Merge pull request #272 from QMatrixClient/kitsune-upload-attachments

Support of attachments uploading

16 files changed, 496 insertions, 77 deletions

diff --git a/.travis.yml b/.travis.yml
index b515b8fb..fc143a62 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ addons:
     packages:
     - g++-5
     - qt57base
+    - qt57multimedia
     - valgrind
   homebrew:
     packages:
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8a3193a4..c48a7ba9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,7 +40,9 @@ foreach (FLAG all "" pedantic extra error=return-type no-unused-parameter no-gnu
     endif ()
 endforeach ()
 
-find_package(Qt5 5.4.1 REQUIRED Network Gui)
+# Qt 5.6+ is the formal requirement but for the sake of supporting UBPorts
+# upstream Qt 5.4 is required.
+find_package(Qt5 5.4.1 REQUIRED Network Gui Multimedia)
 get_filename_component(Qt5_Prefix "${Qt5_DIR}/../../../.." ABSOLUTE)
 
 if (GTAD_PATH)
@@ -140,7 +142,7 @@ add_library(QMatrixClient ${libqmatrixclient_SRCS}
             ${libqmatrixclient_job_SRCS} ${libqmatrixclient_csdef_SRCS}
             ${libqmatrixclient_cswellknown_SRCS}
             ${libqmatrixclient_asdef_SRCS} ${libqmatrixclient_isdef_SRCS})
-set(API_VERSION "0.4")
+set(API_VERSION "0.5")
 set_property(TARGET QMatrixClient PROPERTY VERSION "${API_VERSION}.0")
 set_property(TARGET QMatrixClient PROPERTY SOVERSION ${API_VERSION} )
 set_property(TARGET QMatrixClient PROPERTY
@@ -152,7 +154,7 @@ target_include_directories(QMatrixClient PUBLIC
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/lib>
     $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
 )
-target_link_libraries(QMatrixClient Qt5::Core Qt5::Network Qt5::Gui)
+target_link_libraries(QMatrixClient Qt5::Core Qt5::Network Qt5::Gui Qt5::Multimedia)
 
 add_executable(qmc-example ${example_SRCS})
 target_link_libraries(qmc-example Qt5::Core QMatrixClient)
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 49e0089a..cd5e15ed 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -45,7 +45,7 @@ foreach (FLAG all "" pedantic extra error=return-type no-unused-parameter no-gnu
     endif ()
 endforeach ()
 
-find_package(Qt5 5.6 REQUIRED Network Gui)
+find_package(Qt5 5.6 REQUIRED Network Gui Multimedia)
 get_filename_component(Qt5_Prefix "${Qt5_DIR}/../../../.." ABSOLUTE)
 
 find_package(QMatrixClient REQUIRED)
diff --git a/examples/qmc-example.cpp b/examples/qmc-example.cpp
index 894167a9..8fbf4824 100644
--- a/examples/qmc-example.cpp
+++ b/examples/qmc-example.cpp
@@ -9,6 +9,8 @@
 #include <QtCore/QCoreApplication>
 #include <QtCore/QStringBuilder>
 #include <QtCore/QTimer>
+#include <QtCore/QTemporaryFile>
+#include <QtCore/QFileInfo>
 #include <iostream>
 #include <functional>
 
@@ -20,7 +22,7 @@ using namespace std::placeholders;
 class QMCTest : public QObject
 {
     public:
-        QMCTest(Connection* conn, QString targetRoomName, QString source);
+        QMCTest(Connection* conn, QString testRoomName, QString source);
 
     private slots:
         void setupAndRun();
@@ -29,6 +31,9 @@ class QMCTest : public QObject
         void doTests();
             void loadMembers();
             void sendMessage();
+            void sendFile();
+                void checkFileSendingOutcome(const QString& txnId,
+                                             const QString& fileName);
             void addAndRemoveTag();
             void sendAndRedact();
                 void checkRedactionOutcome(const QString& evtIdToRedact,
@@ -47,6 +52,8 @@ class QMCTest : public QObject
         QString origin;
         QString targetRoomName;
         Room* targetRoom = nullptr;
+
+        bool validatePendingEvent(const QString& txnId);
 };
 
 #define QMC_CHECK(description, condition) \
@@ -69,6 +76,14 @@ class QMCTest : public QObject
     } \
 }
 
+bool QMCTest::validatePendingEvent(const QString& txnId)
+{
+    auto it = targetRoom->findPendingEvent(txnId);
+    return it != targetRoom->pendingEvents().end() &&
+            it->deliveryStatus() == EventStatus::Submitted &&
+            (*it)->transactionId() == txnId;
+}
+
 QMCTest::QMCTest(Connection* conn, QString testRoomName, QString source)
     : c(conn), origin(std::move(source)), targetRoomName(std::move(testRoomName))
 {
@@ -142,7 +157,8 @@ void QMCTest::run()
         {
             // TODO: Waiting for proper futures to come so that it could be:
 //            targetRoom->postPlainText(origin % ": All tests finished")
-//            .then(this, &QMCTest::leave);
+//            .then(this, &QMCTest::leave); // Qt-style
+//            .then([this] { leave(); }); // STL-style
             auto txnId =
                     targetRoom->postPlainText(origin % ": All tests finished");
             connect(targetRoom, &Room::messageSent, this,
@@ -166,6 +182,7 @@ void QMCTest::doTests()
         return;
 
