Merge pull request #3804 from Janrupf/feature/default-server

Add ability to select a server to join in the instance settings

29 files changed, 520 insertions, 37 deletions

diff --git a/api/logic/BaseInstance.h b/api/logic/BaseInstance.h
index bbeabb41..64de4bb3 100644
--- a/api/logic/BaseInstance.h
+++ b/api/logic/BaseInstance.h
@@ -34,6 +34,8 @@
 
 #include "multimc_logic_export.h"
 
+#include "minecraft/launch/MinecraftServerTarget.h"
+
 class QDir;
 class Task;
 class LaunchTask;
@@ -145,7 +147,8 @@ public:
     virtual shared_qobject_ptr<Task> createUpdateTask(Net::Mode mode) = 0;
 
     /// returns a valid launcher (task container)
-    virtual shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr account) = 0;
+    virtual shared_qobject_ptr<LaunchTask> createLaunchTask(
+            AuthSessionPtr account, MinecraftServerTargetPtr serverToJoin) = 0;
 
     /// returns the current launch task (if any)
     shared_qobject_ptr<LaunchTask> getLaunchTask();
@@ -221,9 +224,9 @@ public:
     bool reloadSettings();
 
     /**
-     * 'print' a verbose desription of the instance into a QStringList
+     * 'print' a verbose description of the instance into a QStringList
      */
-    virtual QStringList verboseDescription(AuthSessionPtr session) = 0;
+    virtual QStringList verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) = 0;
 
     Status currentStatus() const;
 
diff --git a/api/logic/CMakeLists.txt b/api/logic/CMakeLists.txt
index 91155ea7..c3322955 100644
--- a/api/logic/CMakeLists.txt
+++ b/api/logic/CMakeLists.txt
@@ -124,6 +124,8 @@ set(NET_SOURCES
 
 # Game launch logic
 set(LAUNCH_SOURCES
+    launch/steps/LookupServerAddress.cpp
+    launch/steps/LookupServerAddress.h
     launch/steps/PostLaunchCommand.cpp
     launch/steps/PostLaunchCommand.h
     launch/steps/PreLaunchCommand.cpp
@@ -236,6 +238,8 @@ set(MINECRAFT_SOURCES
     minecraft/launch/ExtractNatives.h
     minecraft/launch/LauncherPartLaunch.cpp
     minecraft/launch/LauncherPartLaunch.h
+    minecraft/launch/MinecraftServerTarget.cpp
+    minecraft/launch/MinecraftServerTarget.h
     minecraft/launch/PrintInstanceInfo.cpp
     minecraft/launch/PrintInstanceInfo.h
     minecraft/launch/ReconstructAssets.cpp
diff --git a/api/logic/NullInstance.h b/api/logic/NullInstance.h
index e9ba1a13..94ed6c3a 100644
--- a/api/logic/NullInstance.h
+++ b/api/logic/NullInstance.h
@@ -27,7 +27,7 @@ public:
     {
         return instanceRoot();
     };
-    shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr) override
+    shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr, MinecraftServerTargetPtr) override
     {
         return nullptr;
     }
@@ -67,7 +67,7 @@ public:
     {
         return false;
     }
-    QStringList verboseDescription(AuthSessionPtr session) override
+    QStringList verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) override
     {
         QStringList out;
         out << "Null instance - placeholder.";
diff --git a/api/logic/launch/steps/LookupServerAddress.cpp b/api/logic/launch/steps/LookupServerAddress.cpp
new file mode 100644
index 00000000..de56c28a
--- /dev/null
+++ b/api/logic/launch/steps/LookupServerAddress.cpp
@@ -0,0 +1,95 @@
+/* Copyright 2013-2021 MultiMC Contributors
+ *
+ * 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.
+ */
+
+
+#include "LookupServerAddress.h"
+
+#include <launch/LaunchTask.h>
+
+LookupServerAddress::LookupServerAddress(LaunchTask *parent) :
+    LaunchStep(parent), m_dnsLookup(new QDnsLookup(this))
+{
+    connect(m_dnsLookup, &QDnsLookup::finished, this, &LookupServerAddress::on_dnsLookupFinished);
+
+    m_dnsLookup->setType(QDnsLookup::SRV);
+}
+
+void LookupServerAddress::setLookupAddress(const QString &lookupAddress)
+{
+    m_lookupAddress = lookupAddress;
+    m_dnsLookup->setName(QString("_minecraft._tcp.%1").arg(lookupAddress));
+}
+
+void LookupServerAddress::setOutputAddressPtr(MinecraftServerTargetPtr output)
+{
+    m_output = std::move(output);
+}
+
+bool LookupServerAddress::abort()
+{
+    m_dnsLookup->abort();
+    emitFailed("Aborted");
+    return true;
+}
+
+void LookupServerAddress::executeTask()
+{
+    m_dnsLookup->lookup();
+}
+
+void LookupServerAddress::on_dnsLookupFinished()
+{
+    if (isFinished())
+    {
+        // Aborted
+        return;
+    }
+
+    if (m_dnsLookup->error() != QDnsLookup::NoError)
+    {
+        emit logLine(QString("Failed to resolve server address (this is NOT an error!) %1: %2\n")
+            .arg(m_dnsLookup->name(), m_dnsLookup->errorString()), MessageLevel::MultiMC);
+        resolve(m_lookupAddress, 25565); // Technically the task failed, however, we don't abort the launch
+                                                      // and leave it up to minecraft to fail (or maybe not) when connecting
+        return;
+    }
+
+    const auto records = m_dnsLookup->serviceRecords();
+    if (records.empty())
+    {
+        emit logLine(
+                QString("Failed to resolve server address %1: the DNS lookup succeeded, but no records were returned.\n")
+                .arg(m_dnsLookup->name()), MessageLevel::Warning);
+        resolve(m_lookupAddress, 25565); // Technically the task failed, however, we don't abort the launch
+                                                      // and leave it up to minecraft to fail (or maybe not) when connecting
+        return;
+    }
+
+    const auto &firstRecord = records.at(0);
+    quint16 port = firstRecord.port();
+
+    emit logLine(QString("Resolved server address %1 to %2 with port %3\n").arg(
+            m_dnsLookup->name(), firstRecord.target(), QString::number(port)),MessageLevel::MultiMC);
+    resolve(firstRecord.target(), port);
+}
+
+void LookupServerAddress::resolve(const QString &address, quint16 port)
+{
+    m_output->address = address;
+    m_output->port = port;
+
+    emitSucceeded();
+    m_dnsLookup->deleteLater();
+}
diff --git a/api/logic/launch/steps/LookupServerAddress.h b/api/logic/launch/steps/LookupServerAddress.h
new file mode 100644
index 00000000..5a5c3de1
--- /dev/null
+++ b/api/logic/launch/steps/LookupServerAddress.h
@@ -0,0 +1,49 @@
+/* Copyright 2013-2021 MultiMC Contributors
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <launch/LaunchStep.h>
+#include <QObjectPtr.h>
+#include <QDnsLookup>
+
+#include "minecraft/launch/MinecraftServerTarget.h"
+
+class LookupServerAddress: public LaunchStep {
+Q_OBJECT
+public:
+    explicit LookupServerAddress(LaunchTask *parent);
+    virtual ~LookupServerAddress() {};
+
+    virtual void executeTask();
+    virtual bool abort();
+    virtual bool canAbort() const
+    {
+        return true;
+    }
+
+    void setLookupAddress(const QString &lookupAddress);
+    void setOutputAddressPtr(MinecraftServerTargetPtr output);
+
+private slots:
+    void on_dnsLookupFinished();
+
+private:
+    void resolve(const QString &address, quint16 port);
+
+    QDnsLookup *m_dnsLookup;
+    QString m_lookupAddress;
+    MinecraftServerTargetPtr m_output;
+};
diff --git a/api/logic/minecraft/MinecraftInstance.cpp b/api/logic/minecraft/MinecraftInstance.cpp
index 2d112757..a1341e69 100644
--- a/api/logic/minecraft/MinecraftInstance.cpp
+++ b/api/logic/minecraft/MinecraftInstance.cpp
@@ -12,6 +12,7 @@
 #include <java/JavaVersion.h>
 
