Merge branch 'feature_yggdrasil' into develop

Conflicts:
	gui/MainWindow.cpp
	logic/OneSixInstance.h

Fix missing session id functionality for legacy and old onesix.

6 files changed, 910 insertions, 0 deletions

diff --git a/logic/auth/AuthenticateTask.cpp b/logic/auth/AuthenticateTask.cpp
new file mode 100644
index 00000000..a9c2c03f
--- /dev/null
+++ b/logic/auth/AuthenticateTask.cpp
@@ -0,0 +1,180 @@
+
+/* Copyright 2013 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 <logic/auth/AuthenticateTask.h>
+
+#include <logic/auth/MojangAccount.h>
+
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QJsonArray>
+#include <QVariant>
+#include <QDebug>
+
+#include "logger/QsLog.h"
+
+AuthenticateTask::AuthenticateTask(MojangAccountPtr account, const QString& password, QObject* parent) :
+	YggdrasilTask(account, parent), m_password(password)
+{
+}
+
+QJsonObject AuthenticateTask::getRequestContent() const
+{
+	/*
+	 * {
+	 *   "agent": {								// optional
+	 *   "name": "Minecraft",					// So far this is the only encountered value
+ 	 *   "version": 1							// This number might be increased
+	 * 											// by the vanilla client in the future
+	 *   },
+	 *   "username": "mojang account name",		// Can be an email address or player name for
+												// unmigrated accounts
+	 *  "password": "mojang account password",
+	 *  "clientToken": "client identifier"		// optional
+	 * }
+	 */
+	QJsonObject req;
+
+	{
+		QJsonObject agent;
+		// C++ makes string literals void* for some stupid reason, so we have to tell it QString... Thanks Obama.
+		agent.insert("name", QString("Minecraft"));
+		agent.insert("version", 1);
+		req.insert("agent", agent);
+	}
+
+	req.insert("username", getMojangAccount()->username());
+	req.insert("password", m_password);
+
+	// If we already have a client token, give it to the server.
+	// Otherwise, let the server give us one.
+	if (!getMojangAccount()->clientToken().isEmpty())
+		req.insert("clientToken", getMojangAccount()->clientToken());
+
+	return req;
+}
+
+bool AuthenticateTask::processResponse(QJsonObject responseData)
+{
+	// Read the response data. We need to get the client token, access token, and the selected profile.
+	QLOG_DEBUG() << "Processing authentication response.";
+	
+	// If we already have a client token, make sure the one the server gave us matches our existing one.
+	QLOG_DEBUG() << "Getting client token.";
+	QString clientToken = responseData.value("clientToken").toString("");
+	if (clientToken.isEmpty())
+	{
+		// Fail if the server gave us an empty client token
+		// TODO: Set an error properly to display to the user.
+		QLOG_ERROR() << "Server didn't send a client token.";
+		return false;
+	}
+	if (!getMojangAccount()->clientToken().isEmpty() && clientToken != getMojangAccount()->clientToken())
+	{
+		// The server changed our client token! Obey its wishes, but complain. That's what I do for my parents, so...
+		QLOG_WARN() << "Server changed our client token to '" << clientToken 
+					<< "'. This shouldn't happen, but it isn't really a big deal.";
+	}
+	// Set the client token.
+	getMojangAccount()->setClientToken(clientToken);
+
+
+	// Now, we set the access token.
+	QLOG_DEBUG() << "Getting access token.";
+	QString accessToken = responseData.value("accessToken").toString("");
+	if (accessToken.isEmpty())
+	{
+		// Fail if the server didn't give us an access token.
+		// TODO: Set an error properly to display to the user.
+		QLOG_ERROR() << "Server didn't send an access token.";
+	}
+	// Set the access token.
+	getMojangAccount()->setAccessToken(accessToken);
+
+
+	// Now we load the list of available profiles.
+	// Mojang hasn't yet implemented the profile system, 
+	// but we might as well support what's there so we 
+	// don't have trouble implementing it later.
+	QLOG_DEBUG() << "Loading profile list.";
+	QJsonArray availableProfiles = responseData.value("availableProfiles").toArray();
+	ProfileList loadedProfiles;
+	for (auto iter : availableProfiles)
+	{
+		QJsonObject profile = iter.toObject();
+		// Profiles are easy, we just need their ID and name.
