--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Loaders/SeriesThumbnailsLoader.cpp	Tue Jul 07 16:21:02 2020 +0200
@@ -0,0 +1,773 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "SeriesThumbnailsLoader.h"
+
+#include "LoadedDicomResources.h"
+#include "../Oracle/ParseDicomFromWadoCommand.h"
+#include "../Toolbox/ImageToolbox.h"
+
+#include <DicomFormat/DicomMap.h>
+#include <DicomFormat/DicomInstanceHasher.h>
+#include <Images/Image.h>
+#include <Images/ImageProcessing.h>
+#include <Images/JpegReader.h>
+#include <Images/JpegWriter.h>
+#include <OrthancException.h>
+
+#include <boost/algorithm/string/predicate.hpp>
+
+#if ORTHANC_ENABLE_DCMTK == 1
+#  include <DicomParsing/ParsedDicomFile.h>
+#  include <DicomParsing/Internals/DicomImageDecoder.h>
+#endif 
+
+
+static const unsigned int JPEG_QUALITY = 70;  // Only used for Orthanc source
+
+namespace OrthancStone
+{
+  static SeriesThumbnailType ExtractSopClassUid(const std::string& sopClassUid)
+  {
+    if (sopClassUid == "1.2.840.10008.5.1.4.1.1.104.1")  // Encapsulated PDF Storage
+    {
+      return SeriesThumbnailType_Pdf;
+    }
+    else if (sopClassUid == "1.2.840.10008.5.1.4.1.1.77.1.1.1" ||  // Video Endoscopic Image Storage
+             sopClassUid == "1.2.840.10008.5.1.4.1.1.77.1.2.1" ||  // Video Microscopic Image Storage
+             sopClassUid == "1.2.840.10008.5.1.4.1.1.77.1.4.1")    // Video Photographic Image Storage
+    {
+      return SeriesThumbnailType_Video;
+    }
+    else
+    {
+      return SeriesThumbnailType_Unsupported;
+    }
+  }
+
+
+  SeriesThumbnailsLoader::Thumbnail::Thumbnail(const std::string& image,
+                                               const std::string& mime) :
+    type_(SeriesThumbnailType_Image),
+    image_(image),
+    mime_(mime)
+  {
+  }
+
+
+  SeriesThumbnailsLoader::Thumbnail::Thumbnail(SeriesThumbnailType type) :
+    type_(type)
+  {
+    if (type == SeriesThumbnailType_Image)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
+    }
+  }
+
+
+  Orthanc::ImageAccessor* SeriesThumbnailsLoader::SuccessMessage::DecodeImage() const
+  {
+    if (GetType() != SeriesThumbnailType_Image)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+    }
+
+    Orthanc::MimeType mime;
+    if (!Orthanc::LookupMimeType(mime, GetMime()))
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
+                                      "Unsupported MIME type for thumbnail: " + GetMime());
+    }
+
+    switch (mime)
+    {
+      case Orthanc::MimeType_Jpeg:
+      {
+        std::unique_ptr<Orthanc::JpegReader> reader(new Orthanc::JpegReader);
+        reader->ReadFromMemory(GetEncodedImage());
+        return reader.release();
+      }
+
+      default:
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
+                                        "Cannot decode MIME type for thumbnail: " + GetMime());
+    }
+  }
+
+
+
+  void SeriesThumbnailsLoader::AcquireThumbnail(const DicomSource& source,
+                                                const std::string& studyInstanceUid,
+                                                const std::string& seriesInstanceUid,
+                                                SeriesThumbnailsLoader::Thumbnail* thumbnail)
+  {
+    assert(thumbnail != NULL);
+  
+    std::unique_ptr<Thumbnail> protection(thumbnail);
+
+    Thumbnails::iterator found = thumbnails_.find(seriesInstanceUid);
+    if (found == thumbnails_.end())
+    {
+      thumbnails_[seriesInstanceUid] = protection.release();
+    }
+    else
+    {
+      assert(found->second != NULL);
+      if (protection->GetType() == SeriesThumbnailType_NotLoaded ||
+          protection->GetType() == SeriesThumbnailType_Unsupported)
+      {
+        // Don't replace an old entry if the current one is worse
