From: http://en.wikipedia.org/wiki/Gopher_(protocol)
The Gopher protocol is a TCP/IP Application layer protocol designed for distributing, searching, and retrieving documents over the Internet [...]. The protocol offers some features not natively supported by the Web and imposes a much stronger hierarchy on information stored on it.
You can find more info here:
The command mkgopher
can be used to create and manage
your gopherspace.
When you run mkgopher
, you will be given a command
prompt. You can issue the HELP
command here to get
a list of the available commands:
HOWTO - Tips on managing your GOPHERSPACE
setup - First step, create your GOPHERSPACE
chmod - Set/Restore file permissions
title - Title your site
describe - Create a site description
mkdir {directory} - Create a directory
rmdir {directory} - Delete a directory
edit {filename} - Publish a document
upload {filename} - Transfer a file via ZMODEM to SDF
ls - List the current directory
cd {directory} - Change directory
pwd - Present working directory
gopher - Browse your site
quit
The setup
command will create a directory in your $HOME
called gopher
(This directory is a link to
/ftp/pub/users/$USER/ ). On it, you can put all the files you want to
be available in your Gopherspace.
Once you create your Gopherspace, the files you publish will be available
at
gopher://sdf.org:70/1/users/$USER/
(note: currently, the directory listing at gopher://sdf.org:70/1/users/
doesn't appear to list all user directories. You may have to directly
navigate to gopher://sdf.org:70/1/users/$USER/ in order to view your
files.
There are many ways to view gopherspace. The easiest for new users is one of the following:
You can issue the gopher
command, either from the SDF shell or
from within the mkgopher
command prompt. This gives a very basic
browser to explore gopherspace.
Lynx is the text web browser.
In addition to web browsing, Lynx is also capable of browsing gopherspace.
From the SDF shell, you can issue the command:
$ lynx gopher://sdf.org/
and Lynx will start up at sdf.org's gopher root menu.
Floodgap.com provides a public gopher proxy that you can view in your
web browser at https://gopher.floodgap.com/gopher/gw.
For more information, see the proxy info page:
https://gopher.floodgap.com/gopher/
You can use mkgopher to publish documents, create directories, etc. You can also manage your Gopherspace manually. If you decide to do so, remember that the server will not display your content if it is not already visible to everyone. That is, files need to world-readable (chmod o+r $HOME/gopher/yourfile), directories need also to be world executable (chmod o+rx $HOME/gopher/yourdir), etc. The gopher server (Gophernicus) will serve executable files under /cgi-bin and also gophermaps which have executable permission as gopher CGIs or "moles" (see below). In the case of gophermaps, this is likely to result in errors, so make sure your gophermaps do not have execute permission (chmod -x $HOME/gopher/yourdir/gophermap).
The usual 'mkgopher -p' command has not yet been updated to reflect Gophernicus' permissions requirements. So you may need to reset your permissions for all files and directories in your gopher directory as noted above. The following two commands will revert all files to world-readable but non-executable, and all directories to world-readable but executable.
find ~/gopher/ -type f -print0 | xargs -0 chmod 644
find ~/gopher/ -type d -print0 | xargs -0 chmod 755
You may need to manually add execute permissions to any dynamic gophermaps or files under /cgi-bin after runnig these two commands.
Note: You can view the sample gophermap that comes with Gophernicus here: README.Gophermap
Say that you have file1.txt
, file2.pdf
, file3.rtf
and dir
in your Gopherspace (dir
is a directory). That is,
$ ls -lF drwxr-x--- 2 $USER nobody 512 Dec 2 10:15 dir/ -rw-r----- 1 $USER nobody 6 Dec 2 10:14 file1.txt -rw-r----- 1 $USER nobody 6 Dec 2 10:14 file2.pdf -rw-r----- 1 $USER nobody 6 Dec 2 10:14 file3.rtf
When you visit it, if there is no file named gophermap
(yes, this
file has no extension) you'll see a list of the files and the directory,
like this:
,,, Gopher Menu
Gopher Menu
(DIR) dir
(FILE) file1.txt
(FILE) file2.pdf
(FILE) file3.rtf
If there is a gophermap file, the server will parse it and will present the content as you specified in gophermap.
