Added ability to fetch song cover from external resource.

Telegram/CMakeLists.txt

@@ -961,6 +961,8 @@ PRIVATE
     storage/storage_account.h
     storage/storage_cloud_blob.cpp
     storage/storage_cloud_blob.h
+    storage/storage_cloud_song_cover.cpp
+    storage/storage_cloud_song_cover.h
     storage/storage_domain.cpp
     storage/storage_domain.h
     storage/storage_facade.cpp

Telegram/SourceFiles/data/data_document.cpp

@@ -36,6 +36,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/view/media/history_view_gif.h"
 #include "window/window_session_controller.h"
 #include "storage/cache/storage_cache_database.h"
+#include "storage/storage_cloud_song_cover.h"
 #include "boxes/confirm_box.h"
 #include "ui/image/image.h"
 #include "ui/text/text_utilities.h"
@@ -540,6 +541,13 @@ void DocumentData::setattributes(
 				songData->duration = data.vduration().v;
 				songData->title = qs(data.vtitle().value_or_empty());
 				songData->performer = qs(data.vperformer().value_or_empty());
+
+				if (!hasThumbnail()
+					&& !songData->title.isEmpty()
+					&& !songData->performer.isEmpty()) {
+
+					Storage::CloudSongCover::LoadThumbnailFromExternal(this);
+				}
 			}
 		}, [&](const MTPDdocumentAttributeFilename &data) {
 			_filename = qs(data.vfile_name());

Telegram/SourceFiles/storage/storage_cloud_song_cover.cpp

@@ -0,0 +1,151 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "storage/storage_cloud_song_cover.h"
+
+#include "data/data_cloud_file.h"
+#include "data/data_document.h"
+#include "data/data_file_origin.h"
+#include "data/data_session.h"
+#include "main/main_session.h"
+#include "storage/file_download.h"
+
+#include <QtCore/QJsonArray>
+#include <QtCore/QJsonDocument>
+#include <QtCore/QJsonObject>
+#include <QtCore/QJsonValue>
+
+namespace Storage::CloudSongCover {
+namespace {
+
+constexpr auto kMaxResponseSize = 1024 * 1024;
+constexpr auto kDefaultCoverSize = 100;
+
+struct Responce {
+	const QString artworkUrl;
+	const int size;
+};
+
+auto Location(const QString &url) {
+	return DownloadLocation{ PlainUrlLocation{ url } };
+}
+
+auto JsonUrl(not_null<SongData*> song) {
+	return QString("https://itunes.apple.com/search?term=" \
+		"%1 %2&entity=song&limit=4").arg(song->performer).arg(song->title);
+}
+
+// Dummy JSON responce.
+// {
+//     "resultCount": 2,
+//     "results": [
+//         {
+//             "artworkUrl100": ""
+//         },
+//         {
+//             "artworkUrl100": ""
+//         }
+//     ]
+// }
+
+std::optional<Responce> ParseResponce(const QByteArray &response) {
+	if (response.size() >= kMaxResponseSize) {
+		return std::nullopt;
+	}
+	auto error = QJsonParseError{ 0, QJsonParseError::NoError };
+	const auto document = QJsonDocument::fromJson(response, &error);
+
+	const auto log = [](const QString &message) {
+		DEBUG_LOG(("Parse Artwork JSON Error: %1.").arg(message));
+	};
+
+	if (error.error != QJsonParseError::NoError) {
+		log(error.errorString());
+		return std::nullopt;
+	} else if (!document.isObject()) {
+		log("not an object received in JSON");
+		return std::nullopt;
+	}
+	const auto results = document.object().value("results");
+	if (!results.isArray()) {
+		log("'results' field not found");
+		return std::nullopt;
+	}
+	const auto resultsArray = results.toArray();
+	if (resultsArray.empty()) {
+		return std::nullopt;
+	}
+	const auto artworkUrl = resultsArray.first().toObject()
+		.value("artworkUrl100").toString();
+	if (artworkUrl.isEmpty()) {
+		log("'artworkUrl100' field is empty");
+		return std::nullopt;
+	}
+
+	return Responce{ artworkUrl, kDefaultCoverSize };
+}
+
+void LoadAndApplyThumbnail(
+		not_null<DocumentData*> document,
+		const Responce &responce) {
+	const auto size = responce.size;
+	const auto imageWithLocation = ImageWithLocation{
+		.location = ImageLocation(Location(responce.artworkUrl), size, size)
+	};
+
+	document->updateThumbnails(
+		QByteArray(),
+		imageWithLocation,
+		ImageWithLocation{ .location = ImageLocation() });
+
+	document->loadThumbnail(Data::FileOrigin());
+}
+
+}
+
+void LoadThumbnailFromExternal(not_null<DocumentData*> document) {
+	const auto songData = document->song();
+	if (!songData
+		|| songData->performer.isEmpty()
+		|| songData->title.isEmpty()) {
+		return;
+	}
+
+	const auto &size = kDefaultCoverSize;
+	const auto jsonLocation = ImageWithLocation{
+		.location = ImageLocation(Location(JsonUrl(songData)), size, size)
+	};
+
+	const auto jsonCloudFile = std::make_shared<Data::CloudFile>();
+	Data::UpdateCloudFile(
+		*jsonCloudFile,
+		jsonLocation,
+		document->owner().cache(),
+		0, // Cache tag.
+		nullptr,
+		nullptr);
+
+	auto done = [=](const QByteArray &result) {
+		if (!jsonCloudFile) {
+			return;
+		}
+		if (const auto responce = ParseResponce(result)) {
+			LoadAndApplyThumbnail(document, *responce);
+		}
+	};
+	Data::LoadCloudFile(
+		&document->session(),
+		*jsonCloudFile,
+		Data::FileOrigin(),
+		LoadFromCloudOrLocal,
+		true,
+		0,
+		[] { return true; },
+		std::move(done));
+}
+
+} // namespace Storage::CloudSongCover

Telegram/SourceFiles/storage/storage_cloud_song_cover.h

@@ -0,0 +1,16 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+class DocumentData;
+
+namespace Storage::CloudSongCover {
+
+void LoadThumbnailFromExternal(not_null<DocumentData*> document);
+
+} // namespace Storage::CloudSongCover