NAME

Phoebe - serve a wiki as a Gemini site

SYNOPSIS

phoebe [--host=hostname ...] [--port=port] [--cert_file=filename] [--key_file=filename] [--log_level=error|warn|info|debug] [--log_file=filename] [--wiki_dir=directory] [--wiki_token=token ...] [--wiki_page=pagename ...] [--wiki_main_page=pagename] [--wiki_mime_type=mimetype ...] [--wiki_page_size_limit=n] [--wiki_space=space ...]

DESCRIPTION

Phoebe does two and a half things:

It's a program that you run on a computer and other people connect to it using their Gemini client in order to read the pages on it.

It's a wiki, which means that people can edit the pages without needing an account. All they need is a client that speaks both Gemini and Titan, and the password. The default password is "hello". 😃

People can also access it using a regular web browser. They'll get a very simple, read-only version of the site.

To take a look for yourself, check out the test wiki via the web or via the web.

https://gemini.circumlunar.space/clients.html
https://transjovian.org:1965/test
gemini://transjovian.org/test

GEMTEXT

Pages are written in gemtext, a lightweight hypertext format. You can use your favourite text editor to write them.

A text line is a paragraph of text.

    This is a paragraph.
    This is another paragraph.

A link line starts with "=>", a space, a URL, optionally followed by whitespace and some text; the URL can be absolute or relative.

    => http://transjovian.org/ The Transjovian Council on the web
    => Welcome                 Welcome to The Transjovian Council

A line starting with "```" toggles preformatting on and off.

    Example:
    ```
    ./phoebe
    ```

A line starting with "#", "##", or "###", followed by a space and some text is a heading.

    ## License
    The GNU Affero General Public License.

A line starting with "*", followed by a space and some text is a list item.

    * one item
    * another item

A line starting with ">", followed by a space and some text is a quote.

    The monologue at the end is fantastic, with the city lights and the rain.
    > I've seen things you people wouldn't believe.

EDITING THE WIKI

How do you edit a Phoebe wiki? You need to use a Titan-enabled client.

Titan is a companion protocol to Gemini: it allows clients to upload files to Gemini sites, if servers allow this. On Phoebe, you can edit "raw" pages. That is, at the bottom of a page you'll see a link to the "raw" page. If you follow it, you'll see the page content as plain text. You can submit a changed version of this text to the same URL using Titan. There is more information for developers available on Community Wiki. https://communitywiki.org/wiki/Titan

Known clients:

This repository comes with a Perl script called titan to upload files. https://alexschroeder.ch/cgit/phoebe/plain/titan

Gemini Write is an extension for the Emacs Gopher and Gemini client Elpher. https://alexschroeder.ch/cgit/gemini-write/ https://thelambdalab.xyz/elpher/

Gemini & Titan for Bash are two shell functions that allow you to download and upload files. https://alexschroeder.ch/cgit/gemini-titan/about/

INSTALLATION

Using cpan:

    cpan App::phoebe

Manual install:

    perl Makefile.PL
    make
    make install

Dependencies

Perl libraries you need to install if you want to run Phoebe:

Algorithm::Diff, or libalgorithm-diff-xs-perl
File::ReadBackwards, or libfile-readbackwards-perl
File::Slurper, or libfile-slurper-perl
Mojolicious, or libmojolicious-perl
IO::Socket::SSL, or libio-socket-ssl-perl
Modern::Perl, or libmodern-perl-perl
URI::Escape, or liburi-escape-xs-perl
Net::IDN::Encode, or libnet-idn-encode-perl
Encode::Locale, or libencode-locale-perl

I'm going to be using curl and openssl in the "Quickstart" instructions, so you'll need those tools as well. And finally, when people download their data, the code calls tar (available from packages with the same name on Debian derived systems).

