ENiGMA½ currently relies on external executable binaries for "legacy" file transfer protocols such as X, Y, and ZModem. Remember that ENiGMA½ also support modern web (HTTP/HTTPS) downloads!
File transfer protocols are managed via the `fileTransferProtocols` configuration block of `config.hjson`. Each entry defines an **external** protocol handler that can be used for uploads (recv), downloads (send), or both. Depending on the protocol and handler, batch receiving of files (uploads) may also be available.
The following file transfer protocols are pre-configured in ENiGMA½ as of this writing. System operators may override or extend this list. PRs are welcome for pre-configured additions!
[SEXYZ from Synchronet](http://wiki.synchro.net/util:sexyz) offers a nice X, Y, and ZModem implementation including ZModem-8k & works under *nix and Windows based systems. As of this writing, ENiGMA½ is pre-configured to support ZModem-8k, XModem, and YModem using SEXYZ. An x86_64 Linux binary, and hopefully more in the future, [can be downloaded here](https://l33t.codes/bbs-linux-binaries/).
ZModem-8k is configured using the standard Linux [sz(1)](https://linux.die.net/man/1/sz) and [rz(1)](https://linux.die.net/man/1/rz) binaries. Note that these binaries also support XModem and YModem, and as such adding the configurations to your system should be fairly straight forward.
Generally available as `lrzsz` under Apt or Yum type packaging.
### File Transfer Protocol Configuration
The following top-level members are available to an external protocol configuration:
*`name`: Required; Display name of the protocol
*`type`: Required; Currently must be `external`. This will be expanded upon in the future with built in protocols.
*`sort`: Optional; Sort key. If not provided, `name` will be used for sorting.
For protocols of type `external` the following members may be defined:
*`sendCmd`: Required for protocols that can send (allow user downloads); The command/binary to execute.
*`sendArgs`: Required if using `sendCmd`; An array of arguments. A placeholder of `{fileListPath}` may be used to supply a path to a **file containing** a list of files to send, or `{filePaths}` to supply *1:n* individual file paths to send.
*`recvCmd`: Required for protocols that can receive (allow user uploads); The command/binary to execute.
*`recvArgs`: Required if using `recvCmd` and supporting **batch** uploads; An array of arguments. A placeholder of `{uploadDir}` may be used to supply the system provided upload directory. If `{uploadDir}` is not present, the system expects uploaded files to be placed in CWD which will be set to the upload directory.
*`recvArgsNonBatch`: Required if using `recvCmd` and supporting non-batch (single file) uploads; A placeholder of `{fileName}` may be supplied to indicate to the protocol what the uploaded file should be named (this will be collected from the user before the upload starts).
*`escapeTelnet`: Optional; If set to `true`, escape all internal Telnet related codes such as IAC's. This option is required for external protocol handlers such as `sz` and `rz` that do not escape themselves.