+		QString id = profile.value("id").toString("");
+		QString name = profile.value("name").toString("");
+
+		if (id.isEmpty() || name.isEmpty())
+		{
+			// This should never happen, but we might as well 
+			// warn about it if it does so we can debug it easily.
+			// You never know when Mojang might do something truly derpy.
+			QLOG_WARN() << "Found entry in available profiles list with missing ID or name field. Ignoring it.";
+		}
+
+		// Now, add a new AccountProfile entry to the list.
+		loadedProfiles.append(AccountProfile(id, name));
+	}
+	// Put the list of profiles we loaded into the MojangAccount object.
+	getMojangAccount()->loadProfiles(loadedProfiles);
+
+
+	// Finally, we set the current profile to the correct value. This is pretty simple.
+	// We do need to make sure that the current profile that the server gave us 
+	// is actually in the available profiles list.
+	// If it isn't, we'll just fail horribly (*shouldn't* ever happen, but you never know).
+	QLOG_DEBUG() << "Setting current profile.";
+	QJsonObject currentProfile = responseData.value("selectedProfile").toObject();
+	QString currentProfileId = currentProfile.value("id").toString("");
+	if (currentProfileId.isEmpty())
+	{
+		// TODO: Set an error to display to the user.
+		QLOG_ERROR() << "Server didn't specify a currently selected profile.";
+		return false;
+	}
+	if (!getMojangAccount()->setProfile(currentProfileId))
+	{
+		// TODO: Set an error to display to the user.
+		QLOG_ERROR() << "Server specified a selected profile that wasn't in the available profiles list.";
+		return false;
+	}
+	
+	
+	// We've made it through the minefield of possible errors. Return true to indicate that we've succeeded.
+	QLOG_DEBUG() << "Finished reading authentication response.";
+	return true;
+}
+
+QString AuthenticateTask::getEndpoint() const
+{
+	return "authenticate";
+}
+
+QString AuthenticateTask::getStateMessage(const YggdrasilTask::State state) const
+{
+	switch (state)
+	{
+	case STATE_SENDING_REQUEST:
+		return tr("Authenticating: Sending request.");
+	case STATE_PROCESSING_RESPONSE:
+		return tr("Authenticating: Processing response.");
+	default:
+		return YggdrasilTask::getStateMessage(state);
+	}
+}
+
diff --git a/logic/auth/AuthenticateTask.h b/logic/auth/AuthenticateTask.h
new file mode 100644
index 00000000..54a6b79a
--- /dev/null
+++ b/logic/auth/AuthenticateTask.h
@@ -0,0 +1,46 @@
+/* Copyright 2013 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 <logic/auth/YggdrasilTask.h>
+
+#include <QObject>
+#include <QString>
+#include <QJsonObject>
+
+/**
+ * The authenticate task takes a MojangAccount with no access token and password and attempts to authenticate with Mojang's servers.
+ * If successful, it will set the MojangAccount's access token.
+ */
+class AuthenticateTask : public YggdrasilTask
+{
+Q_OBJECT
+public:
+	AuthenticateTask(MojangAccountPtr account, const QString& password, QObject* parent=0);
+
+protected:
+	virtual QJsonObject getRequestContent() const;
+	
+	virtual QString getEndpoint() const;
+
+	virtual bool processResponse(QJsonObject responseData);
+	
+	QString getStateMessage(const YggdrasilTask::State state) const;
+
+private:
+	QString m_password;
+};
+
diff --git a/logic/auth/MojangAccount.cpp b/logic/auth/MojangAccount.cpp
new file mode 100644
index 00000000..4f3839bc
--- /dev/null
+++ b/logic/auth/MojangAccount.cpp
@@ -0,0 +1,220 @@
+/* Copyright 2013 MultiMC Contributors
+ *
+ * Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ *
+ * 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 "MojangAccount.h"
+
+#include <QUuid>
+#include <QJsonObject>
+#include <QJsonArray>
+
+#include <logger/QsLog.h>
+
+MojangAccount::MojangAccount(const QString& username, QObject* parent) :
+	QObject(parent)
+{
+	// Generate a client token.
