Android Question Amazon AWS Signature Problem


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I'm trying to upload a file to Amazon S3 and haven't been able to get it to work. I've tried several different things such as an aws library on this forum that didn't work for me. (BTW - I would be willing to pay money for someone to wrap the official AWS SDK ).

Essentially I have a server where i request and receive a pre-signed url to s3. All I have to do is do a PUT on the file to s3 with the url and it should work. In fact, If I paste that url into version of a simple upload routine it works fine. If I try it with B4A i get a Forbidden-403 response. I'm curious if anyone else here has had ANY success uploading files to S3 as I use this functionality all of the time.

Here's a copy of the code to upload based on a pre-signed url I received and then a copy of the b4a code with the same url. version
    Sub PostToS3()
        'use a presigned url
        Dim filePath As String = "C:\temp\Agreement.pdf"
        Dim url As String = "*** PUT REAL URL HERE ***"
        Dim request As HttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)

            request.Method = "PUT"
            Using fileStream As FileStream = File.OpenRead(filePath)
                Using requestStream As Stream = request.GetRequestStream()
                    Dim bufferSize As Integer = 1024
                    Dim buffer(bufferSize - 1) As Byte
                    Dim byteCount As Integer = 0
                    byteCount = fileStream.Read(buffer, 0, bufferSize)
                    Do While byteCount > 0
                        requestStream.Write(buffer, 0, byteCount)
                        byteCount = fileStream.Read(buffer, 0, bufferSize)
                End Using
            End Using
            Dim result As String

            Using response As WebResponse = request.GetResponse()
                Using reader As New StreamReader(response.GetResponseStream())
                    result = reader.ReadToEnd()
                End Using
            End Using


        Catch ex As Exception
        End Try
    End Sub

Here's a portion of my b4a code with the same url
Sub Process_Globals
    Dim hClient As HttpClient
End Sub

Sub Activity_Create(FirstTime As Boolean)
    If FirstTime Then
    End If
End Sub

Sub DoTest()
        Dim req As HttpRequest
        Dim MyArray() As Byte
        MyArray = ReadFile(File.DirRootExternal,"Application.pdf")
        req.InitializePut2("*** same url here ***", MyArray)   
        req.SetContentType("application/pdf")    'Ive done it with and without this
End Sub

I looked at the packets going through and the file is PUT to s3 and the headers seem to be alright but i get the Forbidden response. The code in .net works fine with the url so I can only assume it's something in my b4a code or how I'm doing it. I don't know what else to do. I've tried using the httputils2 library also and no success. Please help! Thx.


Licensed User
Longtime User
Wrong forum? this seems to be an B4J issue, not B4A
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