rev 2 of the FRequest protocol

FRequest/FRequest-protocol.md

@@ -1,10 +1,39 @@
-# FRequest - Simple file transfer protocol
+# FRequest - Simple file transfer protocol - Revision 1
 
-FRequest is a <del>dumb</del> simple file transfer protocol for use on Minitel networks. A file transfer occurs as follows:
+FRequest is a simple file transfer protocol for use on Minitel or similar networks.
+
+## Requests
+
+A client request consists of the following:
+
+ - A single-character request type
+ - The path for the file the client is requesting
+ - A newline
+
+Request types can be the following characters:
+
+ - t - **t**ransfer - request file contents
+ - s - **s**tat - request file size and type (format: (d or f)&lt;size&gt;)
+
+## Server responses
+
+The server should respond with:
+
+ - A single character status code
+ - The result of the request
+
+Status codes can be the following characters:
+
+ - y - **y**es - file found, read and sent
+ - d - **d**irectory - directory listing sent
+ - n - **n**ot found - no such file or directory
+ - f - **f**ailure - other type of failure, reason sent
+
+## Example exchange
 
 1. The client initiates a connection to the server on the FRequest port (default 70)
-2. The client sends the path to the file they want, followed by a newline.
-3. The server responds with either the contents of the requested file, a directory listing, or "file not found" if there is an error.
-4. The server closes the connection.
+2. The client sends *t* to ask for a transfer, the path *example.txt*, and a newline.
+3. The server finds the file and responds with *y* followed by the file contents.
+4. The server closes the connection when the transfer is completed.
 
 Servers may wish to implement restricting users to a specific directory.