+	m_clientToken = QUuid::createUuid().toString();
+
+	m_username = username;
+
+	m_currentProfile = -1;
+}
+
+MojangAccount::MojangAccount(const QString& username, const QString& clientToken, 
+							 const QString& accessToken, QObject* parent) :
+	QObject(parent)
+{
+	m_username = username;
+	m_clientToken = clientToken;
+	m_accessToken = accessToken;
+
+	m_currentProfile = -1;
+}
+
+MojangAccount::MojangAccount(const MojangAccount& other, QObject* parent)
+{
+	m_username = other.username();
+	m_clientToken = other.clientToken();
+	m_accessToken = other.accessToken();
+
+	m_profiles = other.m_profiles;
+	m_currentProfile = other.m_currentProfile;
+}
+
+
+QString MojangAccount::username() const
+{
+	return m_username;
+}
+
+QString MojangAccount::clientToken() const
+{
+	return m_clientToken;
+}
+
+void MojangAccount::setClientToken(const QString& clientToken)
+{
+	m_clientToken = clientToken;
+}
+
+
+QString MojangAccount::accessToken() const
+{
+	return m_accessToken;
+}
+
+void MojangAccount::setAccessToken(const QString& accessToken)
+{
+	m_accessToken = accessToken;
+}
+
+QString MojangAccount::sessionId() const
+{
+	return "token:" + m_accessToken + ":" + currentProfile()->id();
+}
+
+const QList<AccountProfile> MojangAccount::profiles() const
+{
+	return m_profiles;
+}
+
+const AccountProfile* MojangAccount::currentProfile() const
+{
+	if (m_currentProfile < 0)
+	{
+		if (m_profiles.length() > 0)
+			return &m_profiles.at(0);
+		else
+			return nullptr;
+	}
+	else
+		return &m_profiles.at(m_currentProfile);
+}
+
+bool MojangAccount::setProfile(const QString& profileId)
+{
+	const QList<AccountProfile>& profiles = this->profiles();
+	for (int i = 0; i < profiles.length(); i++)
+	{
+		if (profiles.at(i).id() == profileId)
+		{
+			m_currentProfile = i;
+			return true;
+		}
+	}
+	return false;
+}
+
+void MojangAccount::loadProfiles(const ProfileList& profiles)
+{
+	m_profiles.clear();
+	for (auto profile : profiles)
+		m_profiles.append(profile);
+}
+
+MojangAccountPtr MojangAccount::loadFromJson(const QJsonObject& object)
+{
+	// The JSON object must at least have a username for it to be valid.
+	if (!object.value("username").isString())
+	{
+		QLOG_ERROR() << "Can't load Mojang account info from JSON object. Username field is missing or of the wrong type.";
+		return nullptr;
+	}
+	
+	QString username = object.value("username").toString("");
+	QString clientToken = object.value("clientToken").toString("");
+	QString accessToken = object.value("accessToken").toString("");
+
+	QJsonArray profileArray = object.value("profiles").toArray();
+	if (profileArray.size() < 1)
+	{
+		QLOG_ERROR() << "Can't load Mojang account with username \"" << username << "\". No profiles found.";
+		return nullptr;
+	}
+
+	ProfileList profiles;
+	for (QJsonValue profileVal : profileArray)
+	{
+		QJsonObject profileObject = profileVal.toObject();
+		QString id = profileObject.value("id").toString("");
+		QString name = profileObject.value("name").toString("");
+		if (id.isEmpty() || name.isEmpty())
+		{
+			QLOG_WARN() << "Unable to load a profile because it was missing an ID or a name.";
+			continue;
+		}
+		profiles.append(AccountProfile(id, name));
+	}
+
+	MojangAccountPtr account(new MojangAccount(username, clientToken, accessToken));
+	account->loadProfiles(profiles);
+
+	// Get the currently selected profile.
+	QString currentProfile = object.value("activeProfile").toString("");
+	if (!currentProfile.isEmpty())
+		account->setProfile(currentProfile);
+
+	return account;
+}
+
+QJsonObject MojangAccount::saveToJson()
+{
+	QJsonObject json;
+	json.insert("username", username());
+	json.insert("clientToken", clientToken());
+	json.insert("accessToken", accessToken());
+
+	QJsonArray profileArray;
+	for (AccountProfile profile : m_profiles)
+	{
+		QJsonObject profileObj;
+		profileObj.insert("id", profile.id());
+		profileObj.insert("name", profile.name());
+		profileArray.append(profileObj);
+	}
+	json.insert("profiles", profileArray);
+
+	if (currentProfile() != nullptr)
+		json.insert("activeProfile", currentProfile()->id());
+
+	return json;
+}
+
+
+AccountProfile::AccountProfile(const QString& id, const QString& name)
+{
+	m_id = id;
+	m_name = name;
+}
+
+AccountProfile::AccountProfile(const AccountProfile& other)
+{
+	m_id = other.m_id;
+	m_name = other.m_name;
+}
+
+QString AccountProfile::id() const
+{
+	return m_id;
+}
+
+QString AccountProfile::name() const
+{
+	return m_name;
+}
+
+
diff --git a/logic/auth/MojangAccount.h b/logic/auth/MojangAccount.h
new file mode 100644
index 00000000..062b8aa2
--- /dev/null
+++ b/logic/auth/MojangAccount.h
@@ -0,0 +1,154 @@
+/* Copyright 2013 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 <QObject>
+#include <QString>
+#include <QList>
+#include <QJsonObject>
+
+#include <memory>
+
+class MojangAccount;
+
+typedef std::shared_ptr<MojangAccount> MojangAccountPtr;
+Q_DECLARE_METATYPE(MojangAccountPtr)
+
+
+/**
+ * Class that represents a profile within someone's Mojang account.