+        return;
+      }
+      else
+      {
+        delete found->second;
+        found->second = protection.release();
+      }
+    }
+
+    LOG(INFO) << "Thumbnail updated for series: " << seriesInstanceUid << ": " << thumbnail->GetType();
+    
+    SuccessMessage message(*this, source, studyInstanceUid, seriesInstanceUid, *thumbnail);
+    BroadcastMessage(message);
+  }
+
+
+  class SeriesThumbnailsLoader::Handler : public Orthanc::IDynamicObject
+  {
+  private:
+    boost::shared_ptr<SeriesThumbnailsLoader>  loader_;
+    DicomSource                                source_;
+    std::string                                studyInstanceUid_;
+    std::string                                seriesInstanceUid_;
+
+  public:
+    Handler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+            const DicomSource& source,
+            const std::string& studyInstanceUid,
+            const std::string& seriesInstanceUid) :
+      loader_(loader),
+      source_(source),
+      studyInstanceUid_(studyInstanceUid),
+      seriesInstanceUid_(seriesInstanceUid)
+    {
+      if (!loader)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NullPointer);
+      }
+    }
+
+    boost::shared_ptr<SeriesThumbnailsLoader> GetLoader()
+    {
+      return loader_;
+    }
+
+    const DicomSource& GetSource() const
+    {
+      return source_;
+    }
+
+    const std::string& GetStudyInstanceUid() const
+    {
+      return studyInstanceUid_;
+    }
+
+    const std::string& GetSeriesInstanceUid() const
+    {
+      return seriesInstanceUid_;
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers) = 0;
+
+    virtual void HandleError()
+    {
+      LOG(INFO) << "Cannot generate thumbnail for SeriesInstanceUID: " << seriesInstanceUid_;
+    }
+  };
+
+
+  class SeriesThumbnailsLoader::DicomWebSopClassHandler : public SeriesThumbnailsLoader::Handler
+  {
+  private:
+    static bool GetSopClassUid(std::string& sopClassUid,
+                               const Json::Value& json)
+    {
+      Orthanc::DicomMap dicom;
+      dicom.FromDicomWeb(json);
+
+      return dicom.LookupStringValue(sopClassUid, Orthanc::DICOM_TAG_SOP_CLASS_UID, false);
+    }
+  
+  public:
+    DicomWebSopClassHandler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+                            const DicomSource& source,
+                            const std::string& studyInstanceUid,
+                            const std::string& seriesInstanceUid) :
+      Handler(loader, source, studyInstanceUid, seriesInstanceUid)
+    {
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers)
+    {
+      Json::Reader reader;
+      Json::Value value;
+
+      if (!reader.parse(body, value) ||
+          value.type() != Json::arrayValue)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NetworkProtocol);
+      }
+      else
+      {
+        SeriesThumbnailType type = SeriesThumbnailType_Unsupported;
+
+        std::string sopClassUid;
+        if (value.size() > 0 &&
+            GetSopClassUid(sopClassUid, value[0]))
+        {
+          bool ok = true;
+        
+          for (Json::Value::ArrayIndex i = 1; i < value.size() && ok; i++)
+          {
+            std::string s;
+            if (!GetSopClassUid(s, value[i]) ||
+                s != sopClassUid)
+            {
+              ok = false;
+            }
+          }
+
+          if (ok)
+          {
+            type = ExtractSopClassUid(sopClassUid);
+          }
+        }
+      
+        GetLoader()->AcquireThumbnail(GetSource(), GetStudyInstanceUid(),
+                                      GetSeriesInstanceUid(), new Thumbnail(type));
+      }
+    }
+  };
+
+
+  class SeriesThumbnailsLoader::DicomWebThumbnailHandler : public SeriesThumbnailsLoader::Handler