     sendMessage();
+    sendFile();
     addAndRemoveTag();
     sendAndRedact();
     markDirectChat();
@@ -206,19 +223,133 @@ void QMCTest::sendMessage()
     running.push_back("Message sending");
     cout << "Sending a message" << endl;
     auto txnId = targetRoom->postPlainText("Hello, " % origin % " is here");
-    auto& pending = targetRoom->pendingEvents();
-    if (pending.empty())
+    if (!validatePendingEvent(txnId))
     {
+        cout << "Invalid pending event right after submitting" << endl;
         QMC_CHECK("Message sending", false);
         return;
     }
-    auto it = std::find_if(pending.begin(), pending.end(),
-                [&txnId] (const auto& e) {
-                    return e->transactionId() == txnId;
+
+    QMetaObject::Connection sc;
+    sc = connect(targetRoom, &Room::pendingEventAboutToMerge, this,
+        [this,sc,txnId] (const RoomEvent* evt, int pendingIdx) {
+            const auto& pendingEvents = targetRoom->pendingEvents();
+            Q_ASSERT(pendingIdx >= 0 && pendingIdx < int(pendingEvents.size()));
+
+            if (evt->transactionId() != txnId)
+                return;
+
+            disconnect(sc);
+
+            QMC_CHECK("Message sending",
+                is<RoomMessageEvent>(*evt) && !evt->id().isEmpty() &&
+                pendingEvents[size_t(pendingIdx)]->transactionId()
+                    == evt->transactionId());
+        });
+}
+
+void QMCTest::sendFile()
+{
+    running.push_back("File sending");
+    cout << "Sending a file" << endl;
+    auto* tf = new QTemporaryFile;
+    if (!tf->open())
+    {
+        cout << "Failed to create a temporary file" << endl;
+        QMC_CHECK("File sending", false);
+        return;
+    }
+    tf->write("Test");
+    tf->close();
+    // QFileInfo::fileName brings only the file name; QFile::fileName brings
+    // the full path
+    const auto tfName = QFileInfo(*tf).fileName();
+    cout << "Sending file" << tfName.toStdString() << endl;
+    const auto txnId = targetRoom->postFile("Test file",
+                                            QUrl::fromLocalFile(tf->fileName()));
+    if (!validatePendingEvent(txnId))
+    {
+        cout << "Invalid pending event right after submitting" << endl;
+        QMC_CHECK("File sending", false);
+        delete tf;
+        return;
+    }
+
+    QMetaObject::Connection scCompleted, scFailed;
+    scCompleted = connect(targetRoom, &Room::fileTransferCompleted, this,
+        [this,txnId,tf,tfName,scCompleted,scFailed] (const QString& id) {
+            auto fti = targetRoom->fileTransferInfo(id);
+            Q_ASSERT(fti.status == FileTransferInfo::Completed);
+
+            if (id != txnId)
+                return;
+
+            disconnect(scCompleted);
+            disconnect(scFailed);
+            delete tf;
+
+            checkFileSendingOutcome(txnId, tfName);
+        });
+    scFailed = connect(targetRoom, &Room::fileTransferFailed, this,
+        [this,txnId,tf,scCompleted,scFailed]
+        (const QString& id, const QString& error) {
+            if (id != txnId)
+                return;
+
+            targetRoom->postPlainText(origin % ": File upload failed: " % error);
+            disconnect(scCompleted);
+            disconnect(scFailed);
+            delete tf;
+
+            QMC_CHECK("File sending", false);
+        });
+}
+
+void QMCTest::checkFileSendingOutcome(const QString& txnId,
+                                      const QString& fileName)
+{
+    auto it = targetRoom->findPendingEvent(txnId);
+    if (it == targetRoom->pendingEvents().end())
+    {
+        cout << "Pending file event dropped before upload completion"
+             << endl;
+        QMC_CHECK("File sending", false);
+        return;
+    }
+    if (it->deliveryStatus() != EventStatus::FileUploaded)
+    {
+        cout << "Pending file event status upon upload completion is "
+             << it->deliveryStatus() << " != FileUploaded("
+             << EventStatus::FileUploaded << ')' << endl;
+        QMC_CHECK("File sending", false);
+        return;
+    }
+
+    QMetaObject::Connection sc;
+    sc = connect(targetRoom, &Room::pendingEventAboutToMerge, this,
+        [this,sc,txnId,fileName] (const RoomEvent* evt, int pendingIdx) {
+            const auto& pendingEvents = targetRoom->pendingEvents();
+            Q_ASSERT(pendingIdx >= 0 && pendingIdx < int(pendingEvents.size()));
+
+            if (evt->transactionId() != txnId)
+                return;
+
+            cout << "Event " << txnId.toStdString()
+                 << " arrived in the timeline" << endl;
+            disconnect(sc);
+            visit(*evt,
+                [&] (const RoomMessageEvent& e) {
+                    QMC_CHECK("File sending",
+                        !e.id().isEmpty() &&
+                        pendingEvents[size_t(pendingIdx)]
+                            ->transactionId() == txnId &&
+                        e.hasFileContent() &&
+                        e.content()->fileInfo()->originalName == fileName);
+                },
+                [this] (const RoomEvent&) {
+                    QMC_CHECK("File sending", false);
                 });
-    QMC_CHECK("Message sending", it != pending.end());
-    // TODO: Wait when it actually gets sent; check that it obtained an id
-    // Independently, check when it shows up in the timeline.
+        });
 }
 
 void QMCTest::addAndRemoveTag()
diff --git a/lib/connection.cpp b/lib/connection.cpp
index a16bc753..c17cbffc 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -43,6 +43,7 @@
 #include <QtCore/QStringBuilder>
 #include <QtCore/QElapsedTimer>
 #include <QtCore/QRegularExpression>
+#include <QtCore/QMimeDatabase>
 #include <QtCore/QCoreApplication>
 
 using namespace QMatrixClient;
@@ -466,13 +467,21 @@ MediaThumbnailJob* Connection::getThumbnail(const QUrl& url,
 }
 
 UploadContentJob* Connection::uploadContent(QIODevice* contentSource,
-        const QString& filename, const QString& contentType) const
+        const QString& filename, const QString& overrideContentType) const
 {
+    auto contentType = overrideContentType;
+    if (contentType.isEmpty())
+    {
+        contentType =
+            QMimeDatabase().mimeTypeForFileNameAndData(filename, contentSource)
+            .name();
+        contentSource->open(QIODevice::ReadOnly);
+    }
     return callApi<UploadContentJob>(contentSource, filename, contentType);
 }
 
 UploadContentJob* Connection::uploadFile(const QString& fileName,
-                                         const QString& contentType)
+                                         const QString& overrideContentType)
 {
     auto sourceFile = new QFile(fileName);
     if (!sourceFile->open(QIODevice::ReadOnly))
@@ -482,7 +491,7 @@ UploadContentJob* Connection::uploadFile(const QString& fileName,
         return nullptr;
     }
     return uploadContent(sourceFile, QFileInfo(*sourceFile).fileName(),
-                         contentType);
+                         overrideContentType);
 }
 