 #include "launch/LaunchTask.h"
+#include "launch/steps/LookupServerAddress.h"
 #include "launch/steps/PostLaunchCommand.h"
 #include "launch/steps/Update.h"
 #include "launch/steps/PreLaunchCommand.h"
@@ -111,6 +112,10 @@ MinecraftInstance::MinecraftInstance(SettingsObjectPtr globalSettings, SettingsO
     m_settings->registerOverride(globalSettings->getSetting("ShowGameTime"), gameTimeOverride);
     m_settings->registerOverride(globalSettings->getSetting("RecordGameTime"), gameTimeOverride);
 
+    // Join server on launch, this does not have a global override
+    m_settings->registerSetting("JoinServerOnLaunch", false);
+    m_settings->registerSetting("JoinServerOnLaunchAddress", "");
+
     // DEPRECATED: Read what versions the user configuration thinks should be used
     m_settings->registerSetting({"IntendedVersion", "MinecraftVersion"}, "");
     m_settings->registerSetting("LWJGLVersion", "");
@@ -395,7 +400,8 @@ static QString replaceTokensIn(QString text, QMap<QString, QString> with)
     return result;
 }
 
-QStringList MinecraftInstance::processMinecraftArgs(AuthSessionPtr session) const
+QStringList MinecraftInstance::processMinecraftArgs(
+        AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) const
 {
     auto profile = m_components->getProfile();
     QString args_pattern = profile->getMinecraftArguments();
@@ -404,6 +410,12 @@ QStringList MinecraftInstance::processMinecraftArgs(AuthSessionPtr session) cons
         args_pattern += " --tweakClass " + tweaker;
     }
 
+    if (serverToJoin && !serverToJoin->address.isEmpty())
+    {
+        args_pattern += " --server " + serverToJoin->address;
+        args_pattern += " --port " + QString::number(serverToJoin->port);
+    }
+
     QMap<QString, QString> token_mapping;
     // yggdrasil!
     if(session)
@@ -440,7 +452,7 @@ QStringList MinecraftInstance::processMinecraftArgs(AuthSessionPtr session) cons
     return parts;
 }
 
-QString MinecraftInstance::createLaunchScript(AuthSessionPtr session)
+QString MinecraftInstance::createLaunchScript(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin)
 {
     QString launchScript;
 
@@ -461,8 +473,17 @@ QString MinecraftInstance::createLaunchScript(AuthSessionPtr session)
         launchScript += "appletClass " + appletClass + "\n";
     }
 
+    if (serverToJoin && !serverToJoin->address.isEmpty())
+    {
+        launchScript += "serverAddress " + serverToJoin->address + "\n";
+        launchScript += "serverPort " + QString::number(serverToJoin->port) + "\n";
+    }
+
     // generic minecraft params
-    for (auto param : processMinecraftArgs(session))
+    for (auto param : processMinecraftArgs(
+            session,
+            nullptr /* When using a launch script, the server parameters are handled by it*/
+    ))
     {
         launchScript += "param " + param + "\n";
     }
@@ -512,7 +533,7 @@ QString MinecraftInstance::createLaunchScript(AuthSessionPtr session)
     return launchScript;
 }
 