+  {
+  public:
+    DicomWebThumbnailHandler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+                             const DicomSource& source,
+                             const std::string& studyInstanceUid,
+                             const std::string& seriesInstanceUid) :
+      Handler(loader, source, studyInstanceUid, seriesInstanceUid)
+    {
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers)
+    {
+      std::string mime = Orthanc::MIME_JPEG;
+      for (std::map<std::string, std::string>::const_iterator
+             it = headers.begin(); it != headers.end(); ++it)
+      {
+        if (boost::iequals(it->first, "content-type"))
+        {
+          mime = it->second;
+        }
+      }
+
+      GetLoader()->AcquireThumbnail(GetSource(), GetStudyInstanceUid(),
+                                    GetSeriesInstanceUid(), new Thumbnail(body, mime));
+    }
+
+    virtual void HandleError()
+    {
+      // The DICOMweb wasn't able to generate a thumbnail, try to
+      // retrieve the SopClassUID tag using QIDO-RS
+
+      std::map<std::string, std::string> arguments, headers;
+      arguments["0020000D"] = GetStudyInstanceUid();
+      arguments["0020000E"] = GetSeriesInstanceUid();
+      arguments["includefield"] = "00080016";  // SOP Class UID
+      
+      std::unique_ptr<IOracleCommand> command(
+        GetSource().CreateDicomWebCommand(
+          "/instances", arguments, headers, new DicomWebSopClassHandler(
+            GetLoader(), GetSource(), GetStudyInstanceUid(), GetSeriesInstanceUid())));
+      GetLoader()->Schedule(command.release());
+    }
+  };
+
+
+  class SeriesThumbnailsLoader::ThumbnailInformation : public Orthanc::IDynamicObject
+  {
+  private:
+    DicomSource  source_;
+    std::string  studyInstanceUid_;
+    std::string  seriesInstanceUid_;
+
+  public:
+    ThumbnailInformation(const DicomSource& source,
+                         const std::string& studyInstanceUid,
+                         const std::string& seriesInstanceUid) :
+      source_(source),
+      studyInstanceUid_(studyInstanceUid),
+      seriesInstanceUid_(seriesInstanceUid)
+    {
+    }
+
+    const DicomSource& GetDicomSource() const
+    {
+      return source_;
+    }
+
+    const std::string& GetStudyInstanceUid() const
+    {
+      return studyInstanceUid_;
+    }
+
+    const std::string& GetSeriesInstanceUid() const
+    {
+      return seriesInstanceUid_;
+    }
+  };
+
+
+  class SeriesThumbnailsLoader::OrthancSopClassHandler : public SeriesThumbnailsLoader::Handler
+  {
+  private:
+    std::string instanceId_;
+      
+  public:
+    OrthancSopClassHandler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+                           const DicomSource& source,
+                           const std::string& studyInstanceUid,
+                           const std::string& seriesInstanceUid,
+                           const std::string& instanceId) :
+      Handler(loader, source, studyInstanceUid, seriesInstanceUid),
+      instanceId_(instanceId)
+    {
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers)
+    {
+      SeriesThumbnailType type = ExtractSopClassUid(body);
+
+      if (type == SeriesThumbnailType_Pdf ||
+          type == SeriesThumbnailType_Video)
+      {
+        GetLoader()->AcquireThumbnail(GetSource(), GetStudyInstanceUid(),
+                                      GetSeriesInstanceUid(), new Thumbnail(type));
+      }
+      else
+      {
+        std::unique_ptr<GetOrthancImageCommand> command(new GetOrthancImageCommand);
+        command->SetUri("/instances/" + instanceId_ + "/preview");
+        command->SetHttpHeader("Accept", Orthanc::MIME_JPEG);