The update-readme.pl script I use to generate README.md also requires some libraries:

Pod::Markdown, or libpod-markdown-perl
Text::Slugify, which has no Debian package, apparently 😭

Quickstart

I'm going to assume that you're going to create a new user just to be safe.

    sudo adduser --disabled-login --disabled-password phoebe
    sudo su phoebe --shell=/bin/bash
    cd

Now you're in your home directory, /home/phoebe. We're going to install things right here.

    cpan App::phoebe

Start Phoebe. It's going to prompt you for a hostname and create certificates for you. If in doubt, answer localhost. The certificate and a private key are stored in the cert.pem and key.pem files, using elliptic curves, valid for five years, without password protection.

    perl5/bin/phoebe

This starts the server in the foreground. If it aborts, see the "Troubleshooting" section below. If it runs, open a second terminal and test it:

    perl5/bin/gemini gemini://localhost/

You should see a Gemini page starting with the following:

    20 text/gemini; charset=UTF-8
    Welcome to Phoebe!

Success!! 😀 🚀🚀

Let's create a new page using the Titan protocol, from the command line:

    echo "Welcome to the wiki!" > test.txt
    echo "Please be kind." >> test.txt
    perl5/bin/titan --url=titan://localhost/raw/Welcome --token=hello test.txt

You should get a nice redirect message, with an appropriate date.

    30 gemini://localhost:1965/page/Welcome

You can check the page, now (replacing the appropriate date):

    perl5/bin/gemini gemini://localhost:1965/page/Welcome

You should get back a page that starts as follows:

    20 text/gemini; charset=UTF-8
    Welcome to the wiki!
    Please be kind.

Yay! 😁🎉 🚀🚀

If you have a bunch of Gemtext files in a directory, you can upload them all in one go:

    titan --url=titan://localhost/ --token=hello *.gmi

Image uploads

OK, how do image uploads work? First, we need to specify which MIME types Phoebe accepts. The files are going to be served back with that MIME type, so even if somebody uploads an executable and claim it's an image, other people's clients will treat it as an image instead of executing it (one hopes!) – so let's start with a list of common MIME types.

image/jpeg is for photos (usually with the jpg extension)
image/png is for graphics (usually with the png extension)
audio/mpeg is for sound (usually with the mp3 extension)

Let's continue using the setup we used for the "Quickstart" section. Restart the server and allow photos:

    perl5/bin/phoebe --wiki_mime_type=image/jpeg

Upload the image using the titan script:

    perl5/bin/titan --url=titan://localhost:1965/jupiter.jpg \
      --token=hello Pictures/Planets/Juno.jpg

You should get back a redirect to the uploaded image:

    30 gemini://localhost:1965/file/jupiter.jpg

How did the titan script know the MIME-type to use for the upload? If you don't specify a MIME-type using --mime, the file utility is called to guess the MIME type of the file.

Test it:

    file --mime-type --brief Pictures/Planets/Juno.jpg

The result is the MIME-type we enabled for our wiki:

    image/jpeg

Here's what happens when you're trying to upload an unsupported MIME-type:

    titan --url=titan://localhost:1965/earth.png \
      --token=hello Pictures/Planets/Earth.png

What you get back explains the problem:

    59 This wiki does not allow image/png

In order to allow such graphics as well, you need to restart Phoebe:

    perl phoebe --wiki_mime_type=image/jpeg --wiki_mime_type=image/png

Except that in my case, the image is too big:

    59 This wiki does not allow more than 100000 bytes per page

I could scale it down before I upload the image, using convert (which is part of ImageMagick):

    convert -scale 20% Pictures/Planets/Earth.png earth-small.png

Try again:

    titan --url=titan://localhost:1965/earth.png \
      --token=hello earth-small.png

Alternatively, you can increase the size limit using the --wiki_page_size_limit option, but you need to restart Phoebe:

    perl phoebe --wiki_page_size_limit=10000000 \
      --wiki_mime_type=image/jpeg --wiki_mime_type=image/png

Now you can upload about 10MB…

Using systemd

Systemd is going to handle daemonisation for us. There's more documentation available online. https://www.freedesktop.org/software/systemd/man/systemd.service.html.