-QStringList MinecraftInstance::verboseDescription(AuthSessionPtr session)
+QStringList MinecraftInstance::verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin)
 {
     QStringList out;
     out << "Main Class:" << "  " + getMainClass() << "";
@@ -627,7 +648,7 @@ QStringList MinecraftInstance::verboseDescription(AuthSessionPtr session)
         out << "";
     }
 
-    auto params = processMinecraftArgs(nullptr);
+    auto params = processMinecraftArgs(nullptr, serverToJoin);
     out << "Params:";
     out << "  " + params.join(' ');
     out << "";
@@ -801,7 +822,7 @@ shared_qobject_ptr<Task> MinecraftInstance::createUpdateTask(Net::Mode mode)
     return nullptr;
 }
 
-shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPtr session)
+shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin)
 {
     // FIXME: get rid of shared_from_this ...
     auto process = LaunchTask::create(std::dynamic_pointer_cast<MinecraftInstance>(shared_from_this()));
@@ -833,6 +854,21 @@ shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPt
         process->appendStep(new CreateGameFolders(pptr));
     }
 
+    if (!serverToJoin && m_settings->get("JoinServerOnLaunch").toBool())
+    {
+        QString fullAddress = m_settings->get("JoinServerOnLaunchAddress").toString();
+        serverToJoin.reset(new MinecraftServerTarget(MinecraftServerTarget::parse(fullAddress)));
+    }
+
+    if(serverToJoin && serverToJoin->port == 25565)
+    {
+        // Resolve server address to join on launch
+        auto *step = new LookupServerAddress(pptr);
+        step->setLookupAddress(serverToJoin->address);
+        step->setOutputAddressPtr(serverToJoin);
+        process->appendStep(step);
+    }
+
     // run pre-launch command if that's needed
     if(getPreLaunchCommand().size())
     {
@@ -864,7 +900,7 @@ shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPt
 
     // print some instance info here...
     {
-        process->appendStep(new PrintInstanceInfo(pptr, session));
+        process->appendStep(new PrintInstanceInfo(pptr, session, serverToJoin));
     }
 
     // extract native jars if needed
@@ -885,6 +921,7 @@ shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPt
             auto step = new LauncherPartLaunch(pptr);
             step->setWorkingDirectory(gameRoot());
             step->setAuthSession(session);
+            step->setServerToJoin(serverToJoin);
             process->appendStep(step);
         }
         else if (method == "DirectJava")
@@ -892,6 +929,7 @@ shared_qobject_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPt
             auto step = new DirectJavaLaunch(pptr);
             step->setWorkingDirectory(gameRoot());
             step->setAuthSession(session);
+            step->setServerToJoin(serverToJoin);
             process->appendStep(step);
         }
     }
diff --git a/api/logic/minecraft/MinecraftInstance.h b/api/logic/minecraft/MinecraftInstance.h
index 985a8a76..05600797 100644
--- a/api/logic/minecraft/MinecraftInstance.h
+++ b/api/logic/minecraft/MinecraftInstance.h
@@ -5,6 +5,7 @@
 #include <QProcess>
 #include <QDir>
 #include "multimc_logic_export.h"
+#include "minecraft/launch/MinecraftServerTarget.h"
 
 class ModFolderModel;
 class WorldList;
@@ -76,11 +77,11 @@ public:
 
     //////  Launch stuff //////
     shared_qobject_ptr<Task> createUpdateTask(Net::Mode mode) override;
-    shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr account) override;
+    shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr account, MinecraftServerTargetPtr serverToJoin) override;
     QStringList extraArguments() const override;
-    QStringList verboseDescription(AuthSessionPtr session) override;
+    QStringList verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) override;
     QList<Mod> getJarMods() const;
-    QString createLaunchScript(AuthSessionPtr session);
+    QString createLaunchScript(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin);
     /// get arguments passed to java
     QStringList javaArguments() const;
 
@@ -107,7 +108,7 @@ public:
     virtual QString getMainClass() const;
 
     // FIXME: remove
-    virtual QStringList processMinecraftArgs(AuthSessionPtr account) const;
+    virtual QStringList processMinecraftArgs(AuthSessionPtr account, MinecraftServerTargetPtr serverToJoin) const;
 
     virtual JavaVersion getJavaVersion() const;
 
diff --git a/api/logic/minecraft/launch/DirectJavaLaunch.cpp b/api/logic/minecraft/launch/DirectJavaLaunch.cpp
index d9841a43..cf4564b6 100644
--- a/api/logic/minecraft/launch/DirectJavaLaunch.cpp
+++ b/api/logic/minecraft/launch/DirectJavaLaunch.cpp
@@ -55,7 +55,7 @@ void DirectJavaLaunch::executeTask()
     // make detachable - this will keep the process running even if the object is destroyed
     m_process.setDetachable(true);
 
-    auto mcArgs = minecraftInstance->processMinecraftArgs(m_session);
+    auto mcArgs = minecraftInstance->processMinecraftArgs(m_session, m_serverToJoin);
     args.append(mcArgs);
 
     QString wrapperCommandStr = instance->getWrapperCommand().trimmed();
diff --git a/api/logic/minecraft/launch/DirectJavaLaunch.h b/api/logic/minecraft/launch/DirectJavaLaunch.h
index d9d9bdc2..58b119b8 100644
--- a/api/logic/minecraft/launch/DirectJavaLaunch.h
+++ b/api/logic/minecraft/launch/DirectJavaLaunch.h
@@ -19,6 +19,8 @@
 #include <LoggedProcess.h>
 #include <minecraft/auth/AuthSession.h>
 
