Subsonic API: added timestamps into coverart ids, Made use of image ids to save a lookup, ref #558

src/libs/subsonic/impl/CoverArtId.cpp

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2024 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 "CoverArtId.hpp"
+
+#include "SubsonicId.hpp"
+#include "core/String.hpp"
+
+namespace lms::api::subsonic
+{
+    namespace
+    {
+        constexpr char timestampSeparatorChar{ ':' };
+    }
+
+    std::string idToString(db::ImageId id)
+    {
+        return "im-" + id.toString();
+    }
+
+    std::string idToString(CoverArtId coverId)
+    {
+        // produce "id:timestamp"
+        std::string res{ std::visit([](auto&& id) {
+            return idToString(id);
+        },
+            coverId.id) };
+
+        res += timestampSeparatorChar;
+        res += std::to_string(coverId.timestamp);
+
+        return res;
+    }
+} // namespace lms::api::subsonic
+
+// Used to parse parameters
+namespace lms::core::stringUtils
+{
+    template<>
+    std::optional<db::ImageId> readAs(std::string_view str)
+    {
+        std::vector<std::string_view> values{ core::stringUtils::splitString(str, '-') };
+        if (values.size() != 2)
+            return std::nullopt;
+
+        if (values[0] != "im")
+            return std::nullopt;
+
+        if (const auto value{ core::stringUtils::readAs<db::ReleaseId::ValueType>(values[1]) })
+            return db::ImageId{ *value };
+
+        return std::nullopt;
+    }
+
+    template<>
+    std::optional<api::subsonic::CoverArtId> readAs(std::string_view str)
+    {
+        // expect "id:timestamp"
+        auto timeStampSeparator{ str.find_last_of(api::subsonic::timestampSeparatorChar) };
+        if (timeStampSeparator == std::string_view::npos)
+            return std::nullopt;
+
+        std::string_view strId{ str.substr(0, timeStampSeparator) };
+        std::string_view strTimestamp{ str.substr(timeStampSeparator + 1) };
+
+        api::subsonic::CoverArtId cover;
+        if (const auto imagetId{ readAs<db::ImageId>(strId) })
+            cover.id = *imagetId;
+        else if (const auto trackId{ readAs<db::TrackId>(strId) })
+            cover.id = *trackId;
+        else
+            return std::nullopt;
+
+        if (const auto timestamp{ readAs<std::time_t>(strTimestamp) })
+            cover.timestamp = *timestamp;
+        else
+            return std::nullopt;
+
+        return cover;
+    }
+} // namespace lms::core::stringUtils