Basically, this is the template for our service:

    [Unit]
    Description=Phoebe
    After=network.target
    [Service]
    Type=simple
    WorkingDirectory=/home/phoebe
    ExecStart=/home/phoebe/phoebe
    Restart=always
    User=phoebe
    Group=phoebe
    MemoryMax=100M
    MemoryHigh=90M
    [Install]
    WantedBy=multi-user.target

Save this as phoebe.service, and then link it:

    sudo ln -s /home/phoebe/phoebe.service /etc/systemd/system/

Reload systemd:

    sudo systemctl daemon-reload

Start Phoebe:

    sudo systemctl start phoebe

Check the log output:

    sudo journalctl --unit phoebe

Troubleshooting

🔥 1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher 🔥 If you created a new certificate and key using elliptic curves using an older OpenSSL, you might run into this. Try to create a RSA key instead. It is larger, but at least it'll work.

    openssl req -new -x509 -newkey rsa \
    -days 1825 -nodes -out cert.pem -keyout key.pem

FILES

Your home directory should now also contain a wiki directory called wiki, your wiki directory. In it, you'll find a few more files:

page is the directory with all the page files in it; each file has the gmi extension and should be written in Gemtext format

index is a file containing all the files in your page directory for quick access; if you create new files in the page directory, you should delete the index file – it will get regenerated when needed; the format is one page name (without the .gmi extension) per line, with lines separated from each other by a single \n

keep is the directory with all the old revisions of pages in it – if you've only made one change, then it won't exist; if you don't care about the older revisions, you can delete them; assuming you have a page called Welcome and edit it once, you have the current revision as page/Welcome.gmi, and the old revision in keep/Welcome/1.gmi (the page name turns into a subdirectory and each revision gets an apropriate number)

file is the directory with all the uploaded files in it – if you haven't uploaded any files, then it won't exist; you must explicitly allow MIME types for upload using the --wiki_mime_type option (see Options below)

meta is the directory with all the meta data for uploaded files in it – there should be a file here for every file in the file directory; if you create new files in the file directory, you should create a matching file here; if you have a file file/alex.jpg you want to create a file meta/alex.jpg containing the line content-type: image/jpeg

changes.log is a file listing all the pages made to the wiki; if you make changes to the files in the page or file directory, they aren't going to be listed in this file and thus people will be confused by the changes you made – your call (but in all fairness, if you're collaborating with others you probably shouldn't do this); the format is one change per line, with lines separated from each other by a single \n, and each line consisting of time stamp, pagename or filename, revision number if a page or 0 if a file, and the numeric code of the user making the edit (see "Privacy" below), all separated from each other with a \x1f

config probably doesn't exist, yet; it is an optional file containing Perl code where you can add new features and change how Phoebe works (see "Configuration" below)

conf.d probably doesn't exist, either; it is an optional directory containing even more Perl files where you can add new features and change how Phoebe works (see "Configuration" below); the idea is that people can share stand-alone configurations that you can copy into this directory without having to edit your own config file.

OPTIONS

--wiki_token is for the token that users editing pages have to provide; the default is "hello"; you can use this option multiple times and give different users different passwords, if you want
--wiki_page is an extra page to show in the main menu; you can use this option multiple times; this is ideal for general items like About or Contact
--wiki_main_page is the page containing your header for the main page; that's were you would put your ASCII art header, your welcome message, and so on, see "Main Page and Title" below
--wiki_mime_type is a MIME type to allow for uploads; text/plain is always allowed and doesn't need to be listed; you can also just list the type without a subtype, eg. image will allow all sorts of images (make sure random people can't use your server to exchange images – set a password using --wiki_token)
--wiki_page_size_limit is the number of bytes to allow for uploads, both for pages and for files; the default is 10000 (10kB)
--host is the hostname to serve; the default is localhost – you probably want to pick the name of your machine, if it is reachable from the Internet; if you use it multiple times, each host gets its own wiki space (see --wiki_space below)
--port is the port to use; the default is 1965
--wiki_dir is the wiki data directory to use; the default is either the value of the PHOEBE_DATA_DIR environment variable, or the "./wiki" subdirectory
--wiki_space adds an extra space that acts as its own wiki; a subdirectory with the same name gets created in your wiki data directory and thus you shouldn't name spaces like any of the files and directories already there (see "Wiki Directory"); not that settings such as --wiki_page and --wiki_main_page apply to all spaces, but the page content will be different for every wiki space
--cert_file is the certificate PEM file to use; the default is cert.pem
--key_file is the private key PEM file to use; the default is key.pem
--log_level is the log level to use (fatal, error, warn, info, debug); the default is warn
--log_file is the log file to use; the default is undefined, which means that STDERR is used

FILES

If you allow uploads of binary files, these are stored separately from the regular pages; the wiki doesn't keep old revisions of files around. If somebody overwrites a file, the old revision is gone.