+#include "MinecraftServerTarget.h"
+
 class DirectJavaLaunch: public LaunchStep
 {
     Q_OBJECT
@@ -38,6 +40,12 @@ public:
     {
         m_session = session;
     }
+
+    void setServerToJoin(MinecraftServerTargetPtr serverToJoin)
+    {
+        m_serverToJoin = std::move(serverToJoin);
+    }
+
 private slots:
     void on_state(LoggedProcess::State state);
 
@@ -45,5 +53,6 @@ private:
     LoggedProcess m_process;
     QString m_command;
     AuthSessionPtr m_session;
+    MinecraftServerTargetPtr m_serverToJoin;
 };
 
diff --git a/api/logic/minecraft/launch/LauncherPartLaunch.cpp b/api/logic/minecraft/launch/LauncherPartLaunch.cpp
index 1408e6ad..ab3b6d10 100644
--- a/api/logic/minecraft/launch/LauncherPartLaunch.cpp
+++ b/api/logic/minecraft/launch/LauncherPartLaunch.cpp
@@ -59,7 +59,7 @@ void LauncherPartLaunch::executeTask()
     auto instance = m_parent->instance();
     std::shared_ptr<MinecraftInstance> minecraftInstance = std::dynamic_pointer_cast<MinecraftInstance>(instance);
 
-    m_launchScript = minecraftInstance->createLaunchScript(m_session);
+    m_launchScript = minecraftInstance->createLaunchScript(m_session, m_serverToJoin);
     QStringList args = minecraftInstance->javaArguments();
     QString allArgs = args.join(", ");
     emit logLine("Java Arguments:\n[" + m_parent->censorPrivateInfo(allArgs) + "]\n\n", MessageLevel::MultiMC);
diff --git a/api/logic/minecraft/launch/LauncherPartLaunch.h b/api/logic/minecraft/launch/LauncherPartLaunch.h
index 9e951849..6a7ee0e5 100644
--- a/api/logic/minecraft/launch/LauncherPartLaunch.h
+++ b/api/logic/minecraft/launch/LauncherPartLaunch.h
@@ -19,6 +19,8 @@
 #include <LoggedProcess.h>
 #include <minecraft/auth/AuthSession.h>
 
+#include "MinecraftServerTarget.h"
+
 class LauncherPartLaunch: public LaunchStep
 {
     Q_OBJECT
@@ -39,6 +41,11 @@ public:
         m_session = session;
     }
 
+    void setServerToJoin(MinecraftServerTargetPtr serverToJoin)
+    {
+        m_serverToJoin = std::move(serverToJoin);
+    }
+
 private slots:
     void on_state(LoggedProcess::State state);
 
@@ -47,5 +54,7 @@ private:
     QString m_command;
     AuthSessionPtr m_session;
     QString m_launchScript;
+    MinecraftServerTargetPtr m_serverToJoin;
+
     bool mayProceed = false;
 };
diff --git a/api/logic/minecraft/launch/MinecraftServerTarget.cpp b/api/logic/minecraft/launch/MinecraftServerTarget.cpp
new file mode 100644
index 00000000..569273b6
--- /dev/null
+++ b/api/logic/minecraft/launch/MinecraftServerTarget.cpp
@@ -0,0 +1,66 @@
+/* Copyright 2013-2021 MultiMC Contributors
+ *
+ * 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.
+ */
+
+#include "MinecraftServerTarget.h"
+
+#include <QStringList>
+
+MinecraftServerTarget MinecraftServerTarget::parse(const QString &fullAddress) {
+    QStringList split = fullAddress.split(":");
+
+    // The logic below replicates the exact logic minecraft uses for parsing server addresses.
+    // While the conversion is not lossless and eats errors, it ensures the same behavior
+    // within Minecraft and MultiMC when entering server addresses.
+    if (fullAddress.startsWith("["))
+    {
+        int bracket = fullAddress.indexOf("]");
+        if (bracket > 0)
+        {
+            QString ipv6 = fullAddress.mid(1, bracket - 1);
+            QString port = fullAddress.mid(bracket + 1).trimmed();
+
+            if (port.startsWith(":") && !ipv6.isEmpty())
+            {
+                port = port.mid(1);
+                split = QStringList({ ipv6, port });
+            }
+            else
+            {
+                split = QStringList({ipv6});
+            }
+        }
+    }
+
+    if (split.size() > 2)
+    {
+        split = QStringList({fullAddress});
+    }
+
+    QString realAddress = split[0];
+
+    quint16 realPort = 25565;
+    if (split.size() > 1)
+    {
+        bool ok;
+        realPort = split[1].toUInt(&ok);
+
+        if (!ok)
+        {
+            realPort = 25565;
+        }
+    }
+
+    return MinecraftServerTarget { realAddress, realPort };
+}
diff --git a/api/logic/minecraft/launch/MinecraftServerTarget.h b/api/logic/minecraft/launch/MinecraftServerTarget.h
new file mode 100644
index 00000000..3c5786f4
--- /dev/null
+++ b/api/logic/minecraft/launch/MinecraftServerTarget.h
@@ -0,0 +1,30 @@
+/* Copyright 2013-2021 MultiMC Contributors
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <memory>
+
+#include <QString>
+#include <multimc_logic_export.h>
+
+struct MinecraftServerTarget {
+    QString address;
+    quint16 port;
+
+    static MULTIMC_LOGIC_EXPORT MinecraftServerTarget parse(const QString &fullAddress);
+};
+
+typedef std::shared_ptr<MinecraftServerTarget> MinecraftServerTargetPtr;
diff --git a/api/logic/minecraft/launch/PrintInstanceInfo.cpp b/api/logic/minecraft/launch/PrintInstanceInfo.cpp
index af0b5bbf..0b9611ad 100644
--- a/api/logic/minecraft/launch/PrintInstanceInfo.cpp
+++ b/api/logic/minecraft/launch/PrintInstanceInfo.cpp
@@ -101,6 +101,6 @@ void PrintInstanceInfo::executeTask()
 #endif
 
