input/qobuz: new input plugin to receive Qobuz streams

src/input/plugins/QobuzClient.cxx

@@ -0,0 +1,201 @@
+/*
+ * Copyright 2003-2018 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "QobuzClient.hxx"
+#include "lib/gcrypt/MD5.hxx"
+#include "util/ConstBuffer.hxx"
+
+#include <stdexcept>
+
+#include <assert.h>
+
+namespace {
+
+class QueryStringBuilder {
+	bool first = true;
+
+public:
+	QueryStringBuilder &operator()(std::string &dest, const char *name,
+				       const char *value) noexcept {
+		dest.push_back(first ? '?' : '&');
+		first = false;
+
+		dest += name;
+		dest.push_back('=');
+		dest += value; // TODO: escape
+
+		return *this;
+	}
+};
+
+}
+
+QobuzClient::QobuzClient(EventLoop &event_loop,
+			 const char *_base_url,
+			 const char *_app_id, const char *_app_secret,
+			 const char *_device_manufacturer_id,
+			 const char *_username, const char *_email,
+			 const char *_password)
+	:base_url(_base_url), app_id(_app_id), app_secret(_app_secret),
+	 device_manufacturer_id(_device_manufacturer_id),
+	 username(_username), email(_email), password(_password),
+	 curl(event_loop),
+	 defer_invoke_handlers(event_loop, BIND_THIS_METHOD(InvokeHandlers))
+{
+}
+
+CurlGlobal &
+QobuzClient::GetCurl() noexcept
+{
+	return *curl;
+}
+
+void
+QobuzClient::StartLogin() noexcept
+{
+	assert(!session.IsDefined());
+	assert(!login_request);
+	assert(!handlers.empty());
+
+	QobuzLoginHandler &handler = *this;
+	login_request = std::make_unique<QobuzLoginRequest>(*curl, base_url,
+							    app_id,
+							    username, email,
+							    password,
+							    device_manufacturer_id,
+							    handler);
+	login_request->Start();
+}
+
+void
+QobuzClient::AddLoginHandler(QobuzSessionHandler &h) noexcept
+{
+	const std::lock_guard<Mutex> protect(mutex);
+	assert(!h.is_linked());
+
+	const bool was_empty = handlers.empty();
+	handlers.push_front(h);
+
+	if (!was_empty || login_request)
+		return;
+
+	if (session.IsDefined()) {
+		ScheduleInvokeHandlers();
+	} else {
+		// TODO: throttle login attempts?
+
+		std::string login_uri(base_url);
+		login_uri += "/login/username";
+
+		try {
+			StartLogin();
+		} catch (...) {
+			error = std::current_exception();
+			ScheduleInvokeHandlers();
+			return;
+		}
+	}
+}
+
+QobuzSession
+QobuzClient::GetSession() const
+{
+	const std::lock_guard<Mutex> protect(mutex);
+
+	if (error)
+		std::rethrow_exception(error);
+
+	if (!session.IsDefined())
+		throw std::runtime_error("No session");
+
+	return session;
+}
+
+void
+QobuzClient::OnQobuzLoginSuccess(QobuzSession &&_session) noexcept
+{
+	{
+		const std::lock_guard<Mutex> protect(mutex);
+		session = std::move(_session);
+	}
+
+	ScheduleInvokeHandlers();
+}
+
+void
+QobuzClient::OnQobuzLoginError(std::exception_ptr _error) noexcept
+{
+	{
+		const std::lock_guard<Mutex> protect(mutex);
+		error = std::move(_error);
+	}
+
+	ScheduleInvokeHandlers();
+}
+
+void
+QobuzClient::InvokeHandlers() noexcept
+{
+	const std::lock_guard<Mutex> protect(mutex);
+	while (!handlers.empty()) {
+		auto &h = handlers.front();
+		handlers.pop_front();
+
+		const ScopeUnlock unlock(mutex);
+		h.OnQobuzSession();
+	}
+
+	login_request.reset();
+}
+
+std::string
+QobuzClient::MakeSignedUrl(const char *object, const char *method,
+			   const std::multimap<std::string, std::string> &query) const noexcept
+{
+	assert(!query.empty());
+
+	std::string uri(base_url);
+	uri += object;
+	uri.push_back('/');
+	uri += method;
+
+	QueryStringBuilder q;
+	std::string concatenated_query(object);
+	concatenated_query += method;
+	for (const auto &i : query) {
+		q(uri, i.first.c_str(), i.second.c_str());
+
+		concatenated_query += i.first;
+		concatenated_query += i.second;
+	}
+
+	q(uri, "app_id", app_id);
+
+	const auto request_ts = std::to_string(time(nullptr));
+	q(uri, "request_ts", request_ts.c_str());
+	concatenated_query += request_ts;
+
+	concatenated_query += app_secret;
+
+	const auto md5_hex = MD5Hex({concatenated_query.data(), concatenated_query.size()});
+	q(uri, "request_sig", &md5_hex.front());
+
+	return uri;
+}