Android Question [SOLVED] Broken PostMultipart in OkHttpUtils2 / iHttpUtils2 / HttpUtils2?

[Sandman]

I have found something in the [B4X] OkHttpUtils2 / iHttpUtils2 / HttpUtils2 source code that confuses me. I think it might be broken, or perhaps I'm missing something obvious in the logic.

The issue is with the boolean called empty. Its only use is for the sub MultipartStartSection. It is initially set to True, but after the first call to MultipartStartSection it gets set to False and that never changes anywhere. I can't help but think that an empty = True should be added somewhere, perhaps just before the (potential) files are added?

This is an exact copy from the file HttpJob.bas in the file B4A_Modules.zip where I have added comments to almost all lines with the variable empty.

'Sends a multipart POST request.
'NameValues - A map with the keys and values. Pass Null if not needed.
'Files - List of MultipartFileData items. Pass Null if not needed.
Public Sub PostMultipart(Link As String, NameValues As Map, Files As List)
    Dim boundary As String = "---------------------------1461124740692"
    Dim stream As OutputStream
    stream.InitializeToBytesArray(0)
    Dim b() As Byte
    Dim eol As String = Chr(13) & Chr(10)
    Dim empty As Boolean = True ' <--- empty is set to True
    If NameValues <> Null And NameValues.IsInitialized Then
        For Each key As String In NameValues.Keys
            Dim value As String = NameValues.Get(key)
            empty = MultipartStartSection (stream, empty) ' <--- empty is set to False
            Dim s As String = _
$"--${boundary}
Content-Disposition: form-data; name="${key}"

${value}"$
            b = s.Replace(CRLF, eol).GetBytes("UTF8")
            stream.WriteBytes(b, 0, b.Length)
        Next
    End If
    If Files <> Null And Files.IsInitialized Then
        For Each fd As MultipartFileData In Files
            empty = MultipartStartSection (stream, empty) ' <--- empty is set to False
            Dim s As String = _
$"--${boundary}
Content-Disposition: form-data; name="${fd.KeyName}"; filename="${fd.FileName}"
Content-Type: ${fd.ContentType}

"$
            b = s.Replace(CRLF, eol).GetBytes("UTF8")
            stream.WriteBytes(b, 0, b.Length)
            Dim in As InputStream = File.OpenInput(fd.Dir, fd.FileName)
            File.Copy2(in, stream)
        Next
    End If
    empty = MultipartStartSection (stream, empty) ' <--- empty is set to False
    s = _
$"--${boundary}--
"$
    b = s.Replace(CRLF, eol).GetBytes("UTF8")
    stream.WriteBytes(b, 0, b.Length)
    PostBytes(Link, stream.ToBytesArray)
    req.SetContentType("multipart/form-data; boundary=" & boundary)
    req.SetContentEncoding("UTF8")
End Sub

Private Sub MultipartStartSection (stream As OutputStream, empty As Boolean) As Boolean
    If empty = False Then
        stream.WriteBytes(Array As Byte(13, 10), 0, 2)
    Else
        empty = False
    End If
    Return empty ' <--- empty is always returned as False
End Sub

 

[Erel]

Moved to the questions forum.

There is no bug here as it works correctly. It adds the "prefix" once. You are correct that it is complicated for no real reason as the "prefix" can be just written at the beginning.

I guess that it was implemented like this because it was added as a fix for a different bug where the prefix was added multiple times.

 

[Sandman]

Thanks for the explanation Erel, appreciated.