     logLines(log, MessageLevel::MultiMC);
-    logLines(instance->verboseDescription(m_session), MessageLevel::MultiMC);
+    logLines(instance->verboseDescription(m_session, m_serverToJoin), MessageLevel::MultiMC);
     emitSucceeded();
 }
diff --git a/api/logic/minecraft/launch/PrintInstanceInfo.h b/api/logic/minecraft/launch/PrintInstanceInfo.h
index 168eff9d..fdc30f31 100644
--- a/api/logic/minecraft/launch/PrintInstanceInfo.h
+++ b/api/logic/minecraft/launch/PrintInstanceInfo.h
@@ -18,13 +18,15 @@
 #include <launch/LaunchStep.h>
 #include <memory>
 #include "minecraft/auth/AuthSession.h"
+#include "minecraft/launch/MinecraftServerTarget.h"
 
 // FIXME: temporary wrapper for existing task.
 class PrintInstanceInfo: public LaunchStep
 {
     Q_OBJECT
 public:
-    explicit PrintInstanceInfo(LaunchTask *parent, AuthSessionPtr session) : LaunchStep(parent), m_session(session) {};
+    explicit PrintInstanceInfo(LaunchTask *parent, AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) :
+        LaunchStep(parent), m_session(session), m_serverToJoin(serverToJoin) {};
     virtual ~PrintInstanceInfo(){};
 
     virtual void executeTask();
@@ -34,5 +36,6 @@ public:
     }
 private:
     AuthSessionPtr m_session;
+    MinecraftServerTargetPtr m_serverToJoin;
 };
 
diff --git a/api/logic/minecraft/legacy/LegacyInstance.cpp b/api/logic/minecraft/legacy/LegacyInstance.cpp
index f86e5d05..9f9bda5a 100644
--- a/api/logic/minecraft/legacy/LegacyInstance.cpp
+++ b/api/logic/minecraft/legacy/LegacyInstance.cpp
@@ -225,7 +225,7 @@ QString LegacyInstance::getStatusbarDescription()
     return tr("Instance from previous versions.");
 }
 
-QStringList LegacyInstance::verboseDescription(AuthSessionPtr session)
+QStringList LegacyInstance::verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin)
 {
     QStringList out;
 
diff --git a/api/logic/minecraft/legacy/LegacyInstance.h b/api/logic/minecraft/legacy/LegacyInstance.h
index 9caddcba..325bac7a 100644
--- a/api/logic/minecraft/legacy/LegacyInstance.h
+++ b/api/logic/minecraft/legacy/LegacyInstance.h
@@ -111,7 +111,8 @@ public:
     {
         return false;
     }
-    shared_qobject_ptr<LaunchTask> createLaunchTask(AuthSessionPtr account) override
+    shared_qobject_ptr<LaunchTask> createLaunchTask(
+            AuthSessionPtr account, MinecraftServerTargetPtr serverToJoin) override
     {
         return nullptr;
     }
@@ -125,7 +126,7 @@ public:
     }
 
     QString getStatusbarDescription() override;
-    QStringList verboseDescription(AuthSessionPtr session) override;
+    QStringList verboseDescription(AuthSessionPtr session, MinecraftServerTargetPtr serverToJoin) override;
 
     QProcessEnvironment createEnvironment() override
     {
diff --git a/application/InstancePageProvider.h b/application/InstancePageProvider.h
index dde36aef..3cb723c4 100644
--- a/application/InstancePageProvider.h
+++ b/application/InstancePageProvider.h
@@ -46,7 +46,7 @@ public:
             values.append(new TexturePackPage(onesix.get()));
             values.append(new NotesPage(onesix.get()));
             values.append(new WorldListPage(onesix.get(), onesix->worldList()));
-            values.append(new ServersPage(onesix.get()));
+            values.append(new ServersPage(onesix));
             // values.append(new GameOptionsPage(onesix.get()));
             values.append(new ScreenshotsPage(FS::PathCombine(onesix->gameRoot(), "screenshots")));
             values.append(new InstanceSettingsPage(onesix.get()));
diff --git a/application/LaunchController.cpp b/application/LaunchController.cpp
index bebc3db1..3c4491a3 100644
--- a/application/LaunchController.cpp
+++ b/application/LaunchController.cpp
@@ -197,7 +197,7 @@ void LaunchController::launchInstance()
         return;
     }
 
-    m_launcher = m_instance->createLaunchTask(m_session);
+    m_launcher = m_instance->createLaunchTask(m_session, m_serverToJoin);
     if (!m_launcher)
     {
         emitFailed(tr("Couldn't instantiate a launcher."));
diff --git a/application/LaunchController.h b/application/LaunchController.h
index 1d879028..5f177e00 100644
--- a/application/LaunchController.h
+++ b/application/LaunchController.h
@@ -3,6 +3,8 @@
 #include <BaseInstance.h>
 #include <tools/BaseProfiler.h>
 
