+        public byte[] asBytes() {
+            return contentSupplier.get();
+        }
+
+        @Override
+        public String asString() {
+            return new String(asBytes(), StandardCharsets.UTF_8);
+        }
+
+        @Override
+        public InputStream asStream() {
+            return inputStreamSupplier.get();
+        }
+
+        @Override
+        public Optional<Long> getLastModified() {
+            return Optional.ofNullable(lastModified);
+        }
     }
 }

Plan/bukkit/src/main/java/com/djrapitops/plan/addons/placeholderapi/PlanPlaceholderExtension.java

@@ -96,7 +96,9 @@ public String onRequest(OfflinePlayer player, @Untrusted String params) {
             if ("Server thread".equalsIgnoreCase(Thread.currentThread().getName())) {
                 return getCached(params, uuid);
             }
-            return getPlaceholderValue(params, uuid);
+
+            return Optional.ofNullable(getCached(params, uuid))
+                    .orElseGet(() -> getPlaceholderValue(params, uuid));
         } catch (IllegalStateException e) {
             if ("zip file closed".equals(e.getMessage())) {
                 return null; // Plan is disabled.

Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/json/PlayerJSONCreator.java

@@ -46,6 +46,7 @@
 import com.djrapitops.plan.storage.database.Database;
 import com.djrapitops.plan.storage.database.queries.containers.PlayerContainerQuery;
 import com.djrapitops.plan.storage.database.queries.objects.ServerQueries;
+import com.djrapitops.plan.storage.database.queries.objects.SessionQueries;
 import com.djrapitops.plan.utilities.comparators.DateHolderRecentComparator;
 import com.djrapitops.plan.utilities.java.Lists;
 import com.djrapitops.plan.utilities.java.Maps;
@@ -91,6 +92,10 @@ public PlayerJSONCreator(
         this.graphs = graphs;
     }
 
+    public long getLastSeen(UUID playerUUID) {
+        return dbSystem.getDatabase().query(SessionQueries.lastSeen(playerUUID));
+    }
+
     public Map<String, Object> createJSONAsMap(UUID playerUUID) {
         Database db = dbSystem.getDatabase();
 
@@ -226,6 +231,7 @@ private Map<String, Object> createInfoJSONMap(PlayerContainer player, Map<Server
         info.put("best_ping", bestPing != -1.0 ? bestPing + " ms" : unavailable);
         info.put("registered", player.getValue(PlayerKeys.REGISTERED).map(year).orElse("-"));
         info.put("last_seen", player.getValue(PlayerKeys.LAST_SEEN).map(year).orElse("-"));
+        info.put("last_seen_raw_value", player.getValue(PlayerKeys.LAST_SEEN).orElse(0L));
 
         return info;
     }

Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/pages/LoginPage.java

@@ -17,6 +17,7 @@
 package com.djrapitops.plan.delivery.rendering.pages;
 
 import com.djrapitops.plan.delivery.formatting.PlaceholderReplacer;
+import com.djrapitops.plan.delivery.web.resource.WebResource;
 import com.djrapitops.plan.identification.ServerInfo;
 import com.djrapitops.plan.settings.locale.Locale;
 import com.djrapitops.plan.settings.theme.Theme;
@@ -30,15 +31,15 @@
  */
 public class LoginPage implements Page {
 
-    private final String template;
+    private final WebResource template;
     private final ServerInfo serverInfo;
     private final Locale locale;
     private final Theme theme;
 
     private final VersionChecker versionChecker;
 
     LoginPage(
-            String htmlTemplate,
+            WebResource htmlTemplate,
             ServerInfo serverInfo,
             Locale locale,
             Theme theme,
@@ -51,12 +52,17 @@ public class LoginPage implements Page {
         this.versionChecker = versionChecker;
     }
 
+    @Override
+    public long lastModified() {
+        return template.getLastModified().orElseGet(System::currentTimeMillis);
+    }
+
     @Override
     public String toHtml() {
         PlaceholderReplacer placeholders = new PlaceholderReplacer();
         placeholders.put("command", getCommand());
         placeholders.put("version", versionChecker.getCurrentVersion());
-        return UnaryChain.of(template)
+        return UnaryChain.of(template.asString())
                 .chain(theme::replaceThemeColors)
                 .chain(placeholders::apply)
                 .chain(locale::replaceLanguageInHtml)

Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/pages/Page.java

@@ -23,4 +23,8 @@
  */
 public interface Page {
     String toHtml();
+
+    default long lastModified() {
+        return System.currentTimeMillis();
+    }
 }

Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/pages/PageFactory.java

@@ -22,6 +22,7 @@
 import com.djrapitops.plan.delivery.rendering.html.icon.Icon;
 import com.djrapitops.plan.delivery.web.ResourceService;
 import com.djrapitops.plan.delivery.web.resolver.exception.NotFoundException;
+import com.djrapitops.plan.delivery.web.resource.WebResource;
 import com.djrapitops.plan.delivery.webserver.Addresses;
 import com.djrapitops.plan.delivery.webserver.cache.JSONStorage;
 import com.djrapitops.plan.extension.implementation.results.ExtensionData;
@@ -41,7 +42,6 @@
 import com.djrapitops.plan.utilities.dev.Untrusted;
 import com.djrapitops.plan.version.VersionChecker;
 import dagger.Lazy;
-import org.apache.commons.lang3.StringUtils;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -101,15 +101,12 @@ public Page playersPage() throws IOException {
             return reactPage();
         }
 
-        return new PlayersPage(getResource("players.html"), versionChecker.get(),
+        return new PlayersPage(getResourceAsString("players.html"), versionChecker.get(),
                 config.get(), theme.get(), serverInfo.get());
     }
 
     public Page reactPage() throws IOException {
-        String reactHtml = StringUtils.replace(
-                getResource("index.html"),
-                "/static", getBasePath() + "/static");
-        return () -> reactHtml;
+        return new ReactPage(getBasePath(), getResource("index.html"));
     }
 
     private String getBasePath() {
@@ -135,7 +132,7 @@ public Page serverPage(ServerUUID serverUUID) throws IOException {
         }
 
         return new ServerPage(
-                getResource("server.html"),
+                getResourceAsString("server.html"),
                 server,
                 config.get(),
                 theme.get(),
@@ -158,7 +155,7 @@ public Page playerPage(UUID playerUUID) throws IOException {
         }
 
         return new PlayerPage(
-                getResource("player.html"), player,
+                getResourceAsString("player.html"), player,
                 versionChecker.get(),
                 config.get(),
                 this,
@@ -207,7 +204,7 @@ public Page networkPage() throws IOException {
             return reactPage();
         }
 
-        return new NetworkPage(getResource("network.html"),
+        return new NetworkPage(getResourceAsString("network.html"),
                 dbSystem.get(),
                 versionChecker.get(),
                 config.get(),
@@ -223,7 +220,7 @@ public Page networkPage() throws IOException {
     public Page internalErrorPage(String message, @Untrusted Throwable error) {
         try {
             return new InternalErrorPage(
-                    getResource("error.html"), message, error,
+                    getResourceAsString("error.html"), message, error,
                     versionChecker.get());
         } catch (IOException noParse) {
             return () -> "Error occurred: " + error.toString() +
@@ -234,20 +231,24 @@ public Page internalErrorPage(String message, @Untrusted Throwable error) {
 
     public Page errorPage(String title, String error) throws IOException {
         return new ErrorMessagePage(
-                getResource("error.html"), title, error,
+                getResourceAsString("error.html"), title, error,
                 versionChecker.get(), theme.get());
     }
 
     public Page errorPage(Icon icon, String title, String error) throws IOException {
         return new ErrorMessagePage(
-                getResource("error.html"), icon, title, error, theme.get(), versionChecker.get());
+                getResourceAsString("error.html"), icon, title, error, theme.get(), versionChecker.get());
     }
 
-    public String getResource(String name) throws IOException {
+    public String getResourceAsString(String name) throws IOException {
+        return getResource(name).asString();
+    }
+
+    public WebResource getResource(String name) throws IOException {
         try {
             return ResourceService.getInstance().getResource("Plan", name,
                     () -> files.get().getResourceFromJar("web/" + name).asWebResource()
-            ).asString();
+            );
         } catch (UncheckedIOException readFail) {
             throw readFail.getCause();
         }
@@ -274,7 +275,7 @@ public Page queryPage() throws IOException {
             return reactPage();
         }
         return new QueryPage(
-                getResource("query.html"),
+                getResourceAsString("query.html"),
                 locale.get(), theme.get(), versionChecker.get()
         );
     }

Plan/common/src/main/java/com/djrapitops/plan/delivery/rendering/pages/ReactPage.java

@@ -0,0 +1,48 @@
+/*
+ *  This file is part of Player Analytics (Plan).
+ *
+ *  Plan is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License v3 as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Plan 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 Plan. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.djrapitops.plan.delivery.rendering.pages;
+
+import com.djrapitops.plan.delivery.web.resource.WebResource;
+import org.apache.commons.lang3.StringUtils;
+
+/**
+ * Represents React index.html.
+ *
+ * @author AuroraLS3
+ */
+public class ReactPage implements Page {
+
+    private final String basePath;
+    private final WebResource reactHtml;
+
+    public ReactPage(String basePath, WebResource reactHtml) {
+        this.basePath = basePath;
+        this.reactHtml = reactHtml;
+    }
+
+    @Override
+    public String toHtml() {
+        return StringUtils.replace(
+                reactHtml.asString(),
+                "/static", basePath + "/static");
+    }
+
+    @Override
+    public long lastModified() {
+        return reactHtml.getLastModified().orElseGet(System::currentTimeMillis);
+    }
+}