 GetContentJob* Connection::getContent(const QString& mediaId) const
diff --git a/lib/connection.h b/lib/connection.h
index 9a94aad6..ff3e2028 100644
--- a/lib/connection.h
+++ b/lib/connection.h
@@ -402,10 +402,10 @@ namespace QMatrixClient
 
             // QIODevice* should already be open
             UploadContentJob* uploadContent(QIODevice* contentSource,
-                            const QString& filename = {},
-                            const QString& contentType = {}) const;
+                                const QString& filename = {},
+                                const QString& overrideContentType = {}) const;
             UploadContentJob* uploadFile(const QString& fileName,
-                                         const QString& contentType = {});
+                                const QString& overrideContentType = {});
             GetContentJob* getContent(const QString& mediaId) const;
             GetContentJob* getContent(const QUrl& url) const;
             // If localFilename is empty, a temporary file will be created
diff --git a/lib/eventitem.cpp b/lib/eventitem.cpp
index 79ef769c..8ec3fe48 100644
--- a/lib/eventitem.cpp
+++ b/lib/eventitem.cpp
@@ -17,3 +17,29 @@
  */
 
 #include "eventitem.h"
+
+#include "events/roommessageevent.h"
+#include "events/roomavatarevent.h"
+
+using namespace QMatrixClient;
+
+void PendingEventItem::setFileUploaded(const QUrl& remoteUrl)
+{
+    // TODO: eventually we might introduce hasFileContent to RoomEvent,
+    // and unify the code below.
+    if (auto* rme = getAs<RoomMessageEvent>())
+    {
+        Q_ASSERT(rme->hasFileContent());
+        rme->editContent([remoteUrl] (EventContent::TypedBase& ec) {
+            ec.fileInfo()->url = remoteUrl;
+        });
+    }
+    if (auto* rae = getAs<RoomAvatarEvent>())
+    {
+        Q_ASSERT(rae->content().fileInfo());
+        rae->editContent([remoteUrl] (EventContent::FileInfo& fi) {
+            fi.url = remoteUrl;
+        });
+    }
+    setStatus(EventStatus::FileUploaded);
+}
diff --git a/lib/eventitem.h b/lib/eventitem.h
index 5f1d10c9..36ed2132 100644
--- a/lib/eventitem.h
+++ b/lib/eventitem.h
@@ -33,16 +33,17 @@ namespace QMatrixClient
             /** Special marks an event can assume
              *
              * This is used to hint at a special status of some events in UI.
-             * Most status values are mutually exclusive.
+             * All values except Redacted and Hidden are mutually exclusive.
              */
             enum Code {
                 Normal = 0x0,         //< No special designation
                 Submitted = 0x01,     //< The event has just been submitted for sending
-                Departed = 0x02,      //< The event has left the client
-                ReachedServer = 0x03, //< The server has received the event
-                SendingFailed = 0x04, //< The server could not receive the event
+                FileUploaded = 0x02,  //< The file attached to the event has been uploaded to the server
+                Departed = 0x03,      //< The event has left the client
+                ReachedServer = 0x04, //< The server has received the event
+                SendingFailed = 0x05, //< The server could not receive the event
                 Redacted = 0x08,      //< The event has been redacted
-                Hidden = 0x10,        //< The event should be hidden
+                Hidden = 0x10,        //< The event should not be shown in the timeline
             };
             Q_DECLARE_FLAGS(Status, Code)
             Q_FLAG(Status)
@@ -70,6 +71,9 @@ namespace QMatrixClient
                 return std::exchange(evt, move(other));
             }
 
+        protected:
+            template <typename EventT>
+            EventT* getAs() { return eventCast<EventT>(evt); }
         private:
             RoomEventPtr evt;
     };
@@ -116,6 +120,7 @@ namespace QMatrixClient
             QString annotation() const { return _annotation; }
 
             void setDeparted() { setStatus(EventStatus::Departed); }
+            void setFileUploaded(const QUrl& remoteUrl);
             void setReachedServer(const QString& eventId)
             {
                 setStatus(EventStatus::ReachedServer);
diff --git a/lib/events/eventcontent.cpp b/lib/events/eventcontent.cpp
index a6b1c763..9a5e872c 100644
--- a/lib/events/eventcontent.cpp
+++ b/lib/events/eventcontent.cpp
@@ -17,6 +17,8 @@
  */
 
 #include "eventcontent.h"
+
+#include "converters.h"
 #include "util.h"
 
 #include <QtCore/QMimeDatabase>
@@ -30,7 +32,7 @@ QJsonObject Base::toJson() const
     return o;
 }
 
-FileInfo::FileInfo(const QUrl& u, int payloadSize, const QMimeType& mimeType,
+FileInfo::FileInfo(const QUrl& u, qint64 payloadSize, const QMimeType& mimeType,
                    const QString& originalFilename)
     : mimeType(mimeType), url(u), payloadSize(payloadSize)
     , originalName(originalFilename)
@@ -41,7 +43,7 @@ FileInfo::FileInfo(const QUrl& u, const QJsonObject& infoJson,
     : originalInfoJson(infoJson)
     , mimeType(QMimeDatabase().mimeTypeForName(infoJson["mimetype"_ls].toString()))
     , url(u)
-    , payloadSize(infoJson["size"_ls].toInt())
+    , payloadSize(fromJson<qint64>(infoJson["size"_ls]))
     , originalName(originalFilename)
 {
     if (!mimeType.isValid())
@@ -51,13 +53,15 @@ FileInfo::FileInfo(const QUrl& u, const QJsonObject& infoJson,
 void FileInfo::fillInfoJson(QJsonObject* infoJson) const
 {
     Q_ASSERT(infoJson);
-    infoJson->insert(QStringLiteral("size"), payloadSize);
-    infoJson->insert(QStringLiteral("mimetype"), mimeType.name());
+    if (payloadSize != -1)
+        infoJson->insert(QStringLiteral("size"), payloadSize);
+    if (mimeType.isValid())
+        infoJson->insert(QStringLiteral("mimetype"), mimeType.name());
 }
 