+ *
+ * Currently, the profile system has not been implemented by Mojang yet,
+ * but we might as well add some things for it in MultiMC right now so
+ * we don't have to rip the code to pieces to add it later.
+ */
+class AccountProfile
+{
+public:
+	AccountProfile(const QString& id, const QString& name);
+	AccountProfile(const AccountProfile& other);
+
+	QString id() const;
+	QString name() const;
+protected:
+	QString m_id;
+	QString m_name;
+};
+
+
+typedef QList<AccountProfile> ProfileList;
+
+
+/**
+ * Object that stores information about a certain Mojang account.
+ *
+ * Said information may include things such as that account's username, client token, and access 
+ * token if the user chose to stay logged in.
+ */
+class MojangAccount : public QObject
+{
+Q_OBJECT
+public:
+	/**
+	 * Constructs a new MojangAccount with the given username.
+	 * The client token will be generated automatically and the access token will be blank.
+	 */
+	explicit MojangAccount(const QString& username, QObject* parent = 0);
+
+	/**
+	 * Constructs a new MojangAccount with the given username, client token, and access token.
+	 */
+	explicit MojangAccount(const QString& username, const QString& clientToken, const QString& accessToken, QObject* parent = 0);
+
+	/**
+	 * Constructs a new MojangAccount matching the given account.
+	 */
+	MojangAccount(const MojangAccount& other, QObject* parent);
+
+	/**
+	 * Loads a MojangAccount from the given JSON object.
+	 */
+	static MojangAccountPtr loadFromJson(const QJsonObject& json);
+
+	/**
+	 * Saves a MojangAccount to a JSON object and returns it.
+	 */
+	QJsonObject saveToJson();
+
+
+	/**
+	 * This MojangAccount's username. May be an email address if the account is migrated.
+	 */
+	QString username() const;
+
+	/**
+	 * This MojangAccount's client token. This is a UUID used by Mojang's auth servers to identify this client.
+	 * This is unique for each MojangAccount.
+	 */
+	QString clientToken() const;
+
+	/**
+	 * Sets the MojangAccount's client token to the given value.
+	 */
+	void setClientToken(const QString& token);
+
+	/**
+	 * This MojangAccount's access token.
+	 * If the user has not chosen to stay logged in, this will be an empty string.
+	 */
+	QString accessToken() const;
+
+	/**
+	 * Changes this MojangAccount's access token to the given value.
+	 */
+	void setAccessToken(const QString& token);
+
+	/**
+	 * Get full session ID
+	 */
+	QString sessionId() const;
+
+	/**
+	 * Returns a list of the available account profiles.
+	 */
+	const ProfileList profiles() const;
+
+	/**
+	 * Returns a pointer to the currently selected profile.
+	 * If no profile is selected, returns the first profile in the profile list or nullptr if there are none.
+	 */
+	const AccountProfile* currentProfile() const;
+
+	/**
+	 * Sets the currently selected profile to the profile with the given ID string.
+	 * If profileId is not in the list of available profiles, the function will simply return false.
+	 */
+	bool setProfile(const QString& profileId);
+
+	/**
+	 * Clears the current account profile list and replaces it with the given profile list.
+	 */
+	void loadProfiles(const ProfileList& profiles);
+
+
+protected:
+	QString m_username;
+	QString m_clientToken;
+	QString m_accessToken; // Blank if not logged in.
+	int m_currentProfile; // Index of the selected profile within the list of available profiles. -1 if nothing is selected.
+	ProfileList m_profiles; // List of available profiles.