The gophermap syntax is:
XSome text here<TAB>/path/to/content<TAB>example.org<TAB>N
where the first character (X
in the example) is an
itemtype
(more below), Some text here
is the text that
you want to be displayed, <TAB> is a tab character,
/path/to/content
is the location of the content,
example.org
is the server where the content is located and
the last character (N
in the example) is the server port
(usually it's 70). Content after the second <TAB> is optional if
you are linking to content in your Gopherspace.
The itemtype
is one of these characters:
| Itemtype | Content |
|---|---|
| 0 | Text file |
| 1 | Directory |
| 2 | CSO name server |
| 3 | Error |
| 4 | Mac HQX filer |
| 5 | PC binary |
| 6 | UNIX uuencoded file |
| 7 | Search server |
| 8 | Telnet Session |
| 9 | Binary File |
| c | Calendar (not in 2.06) |
| e | Event (not in 2.06) |
| g | GIF image |
| h | HTML, Hypertext Markup Language |
| i | "inline" text type |
| s | Sound |
| I | Image (other than GIF) |
| M | MIME multipart/mixed message |
| T | TN3270 Session/ |
OK, let's say that you want to display a welcome message, a description for
file1.txt
, file2.pdf
and dir
, a link to an external server, a
link to an http URL. Your gophermap should be like
this:
Welcome to my Gopherspace! 0My text file file1.txt 9My pdf file file2.pdf 1My dir dir 0Why is Gopher Still Relevant? /gopher/relevance.txt gopher.floodgap.com 70 hAn http link URL:http://sdf.org/
Remember the gophermap syntax? Then be careful about tab characters. In the example above, there are some <TAB>s. For instance, the third line is
0My text file<TAB>file1.txt
while the seventh is
0Why is Gopher Still Relevant?<TAB>/gopher/relevance.txt<TAB>gopher.floodgap.com<TAB>70
How come the pdf file has an itemtype 9? Well, not every kind of file has its own itemtype, so you can use one that makes more sense.
Even if you don't need a blank line as the second line of your document, you can find this useful as there is a known Lynx bug that makes it display the second line together with the first (you can find a patch for this here: gopher://sdf.org/0/users/bulibuta/openbsd/patches/lynx-gopher-newline.patch).
This is (more or less) the output you'll see if you use a gophermap like the one in the example above:
,,, Gopher Menu
Gopher Menu
Welcome to my Gopherspace!
(FILE) My text file
(BIN) My pdf file
(DIR) My dir
(FILE) Why is Gopher Still Relevant?
(HTML) An http link
A gopher log (glog
or phlog
) is similar to a blog, but
on gopherspace. You can create your phlog and add it to the phlogosphere.
Maintaining a glog consists basically (but not necessarily) in creating an
entry (in your log directory) and modifying your phlog gophermap so that the
new entry is displayed with its creation date. There's a script that you can
run on SDF called mkgopherentry
(located in /sys/sdf/bin/mkgopherentry)
that will allow you to do exactly that. It will also extract the first
paragraph from the entry and will add it on the gophermap with a
Continued...
link that will point to the full post. Creating an entry
is as simple as:
mkgopherentry title textfile
where the 2 arguments are self-explaining.
Say that you have two entries in your diary. If you use mkgopherentry
,
they will appear like:
--This is my second post!--
Tuesday, December 01th, 2009
Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Cras eros turpis, tristique semper aliquet sit amet,
hendrerit vel enim. Integer pulvinar leo in dolor posuere
blandit.
Continued...
--First post--
Monday, November 30th, 2009
First entry in my gopher log at SDF.
Continued...
NOTE: You can use the 'phlog' command to add your phlog/glog to the gopher.club phlog listing, and
you can then update the listing after you create a post by running the following command: touch ~ftp/pub/users/$LOGNAME
There are some software authored by SDF members that you could find useful if you want to maintain a gopher log.
You can find more resources in the Glogging/Phlogging
section at
gopher://sdf.org/1/users/wt/soft/gopher.