-ImageInfo::ImageInfo(const QUrl& u, int fileSize, QMimeType mimeType,
-                     const QSize& imageSize)
-    : FileInfo(u, fileSize, mimeType), imageSize(imageSize)
+ImageInfo::ImageInfo(const QUrl& u, qint64 fileSize, QMimeType mimeType,
+                     const QSize& imageSize, const QString& originalFilename)
+    : FileInfo(u, fileSize, mimeType, originalFilename), imageSize(imageSize)
 { }
 
 ImageInfo::ImageInfo(const QUrl& u, const QJsonObject& infoJson,
@@ -69,8 +73,10 @@ ImageInfo::ImageInfo(const QUrl& u, const QJsonObject& infoJson,
 void ImageInfo::fillInfoJson(QJsonObject* infoJson) const
 {
     FileInfo::fillInfoJson(infoJson);
-    infoJson->insert(QStringLiteral("w"), imageSize.width());
-    infoJson->insert(QStringLiteral("h"), imageSize.height());
+    if (imageSize.width() != -1)
+        infoJson->insert(QStringLiteral("w"), imageSize.width());
+    if (imageSize.height() != -1)
+        infoJson->insert(QStringLiteral("h"), imageSize.height());
 }
 
 Thumbnail::Thumbnail(const QJsonObject& infoJson)
@@ -80,7 +86,9 @@ Thumbnail::Thumbnail(const QJsonObject& infoJson)
 
 void Thumbnail::fillInfoJson(QJsonObject* infoJson) const
 {
-    infoJson->insert(QStringLiteral("thumbnail_url"), url.toString());
-    infoJson->insert(QStringLiteral("thumbnail_info"),
-                     toInfoJson<ImageInfo>(*this));
+    if (url.isValid())
+        infoJson->insert(QStringLiteral("thumbnail_url"), url.toString());
+    if (!imageSize.isEmpty())
+        infoJson->insert(QStringLiteral("thumbnail_info"),
+                         toInfoJson<ImageInfo>(*this));
 }
diff --git a/lib/events/eventcontent.h b/lib/events/eventcontent.h
index ea321fb6..0588c0e2 100644
--- a/lib/events/eventcontent.h
+++ b/lib/events/eventcontent.h
@@ -88,7 +88,7 @@ namespace QMatrixClient
         class FileInfo
         {
             public:
-                explicit FileInfo(const QUrl& u, int payloadSize = -1,
+                explicit FileInfo(const QUrl& u, qint64 payloadSize = -1,
                                   const QMimeType& mimeType = {},
                                   const QString& originalFilename = {});
                 FileInfo(const QUrl& u, const QJsonObject& infoJson,
@@ -109,7 +109,7 @@ namespace QMatrixClient
                 QJsonObject originalInfoJson;
                 QMimeType mimeType;
                 QUrl url;
-                int payloadSize;
+                qint64 payloadSize;
                 QString originalName;
         };
 
@@ -127,9 +127,10 @@ namespace QMatrixClient
         class ImageInfo : public FileInfo
         {
             public:
-                explicit ImageInfo(const QUrl& u, int fileSize = -1,
+                explicit ImageInfo(const QUrl& u, qint64 fileSize = -1,
                                    QMimeType mimeType = {},
-                                   const QSize& imageSize = {});
+                                   const QSize& imageSize = {},
+                                   const QString& originalFilename = {});
                 ImageInfo(const QUrl& u, const QJsonObject& infoJson,
                           const QString& originalFilename = {});
 
@@ -167,6 +168,7 @@ namespace QMatrixClient
                 explicit TypedBase(const QJsonObject& o = {}) : Base(o) { }
                 virtual QMimeType type() const = 0;
                 virtual const FileInfo* fileInfo() const { return nullptr; }
+                virtual FileInfo* fileInfo() { return nullptr; }
                 virtual const Thumbnail* thumbnailInfo() const { return nullptr; }
         };
 
@@ -196,6 +198,7 @@ namespace QMatrixClient
 
                 QMimeType type() const override { return InfoT::mimeType; }
                 const FileInfo* fileInfo() const override { return this; }
+                FileInfo* fileInfo() override { return this; }
 
             protected:
                 void fillJson(QJsonObject* json) const override
diff --git a/lib/events/roommessageevent.cpp b/lib/events/roommessageevent.cpp
index 1c5cf058..c3007fa0 100644
--- a/lib/events/roommessageevent.cpp
+++ b/lib/events/roommessageevent.cpp
@@ -21,6 +21,9 @@
 #include "logging.h"
 
 #include <QtCore/QMimeDatabase>
+#include <QtCore/QFileInfo>
+#include <QtGui/QImageReader>
+#include <QtMultimedia/QMediaResource>
 
 using namespace QMatrixClient;
 using namespace EventContent;
@@ -71,8 +74,8 @@ MsgType jsonToMsgType(const QString& matrixType)
     return MsgType::Unknown;
 }
 
-inline QJsonObject toMsgJson(const QString& plainBody, const QString& jsonMsgType,
-                      TypedBase* content)
+QJsonObject RoomMessageEvent::assembleContentJson(const QString& plainBody,
+                const QString& jsonMsgType, TypedBase* content)
 {
     auto json = content ? content->toJson() : QJsonObject();
     json.insert(QStringLiteral("msgtype"), jsonMsgType);
@@ -86,7 +89,7 @@ static const auto BodyKey = "body"_ls;
 RoomMessageEvent::RoomMessageEvent(const QString& plainBody,
         const QString& jsonMsgType, TypedBase* content)
     : RoomEvent(typeId(), matrixTypeId(),
-                toMsgJson(plainBody, jsonMsgType, content))
+                assembleContentJson(plainBody, jsonMsgType, content))
     , _content(content)
 { }
 
@@ -95,6 +98,40 @@ RoomMessageEvent::RoomMessageEvent(const QString& plainBody,
     : RoomMessageEvent(plainBody, msgTypeToJson(msgType), content)
 { }
 
