Add support for proxying HTTP requests (#1461)

projects/common/src/main/java/dan200/computercraft/shared/config/AddressRuleConfig.java

@@ -45,6 +45,9 @@ class AddressRuleConfig {
 
             config.setComment("max_websocket_message", "The maximum size (in bytes) that a computer can send or receive in one websocket packet.");
             config.set("max_websocket_message", AddressRule.WEBSOCKET_MESSAGE);
+
+            config.setComment("use_proxy", "Enable use of the HTTP/SOCKS proxy if it is configured.");
+            config.set("use_proxy", false);
         }
 
         return config;
@@ -58,6 +61,7 @@ class AddressRuleConfig {
             && check(builder, "max_upload", Number.class)
             && check(builder, "max_download", Number.class)
             && check(builder, "websocket_message", Number.class)
+            && check(builder, "use_proxy", Boolean.class)
             && AddressRule.parse(hostObj, port, PartialOptions.DEFAULT) != null;
     }
 
@@ -71,12 +75,14 @@ class AddressRuleConfig {
         var maxUpload = unboxOptLong(get(builder, "max_upload", Number.class).map(Number::longValue));
         var maxDownload = unboxOptLong(get(builder, "max_download", Number.class).map(Number::longValue));
         var websocketMessage = unboxOptInt(get(builder, "websocket_message", Number.class).map(Number::intValue));
+        var useProxy = get(builder, "use_proxy", Boolean.class);
 
         var options = new PartialOptions(
             action,
             maxUpload,
             maxDownload,
-            websocketMessage
+            websocketMessage,
+            useProxy
         );
 
         return AddressRule.parse(hostObj, port, options);

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigFile.java

@@ -8,6 +8,7 @@ import com.google.common.base.Splitter;
 
 import javax.annotation.Nullable;
 import javax.annotation.OverridingMethodsMustInvokeSuper;
+import java.nio.file.Path;
 import java.util.ArrayDeque;
 import java.util.Deque;
 import java.util.List;
@@ -141,6 +142,18 @@ public interface ConfigFile {
          * @param onChange The function to run on change.
          * @return The built config file.
          */
-        public abstract ConfigFile build(Runnable onChange);
+        public abstract ConfigFile build(ConfigListener onChange);
+    }
+
+    @FunctionalInterface
+    interface ConfigListener {
+        /**
+         * The function called then a config file is changed.
+         *
+         * @param path The path to the config file. This will be {@code null} when the config file does not exist on
+         *             disk, such as when synced from a server to the client.
+         * @see Builder#build(ConfigListener)
+         */
+        void onConfigChanged(@Nullable Path path);
     }
 }

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigSpec.java

@@ -5,10 +5,12 @@
 package dan200.computercraft.shared.config;
 
 import com.electronwill.nightconfig.core.UnmodifiableConfig;
+import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.core.CoreConfig;
 import dan200.computercraft.core.Logging;
 import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.core.apis.http.options.Action;
+import dan200.computercraft.core.apis.http.options.ProxyType;
 import dan200.computercraft.core.computer.mainthread.MainThreadConfig;
 import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
 import dan200.computercraft.shared.platform.PlatformHelper;
@@ -16,6 +18,8 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.core.Filter;
 import org.apache.logging.log4j.core.filter.MarkerFilter;
 
+import javax.annotation.Nullable;
+import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
@@ -49,6 +53,10 @@ public final class ConfigSpec {
     public static final ConfigFile.Value<Integer> httpDownloadBandwidth;
     public static final ConfigFile.Value<Integer> httpUploadBandwidth;
 
+    public static final ConfigFile.Value<ProxyType> httpProxyType;
+    public static final ConfigFile.Value<String> httpProxyHost;
+    public static final ConfigFile.Value<Integer> httpProxyPort;
+
     public static final ConfigFile.Value<Boolean> commandBlockEnabled;
     public static final ConfigFile.Value<Integer> modemRange;
     public static final ConfigFile.Value<Integer> modemHighAltitudeRange;
@@ -222,6 +230,30 @@ public final class ConfigSpec {
 
             builder.pop();
 
