Found it:
uses IdMultipartFormData
...
Stream: TIdMultipartFormDataStream;
EDITED: For this particular problem with Jira REST API, solution would be something like:
Posting against URL: BASE_URL+/rest/api/2/issue/{issueIdOrKey}/attachments
try
lHTTP.Request.CustomHeaders.AddValue('X-Atlassian-Token', 'nocheck');
FileSize := lHTTP.Response.ContentLength;
FileStrm := TFileStream.Create(AFile, fmOpenRead or fmShareDenyWrite);
try
if FileSize < FileStrm.Size then
begin
FileStrm.Position := FileSize;
Stream := TIdMultipartFormDataStream.Create;
try
Stream.AddFile('file', AFile);
with lHTTP do
begin
with Request do
begin
ContentRangeStart := FileSize + 1;
ContentRangeEnd := FileStrm.Size;
end;
Post(self.BASE_URL + SEND_ATTACHEMENT_TO_AN_ISSUE_URL +
IntToStr(IssueID) + '/attachments', Stream);
Result := true;
end;
finally
Stream.Free;
end;
end;
finally
FileStrm.Free;
end;
except
Result := false;
end;
Note: After that one should not forget to change back the headers and to change the "Content Type" to the one that is needed for future requests