+TypedBase* contentFromFile(const QFileInfo& file, bool asGenericFile)
+{
+    auto filePath = file.absoluteFilePath();
+    auto localUrl = QUrl::fromLocalFile(filePath);
+    auto mimeType = QMimeDatabase().mimeTypeForFile(file);
+    if (!asGenericFile)
+    {
+        auto mimeTypeName = mimeType.name();
+        if (mimeTypeName.startsWith("image/"))
+            return new ImageContent(localUrl, file.size(), mimeType,
+                                    QImageReader(filePath).size(),
+                                    file.fileName());
+
+        // duration can only be obtained asynchronously and can only be reliably
+        // done by starting to play the file. Left for a future implementation.
+        if (mimeTypeName.startsWith("video/"))
+            return new VideoContent(localUrl, file.size(), mimeType,
+                                    QMediaResource(localUrl).resolution(),
+                                    file.fileName());
+
+        if (mimeTypeName.startsWith("audio/"))
+            return new AudioContent(localUrl, file.size(), mimeType,
+                                    file.fileName());
+    }
+    return new FileContent(localUrl, file.size(), mimeType, file.fileName());
+}
+
+RoomMessageEvent::RoomMessageEvent(const QString& plainBody,
+        const QFileInfo& file, bool asGenericFile)
+    : RoomMessageEvent(plainBody,
+        asGenericFile ? QStringLiteral("m.file") : rawMsgTypeForFile(file),
+        contentFromFile(file, asGenericFile))
+{ }
+
 RoomMessageEvent::RoomMessageEvent(const QJsonObject& obj)
     : RoomEvent(typeId(), obj), _content(nullptr)
 {
@@ -162,6 +199,25 @@ bool RoomMessageEvent::hasThumbnail() const
     return content() && content()->thumbnailInfo();
 }
 
+QString rawMsgTypeForMimeType(const QMimeType& mimeType)
+{
+    auto name = mimeType.name();
+    return name.startsWith("image/") ? QStringLiteral("m.image") :
+            name.startsWith("video/") ? QStringLiteral("m.video") :
+            name.startsWith("audio/") ? QStringLiteral("m.audio") :
+            QStringLiteral("m.file");
+}
+
+QString RoomMessageEvent::rawMsgTypeForUrl(const QUrl& url)
+{
+    return rawMsgTypeForMimeType(QMimeDatabase().mimeTypeForUrl(url));
+}
+
+QString RoomMessageEvent::rawMsgTypeForFile(const QFileInfo& fi)
+{
+    return rawMsgTypeForMimeType(QMimeDatabase().mimeTypeForFile(fi));
+}
+
 TextContent::TextContent(const QString& text, const QString& contentType)
     : mimeType(QMimeDatabase().mimeTypeForName(contentType)), body(text)
 {
@@ -200,7 +256,8 @@ void TextContent::fillJson(QJsonObject* json) const
     }
 }
 
-LocationContent::LocationContent(const QString& geoUri, const ImageInfo& thumbnail)
+LocationContent::LocationContent(const QString& geoUri,
+                                 const Thumbnail& thumbnail)
     : geoUri(geoUri), thumbnail(thumbnail)
 { }
 
diff --git a/lib/events/roommessageevent.h b/lib/events/roommessageevent.h
index 4c29a93e..d5b570f5 100644
--- a/lib/events/roommessageevent.h
+++ b/lib/events/roommessageevent.h
@@ -21,6 +21,8 @@
 #include "roomevent.h"
 #include "eventcontent.h"
 
+class QFileInfo;
+
 namespace QMatrixClient
 {
     namespace MessageEventContent = EventContent; // Back-compatibility
@@ -49,6 +51,9 @@ namespace QMatrixClient
             explicit RoomMessageEvent(const QString& plainBody,
                                       MsgType msgType = MsgType::Text,
                                       EventContent::TypedBase* content = nullptr);
+            explicit RoomMessageEvent(const QString& plainBody,
+                                      const QFileInfo& file,
+                                      bool asGenericFile = false);
             explicit RoomMessageEvent(const QJsonObject& obj);
 
             MsgType msgtype() const;
@@ -56,14 +61,27 @@ namespace QMatrixClient
             QString plainBody() const;
             EventContent::TypedBase* content() const
                                              { return _content.data(); }
+            template <typename VisitorT>
+            void editContent(VisitorT visitor)
+            {
+                visitor(*_content);
+                editJson()[ContentKeyL] =
+                    assembleContentJson(plainBody(), rawMsgtype(), content());
+            }
             QMimeType mimeType() const;
             bool hasTextContent() const;
             bool hasFileContent() const;
             bool hasThumbnail() const;
 
+            static QString rawMsgTypeForUrl(const QUrl& url);
+            static QString rawMsgTypeForFile(const QFileInfo& fi);
+
         private:
             QScopedPointer<EventContent::TypedBase> _content;
 
+            static QJsonObject assembleContentJson(const QString& plainBody,
+                const QString& jsonMsgType, EventContent::TypedBase* content);
+
             REGISTER_ENUM(MsgType)
     };
     REGISTER_EVENT_TYPE(RoomMessageEvent)
@@ -112,7 +130,7 @@ namespace QMatrixClient
         {
             public:
                 LocationContent(const QString& geoUri,
-                                const ImageInfo& thumbnail);
+                                const Thumbnail& thumbnail = {});
                 explicit LocationContent(const QJsonObject& json);
 
                 QMimeType type() const override;
@@ -132,6 +150,7 @@ namespace QMatrixClient
         class PlayableContent : public ContentT
         {
             public:
+                using ContentT::ContentT;
                 PlayableContent(const QJsonObject& json)
                     : ContentT(json)
                     , duration(ContentT::originalInfoJson["duration"_ls].toInt())
diff --git a/lib/events/stateevent.h b/lib/events/stateevent.h
index d82de7e1..d488c0a0 100644
--- a/lib/events/stateevent.h
+++ b/lib/events/stateevent.h
@@ -88,6 +88,12 @@ namespace QMatrixClient {
             }
 
             const ContentT& content() const { return _content; }
+            template <typename VisitorT>
+            void editContent(VisitorT&& visitor)
+            {
+                visitor(_content);
+                editJson()[ContentKeyL] = _content.toJson();
+            }
             [[deprecated("Use prevContent instead")]]
             const ContentT* prev_content() const { return prevContent(); }
             const ContentT* prevContent() const
diff --git a/lib/room.cpp b/lib/room.cpp
index 156b5b1f..8f50607f 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -53,6 +53,7 @@
 #include <QtCore/QPointer>
 #include <QtCore/QDir>
 #include <QtCore/QTemporaryFile>
+#include <QtCore/QMimeDatabase>
 
