Sean Caron scaron@umich.edu
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acme gophers.c
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specify the FQDN of the host on which the server is running in the HOST_NAME #define.
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mk
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cp ./gophers /usr/you/bin/yourarch
./gophers [port] [gopher root directory] [logfile]
All command line parameters are mandatory.
The gopher server serves up documents from the gopher root directory. The theory of operation is as follows.
repeat forever {
get a request from the client
catenate the request path with the root directory to get a real filesystem path
stat this file to see if it is a file or directory.
if (file) {
spit file out to client
}
if (directory) {
look for .gopher file
if (exists) {
assume it is in 'gopher markup language' and spit it directly to the client
}
else {
generate a basic directory listing in 'gopher markup language' and send it to the client
}
}
}
What I call gopher markup language is really just lines of text formatted in a way that is RFC 1436 compliant. That is, lines of the text that the client will interpret as valid gopher selectors. They must look like this:
[type][selector]\t[path]\t[server name]\t[port]\n
Where \t=tab and \n=hit RETURN.
The [type] field is a one-character code that describes the filetype. It should be one of the following:
0 = plaintext
1 = directory
2 = cso search query
3 = error message
4 = binhex archive
5 = binary archive
6 = uuencoded
7 = search engine query
8 = telnet link
9 = binary file
d = pdf file
g = gif image file
h = html file
i = informational file (just displayed as text)
l = image file (e.g. jpg)
s = audio file
Some of these appear to be somewhat de facto additions to the original standard and might not be supported by all gopher browsers.
The other fields are defined as follows:
[selector] is the text of the link that is visible to the user
[path] is relative to the gopher root, make sure you begin it with a leading slash.
[server name] is the fqdn of the gopher server
[port] is the port number on which the gopher server is running.
If you just type a plain text line into a .gopher file the server will automatically make an i-line out of it. By plain text line, I mean a line that does not contain three tabs and have a first character equal to one of the file type codes above.
Note that gophers doesn't support the h-line URL:http://blah redirect, just file type information only.
If you are hand-coding an i-line it is customary to have a null path, host as error.host and port 1.
After typing the last line in your .gopher file, hit return, so that the file ends with a blank new line.