You definitely don't want random people uploading all sorts of images, videos and binaries to your server. Make sure you set up those tokens using --wiki_token!

NOTES

Security

The server uses "access tokens" to check whether people are allowed to edit files. You could also call them "passwords", if you want. They aren't associated with a username. You set them using the --wiki_token option. By default, the only password is "hello". That's why the Titan command above contained "token=hello". 😊

If you're going to check up on your wiki often (daily!), you could just tell people about the token on a page of your wiki. Spammers would at least have to read the instructions and in my experience the hardly ever do.

You could also create a separate password for every contributor and when they leave the project, you just remove the token from the options and restart Phoebe. They will no longer be able to edit the site.

Privacy

The server only actively logs changes to pages. It calculates a "code" for every contribution: it is a four digit octal code. The idea is that you could colour every digit using one of the eight standard terminal colours and thus get little four-coloured flags.

This allows you to make a pretty good guess about edits made by the same person, without telling you their IP numbers.

The code is computed as follows: the IP numbers is turned into a 32bit number using a hash function, converted to octal, and the first four digits are the code. Thus all possible IP numbers are mapped into 8⁴=4096 codes.

If you increase the log level, the server will produce more output, including information about the connections happening, like 2020/06/29-15:35:59 CONNECT SSL Peer: "[::1]:52730" Local: "[::1]:1965" and the like (in this case ::1 is my local address so that isn't too useful but it could also be your visitor's IP numbers, in which case you will need to tell them about it using in order to comply with the GDPR.

EXAMPLE

Here's an example for how to start Phoebe. It listens on localhost port 1965, adds the "Welcome" and the "About" page to the main menu, and allows editing using one of two tokens.

    perl phoebe \
      --wiki_token=Elrond \
      --wiki_token=Thranduil \
      --wiki_page=Welcome \
      --wiki_page=About

Here's what my phoebe.service file actually looks like:

    [Unit]
    Description=Phoebe
    After=network.target
    [Install]
    WantedBy=multi-user.target
    [Service]
    Type=simple
    WorkingDirectory=/home/alex/farm
    Restart=always
    User=alex
    Group=ssl-cert
    MemoryMax=100M
    MemoryHigh=90M
    ExecStart=/home/alex/src/phoebe/script/phoebe \
     --port=1965 \
     --log_level=debug \
     --wiki_dir=/home/alex/phoebe \
     --host=transjovian.org \
     --cert_file=/var/lib/dehydrated/certs/transjovian.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/transjovian.org/privkey.pem \
     --host=toki.transjovian.org \
     --cert_file=/var/lib/dehydrated/certs/transjovian.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/transjovian.org/privkey.pem \
     --host=vault.transjovian.org \
     --cert_file=/var/lib/dehydrated/certs/transjovian.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/transjovian.org/privkey.pem \
     --host=communitywiki.org \
     --cert_file=/var/lib/dehydrated/certs/communitywiki.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/communitywiki.org/privkey.pem \
     --host=alexschroeder.ch \
     --cert_file=/var/lib/dehydrated/certs/alexschroeder.ch/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/alexschroeder.ch/privkey.pem \
     --host=next.oddmuse.org \
     --cert_file=/var/lib/dehydrated/certs/oddmuse.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/oddmuse.org/privkey.pem \
     --host=emacswiki.org \
     --cert_file=/var/lib/dehydrated/certs/emacswiki.org/fullchain.pem \
     --key_file=/var/lib/dehydrated/certs/emacswiki.org/privkey.pem \
     --wiki_main_page=Welcome \
     --wiki_page=About \
     --wiki_mime_type=image/png \
     --wiki_mime_type=image/jpeg \
     --wiki_mime_type=audio/mpeg \
     --wiki_space=transjovian.org/test \
     --wiki_space=transjovian.org/phoebe \
     --wiki_space=transjovian.org/anthe \
     --wiki_space=transjovian.org/gemini \
     --wiki_space=transjovian.org/titan