 #include <array>
 #include <functional>
@@ -67,9 +68,11 @@ using std::llround;
 
 enum EventsPlacement : int { Older = -1, Newer = 1 };
 
-// A workaround for MSVC 2015 that fails with "error C2440: 'return':
-// cannot convert from 'initializer list' to 'QMatrixClient::FileTransferInfo'"
-#if (defined(_MSC_VER) && _MSC_VER < 1910) || (defined(__GNUC__) && __GNUC__ <= 4)
+// A workaround for MSVC 2015 and older GCC's that don't handle initializer
+// lists right (MSVC 2015, notably, fails with "error C2440: 'return':
+// cannot convert from 'initializer list' to 'QMatrixClient::FileTransferInfo'")
+#if (defined(_MSC_VER) && _MSC_VER < 1910) || \
+    (defined(__GNUC__) && !defined(__clang__) && __GNUC__ <= 4)
 #  define WORKAROUND_EXTENDED_INITIALIZER_LIST
 #endif
 
@@ -126,15 +129,17 @@ class Room::Private
 
         struct FileTransferPrivateInfo
         {
-#ifdef WORKAROUND_EXTENDED_INITIALIZER_LIST
             FileTransferPrivateInfo() = default;
-            FileTransferPrivateInfo(BaseJob* j, QString fileName)
-                : job(j), localFileInfo(fileName)
+            FileTransferPrivateInfo(BaseJob* j, const QString& fileName,
+                                    bool isUploading = false)
+                : status(FileTransferInfo::Started), job(j)
+                , localFileInfo(fileName), isUpload(isUploading)
             { }
-#endif
+
+            FileTransferInfo::Status status = FileTransferInfo::None;
             QPointer<BaseJob> job = nullptr;
             QFileInfo localFileInfo { };
-            FileTransferInfo::Status status = FileTransferInfo::Started;
+            bool isUpload = false;
             qint64 progress = 0;
             qint64 total = -1;
 
@@ -234,6 +239,8 @@ class Room::Private
             return sendEvent(makeEvent<EventT>(std::forward<ArgTs>(eventArgs)...));
         }
 
+        RoomEvent* addAsPending(RoomEventPtr&& event);
+
         QString doSendEvent(const RoomEvent* pEvent);
         PendingEvents::iterator findAsPending(const RoomEvent* rawEvtPtr);
         void onEventSendingFailure(const RoomEvent* pEvent,
@@ -592,6 +599,19 @@ Room::rev_iter_t Room::findInTimeline(const QString& evtId) const
     return timelineEdge();
 }
 
+Room::PendingEvents::iterator Room::findPendingEvent(const QString& txnId)
+{
+    return std::find_if(d->unsyncedEvents.begin(), d->unsyncedEvents.end(),
+            [txnId] (const auto& item) { return item->transactionId() == txnId; });
+}
+
+Room::PendingEvents::const_iterator
+Room::findPendingEvent(const QString& txnId) const
+{
+    return std::find_if(d->unsyncedEvents.cbegin(), d->unsyncedEvents.cend(),
+            [txnId] (const auto& item) { return item->transactionId() == txnId; });
+}
+
 void Room::Private::getAllMembers()
 {
     // If already loaded or already loading, there's nothing to do here.
@@ -909,7 +929,7 @@ QString Room::Private::fileNameToDownload(const RoomMessageEvent* event) const
     return fileName;
 }
 
-QUrl Room::urlToThumbnail(const QString& eventId)
+QUrl Room::urlToThumbnail(const QString& eventId) const
 {
     if (auto* event = d->getEventWithFile(eventId))
         if (event->hasThumbnail())
@@ -923,7 +943,7 @@ QUrl Room::urlToThumbnail(const QString& eventId)
     return {};
 }
 
-QUrl Room::urlToDownload(const QString& eventId)
+QUrl Room::urlToDownload(const QString& eventId) const
 {
     if (auto* event = d->getEventWithFile(eventId))
     {
@@ -935,7 +955,7 @@ QUrl Room::urlToDownload(const QString& eventId)
     return {};
 }
 
-QString Room::fileNameToDownload(const QString& eventId)
+QString Room::fileNameToDownload(const QString& eventId) const
 {
     if (auto* event = d->getEventWithFile(eventId))
         return d->fileNameToDownload(event);
@@ -969,13 +989,28 @@ FileTransferInfo Room::fileTransferInfo(const QString& id) const
     fti.localPath = QUrl::fromLocalFile(infoIt->localFileInfo.absoluteFilePath());
     return fti;
 #else
-    return { infoIt->status, int(progress), int(total),
+    return { infoIt->status, infoIt->isUpload, int(progress), int(total),
         QUrl::fromLocalFile(infoIt->localFileInfo.absolutePath()),
         QUrl::fromLocalFile(infoIt->localFileInfo.absoluteFilePath())
     };
 #endif
 }
 
+QUrl Room::fileSource(const QString& id) const
+{
+    auto url = urlToDownload(id);
+    if (url.isValid())
+        return url;
+
+    // No urlToDownload means it's a pending or completed upload.
+    auto infoIt = d->fileTransfers.find(id);
+    if (infoIt != d->fileTransfers.end())
+        return QUrl::fromLocalFile(infoIt->localFileInfo.absoluteFilePath());
+
+    qCWarning(MAIN) << "File source for identifier" << id << "not found";
+    return {};
+}
+
 QString Room::prettyPrint(const QString& plainText) const
 {
     return QMatrixClient::prettyPrint(plainText);
@@ -1255,7 +1290,7 @@ void Room::updateData(SyncRoomData&& data, bool fromCache)
     }
 }
 