+        command->AcquirePayload(new ThumbnailInformation(
+                                  GetSource(), GetStudyInstanceUid(), GetSeriesInstanceUid()));
+        GetLoader()->Schedule(command.release());
+      }
+    }
+  };
+
+
+  class SeriesThumbnailsLoader::SelectOrthancInstanceHandler : public SeriesThumbnailsLoader::Handler
+  {
+  public:
+    SelectOrthancInstanceHandler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+                                 const DicomSource& source,
+                                 const std::string& studyInstanceUid,
+                                 const std::string& seriesInstanceUid) :
+      Handler(loader, source, studyInstanceUid, seriesInstanceUid)
+    {
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers)
+    {
+      static const char* const INSTANCES = "Instances";
+      
+      Json::Value json;
+      Json::Reader reader;
+      if (!reader.parse(body, json) ||
+          json.type() != Json::objectValue)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NetworkProtocol);
+      }
+
+      if (json.isMember(INSTANCES) &&
+          json[INSTANCES].type() == Json::arrayValue &&
+          json[INSTANCES].size() > 0)
+      {
+        // Select one instance of the series to generate the thumbnail
+        Json::Value::ArrayIndex index = json[INSTANCES].size() / 2;
+        if (json[INSTANCES][index].type() == Json::stringValue)
+        {
+          std::map<std::string, std::string> arguments, headers;
+          arguments["quality"] = boost::lexical_cast<std::string>(JPEG_QUALITY);
+          headers["Accept"] = Orthanc::MIME_JPEG;
+
+          const std::string instance = json[INSTANCES][index].asString();
+
+          std::unique_ptr<OrthancRestApiCommand> command(new OrthancRestApiCommand);
+          command->SetUri("/instances/" + instance + "/metadata/SopClassUid");
+          command->AcquirePayload(
+            new OrthancSopClassHandler(
+              GetLoader(), GetSource(), GetStudyInstanceUid(), GetSeriesInstanceUid(), instance));
+          GetLoader()->Schedule(command.release());
+        }
+      }
+    }
+  };
+
+    
+#if ORTHANC_ENABLE_DCMTK == 1
+  class SeriesThumbnailsLoader::SelectDicomWebInstanceHandler : public SeriesThumbnailsLoader::Handler
+  {
+  public:
+    SelectDicomWebInstanceHandler(boost::shared_ptr<SeriesThumbnailsLoader> loader,
+                                  const DicomSource& source,
+                                  const std::string& studyInstanceUid,
+                                  const std::string& seriesInstanceUid) :
+      Handler(loader, source, studyInstanceUid, seriesInstanceUid)
+    {
+    }
+
+    virtual void HandleSuccess(const std::string& body,
+                               const std::map<std::string, std::string>& headers)
+    {
+      Json::Value json;
+      Json::Reader reader;
+      if (!reader.parse(body, json) ||
+          json.type() != Json::arrayValue)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NetworkProtocol);
+      }
+
+      LoadedDicomResources instances(Orthanc::DICOM_TAG_SOP_INSTANCE_UID);
+      instances.AddFromDicomWeb(json);
+      
+      std::string sopInstanceUid;      
+      if (instances.GetSize() == 0 ||
+          !instances.GetResource(0).LookupStringValue(sopInstanceUid, Orthanc::DICOM_TAG_SOP_INSTANCE_UID, false))
+      {
+        LOG(ERROR) << "Series without an instance: " << GetSeriesInstanceUid();
+      }
+      else
+      {
+        GetLoader()->Schedule(
+          ParseDicomFromWadoCommand::Create(
+            GetSource(), GetStudyInstanceUid(), GetSeriesInstanceUid(), sopInstanceUid, false,
+            Orthanc::DicomTransferSyntax_LittleEndianExplicit /* useless, as no transcoding */,