+            builder
+                .comment("""
+                    Tunnels HTTP and websocket requests through a proxy server. Only affects HTTP
+                    rules with "use_proxy" set to true (off by default).
+                    If authentication is required for the proxy, create a "computercraft-proxy.pw"
+                    file in the same directory as "computercraft-server.toml", containing the
+                    username and password separated by a colon, e.g. "myuser:mypassword". For
+                    SOCKS4 proxies only the username is required.""")
+                .push("proxy");
+
+            httpProxyType = builder
+                .comment("The type of proxy to use.")
+                .defineEnum("type", CoreConfig.httpProxyType);
+
+            httpProxyHost = builder
+                .comment("The hostname or IP address of the proxy server.")
+                .define("host", CoreConfig.httpProxyHost);
+
+            httpProxyPort = builder
+                .comment("The port of the proxy server.")
+                .defineInRange("port", CoreConfig.httpProxyPort, 1, 65536);
+
+            builder.pop();
+
             builder.pop();
         }
 
@@ -339,7 +371,7 @@ public final class ConfigSpec {
         clientSpec = clientBuilder.build(ConfigSpec::syncClient);
     }
 
-    public static void syncServer() {
+    public static void syncServer(@Nullable Path path) {
         // General
         Config.computerSpaceLimit = computerSpaceLimit.get();
         Config.floppySpaceLimit = floppySpaceLimit.get();
@@ -370,6 +402,13 @@ public final class ConfigSpec {
         CoreConfig.httpMaxWebsockets = httpMaxWebsockets.get();
         CoreConfig.httpDownloadBandwidth = httpDownloadBandwidth.get();
         CoreConfig.httpUploadBandwidth = httpUploadBandwidth.get();
+
+        CoreConfig.httpProxyType = httpProxyType.get();
+        CoreConfig.httpProxyHost = httpProxyHost.get();
+        CoreConfig.httpProxyPort = httpProxyPort.get();
+
+        if (path != null) ProxyPasswordConfig.init(path.resolveSibling(ComputerCraftAPI.MOD_ID + "-proxy.pw"));
+
         NetworkUtils.reloadConfig();
 
         // Peripheral
@@ -396,7 +435,7 @@ public final class ConfigSpec {
         Config.monitorHeight = monitorHeight.get();
     }
 
-    public static void syncClient() {
+    public static void syncClient(@Nullable Path path) {
         Config.monitorRenderer = monitorRenderer.get();
         Config.monitorDistance = monitorDistance.get();
         Config.uploadNagDelay = uploadNagDelay.get();

projects/common/src/main/java/dan200/computercraft/shared/config/ProxyPasswordConfig.java

@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.config;
+
+import dan200.computercraft.core.CoreConfig;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+record ProxyPasswordConfig(String username, String password) {
+    private static final Logger LOG = LoggerFactory.getLogger(ProxyPasswordConfig.class);
+
+    @Nullable
+    private static ProxyPasswordConfig loadFromFile(@Nullable Path path) {
+        if (path == null || !path.toFile().exists()) return null;
+
+        try (var br = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
+            var line = br.readLine();
+            if (line == null) return null;
+
+            var parts = line.trim().split(":", 2);
+            if (parts.length == 0) return null;
+
+            return new ProxyPasswordConfig(parts[0], parts.length == 2 ? parts[1] : "");
+        } catch (IOException e) {
+            LOG.error("Failed to load proxy password from {}.", path, e);
+            return null;
+        }
+    }
+
+    static void init(@Nullable Path path) {
+        var config = loadFromFile(path);
+        if (config == null) {
+            CoreConfig.httpProxyUsername = "";
+            CoreConfig.httpProxyPassword = "";
+        } else {
+            CoreConfig.httpProxyUsername = config.username;
+            CoreConfig.httpProxyPassword = config.password;
+        }
+    }
+}