-QString Room::Private::sendEvent(RoomEventPtr&& event)
+RoomEvent* Room::Private::addAsPending(RoomEventPtr&& event)
 {
     if (event->transactionId().isEmpty())
         event->setTransactionId(connection->generateTxnId());
@@ -1263,7 +1298,12 @@ QString Room::Private::sendEvent(RoomEventPtr&& event)
     emit q->pendingEventAboutToAdd(pEvent);
     unsyncedEvents.emplace_back(move(event));
     emit q->pendingEventAdded();
-    return doSendEvent(pEvent);
+    return pEvent;
+}
+
+QString Room::Private::sendEvent(RoomEventPtr&& event)
+{
+    return doSendEvent(addAsPending(std::move(event)));
 }
 
 QString Room::Private::doSendEvent(const RoomEvent* pEvent)
@@ -1336,10 +1376,35 @@ void Room::Private::onEventSendingFailure(const RoomEvent* pEvent,
 
 QString Room::retryMessage(const QString& txnId)
 {
-    auto it = std::find_if(d->unsyncedEvents.begin(), d->unsyncedEvents.end(),
-            [txnId] (const auto& evt) { return evt->transactionId() == txnId; });
+    const auto it = findPendingEvent(txnId);
     Q_ASSERT(it != d->unsyncedEvents.end());
     qDebug(EVENTS) << "Retrying transaction" << txnId;
+    const auto& transferIt = d->fileTransfers.find(txnId);
+    if (transferIt != d->fileTransfers.end())
+    {
+        Q_ASSERT(transferIt->isUpload);
+        if (transferIt->status == FileTransferInfo::Completed)
+        {
+            qCDebug(MAIN) << "File for transaction" << txnId
+                          << "has already been uploaded, bypassing re-upload";
+        } else {
+            if (isJobRunning(transferIt->job))
+            {
+                qCDebug(MAIN) << "Abandoning the upload job for transaction"
+                              << txnId << "and starting again";
+                transferIt->job->abandon();
+                emit fileTransferFailed(txnId, tr("File upload will be retried"));
+            }
+            uploadFile(txnId,
+                QUrl::fromLocalFile(transferIt->localFileInfo.absoluteFilePath()));
+            // FIXME: Content type is no more passed here but it should
+        }
+    }
+    if (it->deliveryStatus() == EventStatus::ReachedServer)
+    {
+        qCWarning(MAIN) << "The previous attempt has reached the server; two"
+                           " events are likely to be in the timeline after retry";
+    }
     it->resetStatus();
     return d->doSendEvent(it->event());
 }
@@ -1350,7 +1415,22 @@ void Room::discardMessage(const QString& txnId)
             [txnId] (const auto& evt) { return evt->transactionId() == txnId; });
     Q_ASSERT(it != d->unsyncedEvents.end());
     qDebug(EVENTS) << "Discarding transaction" << txnId;
-    emit pendingEventAboutToDiscard(it - d->unsyncedEvents.begin());
+    const auto& transferIt = d->fileTransfers.find(txnId);
+    if (transferIt != d->fileTransfers.end())
+    {
+        Q_ASSERT(transferIt->isUpload);
+        if (isJobRunning(transferIt->job))
+        {
+            transferIt->status = FileTransferInfo::Cancelled;
+            transferIt->job->abandon();
+            emit fileTransferFailed(txnId, tr("File upload cancelled"));
+        } else if (transferIt->status == FileTransferInfo::Completed)
+        {
+            qCWarning(MAIN) << "File for transaction" << txnId
+                            << "has been uploaded but the message was discarded";
+        }
+    }
+    emit pendingEventAboutToDiscard(int(it - d->unsyncedEvents.begin()));
     d->unsyncedEvents.erase(it);
     emit pendingEventDiscarded();
 }
@@ -1377,6 +1457,61 @@ QString Room::postHtmlText(const QString& plainText, const QString& html)
     return postHtmlMessage(plainText, html, MessageEventType::Text);
 }
 
+QString Room::postFile(const QString& plainText, const QUrl& localPath,
+                       bool asGenericFile)
+{
+    QFileInfo localFile { localPath.toLocalFile() };
+    Q_ASSERT(localFile.isFile());
+    // Remote URL will only be known after upload; fill in the local path
+    // to enable the preview while the event is pending.
+    auto* pEvent = d->addAsPending(
+            makeEvent<RoomMessageEvent>(plainText, localFile, asGenericFile));
+    const auto txnId = pEvent->transactionId();
+    uploadFile(txnId, localPath);
+    QMetaObject::Connection cCompleted, cCancelled;
+    cCompleted = connect(this, &Room::fileTransferCompleted, this,
+            [cCompleted,cCancelled,this,pEvent,txnId]
+            (const QString& id, QUrl, const QUrl& mxcUri) {
+                if (id == txnId)
+                {
+                    auto it = d->findAsPending(pEvent);
+                    if (it != d->unsyncedEvents.end())
+                    {
+                        it->setFileUploaded(mxcUri);
+                        emit pendingEventChanged(
+                                    int(it - d->unsyncedEvents.begin()));
+                        d->doSendEvent(pEvent);
+                    } else {
+                        // Normally in this situation we should instruct
+                        // the media server to delete the file; alas, there's no
+                        // API specced for that.
+                        qCWarning(MAIN) << "File uploaded to" << mxcUri
+                            << "but the event referring to it was cancelled";
+                    }
+                    disconnect(cCompleted);
+                    disconnect(cCancelled);
+                }
+            });
+    cCancelled = connect(this, &Room::fileTransferCancelled, this,
+            [cCompleted,cCancelled,this,pEvent,txnId] (const QString& id) {
+                if (id == txnId)
+                {
+                    auto it = d->findAsPending(pEvent);
+                    if (it != d->unsyncedEvents.end())
+                    {
+                        emit pendingEventAboutToDiscard(
+                                    int(it - d->unsyncedEvents.begin()));
+                        d->unsyncedEvents.erase(it);
+                        emit pendingEventDiscarded();
+                    }
+                    disconnect(cCompleted);
+                    disconnect(cCancelled);
+                }
+            });
+
+    return txnId;
+}
+
 QString Room::postEvent(RoomEvent* event)
 {
     if (usesEncryption())
@@ -1532,7 +1667,7 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
     auto job = connection()->uploadFile(fileName, overrideContentType);
     if (isJobRunning(job))
     {
-        d->fileTransfers.insert(id, { job, fileName });
+        d->fileTransfers.insert(id, { job, fileName, true });
         connect(job, &BaseJob::uploadProgress, this,
                 [this,id] (qint64 sent, qint64 total) {
                     d->fileTransfers[id].update(sent, total);
@@ -1555,8 +1690,8 @@ void Room::downloadFile(const QString& eventId, const QUrl& localFilename)
     if (ongoingTransfer != d->fileTransfers.end() &&
             ongoingTransfer->status == FileTransferInfo::Started)
     {
-        qCWarning(MAIN) << "Download for" << eventId
-                        << "already started; to restart, cancel it first";
+        qCWarning(MAIN) << "Transfer for" << eventId
+                        << "is ongoing; download won't start";
         return;
     }
 
