Introducting VF-1

Well, as threatened I have written a basic Gopher client. This post is an

introduction and brief tutorial for those who want to play around with it, offer

feedback, hunt oug bugs (which surely exist, etc).

Firstly, I've called the client "VF-1", after the VF-1 Valkyrie aircraft in the

Macross anime. This is, of course, a nod to SDF and the role it has played in

keeping Gopher alive (for the unaware, SDF was originally a bulletin board for

anime fans to discuss Macross). I fully acknowledge that this is an awkward

name. I originally intended it only as a working name until I thought of

something better, but it's grown on me.

VF-1 is written in Python, specifically in Python 3. All of the "gopher stuff"

is done using code I lifted from the old "gopherlib" module which used to be

part of the Python standard library until it was removed in Python 2.5. I have

made the bare minimum of changes to the original library's code, basically just

done what I had to do to make it play nicely with Python 3 and unicode.

Everything is done using the standard library, there are no dependencies. Right

now it is in one file. You can find it in my Gopherhole if you go to the

"Misc files" section from the front page. If you are a SDF user, it is also in

my home directory with globally readable permissions. There is no hashbang

magic at the start of the file, so invoke it using e.g. "python3 ~/vf1.py" or,

on SDF, "python3.6 ~/vf1.py". If you want to use it on SDF, you will first

need to set the environment variable PYTHONIOENCODING="UTF-8". I think this

has something to do with local settings on SDF. I did not need to do this on

my Debian machine which I developed the client on.

Assuming you have been able to run it, you should now be staring at a "VF-1>"

prompt. Yep, VF-1 is built around an interactive command prompt, and has a very

"REPL" feeling. You only need a small number of commands to get around, and

most of them can be abbreviated to one or two chars, so with practice you can

get around very quickly. You can safely unplug your mouse the entire time you

are using VF-1. :)

Well, let's start off by heading to SDF to check out some nice phlogs! Use the

"go" command:

VF-1> go sdf.org/

(don't leave off the trailing slash - this won't be necessary in future

releases, but right now it is required for technical reasons I won't get into)

(if you are very lazy, you can type "g sdf.org/" instead, i.e. you can

abbreviate "go" to "g")

You should see a listing of the SDF Gopherspace. The different menu items are

indicated by numbers in square brackets, and the SDF Member PHLOGOSPHERE is

option [1], so go ahead and type "1" and then enter:

VF-1> 1

You should see all the phlogs fly by, and unless you have a very large monitor

some have probably run off the top of the screen. This will not be an uncommon

problem, and there are various ways to deal with it. Obviously, you can scroll

up in your terminal like always, but VF-1 gives you other ways to deal with

this. After you have visited a gopher menu (as opposed to a document), if you

just press Enter (i.e. execute an empty line), VF-1 will print the first 10

items in the menu by themselves (any ASCII art etc. in the original listing is

removed in this mode). Each time you press enter you will see the next ten

items in the listing. Page through a few times to get a feel for it.

If you just want to see which phlogs have been updated lately, that's probably

enough for you. But suppose you are really curious about one phlog in

particular. Say you want to know what Tomasino has been up to. You could

search for his phlog specifically:

VF-1> search tom

(if you are very lazy, you can use "/" instead of "search", i.e. "/ tom")

This will show you the phlogs with "tom" in them (it's a simple case-insensitive

search). Tomasino will probably be [1] or [2] (depends whether tomatobodhi has

updated more recently :). So go ahead and type "1" and hit enter again to enter

Tomasino's gopherhole. Then you can type "2" and enter to go to his phlog, and

then "1" and enter to read his most recent entry about Kindles.

Suppose now you want to go back to the main SDF phlog listing. Let's check out

your history:

VF-1> history

(if you are very lazy, you can abbreviate "history" to "hist", and in fact if

you are fiendishly lazy you can just use "h")

You should this time see a menu of the few places you've been so far. The

phlogosphere list will probably be [2], so type "2" and enter to go back there.

By now you are probably getting the hang of using numbers to get around.

For this next bit, let's focus on gunnarfrost's phlog, because he writes very

nice short entries which work well for this. Once you're at the main phlog

listing, do a:

VF-1> search frost

To easily find gunnarfrost's phlog and then press [1] to type the first entry.

Short and sweet! Now, suppose you want to read his next post. You could use

the "back" command to go back to the menu listing and then press "2", and then

do "back" and "3", "back" and "4", etc. But it's much easier to just type:

VF-1> next

(or, if you are lazy, just "n")

This will automatically take you to the next item in the most recently seen

gopher menu after the one you just viewed. So you can just hit "n" and enter

again and again to flip through the pages of gunnar's phlog. Each one is much

shorter than a full screen, so this works very nicely.

