#MaxThreads 255
SetBatchLines, -1
start := A_TickCount
Clipboard := UploadFileToFilemail("from@gmail.com", "to@gmail.com", "file", "hello!")
MsgBox, % (A_TickCount - start)//1000

UploadFileToFilemail(from, to, subject, message) {
   FileSelectFile, filePath,,, Choose file to upload, All Files (*.*)
   if !filePath
      ExitApp
   
   json := Init(from, to, subject, message)
   if error := JsonRead(json, transferID, transferKEY, transferURL)
      Return error
      
   SplitPath, filePath, fileName
   fileName := URIEncode(fileName)
   oFile := FileOpen(filePath, "r")
   fileSize := oFile.length
   chunkSize := 5242880
   chunksNumber := Ceil(fileSize/chunkSize)
   lastChunkSize := mod(fileSize, chunkSize)
   info := {parts: chunksNumber}
   CoordMode, ToolTip
   ToolTip, % "parts: " chunksNumber, 3, 3, 1
   Loop % chunksNumber {
      currentChunkSize := A_Index = chunksNumber ? lastChunkSize : chunkSize
      link := transferURL . "?transferid=" . transferID . "&transferkey=" . transferKEY
           . "&chunksize=" . chunkSize . "&thefilename=" . fileName . "&totalsize=" . fileSize
           . "&chunks=" . chunksNumber  . "&chunk=" . A_Index - 1 . "&runtime=html5&retry=0"
      SendChunk(oFile, currentChunkSize, link, info)
   }
   oFile.Close()
   ToolTip,,,, 1
   Return GetUrl(transferID, transferKEY)
}

Init(from, to, subject, message) {
   from := URIEncode(from), to := URIEncode(to), subject := URIEncode(subject), message := URIEncode(message)
   body := "sourcedetails=plupload(html5)+`%40+https`%3A`%2F`%2Fwww.filemail.com`%2F&to`%5B`%5D="
          . to "&from=" from "&subject=" subject "&message=" message "&days=7&confirmation=true"
   Return SetRequest(body, "initialize")
}

JsonRead(json, ByRef transferID, ByRef transferKEY, ByRef transferURL) {
   RegexMatch(json, "s)""transferid"": ""(.+?)"".+?""transferkey"": ""(.+?)"".+?""transferurl"": ""(.+?)""", match)
   transferID := match1, transferKEY := match2, transferURL := match3
   if !(transferID && transferKEY && transferURL)
      Return json
}

GetUrl(transferID, transferKEY) {
   body := "transferid=" . transferid . "&transferkey=" . transferkey . "&failed=false"
   responseText := SetRequest(body, "complete")
   RegexMatch(responseText, """downloadurl"": ""\K[^""]+", url)
   Return url ? url : responseText
}

SetRequest(body, mode) {
   HTTP := ComObjCreate("Msxml2.XMLHTTP.6.0")
   HTTP.Open("POST", "https://www.filemail.com/api/transfer/" . mode, false)
   HTTP.SetRequestHeader("Content-Type", "application/x-www-form-urlencoded")
   HTTP.SetRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko")
   HTTP.SetRequestHeader("Source", "Web")
   HTTP.SetRequestHeader("Pragma", "no-cache")
   HTTP.SetRequestHeader("Cache-Control", "no-cache, no-store")
   HTTP.Send(body)
   Return HTTP.responseText
}

SendChunk(ByRef oFile, size, link, info) {
   safeArr := ComObjArray(0x11, size) ; Create SAFEARRAY = VT_ARRAY|VT_UI1
   pData := NumGet( ComObjValue(safeArr) + 8 + A_PtrSize )
   oFile.RawRead(pData + 0, size)
   HTTP := ComObjCreate("WinHttp.WinHttpRequest.5.1")
   HTTP.Open("POST", link, true)
   HTTP.SetRequestHeader("Content-Type", "application/octet-stream")
   HTTP.SetRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko")
   HTTP.Send(safeArr)
   HTTP.WaitForResponse()
   if ( (s := HTTP.Status) != 200)
      throw Exception("Upload Error. Status: " . s)
   ToolTip, % "rest: " . (--info.parts), 3, 3, 1
}

URIEncode(str, encoding := "UTF-8")  {
   VarSetCapacity(var, StrPut(str, encoding))
   StrPut(str, &var, encoding)

   While code := NumGet(Var, A_Index - 1, "UChar")  {
      bool := (code > 0x7F || code < 0x30 || code = 0x3D)
      UrlStr .= bool ? "%" . Format("{:02X}", code) : Chr(code)
   }
   Return UrlStr
}