+            new ThumbnailInformation(
+              GetSource(), GetStudyInstanceUid(), GetSeriesInstanceUid())));
+      }
+    }
+  };
+#endif
+
+    
+  void SeriesThumbnailsLoader::Schedule(IOracleCommand* command)
+  {
+    std::unique_ptr<ILoadersContext::ILock> lock(context_.Lock());
+    lock->Schedule(GetSharedObserver(), priority_, command);
+  }    
+
+  
+  void SeriesThumbnailsLoader::Handle(const HttpCommand::SuccessMessage& message)
+  {
+    assert(message.GetOrigin().HasPayload());
+    dynamic_cast<Handler&>(message.GetOrigin().GetPayload()).HandleSuccess(message.GetAnswer(), message.GetAnswerHeaders());
+  }
+
+
+  void SeriesThumbnailsLoader::Handle(const OrthancRestApiCommand::SuccessMessage& message)
+  {
+    assert(message.GetOrigin().HasPayload());
+    dynamic_cast<Handler&>(message.GetOrigin().GetPayload()).HandleSuccess(message.GetAnswer(), message.GetAnswerHeaders());
+  }
+
+
+  void SeriesThumbnailsLoader::Handle(const GetOrthancImageCommand::SuccessMessage& message)
+  {
+    assert(message.GetOrigin().HasPayload());
+    const ThumbnailInformation& info = dynamic_cast<ThumbnailInformation&>(message.GetOrigin().GetPayload());
+
+    std::unique_ptr<Orthanc::ImageAccessor> resized(Orthanc::ImageProcessing::FitSize(message.GetImage(), width_, height_));
+
+    std::string jpeg;
+    Orthanc::JpegWriter writer;
+    writer.SetQuality(JPEG_QUALITY);
+    writer.WriteToMemory(jpeg, *resized);
+
+    AcquireThumbnail(info.GetDicomSource(), info.GetStudyInstanceUid(),
+                     info.GetSeriesInstanceUid(), new Thumbnail(jpeg, Orthanc::MIME_JPEG));      
+  }
+
+
+#if ORTHANC_ENABLE_DCMTK == 1
+  void SeriesThumbnailsLoader::Handle(const ParseDicomSuccessMessage& message)
+  {
+    assert(message.GetOrigin().HasPayload());
+    const ParseDicomFromWadoCommand& origin =
+      dynamic_cast<const ParseDicomFromWadoCommand&>(message.GetOrigin());
+    const ThumbnailInformation& info = dynamic_cast<ThumbnailInformation&>(origin.GetPayload());
+
+    std::string tmp;
+    Orthanc::DicomTransferSyntax transferSyntax;
+    if (!message.GetDicom().LookupTransferSyntax(tmp))
+    {
+      
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_BadFileFormat,
+                                      "DICOM instance without a transfer syntax: " + origin.GetSopInstanceUid());
+    }
+    else if (!Orthanc::LookupTransferSyntax(transferSyntax, tmp) ||
+             !ImageToolbox::IsDecodingSupported(transferSyntax))
+    {
+      LOG(INFO) << "Asking the DICOMweb server to transcode, "
+                << "as I don't support this transfer syntax: " << tmp;
+
+      Schedule(ParseDicomFromWadoCommand::Create(
+                 origin.GetSource(), info.GetStudyInstanceUid(), info.GetSeriesInstanceUid(),
+                 origin.GetSopInstanceUid(), true, Orthanc::DicomTransferSyntax_LittleEndianExplicit,
+                 new ThumbnailInformation(
+                   origin.GetSource(), info.GetStudyInstanceUid(), info.GetSeriesInstanceUid())));
+    }
+    else
+    {
+      std::unique_ptr<Orthanc::ImageAccessor> frame(
+        Orthanc::DicomImageDecoder::Decode(message.GetDicom(), 0));
+
+      std::unique_ptr<Orthanc::ImageAccessor> thumbnail;
+
+      if (frame->GetFormat() == Orthanc::PixelFormat_RGB24)
+      {
+        thumbnail.reset(Orthanc::ImageProcessing::FitSizeKeepAspectRatio(*frame, width_, height_));
+      }
+      else
+      {
+        std::unique_ptr<Orthanc::ImageAccessor> converted(
+          new Orthanc::Image(Orthanc::PixelFormat_Float32, frame->GetWidth(), frame->GetHeight(), false));
+        Orthanc::ImageProcessing::Convert(*converted, *frame);
+
+        std::unique_ptr<Orthanc::ImageAccessor> resized(