+#include "minecraft/launch/MinecraftServerTarget.h"
+
 class InstanceWindow;
 class LaunchController: public Task
 {
@@ -33,6 +35,10 @@ public:
     {
         m_parentWidget = widget;
     }
+    void setServerToJoin(MinecraftServerTargetPtr serverToJoin)
+    {
+        m_serverToJoin = std::move(serverToJoin);
+    }
     QString id()
     {
         return m_instance->id();
@@ -58,4 +64,5 @@ private:
     InstanceWindow *m_console = nullptr;
     AuthSessionPtr m_session;
     shared_qobject_ptr<LaunchTask> m_launcher;
+    MinecraftServerTargetPtr m_serverToJoin;
 };
diff --git a/application/MultiMC.cpp b/application/MultiMC.cpp
index 3429a377..2dd4f83f 100644
--- a/application/MultiMC.cpp
+++ b/application/MultiMC.cpp
@@ -191,6 +191,11 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
         parser.addOption("launch");
         parser.addShortOpt("launch", 'l');
         parser.addDocumentation("launch", "Launch the specified instance (by instance ID)");
+        // --server
+        parser.addOption("server");
+        parser.addShortOpt("server", 's');
+        parser.addDocumentation("server", "Join the specified server on launch "
+                                          "(only valid in combination with --launch)");
         // --alive
         parser.addSwitch("alive");
         parser.addDocumentation("alive", "Write a small '" + liveCheckFile + "' file after MultiMC starts");
@@ -232,6 +237,7 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
         }
     }
     m_instanceIdToLaunch = args["launch"].toString();
+    m_serverToJoin = args["server"].toString();
     m_liveCheck = args["alive"].toBool();
     m_zipToImport = args["import"].toUrl();
 
@@ -293,6 +299,13 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
         return;
     }
 
+    if(m_instanceIdToLaunch.isEmpty() && !m_serverToJoin.isEmpty())
+    {
+        std::cerr << "--server can only be used in combination with --launch!" << std::endl;
+        m_status = MultiMC::Failed;
+        return;
+    }
+
     /*
      * Establish the mechanism for communication with an already running MultiMC that uses the same data path.
      * If there is one, tell it what the user actually wanted to do and exit.
@@ -318,7 +331,15 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
             }
             else
             {
-                m_peerInstance->sendMessage("launch " + m_instanceIdToLaunch, timeout);
+                if(!m_serverToJoin.isEmpty())
+                {
+                    m_peerInstance->sendMessage(
+                            "launch-with-server " + m_instanceIdToLaunch + " " + m_serverToJoin, timeout);
+                }
+                else
+                {
+                    m_peerInstance->sendMessage("launch " + m_instanceIdToLaunch, timeout);
+                }
             }
             m_status = MultiMC::Succeeded;
             return;
@@ -399,6 +420,10 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
         {
             qDebug() << "ID of instance to launch   : " << m_instanceIdToLaunch;
         }
+        if(!m_serverToJoin.isEmpty())
+        {
+            qDebug() << "Address of server to join  :" << m_serverToJoin;
+        }
         qDebug() << "<> Paths set.";
     }
 
@@ -844,8 +869,19 @@ void MultiMC::performMainStartupAction()
         auto inst = instances()->getInstanceById(m_instanceIdToLaunch);
         if(inst)
         {
-            qDebug() << "<> Instance launching:" << m_instanceIdToLaunch;
-            launch(inst, true, nullptr);
+            MinecraftServerTargetPtr serverToJoin = nullptr;
+
+            if(!m_serverToJoin.isEmpty())
+            {
+                serverToJoin.reset(new MinecraftServerTarget(MinecraftServerTarget::parse(m_serverToJoin)));
+                qDebug() << "<> Instance" << m_instanceIdToLaunch << "launching with server" << m_serverToJoin;
+            }
+            else
+            {
+                qDebug() << "<> Instance" << m_instanceIdToLaunch << "launching";
+            }
+
+            launch(inst, true, nullptr, serverToJoin);
             return;
         }
     }
@@ -927,6 +963,31 @@ void MultiMC::messageReceived(const QString& message)
             launch(inst, true, nullptr);
         }
     }
+    else if(command == "launch-with-server")
+    {
+        QString instanceID = message.section(' ', 1, 1);
+        QString serverToJoin = message.section(' ', 2, 2);
+        if(instanceID.isEmpty())
+        {
+            qWarning() << "Received" << command << "message without an instance ID.";
+            return;
+        }
+        if(serverToJoin.isEmpty())
+        {
+            qWarning() << "Received" << command << "message without a server to join.";
+            return;
+        }
+        auto inst = instances()->getInstanceById(instanceID);
+        if(inst)
+        {
+            launch(
+                    inst,
+                    true,
+                    nullptr,
+                    std::make_shared<MinecraftServerTarget>(MinecraftServerTarget::parse(serverToJoin))
+            );
+        }
+    }
     else
     {
         qWarning() << "Received invalid message" << message;
@@ -1014,8 +1075,12 @@ bool MultiMC::openJsonEditor(const QString &filename)
     }
 }
 
-bool MultiMC::launch(InstancePtr instance, bool online, BaseProfilerFactory *profiler)
-{
+bool MultiMC::launch(
+        InstancePtr instance,
+        bool online,
+        BaseProfilerFactory *profiler,
+        MinecraftServerTargetPtr serverToJoin
+) {
     if(m_updateRunning)
     {
         qDebug() << "Cannot launch instances while an update is running. Please try again when updates are completed.";
@@ -1036,6 +1101,7 @@ bool MultiMC::launch(InstancePtr instance, bool online, BaseProfilerFactory *pro
         controller->setInstance(instance);
         controller->setOnline(online);
         controller->setProfiler(profiler);
+        controller->setServerToJoin(serverToJoin);
         if(window)
         {
             controller->setParentWidget(window);
diff --git a/application/MultiMC.h b/application/MultiMC.h
index e6588a14..af2b41c1 100644
--- a/application/MultiMC.h
+++ b/application/MultiMC.h
@@ -11,6 +11,8 @@
 