Certificates and File Permission

In the example above, I'm using certificates I get from Let's Encrypt. Thus, the regular website served on port 443 and the Phoebe website on port 1965 use the same certificates. My problem is that for the regular website, Apache can read the certificates, but in the setup above Phoebe runs as the user alex and cannot access the certificates. My solution is to use the group ssl-cert. This is the group that already has read access to /etc/ssl/private on my system. I granted the following permissions:

    drwxr-x--- root ssl-cert /var/lib/dehydrated/certs
    drwxr-s--- root ssl-cert /var/lib/dehydrated/certs/*
    drwxr----- root ssl-cert /var/lib/dehydrated/certs/*/*.pem

Main Page and Title

The main page will include ("transclude") a page of your choosing if you use the --wiki_main_page option. This also sets the title of your wiki in various places like the RSS and Atom feeds.

In order to be more flexible, the name of the main page does not get printed. If you want it, you need to add it yourself using a header. This allows you to keep the main page in a page called "Welcome" containing some ASCII art such that the word "Welcome" does not show on the main page. This assumes you're using --wiki_main_page=Welcome, of course.

If you have pages with names that start with an ISO date like 2020-06-30, then I'm assuming you want some sort of blog. In this case, up to ten of them will be shown on your front page.

GUS and robots.txt

There are search machines out there that will index your site. Ideally, these wouldn't index the history pages and all that: they would only get the list of all pages, and all the pages. I'm not even sure that we need them to look at all the files. The Robots Exclusion Standard lets you control what the bots ought to index and what they ought to skip. It doesn't always work. https://en.wikipedia.org/wiki/Robots_exclusion_standard

Here's my suggestion:

    User-agent: *
    Disallow: /raw
    Disallow: /html
    Disallow: /diff
    Disallow: /history
    Disallow: /do/comment
    Disallow: /do/changes
    Disallow: /do/all/changes
    Disallow: /do/all/latest/changes
    Disallow: /do/rss
    Disallow: /do/atom
    Disallow: /do/all/atom
    Disallow: /do/new
    Disallow: /do/more
    Disallow: /do/match
    Disallow: /do/search
    # allowing do/index!
    Crawl-delay: 10

In fact, as long as you don't create a page called robots then this is what gets served. I think it's a good enough way to start. If you're using spaces, the robots pages of all the spaces are concatenated.

If you want to be more paranoid, create a page called robots and put this on it:

    User-agent: *
    Disallow: /

Note that if you've created your own robots page, and you haven't decided to disallow them all, then you also have to do the right thing for all your spaces, if you use them at all.

Limited, read-only HTTP support

You can actually look at your wiki pages using a browser! But beware: these days browser will refuse to connect to sites that have self-signed certificates. You'll have to click buttons and make exceptions and all of that, or get your certificate from Let's Encrypt or the like. Anyway, it works in theory. If you went through the "Quickstart", visiting https://localhost:1965/ should work!

Notice that Phoebe doesn't have to live behind another web server like Apache or nginx. It's a (simple) web server, too!

Here's how you could serve the wiki both on Gemini, and the standard HTTPS port, 443:

    sudo ./phoebe --port=443 --port=1965 \
      --user=$(id --user --name) --group=$(id --group  --name)

We need to use sudo because all the ports below 1024 are priviledge ports and that includes the standard HTTPS port. Since we don't want the server itself to run with all those priviledges, however, I'm using the --user and --group options to change effective and user and group ID. The id command is used to get your user and your group IDs instead. If you've followed the "Quickstart" and created a separate phoebe user, you could simply use --user=phoebe and --group=phoebe instead. 👍

Configuration

This section describes some hooks you can use to customize your wiki using the config file, or using a Perl file (ending in *.pl or *.pm) in the conf.d directory. Once you're happy with the changes you've made, reload the server to make it read the config file. You can do that by sending it the HUP signal, if you know the pid, or if you have a pid file:

    kill -s SIGHUP `cat phoebe.pid`

Here are the ways you can hook into Phoebe code:

