File transfer fails when using SSL

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Support Knowledge Base, Article 224

Product

JFile

Version

2.x

Title

File transfer fails when using SSL

Problem

If an upload or download fails when using SSL, but works without SSL, it could be that your connection method has been unknowingly set to sockets, which does not support SSL.

Version 1.x of JFile had URLConnection as the default transfer method, no matter what size the transfer. URLConnection will work with SSL, but cannot handle large file transfers efficiently. In version 2.0, JFile by default has the AutoSetTransferMethod parameter enabled. This parameter, when set to "1" will automatically switch the connection method to sockets when the tranfer size is greater than 16 MB, except in certain circumstances. (such as when the client is a MAC+IE, or when UseWininet is enabled and the client is a PC+IE. See documentation for details).

Solution

For the greatest support for SSL, the following steps are recommended:

To support PC+IE users, enable the UseWinInet parameter. This connection method will support unlimited size file transfers under SSL when WinInet connection is available. When UseWinInet is set to "1" and the client system is Windows+IE, JFile will ignore other connection method parameters and will only use Wininet connection.
Example:
<param name="UseWinInet" value="1">
To support SSL tranfers for users with Windows/Linux/Unix with supported versions of Netscape, turn off the AutoSetTransferMethod parameter. (Note: for non-SSL transfers, we recommend that you leave the default setting). If you set AutoSetTransferMethod to "0", this will prevent JFile from switching to sockets (which does not support SSL) when a file transfer exceeds a certain size. For these users, the UseWinInet setting will be ignored, and URLConnection will be used. URLConnection can handle up to 50MB transfer efficiently. If you anticipate tranfers larger than 50MB from such client machines, you may want to include browser detection and provide a non-SSL alternative for these users.
Example:
<param name="AutoSetTransferMethod" value="0">
If the client is MAC+IE or other platforms with unsupported versions of Netscape, only sockets connection is available. Therefore, there is no way to provide SSL support for such clients. If you anticipate users whose systems only have sockets connection, you may want to include browser detection and provide a non-SSL alternative for these users.