 #include <BaseInstance.h>
 
+#include "minecraft/launch/MinecraftServerTarget.h"
+
 class LaunchController;
 class LocalPeer;
 class InstanceWindow;
@@ -150,7 +152,12 @@ signals:
     void globalSettingsClosed();
 
 public slots:
-    bool launch(InstancePtr instance, bool online = true, BaseProfilerFactory *profiler = nullptr);
+    bool launch(
+            InstancePtr instance,
+            bool online = true,
+            BaseProfilerFactory *profiler = nullptr,
+            MinecraftServerTargetPtr serverToJoin = nullptr
+    );
     bool kill(InstancePtr instance);
 
 private slots:
@@ -221,6 +228,7 @@ private:
     SetupWizard * m_setupWizard = nullptr;
 public:
     QString m_instanceIdToLaunch;
+    QString m_serverToJoin;
     bool m_liveCheck = false;
     QUrl m_zipToImport;
     std::unique_ptr<QFile> logFile;
diff --git a/application/pages/instance/InstanceSettingsPage.cpp b/application/pages/instance/InstanceSettingsPage.cpp
index 05041c82..00fc19af 100644
--- a/application/pages/instance/InstanceSettingsPage.cpp
+++ b/application/pages/instance/InstanceSettingsPage.cpp
@@ -191,6 +191,18 @@ void InstanceSettingsPage::applySettings()
         m_settings->reset("ShowGameTime");
         m_settings->reset("RecordGameTime");
     }
+
+    // Join server on launch
+    bool joinServerOnLaunch = ui->serverJoinGroupBox->isChecked();
+    m_settings->set("JoinServerOnLaunch", joinServerOnLaunch);
+    if (joinServerOnLaunch)
+    {
+        m_settings->set("JoinServerOnLaunchAddress", ui->serverJoinAddress->text());
+    }
+    else
+    {
+        m_settings->reset("JoinServerOnLaunchAddress");
+    }
 }
 
 void InstanceSettingsPage::loadSettings()
@@ -257,6 +269,9 @@ void InstanceSettingsPage::loadSettings()
     ui->gameTimeGroupBox->setChecked(m_settings->get("OverrideGameTime").toBool());
     ui->showGameTime->setChecked(m_settings->get("ShowGameTime").toBool());
     ui->recordGameTime->setChecked(m_settings->get("RecordGameTime").toBool());
+
+    ui->serverJoinGroupBox->setChecked(m_settings->get("JoinServerOnLaunch").toBool());
+    ui->serverJoinAddress->setText(m_settings->get("JoinServerOnLaunchAddress").toString());
 }
 
 void InstanceSettingsPage::on_javaDetectBtn_clicked()
diff --git a/application/pages/instance/InstanceSettingsPage.ui b/application/pages/instance/InstanceSettingsPage.ui
index 64f90fad..29024b65 100644
--- a/application/pages/instance/InstanceSettingsPage.ui
+++ b/application/pages/instance/InstanceSettingsPage.ui
@@ -454,6 +454,41 @@
         </widget>
        </item>
        <item>
+        <widget class="QGroupBox" name="serverJoinGroupBox">
+         <property name="title">
+          <string>Set a server to join on launch</string>
+         </property>
+         <property name="checkable">
+          <bool>true</bool>
+         </property>
+         <property name="checked">
+          <bool>false</bool>
+         </property>
+         <layout class="QVBoxLayout" name="verticalLayout_11">
+          <item>
+           <layout class="QGridLayout" name="serverJoinLayout">
+            <item row="0" column="0">
+             <widget class="QLabel" name="serverJoinAddressLabel">
+              <property name="sizePolicy">
+               <sizepolicy hsizetype="Expanding" vsizetype="Preferred">
+                <horstretch>0</horstretch>
+                <verstretch>0</verstretch>
+               </sizepolicy>
+              </property>
+              <property name="text">
+               <string>Server address:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="0" column="1">
+             <widget class="QLineEdit" name="serverJoinAddress"/>
+            </item>
+           </layout>
+          </item>
+         </layout>
+        </widget>
+       </item>
+       <item>
         <spacer name="verticalSpacerMiscellanous">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
diff --git a/application/pages/instance/ServersPage.cpp b/application/pages/instance/ServersPage.cpp
index 8b0c655c..d63c6e70 100644
--- a/application/pages/instance/ServersPage.cpp
+++ b/application/pages/instance/ServersPage.cpp
@@ -556,7 +556,7 @@ private:
     QTimer m_saveTimer;
 };
 
-ServersPage::ServersPage(MinecraftInstance * inst, QWidget* parent)
+ServersPage::ServersPage(InstancePtr inst, QWidget* parent)
     : QMainWindow(parent), ui(new Ui::ServersPage)
 {
     ui->setupUi(this);
@@ -579,7 +579,7 @@ ServersPage::ServersPage(MinecraftInstance * inst, QWidget* parent)
 
     auto selectionModel = ui->serversView->selectionModel();
     connect(selectionModel, &QItemSelectionModel::currentChanged, this, &ServersPage::currentChanged);
-    connect(m_inst, &MinecraftInstance::runningStatusChanged, this, &ServersPage::on_RunningState_changed);
+    connect(m_inst.get(), &MinecraftInstance::runningStatusChanged, this, &ServersPage::on_RunningState_changed);
     connect(ui->nameLine, &QLineEdit::textEdited, this, &ServersPage::nameEdited);
     connect(ui->addressLine, &QLineEdit::textEdited, this, &ServersPage::addressEdited);
     connect(ui->resourceComboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(resourceIndexChanged(int)));
@@ -695,6 +695,7 @@ void ServersPage::updateState()
     ui->actionMove_Down->setEnabled(serverEditEnabled);
     ui->actionMove_Up->setEnabled(serverEditEnabled);
     ui->actionRemove->setEnabled(serverEditEnabled);
+    ui->actionJoin->setEnabled(serverEditEnabled);
 
     if(server)
     {
@@ -758,4 +759,10 @@ void ServersPage::on_actionMove_Down_triggered()
     }
 }
 