Lately gunnarfrost is a good phlogger and wraps his entries at 70 or 80 chars or

thereabouts. But if you keep hitting "n" you'll get to early entries where the

lines just keep going until your terminal wraps them (sorry, gunnarfrost, I

don't mean to single you out here, plenty of other folk do this too!). Once

you've found one of these, try running:

VF-1> fold

And VF-1 will wrap the lines at 80 chars for you (assuming you have the "fold"

command installed on whatever system you are using). This isn't the only helper

command of this kind available. Get back to the main SDF phlog listing (either

by running "back" a few times or using "hist" and a number to jump straight to

it) and go to my phlog. Unlike gunnarfrost, I appear to be physiologically

incapable of writing phlog posts which are less than a few whole screens long.

Go to one of these posts (say my most recent "assorted replies and

acknowledgements"), and watch the lines fly by. Now try:

VF-1> less

This will pipe my giant entry through "less", so you can move back and forth and

read it. Just press "q" when you're done like usual to get your VF-1 prompt

back.

I have quite a few references at the end of that entry. You might be tempted to

pick up your mouse, highlight those urls, and use the "go" command to visit

them. Put that rodent down! The mouse, that is, not the gopher. Instead, try

this command:

VF-1> links

VF-1 will then scan the most recently viewed post for URLs. Well, actually, it

scans for words (i.e. things separated by spaces) which contain "://" and at

least one ".". This might not catch all URLs and it might sometimes catch

things which are not URLs, but it works well enough for now. You will see a

menu and now you can use numbers to follow any of those links without your

mouse!

If you want to know the URL of a document you are at so that you can refer to

it, just do:

VF-1> url

If you want to save the document, just do:

VF-1> save ~/some/random/path/somefilename.txt

Everything so far has been text-based. Gopher items with itemtype 0 (text) are

fed to the "cat" command by default, or to "less" or "fold" if you request it.

But VF-1 can handle other itemtypes too. Image files with an item type of "g"

or "I" will be opened using the "feh" image viewer (if installed). HTML

content with an item type of "h" will be fed to "lynx --dump", and audio files

with an item type of "a" will be fed to "mpg123" (e.g. you can listen to jynx's

doom metal songs in this way). Obviously if you do not have one of these

programs installed, it will not work. In future I may provide some nice way to

customise which 3rd party programs are used for different item types. For now,

if you want to use different programs, you will have to edit the code. It's not

hard, just look for the _HANDLERS dictionary near the top of vf1.py and change

accordingly.

This pretty much covers the basics! I hope to add a bookmarking function soon.

In the meantime, I have hardcoded two commands in there. You can always type

"sdf" to jump to sdf.org, and you can always type "bongusa" to go to Bongusta.

To make a few implcit concepts explicit:

• VF-1 always has in it's mind exactly one "index", i.e. a list of places in

Gopherspace with numbers attached to them. By typing "1" and enter, "2" and

enter, etc. you jump to that location in the active index.

• Whenever you visit a gopher menu, the contents of that menu become the active

index, replacing whatever it used to be.

• When you do "search" or "history" or "links", the results of these commands

overwrite your current index. If you want to get your index back to being

the most recently visited gopher menu, you can use the "ls" command. Doing

this means you lose your search results (your history doesn't go away,

though).

• The "search" command runs on whatever the current index is. This might not

be the contents of a gopher menu. You can search your history, and in fact

you can even search the results of an earlier search to narrow things down!

• In general, VF-1 does not remember much. It always has some idea of the most

recently visited gopher menu (i.e. itemtype 1) and the most recently visited

gopher document (i.e. any other itemtype). "ls" always operates on the most

recently visisted gopher menu, even if you have visited some documents since

then. Commands like "fold", "less" and "save" operate on the most recently

visited document, even if you have visited some menus since then. Basically

everything operates one the most recently seen thing of the appropriate type.

Even if it is not terribly intuitive at first, I hope that the interface ends up

being very conceptually simple and also very consistent, so that it won't take

long at all before you know what to expect from a command at any given time, and

how to use commands together to do certain things. I didn't sit down and

carefully plan all this in advance, I just hacked on it until it worked and made

things nice as I thought of them, so right now there are probably plenty of

inconsistencies in the logic. If you spot any, please feel free to let me know.

Well, that's about it. Please give VF-1 a spin and let me know what you think,

either by phlogging about it or emailing me at solderpunk@sdf.org. I'm

interested to hear people's thoughts, regardless of whether they love it or hate

it.

[1] https://en.wikipedia.org/wiki/VF-1_Valkyrie