@extensions is a list of code references allowing you to handle additional URLs; return 1 if you handle a URL; each code reference gets called with $stream (Mojo::IOLoop::Stream), the first line of the request (a Gemini URL, a Gopher selector, a finger user, a HTTP request line), a hash reference for the headers (in the case of HTTP requests), and a buffer of bytes (e.g. for Titan or HTTP PUT or POST requests)

@main_menu adds more lines to the main menu, possibly links that aren't simply links to existing pages

@footer is a list of code references allowing you to add things like licenses or contact information to every page; each code reference gets called with $stream (Mojo::IOLoop::Stream), $host, $space, $id, $revision, and $format ('gemini' or 'html') used to serve the page; return a gemtext string to append at the end; the alternative is to overwrite the footer or html_footer subs – the default implementation for Gemini adds History, Raw text and HTML link, and @footer to the bottom of every page; the default implementation for HTTP just adds @footer to the bottom of every page

If you do hook into Phoebe's code, you probably want to make use of the following variables:

$server stores the command line options provided by the user.

$log is how you log things.

A very simple example to add a contact mail at the bottom of every page; this works for both Gemini and the web:

    package App::Phoebe;
    use Modern::Perl;
    our (@footer);
    push(@footer, sub { '=> mailto:alex@alexschroeder.ch Mail' });

This prints a very simply footer instead of the usual footer for Gemini, as the footer function is redefined. At the same time, the @footer array is still used for the web:

    package App::Phoebe;
    use Modern::Perl;
    our (@footer); # HTML only
    push(@footer, sub { '=> https://alexschroeder.ch/wiki/Contact Contact' });
    # footer sub is Gemini only
    no warnings qw(redefine);
    sub footer {
      return '—' x 10 . "\n" . '=> mailto:alex@alexschroeder.ch Mail';
    }

This example also shows how to redefine existing code in your config file without the warning "Subroutine … redefined".

Here's a more elaborate example to add a new action the main menu and a handler for it:

    package App::Phoebe;
    use Modern::Perl;
    our (@extensions, @main_menu);
    push(@main_menu, "=> gemini://localhost/do/test Test");
    push(@extensions, \&serve_test);
    sub serve_test {
      my $stream = shift;
      my $url = shift;
      my $headers = shift;
      my $host = host_regex();
      my $port = port($stream);
      if ($url =~ m!^gemini://($host)(?::$port)?/do/test$!) {
        $stream->write("20 text/plain\r\n");
        $stream->write("Test\n");
        return 1;
      }
      return;
    }
    1;

Wiki Spaces

Wiki spaces are separate wikis managed by the same Phoebe server, on the same machine, but with data stored in a different directory. If you used --wiki_space=alex and --wiki_space=berta, for example, then you'd have three wikis in total:

gemini://localhost/ is the main space that continues to be available
gemini://localhost/alex/ is the wiki space for Alex
gemini://localhost/berta/ is the wiki space for Berta

Note that all three spaces are still editable by anybody who knows any of the tokens.

Tokens per Wiki Space

Per default, there is simply one set of tokens which allows the editing of the wiki, and all the wiki spaces you defined. If you want to give users a token just for their space, you can do that, too. Doing this is starting to strain the command line interface, however, and therefore the following illustrates how to do more advanced configuration using the config file:

    package App::Phoebe;
    use Modern::Perl;
    our ($server);
    $server->{wiki_space_token}->{alex} = ["*secret*"];

The code above sets up the wiki_space_token property. It's a hash reference where keys are existing wiki spaces and values are array references listing the valid tokens for that space (in addition to the global tokens that you can set up using --wiki_token which defaults to the token "hello"). Thus, the above code sets up the token *secret* for the alex wiki space.

You can use the config file to change the values of other properties as well, even if these properties are set via the command line.

    package App::Phoebe;
    use Modern::Perl;
    our ($server);
    $server->{wiki_token} = [];

This code simply deactivates the token list. No more tokens!