+void ServersPage::on_actionJoin_triggered()
+{
+    const auto &address = m_model->at(currentServer)->m_address;
+    MMC->launch(m_inst, true, nullptr, std::make_shared<MinecraftServerTarget>(MinecraftServerTarget::parse(address)));
+}
+
 #include "ServersPage.moc"
diff --git a/application/pages/instance/ServersPage.h b/application/pages/instance/ServersPage.h
index f164da1e..8c5b7eb8 100644
--- a/application/pages/instance/ServersPage.h
+++ b/application/pages/instance/ServersPage.h
@@ -35,7 +35,7 @@ class ServersPage : public QMainWindow, public BasePage
     Q_OBJECT
 
 public:
-    explicit ServersPage(MinecraftInstance *inst, QWidget *parent = 0);
+    explicit ServersPage(InstancePtr inst, QWidget *parent = 0);
     virtual ~ServersPage();
 
     void openedImpl() override;
@@ -74,6 +74,7 @@ private slots:
     void on_actionRemove_triggered();
     void on_actionMove_Up_triggered();
     void on_actionMove_Down_triggered();
+    void on_actionJoin_triggered();
 
     void on_RunningState_changed(bool running);
 
@@ -88,6 +89,6 @@ private: // data
     bool m_locked = true;
     Ui::ServersPage *ui = nullptr;
     ServersModel * m_model = nullptr;
-    MinecraftInstance * m_inst = nullptr;
+    InstancePtr m_inst = nullptr;
 };
 
diff --git a/application/pages/instance/ServersPage.ui b/application/pages/instance/ServersPage.ui
index e9518e35..d89b7cba 100644
--- a/application/pages/instance/ServersPage.ui
+++ b/application/pages/instance/ServersPage.ui
@@ -148,6 +148,7 @@
    <addaction name="actionRemove"/>
    <addaction name="actionMove_Up"/>
    <addaction name="actionMove_Down"/>
+   <addaction name="actionJoin"/>
   </widget>
   <action name="actionAdd">
    <property name="text">
@@ -169,6 +170,11 @@
     <string>Move Down</string>
    </property>
   </action>
+  <action name="actionJoin">
+   <property name="text">
+    <string>Join</string>
+   </property>
+  </action>
  </widget>
  <customwidgets>
   <customwidget>
diff --git a/libraries/launcher/org/multimc/LegacyFrame.java b/libraries/launcher/org/multimc/LegacyFrame.java
index c72c053e..985a10e6 100644
--- a/libraries/launcher/org/multimc/LegacyFrame.java
+++ b/libraries/launcher/org/multimc/LegacyFrame.java
@@ -46,7 +46,16 @@ public class LegacyFrame extends Frame implements WindowListener
         this.addWindowListener ( this );
     }
 
-    public void start ( Applet mcApplet, String user, String session, int winSizeW, int winSizeH, boolean maximize )
+    public void start (
+        Applet mcApplet,
+        String user,
+        String session,
+        int winSizeW,
+        int winSizeH,
+        boolean maximize,
+        String serverAddress,
+        String serverPort
+    )
     {
         try {
             appletWrap = new Launcher( mcApplet, new URL ( "http://www.minecraft.net/game" ) );
@@ -95,6 +104,13 @@ public class LegacyFrame extends Frame implements WindowListener
             e.printStackTrace(System.err);
             System.exit(-1);
         }
+
+        if (serverAddress != null)
+        {
+            appletWrap.setParameter("server", serverAddress);
+            appletWrap.setParameter("port", serverPort);
+        }
+
         appletWrap.setParameter ( "username", user );
         appletWrap.setParameter ( "sessionid", session );
         appletWrap.setParameter ( "stand-alone", "true" ); // Show the quit button.
diff --git a/libraries/launcher/org/multimc/onesix/OneSixLauncher.java b/libraries/launcher/org/multimc/onesix/OneSixLauncher.java
index b6b384ab..ea445995 100644
--- a/libraries/launcher/org/multimc/onesix/OneSixLauncher.java
+++ b/libraries/launcher/org/multimc/onesix/OneSixLauncher.java
@@ -47,6 +47,9 @@ public class OneSixLauncher implements Launcher
     private boolean maximize;
     private String cwd;
 
+    private String serverAddress;
+    private String serverPort;
+
     // the much abused system classloader, for convenience (for further abuse)
     private ClassLoader cl;
 
@@ -64,6 +67,9 @@ public class OneSixLauncher implements Launcher
         windowTitle = params.firstSafe("windowTitle", "Minecraft");
         windowParams = params.firstSafe("windowParams", "854x480");
 
+        serverAddress = params.firstSafe("serverAddress", null);
+        serverPort = params.firstSafe("serverPort", null);
+
         cwd = System.getProperty("user.dir");
 
         winSizeW = 854;
@@ -122,7 +128,7 @@ public class OneSixLauncher implements Launcher
                 Class<?> MCAppletClass = cl.loadClass(appletClass);
                 Applet mcappl = (Applet) MCAppletClass.newInstance();
                 LegacyFrame mcWindow = new LegacyFrame(windowTitle);
-                mcWindow.start(mcappl, userName, sessionId, winSizeW, winSizeH, maximize);
+                mcWindow.start(mcappl, userName, sessionId, winSizeW, winSizeH, maximize, serverAddress, serverPort);
                 return 0;
             } catch (Exception e)
             {
@@ -164,6 +170,14 @@ public class OneSixLauncher implements Launcher
             mcparams.add(Integer.toString(winSizeH));
         }
 
+        if (serverAddress != null)
+        {
+            mcparams.add("--server");
+            mcparams.add(serverAddress);
+            mcparams.add("--port");
+            mcparams.add(serverPort);
+        }
+
         // Get the Minecraft Class.
         Class<?> mc;
         try