@@ -1819,11 +1954,15 @@ Room::Changes Room::Private::addNewMessageEvents(RoomEvents&& events)
             break;
 
         it = nextPending + 1;
-        emit q->pendingEventAboutToMerge(nextPending->get(),
-                    nextPendingPair.second - unsyncedEvents.begin());
+        auto* nextPendingEvt = nextPending->get();
+        emit q->pendingEventAboutToMerge(nextPendingEvt,
+                    int(nextPendingPair.second - unsyncedEvents.begin()));
         qDebug(EVENTS) << "Merging pending event from transaction"
-                       << (*nextPending)->transactionId() << "into"
-                       << (*nextPending)->id();
+                       << nextPendingEvt->transactionId() << "into"
+                       << nextPendingEvt->id();
+        auto transfer = fileTransfers.take(nextPendingEvt->transactionId());
+        if (transfer.status != FileTransferInfo::None)
+            fileTransfers.insert(nextPendingEvt->id(), transfer);
         unsyncedEvents.erase(nextPendingPair.second);
         if (auto insertedSize = moveEventsToTimeline({nextPending, it}, Newer))
         {
diff --git a/lib/room.h b/lib/room.h
index 6384b706..029f87b7 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -42,10 +42,17 @@ namespace QMatrixClient
     class SetRoomStateWithKeyJob;
     class RedactEventJob;
 
+    /** The data structure used to expose file transfer information to views
+     *
+     * This is specifically tuned to work with QML exposing all traits as
+     * Q_PROPERTY values.
+     */
     class FileTransferInfo
     {
             Q_GADGET
+            Q_PROPERTY(bool isUpload MEMBER isUpload CONSTANT)
             Q_PROPERTY(bool active READ active CONSTANT)
+            Q_PROPERTY(bool started READ started CONSTANT)
             Q_PROPERTY(bool completed READ completed CONSTANT)
             Q_PROPERTY(bool failed READ failed CONSTANT)
             Q_PROPERTY(int progress MEMBER progress CONSTANT)
@@ -53,16 +60,17 @@ namespace QMatrixClient
             Q_PROPERTY(QUrl localDir MEMBER localDir CONSTANT)
             Q_PROPERTY(QUrl localPath MEMBER localPath CONSTANT)
         public:
-            enum Status { None, Started, Completed, Failed };
+            enum Status { None, Started, Completed, Failed, Cancelled };
             Status status = None;
+            bool isUpload = false;
             int progress = 0;
             int total = -1;
             QUrl localDir { };
             QUrl localPath { };
 
-            bool active() const
-            { return status == Started || status == Completed; }
+            bool started() const { return status == Started; }
             bool completed() const { return status == Completed; }
+            bool active() const { return started() || completed(); }
             bool failed() const { return status == Failed; }
     };
 
@@ -226,6 +234,8 @@ namespace QMatrixClient
 
             rev_iter_t findInTimeline(TimelineItem::index_t index) const;
             rev_iter_t findInTimeline(const QString& evtId) const;
+            PendingEvents::iterator findPendingEvent(const QString & txnId);
+            PendingEvents::const_iterator findPendingEvent(const QString & txnId) const;
 
             bool displayed() const;
             /// Mark the room as currently displayed to the user
@@ -334,10 +344,11 @@ namespace QMatrixClient
             /// Get the list of users this room is a direct chat with
             QList<User*> directChatUsers() const;
 
-            Q_INVOKABLE QUrl urlToThumbnail(const QString& eventId);
-            Q_INVOKABLE QUrl urlToDownload(const QString& eventId);
-            Q_INVOKABLE QString fileNameToDownload(const QString& eventId);
+            Q_INVOKABLE QUrl urlToThumbnail(const QString& eventId) const;
+            Q_INVOKABLE QUrl urlToDownload(const QString& eventId) const;
+            Q_INVOKABLE QString fileNameToDownload(const QString& eventId) const;
             Q_INVOKABLE FileTransferInfo fileTransferInfo(const QString& id) const;
+            Q_INVOKABLE QUrl fileSource(const QString& id) const;
 
             /** Pretty-prints plain text into HTML
              * As of now, it's exactly the same as QMatrixClient::prettyPrint();
@@ -365,6 +376,8 @@ namespace QMatrixClient
             QString postHtmlMessage(const QString& plainText,
                                     const QString& html, MessageEventType type);
             QString postHtmlText(const QString& plainText, const QString& html);
+            QString postFile(const QString& plainText, const QUrl& localPath,
+                             bool asGenericFile = false);
             /** Post a pre-created room message event
              *
              * Takes ownership of the event, deleting it once the matching one
diff --git a/libqmatrixclient.pri b/libqmatrixclient.pri
index 8ca43e56..eefaec67 100644
--- a/libqmatrixclient.pri
+++ b/libqmatrixclient.pri
@@ -1,4 +1,4 @@
-QT += network
+QT += network multimedia
 CONFIG += c++14 warn_on rtti_off create_prl object_parallel_to_source
 
 win32-msvc* {