API Subsonic: first working version, still WIP (missing commands, no authentication)

src/api/subsonic/SubsonicResponse.cpp

@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2019 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "SubsonicResponse.hpp"
+
+#include <boost/property_tree/json_parser.hpp>
+#include <boost/property_tree/xml_parser.hpp>
+
+#define API_VERSION	"1.12.0"
+
+namespace API::Subsonic
+{
+
+std::string
+ResponseFormatToMimeType(ResponseFormat format)
+{
+	switch (format)
+	{
+		case ResponseFormat::xml: return "text/xml";
+		case ResponseFormat::json: return "application/json";
+	}
+
+	return "";
+}
+
+static
+const char*
+ErrorCodeToString(Error::Code error)
+{
+	switch (error)
+	{
+		case Error::Code::RequiredParameterMissing:
+			return "Required parameter is missing.";
+		case Error::Code::ClientMustUpgrade:
+			return "Incompatible Subsonic REST protocol version. Client must upgrade.";
+		case Error::Code::ServerMustUpgrade:
+			return "Incompatible Subsonic REST protocol version. Server must upgrade.";
+		case Error::Code::WrongUsernameOrPassword:
+			return "Wrong username or password.";
+		case Error::Code::UserNotAuthorized:
+			return "User is not authorized for the given operation.";
+		case Error::Code::RequestedDataNotFound:
+			return "The requested data was not found.";
+		default:
+			return "Unknown error";
+	}
+}
+
+Error::Error(Code code)
+: _code {code},
+_message {ErrorCodeToString(code)}
+{
+}
+
+Error::Error(const std::string& message)
+: _code {Code::Generic},
+_message {message}
+{
+}
+
+void
+Response::Node::setAttribute(const std::string& key, const std::string& value)
+{
+	attributes[key] = value;
+}
+
+void
+Response::Node::addChild(const std::string& key, Node node)
+{
+	children[key].emplace_back(std::move(node));
+}
+
+void
+Response::Node::addArrayChild(const std::string& key, Node node)
+{
+	childrenArrays[key].emplace_back(std::move(node));
+}
+
+
+Response::Node&
+Response::Node::createChild(const std::string& key)
+{
+	children[key].emplace_back();
+	return children[key].back();
+}
+
+Response::Node&
+Response::Node::createArrayChild(const std::string& key)
+{
+	childrenArrays[key].emplace_back();
+	return childrenArrays[key].back();
+}
+
+Response
+Response::createOkResponse()
+{
+	Response response;
+	Node& responseNode {response._root.createChild("subsonic-response")};
+
+	responseNode.setAttribute("status", "ok");
+	responseNode.setAttribute("version", API_VERSION);
+
+	return response;
+}
+
+Response
+Response::createFailedResponse(const Error& error)
+{
+	Response response;
+	Node& responseNode {response._root.createChild("subsonic-response")};
+
+	responseNode.setAttribute("status", "failed");
+	responseNode.setAttribute("version", API_VERSION);
+
+	Node& errorNode {responseNode.createChild("error")};
+	errorNode.setAttribute("code", std::to_string(static_cast<int>(error.getCode())));
+	errorNode.setAttribute("message", error.getMessage());
+
+	return response;
+}
+
+Response::Node&
+Response::createNode(const std::string& key)
+{
+	return _root.children["subsonic-response"].front().createChild(key);
+}
+
+boost::property_tree::ptree
+NodeToPropertyTree(const Response::Node& node, ResponseFormat format)
+{
+	boost::property_tree::ptree res;
+
+	for (auto itChildNode : node.children)
+	{
+		for (const Response::Node& childNode : itChildNode.second)
+			res.add_child(itChildNode.first, NodeToPropertyTree(childNode, format));
+	}
+
+	for (auto itChildArrayNode : node.childrenArrays)
+	{
+		const std::vector<Response::Node>& childArrayNodes {itChildArrayNode .second};
+
+		if (format == ResponseFormat::json)
+		{
+			boost::property_tree::ptree array;
+
+			for (const Response::Node& childNode : childArrayNodes )
+				array.push_back(std::make_pair("", NodeToPropertyTree(childNode, format)));
+
+			res.add_child(itChildArrayNode.first, array);
+		}
+		else
+		{
+			for (const Response::Node& childNode : childArrayNodes )
+				res.add_child(itChildArrayNode.first, NodeToPropertyTree(childNode, format));
+		}
+	}
+
+	for (auto itAttribute : node.attributes)
+	{
+		std::string key {format == ResponseFormat::xml ? "<xmlattr>." : ""};
+
+		key += itAttribute.first;
+
+		res.put(key, itAttribute.second);
+	}
+
+	return res;
+}
+
+void responseToStream(const Response& response, ResponseFormat format, std::ostream& os)
+{
+	boost::property_tree::ptree root {NodeToPropertyTree(response._root, format)};
+
+	switch (format)
+	{
+		case ResponseFormat::xml:
+			boost::property_tree::write_xml(os, root);
+			break;
+		case ResponseFormat::json:
+			boost::property_tree::write_json(os, root);
+			break;
+
+	}
+}
+
+} // namespace
+