Client Certificates

Phoebe serves a public wiki by default. Limiting editing to known users (that is, known client certificates) is possible. Here's a config file using client certificates to limit writing to a single, known fingerprint:

    package App::Phoebe;
    use Modern::Perl;
    our ($server, @extensions, $log);
    my @fingerprints = ('sha256$e4b871adf0d74d9ab61fbf0b6773d75a152594090916834278d416a769712570');
    push(@extensions, \&protected_wiki);
    sub protected_wiki {
      my $stream = shift;
      my $url = shift;
      my $hosts = host_regex();
      my $port = port($stream);
      my $spaces = space_regex($stream);
      my $fingerprint = $server->{client}->get_fingerprint();
      if (my ($host, $path) = $url =~ m!^titan://($hosts)(?::$port)?([^?#]*)!) {
        my ($space, $resource) = $path =~ m!^(?:/($spaces))?(?:/raw)?/([^/;=&]+(?:;\w+=[^;=&]+)+)!;
        if (not $resource) {
          $log->debug("The Titan URL is malformed: $path $spaces");
          $stream->write("59 The Titan URL is malformed\r\n");
        } elsif ($fingerprint and grep { $_ eq $fingerprint} @fingerprints) {
          $log->info("Successfully identified client certificate");
          my ($id, @params) = split(/[;=&]/, $resource);
          save_page($stream, $host, space($stream, $host, $space), decode_utf8(uri_unescape($id)),
                            {map {decode_utf8(uri_unescape($_))} @params});
        } elsif ($fingerprint) {
          $log->info("Unknown client certificate $fingerprint");
          $stream->write("61 Your client certificate is not authorized for editing\r\n");
        } else {
          $log->info("Requested client certificate");
          $stream->write("60 You need a client certificate to edit this wiki\r\n");
        }
        return 1;
      }
      return;
    }
    1;

@fingerprints is a list, so you could add more fingerprints:

    my @fingerprints = qw(
      sha256$e4b871adf0d74d9ab61fbf0b6773d75a152594090916834278d416a769712570
      sha256$4a948f5a11f4a81d0a2e8b60b1e4b3c9d1e25f4d95694965d98b333a443a3b25);

Or you could read them from a file:

    use File::Slurper qw(read_lines);
    my @fingerprints = read_lines("fingerprints");

The important part is that this code matches the same Titan requests as the default code, and it comes first. Thus, the old code can no longer be reached and this code checks for a known client certificate fingerprint.

To be sure, it doesn't check anything else! It doesn't check whether the client certificate has expired, for example.

You could, for example, install Phoebe, use the code above for your config file, and replace the fingerprint with the fingerprint of your own client certificate. The Makefile allows you to easily create such a certificate:

    make client-cert

Answer at least one of the questions OpenSSL asks of you and you should now have a client-cert.pem and a client-key.pem file. To get the fingerprint of your client certificate:

    make client-fingerprint

The output is the fingerprint you need to put into your config file.

Virtual Hosting

Sometimes you want have a machine reachable under different domain names and you want each domain name to have their own wiki space, automatically. You can do this by using multiple --host options.

Here's a simple, stand-alone setup that will work on your local machine. These are usually reachable using the IPv4 127.0.0.1 or the name localhost. The following command tells Phoebe to serve both 127.0.0.1 and localhost (the default is to just serve localhost).

    perl phoebe --host=127.0.0.1 --host=localhost

Visit both at gemini://localhost/ and gemini://127.0.0.1/, and create a new page in each one, then examine the data directory wiki. You'll see both wiki/localhost and wiki/127.0.0.1.

If you're using more wiki spaces, you need to prefix them with the respective hostname if you use more than one:

    perl phoebe --host=127.0.0.1 --host=localhost \
        --wiki_space=127.0.0.1/alex --wiki_space=localhost/berta

In this situation, you can visit gemini://127.0.0.1/, gemini://127.0.0.1/alex/, gemini://localhost/, and gemini://localhost/berta/, and they will all be different.

If this is confusing, remember that not using virtual hosting and not using spaces is fine, too. 😀

Multiple Certificates

If you're using virtual hosting as discussed above, you have two options: you can use one certificate for all your hostnames, or you can use different certificates for the hosts. If you want to use just one certificate for all your hosts, you don't need to do anything else. If you want to use different certificates for different hosts, you have to specify them all on the command line. Generally speaking, use --host to specifiy one or more hosts, followed by both --cert_file and --key_file to specifiy the certificate and key to use for the hosts.

