WCF Service use FTP as transport - web-services

Question

Bit of an edge question, but here goes.
I'm looking at ways of writing a WCF service that is accessed using the FTP protocol. The system where the client will be running has only got access to FTP via port 21 - all other traffic is blocked, and non-FTP traffic through port 21 gets filtered out aswell (tried running a RESTful service through port 21 with no luck). I have read that SOAP can be used over various protocols (HTTP, FTP, SMTP etc.). I have the service working fine with a HTTP binding on various ports, but am stuck at the point of binding it to FTP. Does anyone have any experience with this?

Answer 1

As an example of a gateway from SOAP into another environment, one can imagine a SOAP to FTP gateway where FTP commands are mapped into a SOAP message. In order to actually talk to the FTP server the calls will have to be expressed in a language understandable by FTP rather than in SOAP.
<?php
$myLogin = 'foo';
$myPass = 'bar';
$env = '<S:Envelope
xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
<S:Header>
<m:path xmlns:m="http://www.soap.org/path">
<m:action>http://www.im.org/chat</m:action>
<m:to>soap://D.com/some/endpoint</m:to>
<m:forward>
<m:via>soap://B.com</m:via>
<m:via>soap://C.com</m:via>
</m:forwawd>
<m:reverse>
<m:via/>
</m:reverse>
<m:from>mailto:frystyk#microsoft.com</m:from>
<m:id>uuid:84b9f5d0-33fb-4a81-b02b-5b760641c1d6</m:id>
</m:path>
</S:Header>
<S:Body>
...
</S:Body>
</S:Envelope>';
$socket=fsockopen('http://example.com', 21);
$t=fgets($socket, 128);
fwrite($socket, "USER $myLogin\r\n");
$t=fgets($socket, 128);
fwrite($socket, "PASS $myPass\r\n");
$t=fgets($socket, 128);
fwrite($socket, "PUTS $env\r\n");
fwrite($socket, "QUIT\r\n");
fclose($socket);
?>
References
SOAP Message Path Modeling
SMTP Transport Binding for SOAP 1.1
Using curl over ftp took 3+ minutes for a 4 byte file w/ EPSV
PHP Manual: fwrite
Describing Media Content of Binary Data in XML
XML-binary Optimized Packaging
SOAP Messages with Attachments
SOAP Version 1.2 Email Binding