+};
+
diff --git a/logic/auth/YggdrasilTask.cpp b/logic/auth/YggdrasilTask.cpp
new file mode 100644
index 00000000..39dfb749
--- /dev/null
+++ b/logic/auth/YggdrasilTask.cpp
@@ -0,0 +1,182 @@
+/* Copyright 2013 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 <logic/auth/YggdrasilTask.h>
+
+#include <QObject>
+#include <QString>
+#include <QJsonObject>
+#include <QJsonDocument>
+#include <QNetworkReply>
+#include <QByteArray>
+
+#include <MultiMC.h>
+#include <logic/auth/MojangAccount.h>
+
+YggdrasilTask::YggdrasilTask(MojangAccountPtr account, QObject* parent) : Task(parent)
+{
+	m_error = nullptr;
+	m_account = account;
+}
+
+
+YggdrasilTask::~YggdrasilTask()
+{
+	if (m_error)
+		delete m_error;
+}
+
+void YggdrasilTask::executeTask()
+{
+	setStatus(getStateMessage(STATE_SENDING_REQUEST));
+
+	// Get the content of the request we're going to send to the server.
+	QJsonDocument doc(getRequestContent());
+
+	auto worker = MMC->qnam();
+	connect(worker.get(), SIGNAL(finished(QNetworkReply*)), this,
+			SLOT(processReply(QNetworkReply*)));
+
+	QUrl reqUrl("https://authserver.mojang.com/" + getEndpoint());
+	QNetworkRequest netRequest(reqUrl);
+	netRequest.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
+	
+	m_netReply = worker->post(netRequest, doc.toJson());
+}
+
+void YggdrasilTask::processReply(QNetworkReply* reply)
+{
+	setStatus(getStateMessage(STATE_PROCESSING_RESPONSE));
+
+	if (m_netReply != reply)
+		// Wrong reply for some reason...
+		return;
+
+	// Check for errors.
+	switch (reply->error())
+	{
+		case QNetworkReply::NoError:
+		{
+			// Try to parse the response regardless of the response code.
+			// Sometimes the auth server will give more information and an error code.
+			QJsonParseError jsonError;
+			QByteArray replyData = reply->readAll();
+			QJsonDocument doc = QJsonDocument::fromJson(replyData, &jsonError);
+
+			// Check the response code.
+			int responseCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
+
+			switch (responseCode)
+			{
+				case 200:
+				{
+					// If the response code was 200, then there shouldn't be an error. Make sure anyways.
+					switch (jsonError.error)
+					{
+						case QJsonParseError::NoError:
+							if (!processResponse(doc.object()))
+							{
+								YggdrasilTask::Error* err = getError();
+								if (err)
+									emitFailed(err->getErrorMessage());
+								else
+									emitFailed(tr("An unknown error occurred when processing the response from the authentication server."));
+							}
+							else
+							{
+								emitSucceeded();
+							}
+						break;
+
+						default:
+						emitFailed(tr("Failed to parse Yggdrasil JSON response: \"%1\".").arg(jsonError.errorString()));
+						break;
+					}
+					break;
+				}
+
+				default:
+					// If the response code was something else, then Yggdrasil may have given us information about the error.
+					// If we can parse the response, then get information from it. Otherwise just say there was an unknown error.
+					switch (jsonError.error)
+					{
+						case QJsonParseError::NoError:
+							// We were able to parse the server's response. Woo!
+							// Call processError. If a subclass has overridden it then they'll handle their stuff there.
+							processError(doc.object());
+							break;
+
+						default:
+							// The server didn't say anything regarding the error. Give the user an unknown error.
+							emitFailed(tr("Login failed: Unknown HTTP code %1 encountered.").arg(responseCode));
+							break;
+					}
+					break;
+			}
+
+			break;
+		}
+
+		case QNetworkReply::OperationCanceledError:
+			emitFailed(tr("Login canceled."));
+			break;
+
+		default:
+			emitFailed(tr("An unknown error occurred when trying to communicate with the authentication server."));
+			break;
+	}
+}
+
+QString YggdrasilTask::processError(QJsonObject responseData)
+{
+	QJsonValue errorVal = responseData.value("error");
+	QJsonValue msgVal = responseData.value("errorMessage");
+	QJsonValue causeVal = responseData.value("cause");
+
+	if (errorVal.isString() && msgVal.isString() && causeVal.isString())
+	{
+		m_error = new Error(errorVal.toString(""), msgVal.toString(""), causeVal.toString(""));
+		return m_error->getDisplayMessage();
+	}
+	else
+	{
+		// Error is not in standard format. Don't set m_error and return unknown error.