For example:

    perl phoebe --host=transjovian.org \
        --cert_file=/var/lib/dehydrated/certs/transjovian.org/cert.pem \
        --key_file=/var/lib/dehydrated/certs/transjovian.org/privkey.pem \
        --host=alexschroeder.ch \
        --cert_file=/var/lib/dehydrated/certs/alexschroeder.ch/cert.pem \
        --key_file=/var/lib/dehydrated/certs/alexschroeder.ch/privkey.pem

CSS for the Web

The wiki can also answer web requests. By default, it only does that on port 1965. The web pages refer to a CSS file at /default.css, and the response to a request for this CSS is served by a function that you can override in your config file. The following would be the beginning of a CSS that supports a dark theme, for example. The Cache-Control header makes sure browsers don't keep trying to revalidate the CSS more than once a day. https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control

    our ($log);

    sub serve_css_via_http {
      my $stream = shift;
      $log->info("Serving CSS via HTTP");
      $stream->write("HTTP/1.1 200 OK\r\n");
      $stream->write("Content-Type: text/css\r\n");
      $stream->write("Cache-Control: public, max-age=86400, immutable\r\n"); # 24h
      $stream->write("\r\n");
      $stream->write(<<'EOT');
    html { max-width: 70ch; padding: 2ch; margin: auto; }
    body { color: #111111; background-color: #fffff8; }
    a:link { color: #0000ee }
    a:visited { color: #551a8b }
    a:hover { color: #7a67ee }
    @media (prefers-color-scheme: dark) {
       body { color: #eeeee8; background-color: #333333; }
       a:link { color: #1e90ff }
       a:hover { color: #63b8ff }
       a:visited { color: #7a67ee }
    }
    EOT
    }

Favicon for the Web

Here's an example where we a little Jupiter SVG is being served for the favicon, for all hosts. You could, of course, accept the $headers as an additional argument to favicon, match hostnames, pass the $host to serve_favicon_via_http, and return different images depending on the host. Let me know if you need this and you are stuck.

    our (@extensions, $log);

    push(@extensions, \&favicon);

    sub favicon {
      my $stream = shift;
      my $url = shift;
      if ($url =~ m!^GET /favicon.ico HTTP/1\.[01]$!) {
        serve_favicon_via_http($stream);
        return 1;
      }
      return 0;
    }

    sub serve_favicon_via_http {
      my $stream = shift;
      $log->info("Serving favicon via HTTP");
      $stream->write("HTTP/1.1 200 OK\r\n");
      $stream->write("Content-Type: image/svg+xml\r\n");
      $stream->write("Cache-Control: public, max-age=86400, immutable\r\n"); # 24h
      $stream->write("\r\n");
      $stream->write(<<'EOT');
    <?xml version="1.0" encoding="UTF-8" standalone="no"?>
    <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
    <circle cx="50" cy="50" r="45" fill="white" stroke="black" stroke-width="5"/>
    <line x1="12" y1="25" x2="88" y2="25" stroke="black" stroke-width="4"/>
    <line x1="5" y1="45" x2="95" y2="45" stroke="black" stroke-width="7"/>
    <line x1="5" y1="60" x2="95" y2="60" stroke="black" stroke-width="4"/>
    <path d="M20,73 C30,65 40,63 60,70 C70,72 80,73 90,72
             L90,74 C80,75 70,74 60,76 C40,83 30,81 20,73" fill="black"/>
    <ellipse cx="40" cy="73" rx="11.5" ry="4.5" fill="red"/>
    <line x1="22" y1="85" x2="78" y2="85" stroke="black" stroke-width="3"/>
    </svg>
    EOT
    }

SEE ALSO

As you might have guessed, the system is easy to tinker with, if you know some Perl. The Transjovian Council has a wiki space dedicated to Phoebe, and it includes a section with more configuration examples, including simple comments (append-only via Gemini), complex comments (editing via Titan or the web), wholesale page editing via the web, user-agent blocking, and so on. gemini://transjovian.org/ https://transjovian.org:1965/

LICENSE

GNU Affero General Public License