+          Orthanc::ImageProcessing::FitSizeKeepAspectRatio(*converted, width_, height_));
+      
+        float minValue, maxValue;
+        Orthanc::ImageProcessing::GetMinMaxFloatValue(minValue, maxValue, *resized);
+        if (minValue + 0.01f < maxValue)
+        {
+          Orthanc::ImageProcessing::ShiftScale(*resized, -minValue, 255.0f / (maxValue - minValue), false);
+        }
+        else
+        {
+          Orthanc::ImageProcessing::Set(*resized, 0);
+        }
+
+        converted.reset(NULL);
+
+        thumbnail.reset(new Orthanc::Image(Orthanc::PixelFormat_Grayscale8, width_, height_, false));
+        Orthanc::ImageProcessing::Convert(*thumbnail, *resized);
+      }
+    
+      std::string jpeg;
+      Orthanc::JpegWriter writer;
+      writer.SetQuality(JPEG_QUALITY);
+      writer.WriteToMemory(jpeg, *thumbnail);
+
+      AcquireThumbnail(info.GetDicomSource(), info.GetStudyInstanceUid(),
+                       info.GetSeriesInstanceUid(), new Thumbnail(jpeg, Orthanc::MIME_JPEG));
+    }
+  }
+#endif
+
+
+  void SeriesThumbnailsLoader::Handle(const OracleCommandExceptionMessage& message)
+  {
+    const OracleCommandBase& command = dynamic_cast<const OracleCommandBase&>(message.GetOrigin());
+    assert(command.HasPayload());
+
+    if (command.GetType() == IOracleCommand::Type_GetOrthancImage)
+    {
+      // This is presumably a HTTP status 301 (Moved permanently)
+      // because of an unsupported DICOM file in "/preview"
+      const ThumbnailInformation& info = dynamic_cast<const ThumbnailInformation&>(command.GetPayload());
+      AcquireThumbnail(info.GetDicomSource(), info.GetStudyInstanceUid(),
+                       info.GetSeriesInstanceUid(), new Thumbnail(SeriesThumbnailType_Unsupported));
+    }
+    else
+    {
+      dynamic_cast<Handler&>(command.GetPayload()).HandleError();
+    }
+  }
+
+
+  SeriesThumbnailsLoader::SeriesThumbnailsLoader(ILoadersContext& context,
+                                                 int priority) :
+    context_(context),
+    priority_(priority),
+    width_(128),
+    height_(128)
+  {
+  }
+    
+  
+  boost::shared_ptr<SeriesThumbnailsLoader> SeriesThumbnailsLoader::Create(ILoadersContext::ILock& stone,
+                                                                           int priority)
+  {
+    boost::shared_ptr<SeriesThumbnailsLoader> result(new SeriesThumbnailsLoader(stone.GetContext(), priority));
+    result->Register<GetOrthancImageCommand::SuccessMessage>(stone.GetOracleObservable(), &SeriesThumbnailsLoader::Handle);
+    result->Register<HttpCommand::SuccessMessage>(stone.GetOracleObservable(), &SeriesThumbnailsLoader::Handle);
+    result->Register<OracleCommandExceptionMessage>(stone.GetOracleObservable(), &SeriesThumbnailsLoader::Handle);
+    result->Register<OrthancRestApiCommand::SuccessMessage>(stone.GetOracleObservable(), &SeriesThumbnailsLoader::Handle);
+
+#if ORTHANC_ENABLE_DCMTK == 1
+    result->Register<ParseDicomSuccessMessage>(stone.GetOracleObservable(), &SeriesThumbnailsLoader::Handle);
+#endif
+    
+    return result;
+  }
+
+
+  void SeriesThumbnailsLoader::SetThumbnailSize(unsigned int width,
+                                                unsigned int height)
+  {
+    if (width <= 0 ||
+        height <= 0)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
+    }
+    else
+    {
+      width_ = width;
+      height_ = height;
+    }
+  }
+
+    
+  void SeriesThumbnailsLoader::Clear()
+  {
+    for (Thumbnails::iterator it = thumbnails_.begin(); it != thumbnails_.end(); ++it)
+    {
+      assert(it->second != NULL);
+      delete it->second;
+    }
+
+    thumbnails_.clear();
+  }
+
+    
+  SeriesThumbnailType SeriesThumbnailsLoader::GetSeriesThumbnail(std::string& image,
