Sending Files with TCP/IP

[Swissmade]

Hello all,
I like to send a image taken with the Camera to a external Server.
I have the Connection to the Server waiting for Data.
The problem is how to send the data with a filename to the Server.

Please Help:sign0085::sign0085:

Thanks

 

[Erel]

Assuming that you are writing the server code as well:
- Convert the file name to bytes with String.GetBytes. (FileName.GetBytes("UTF8"))
- Send the length of this array.
- Send the array (OutputStream.WriteBytes)
- Send the length of the bitmap array.
- Convert the bytes array to InputStream with InputStream.InitializeFromBytesArray.
- Use File.Copy2 to copy the InputStream to the network OutputStream.

Your server code should of course adhere to the same protocol.
Tips: do not use c# ReadString in your server code. It expects a specific .Net protocol.

 

[Swissmade]

using Android

Assuming that you are writing the server code as well:
- Convert the file name to bytes with String.GetBytes. (FileName.GetBytes("UTF8"))
- Send the length of this array.
- Send the array (OutputStream.WriteBytes)
- Send the length of the bitmap array.
- Convert the bytes array to InputStream with InputStream.InitializeFromBytesArray.
- Use File.Copy2 to copy the InputStream to the network OutputStream.

Your server code should of course adhere to the same protocol.
Tips: do not use c# ReadString in your server code. It expects a specific .Net protocol.

Thanks Erel I go to try.

:sign0013: Erel I dont get it completly is there a Code Sample of this.

Hi Erel I found it out many thanks for your Hints.

 

[Erel]

You are more than welcome to post your solution

 

[Swissmade]

Code To Send Files with TCP/IP

Hi Erel,

The Code to Send Files

Sub SendData
Dim In As InputStream 
Dim AddString As String
Dim Buffer() As Byte 
Dim Now As Long
Now = DateTime.Now  

'Send the Stream to the Server after Connection
    IN.InitializeFromBytesArray(OutStream, 0, OutStream.Length)
    File.Copy2(IN,socket1.OutputStream)
'Add File name to Image end
'Get Filename Byte Array place is Buffer
    DateTime.DateFormat = "yyyymmdd"
    AddString = CRLF & "FILENAME=" & DateTime.Date(Now) & "_" & DateTime.Time(Now)
    AddString = AddString & ".jpg"
    Buffer = AddString.GetBytes("UTF8")
'Put 'Filename to the end of the Images Array
    IN.InitializeFromBytesArray(Buffer, 0, Buffer.Length)
    File.Copy2(IN,socket1.OutputStream)
    
    Socket1.Close
End Sub

Hope it helps somebody:sign0060:

 

[Erel]

Thank you for sharing.

 

[Swissmade]

Thank you for sharing.

You more then welcome :icon_clap:
Thanks Erel for your great help.
Good Job

 

[Rusty]

Did you ever get FILE transfer to work from PC to Android? If so, can you provide sample code on both ends?
Thanks,
Rusty

 

[Swissmade]

Sending Files from Android to PC

Did you ever get FILE transfer to work from PC to Android? If so, can you provide sample code on both ends?
Thanks,
Rusty

To do this you need an IP Listener what is receiving the file.
Listener can also be made on Android but only for local Network.


Cheers,
Swissmade.

 

[Rusty]

I have a VB 2010 application that is currently communicating short messages and is receiving SQL data to write on the PC based MS/SQL server database. These all work well, but when I try to get my PC system to send a file (about 1MB), i often get parsing errors.
The reason the parsing errors occur is because I'm handling each "buffer" coming from the PC individually.
The Android max TCP buffer is apparently 1536 bytes and this is very slow, so I'm transmitting 64K bytes from the PC, receiving the 1535 byte "pieces" of the 64K buffer; assembling them in memory and then using them. Sometimes this gets out of sequence (don't know why), I'm debugging this and your post made me think that there might be a simple way to transmit the file using another method.
Thanks for your quick response,
Rusty

 

[Erel]

Do you send the file size before sending the file? How are you sending the file? How are you receiving the file?

 

[Rusty]

Currently, I send the filename and size.
I then begin sending all the data in blocks of 64K
The android receives in 1.5K hunks, assembles the pieces and writes it to a file. Half the time it works perfectly the other half, it fails.
I'm using Astreams on the android side
and Sockets within VB.
Any suggestions are welcome.
Rusty

 

[Swissmade]

Sending From PC To Droid or the other way arraound

Currently, I send the filename and size.
I then begin sending all the data in blocks of 64K
The android receives in 1.5K hunks, assembles the pieces and writes it to a file. Half the time it works perfectly the other half, it fails.
I'm using Astreams on the android side
and Sockets within VB.
Any suggestions are welcome.
Rusty

If you send from Droid to PC you have to send the File in a loop with small junks.
This prevent a slow connection to hang.

Cheers,
Swissmade

 

[Erel]

You can check B4A-Bridge code. It handles large files (few megabytes) and it works reliably.

 

[Rusty]

Thanks Erel,
How large are the buffers being transmitted to the Android from the B4a compiler?
My PC "transmitter" is currently sending 64K "chunks" to the tablet. Each 64K bytes has a length header and I've been trying to patch each block together.
Do you have any PC source for your data/file transmitter I could look at?
Regards,
Rusty

 

[Erel]

The buffer is 8k. AsyncStreams in prefix mode is used so the messages are always complete.

I cannot post the code as it is part of a much larger framework responsible for the communication.