The server used by SDF (Gophernicus) is able to serve moles
. Moles
are executable files under /cgi-bin that are processed by the server as
CGIs. This means that you can write a script, that the server will execute
and it will present the data that your mole dumps to standard output. With
moles you don't have to declare a content type header. Moles get arguments
from the address used to access the document and can be accessed with
whatever itemtype makes sense for the kind of output the mole generates.
You can code moles with the language(s) you are comfortable and can use on SDF. Below we will see some examples using shell scripts.
Remember that your moles need to be executable (and readable) by everyone,
and under /cgi-bin. So you will have to do: chmod 755
YOURSCRIPT.cgi
The following example will generate a random fortune:
#!/bin/sh /usr/pkg/games/fortune
Easy enough, isn't it? As it is raw text, you can access it using am itemtype = 0, that is: gopher://sdf.org/0/users/YOUR-USERNAME/cgi-bin/fortune.cgi
Did you notice that fortune
was called with
a full path? OK, that's because the server's path is
PATH=/sbin:/bin:/usr/sbin:/usr/bin
. That means that if you call
a program without a path, the server will search in /sbin
,
/bin
, /usr/sbin
and /usr/bin
. There's no
/usr/pkg/games
, or other path in the server's $PATH
(eventually, you can add a path of your choice with, e.g.,
PATH=$PATH:/usr/pkg/games).
The following example will generate a list of files on a specified directory. It will be possible to sort the content alphabetically or by modification time, based on how you access the script.
#!/bin/sh
directory=/ftp/pub/users/YOUR-USERNAME
rel_dir=/users/YOUR-USERNAME
server=sdf.org
port=70
# The internal field separator is set to be a newline
IFS='
'
if [ -n "$1" -a "$1" = 'date' ] ; then
ls_arg=t
fi
for i in $(ls -l${ls_arg} $directory) ; do
content=$(echo "$i" | awk '{ print $9}')
date=$(echo "$i" | awk '{ print $6,$7,$8}')
if [ -z "$content" ] ; then
continue
fi
if [ -d $directory/$i ] ; then
itemtype=1
else
itemtype=0
fi
echo "$itemtype$content ($date) $rel_dir $server $port"
done
Note that the echo...
line is
echo "$itemtype$content ($date)<TAB>$rel_dir<TAB>$server<TAB>$port"
If you go to gopher://sdf.org/1/users/YOUR-USERNAME/cgi-bin/ls.cgi , you will see a list of your files sorted alphabetically. If you access your mole as gopher://sdf.org/1/users/YOUR-USERNAME/cgi-bin/ls.cgi?date , then you'll see your files/directories sorted by modification time.
You can add some interactivity by using the itemtype 7. This itemtype
is intended to make it possible to type some characters in a search
field in your browser. However, you can use it to make it possible to
pass arguments to your scripts. The following example will use some
text you digit in the search field and will pass it through the
program figlet
.
#!/bin/sh
IFS='
'
for line in $(/usr/pkg/bin/figlet "$@") ; do
echo "i$line" # This is itemtype=i + text
done
When you access the script via gopher://sdf.org/7/users/YOUR-USERNAME/cgi-bin/figlet.cgi , your browser will ask you to input some text (the way it ask depends on the browser), then it will show your text as figlet transforms it.
The i
in the echo...
line is important here. Indeed, the
document is been accessed with an itemtype 7
(but the same applies
for itemtype 1
), so the document should be structured similarly
to gophermaps. It's not a gophermap, though. That's why you need to
explicitily state the line should be displayed as simple (or inline
)
text.
Besides what was said in the last paragraph of the figlet.cgi
example, there's also another thing to stress. In that example
(as with anything that will be served as a virtual directory or with an
itemtype 1 or 7), content won't be displayed if you access your script
via floodgap proxy (and maybe others). In this case you will need to
format
the output of your script. Luckily this is very easy. For
instance, in the figlet.cgi example you will need to modify the echo
...
line this way:
echo "i$i<TAB><TAB>error.host<TAB>1"
where <TAB> is a tab character (you should already know this!)C
and error.host
and 1
are, respectively, a fake server
and port number (you could also have written fake
instead of
error.host
and 300
instead of 1
).