+		return tr("An unknown Yggdrasil error occurred.");
+	}
+}
+
+QString YggdrasilTask::getStateMessage(const YggdrasilTask::State state) const
+{
+	switch (state)
+	{
+	case STATE_SENDING_REQUEST:
+		return tr("Sending request to auth servers.");
+	case STATE_PROCESSING_RESPONSE:
+		return tr("Processing response from servers.");
+	default:
+		return tr("Processing. Please wait.");
+	}
+}
+
+YggdrasilTask::Error *YggdrasilTask::getError() const
+{
+	return this->m_error;
+}
+
+MojangAccountPtr YggdrasilTask::getMojangAccount() const
+{
+	return this->m_account;
+}
+
diff --git a/logic/auth/YggdrasilTask.h b/logic/auth/YggdrasilTask.h
new file mode 100644
index 00000000..6aebae16
--- /dev/null
+++ b/logic/auth/YggdrasilTask.h
@@ -0,0 +1,128 @@
+/* Copyright 2013 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 <logic/tasks/Task.h>
+
+#include <QString>
+#include <QJsonObject>
+
+#include "logic/auth/MojangAccount.h"
+
+class QNetworkReply;
+
+
+/**
+ * A Yggdrasil task is a task that performs an operation on a given mojang account.
+ */
+class YggdrasilTask : public Task
+{
+Q_OBJECT
+public:
+	explicit YggdrasilTask(MojangAccountPtr account, QObject* parent=0);
+	~YggdrasilTask();
+
+	/**
+	 * Class describing a Yggdrasil error response.
+	 */
+	class Error
+	{
+	public:
+		Error(const QString& shortError, const QString& errorMessage, const QString& cause) : 
+			m_shortError(shortError), m_errorMessage(errorMessage), m_cause(cause) {}
+
+		QString getShortError() const { return m_shortError; }
+		QString getErrorMessage() const { return m_errorMessage; }
+		QString getCause() const { return m_cause; }
+
+		/// Gets the string to display in the GUI for describing this error.
+		QString getDisplayMessage() { return getErrorMessage(); }
+
+	protected:
+		QString m_shortError;
+		QString m_errorMessage;
+		QString m_cause;
+	};
+
+	/**
+	 * Gets the Mojang account that this task is operating on.
+	 */
+	virtual MojangAccountPtr getMojangAccount() const;
+
+	/**
+	 * Returns a pointer to a YggdrasilTask::Error object if an error has occurred.
+	 * If no error has occurred, returns a null pointer.
+	 */
+	virtual Error* getError() const;
+
+protected:
+	/**
+	 * Enum for describing the state of the current task.
+	 * Used by the getStateMessage function to determine what the status message should be.
+	 */
+	enum State
+	{
+		STATE_SENDING_REQUEST,
+		STATE_PROCESSING_RESPONSE,
+		STATE_OTHER,
+	};
+
+	virtual void executeTask();
+
+	/**
+	 * Gets the JSON object that will be sent to the authentication server.
+	 * Should be overridden by subclasses.
+	 */
+	virtual QJsonObject getRequestContent() const = 0;
+
+	/**
+	 * Gets the endpoint to POST to.
+	 * No leading slash.
+	 */
+	virtual QString getEndpoint() const = 0;
+
+	/**
+	 * Processes the response received from the server.
+	 * If an error occurred, this should emit a failed signal and return false.
+	 * If Yggdrasil gave an error response, it should call setError() first, and then return false.
+	 * Otherwise, it should return true.
+	 */
+	virtual bool processResponse(QJsonObject responseData) = 0;
+
+	/**
+	 * Processes an error response received from the server.
+	 * The default implementation will read data from Yggdrasil's standard error response format and set it as this task's Error.
+	 * \returns a QString error message that will be passed to emitFailed.
+	 */
+	virtual QString processError(QJsonObject responseData);
+
+	/**
+	 * Returns the state message for the given state.
+	 * Used to set the status message for the task.
+	 * Should be overridden by subclasses that want to change messages for a given state.
+	 */
+	virtual QString getStateMessage(const State state) const;
+
+	MojangAccountPtr m_account;
+
+	QNetworkReply* m_netReply;
+
+	Error* m_error;
+
+protected slots:
+	void processReply(QNetworkReply* reply);
+};
+