mORMot Open Source

For a start, a word of caution:  I am a beginner is so many ways that I actually find it amusing. I am not a Delphi programmer, and I have never before worked with the Firemonkey, Livebindings or even with Delphi TDatasets. Everything is new to me. If anything I write sounds weird, wrong or over-complicated. I would welcome a constructive comment. I usually work at a design level.

• This approach used in the SynCrossPlatformREST and SynCrossPlatformJSON to address the TObjectList definition is not a good one. It leads to problems due to the fact that projects that use the TObjectList-based LiveBindingsAdapter have to use the "System.Generics.Collections" and not "Contnrs". The result is a nasty type definition conflict.

  {$ifdef NEXTGEN}
    System.Generics.Collections,
  {$else}
    Contnrs,
  {$endif NEXTGEN}

  I actually had to define NEXTGEN globally in the project to get it working Windows platform project because I found no way around the type definition conflict.

• As I was most interest in binary uploads and downloads of the BLOBs I've added and successfully used the following method:

  function TSQLRestClientURI.UpdateBlob(Table: TSQLRecordClass; aID: TID; const BlobFieldName: string;
    const BlobData: TSQLRawBlob; const ContentType: string = 'application/octet-stream'): boolean;
  var tableIndex: Integer;
      Call: TSQLRestURIParams;
  begin
    tableIndex := Model.GetTableIndexExisting(Table);
    Call.Init(getURIID(tableIndex,aID)+'/'+BlobFieldName,'PUT','');
    Call.InBody := THttpBody(BlobData);
    if not ContentType.IsEmpty then
      Call.InHead := trim('Content-Type: '+ContentType);
    URI(Call);
    result := Call.OutStatus=HTTP_SUCCESS;
    Log(LOGLEVELDB[result],'%s.UpdateBlob(ID=%d,"%s") len=%d',
      [Model.Info[tableIndex].Name,aID,BlobFieldName,length(BlobData)]);
  end;

• The SynCrossPlatformSpecific.TWinHttpConnectionClass.URI adds Content-Type twice. When Content-type is already specified in the InHead then the TSQLRestClientHTTP.InternalURI will extract this value correctly and store it in the InDataType. However, it will not remove it from the original header. The duplicate Content-Type header is then appended in the low-level URI method call.
  I have changed the following to get around it:

  procedure TSQLRestClientHTTP.InternalURI(var Call: TSQLRestURIParams);
  var inType: string;
      retry: integer;
  begin
    inType := FindHeader(Call.InHead,'content-type: ');
    if inType='' then begin
      if OnlyJSONRequests then
        inType := JSON_CONTENT_TYPE else
        inType := 'text/plain'; // avoid slow CORS preflighted requests
  //:MM:Avoid adding the Content-Type header twice
      //Call.InHead := trim(Call.InHead+#13#10'content-type: '+inType);
    end else
      inType := '';
  //EOF:MM:Avoid adding the Content-Type header twice
    if fCustomHttpHeader<>'' then
  ...

• D10.1/Android build: I had to use "Indy" based HTTP transport for the Android client to work! That is contrary to the comments within the code.

• When using the "Indy" HTTP transport ProxyPort does not get assigned. WinHTTP parses port number from ProxyServer parameter, but the Indy does not.

• I have already told you that I had to add an additional method override to the RetrieveList method. For me, this was the easiest way to work with the TListBindSourceAdapter which wraps around the TSQLRecords' object list. I found this approach worked well for me as I would empty the list and reload it instead of recreating it.

  procedure TSQLRest.RetrieveList(Table: TSQLRecordClass; const FieldNames,
    SQLWhere: string; const BoundsSQLWhere: array of const; var destObjectList: TObjectList);
  var rows: TSQLTableJSON;
      rec: TSQLRecord;
  begin
    destObjectList.Clear;
    rows := MultiFieldValues(Table,FieldNames,SQLWhere,BoundsSQLWhere);
    if rows<>nil then
      try
        repeat
          rec := Table.Create;
          if not rows.FillOne(rec) then begin
            rec.Free;
            break;
          end;
          destObjectList.Add(rec);
        until false;
      finally
        rows.Free;
      end;
  end;

• I won't comment upon the Update method when working with BLOBs. I had some JSON encoding problems that have most probably resulted from conflicts in strings processing that I have caused by using the NEXTGEN define on the Windows platform. It's quite amazing that so much of the functionality worked correctly.

Have a nice Sunday!

Regards, Matej.