+                                                                 std::string& mime,
+                                                                 const std::string& seriesInstanceUid) const
+  {
+    Thumbnails::const_iterator found = thumbnails_.find(seriesInstanceUid);
+
+    if (found == thumbnails_.end())
+    {
+      return SeriesThumbnailType_NotLoaded;
+    }
+    else
+    {
+      assert(found->second != NULL);
+      image.assign(found->second->GetImage());
+      mime.assign(found->second->GetMime());
+      return found->second->GetType();
+    }
+  }
+
+
+  void SeriesThumbnailsLoader::ScheduleLoadThumbnail(const DicomSource& source,
+                                                     const std::string& patientId,
+                                                     const std::string& studyInstanceUid,
+                                                     const std::string& seriesInstanceUid)
+  {
+    if (IsScheduledSeries(seriesInstanceUid))
+    {
+      return;
+    }
+
+    if (source.IsDicomWeb())
+    {
+      if (!source.HasDicomWebRendered())
+      {
+#if ORTHANC_ENABLE_DCMTK == 1
+        // Issue a QIDO-RS request to select one of the instances in the series
+        std::map<std::string, std::string> arguments, headers;
+        arguments["0020000D"] = studyInstanceUid;
+        arguments["0020000E"] = seriesInstanceUid;
+        arguments["includefield"] = "00080018";  // SOP Instance UID is mandatory
+        
+        std::unique_ptr<IOracleCommand> command(
+          source.CreateDicomWebCommand(
+            "/instances", arguments, headers, new SelectDicomWebInstanceHandler(
+              GetSharedObserver(), source, studyInstanceUid, seriesInstanceUid)));
+        Schedule(command.release());
+#else
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
+                                        "Stone of Orthanc was built without support to decode DICOM images");
+#endif
+      }
+      else
+      {
+        const std::string uri = ("/studies/" + studyInstanceUid +
+                                 "/series/" + seriesInstanceUid + "/rendered");
+
+        std::map<std::string, std::string> arguments, headers;
+        arguments["viewport"] = (boost::lexical_cast<std::string>(width_) + "," +
+                                 boost::lexical_cast<std::string>(height_));
+
+        // Needed to set this header explicitly, as long as emscripten
+        // does not include macro "EMSCRIPTEN_FETCH_RESPONSE_HEADERS"
+        // https://github.com/emscripten-core/emscripten/pull/8486
+        headers["Accept"] = Orthanc::MIME_JPEG;
+
+        std::unique_ptr<IOracleCommand> command(
+          source.CreateDicomWebCommand(
+            uri, arguments, headers, new DicomWebThumbnailHandler(
+              GetSharedObserver(), source, studyInstanceUid, seriesInstanceUid)));
+        Schedule(command.release());
+      }
+
+      scheduledSeries_.insert(seriesInstanceUid);
+    }
+    else if (source.IsOrthanc())
+    {
+      // Dummy SOP Instance UID, as we are working at the "series" level
+      Orthanc::DicomInstanceHasher hasher(patientId, studyInstanceUid, seriesInstanceUid, "dummy");
+
+      std::unique_ptr<OrthancRestApiCommand> command(new OrthancRestApiCommand);
+      command->SetUri("/series/" + hasher.HashSeries());
+      command->AcquirePayload(new SelectOrthancInstanceHandler(
+                                GetSharedObserver(), source, studyInstanceUid, seriesInstanceUid));
+      Schedule(command.release());
+
+      scheduledSeries_.insert(seriesInstanceUid);
+    }
+    else
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_NotImplemented,
+                                      "Can only load thumbnails from Orthanc or DICOMweb");
+    }
+  }
+}