Utiaji

• What and Why
• How
• Bare Necessities

Calendar✓, Wiki✓, Address Book•

Architecture

Data Model

create table kv (
    k varchar not null primary key, /* key */
    v jsonb,                        /* value */
    t timestamp default current_timestamp
);

create table kk (
    f varchar references kv(k) on delete cascade, /* from */
    t varchar references kv(k) on delete cascade, /* to */
    primary key (f,t)
);

Requirements

• Handle GET of HTML
• HTML Templates
• Handle GET and POST of JSON
• Serializing to JSON
• Socket operations
• Routing
• Modeling data
• Database Access

Perl 6

• Grammars
• Concurrency
• Syntax
• Types
• Caveats

Grammars

• Request Line
• Headers
• Templates
• Route Patterns

GET /cal HTTP/1.1

rule TOP { <verb> <path> "HTTP/1.1" }
token path { '/' <segment>* %% '/' }
token segment { [ <alpha> | <digit> | '+' | '-' | '.' | ':' ]* }
        

Host: utiaji.org
Content-Length: 0

rule TOP { [ <header> \n ]* }
rule header { <field-name> ':' <field-value> }

%| :$cal, *%args
%== include $app, 'header', |%args;
<row>
<div class="column" id='content'></div>
<script type='text/javascript'>
  var state = <%==  to-json($cal.initial-state) %>;

rule TOP {
 [ ^ '%|' [ $<signature>=[ \V+ ] ] \n ]?
 [    <line=statement>
    | <line=text>
 ] *
}

/cal
/wiki/:page
/cal/range/Δfrom/Δto

token TOP              { '/' <part> *%% '/' }
token part             { <literal> || <placeholder> }
token placeholder      { <placeholder_word> | <placeholder_date> }
token placeholder_date { 'Δ' <var> }
token placeholder_word { ':' <var> }

Concurrency

my $gatsby = Supplier.new;

# version 1
$gatsby.Supply.tap(
      { say "got $_" },
      done => { say "bye" },
      quit => { say "quitting: $_"} );

$gatsby.emit('wine');
$gatsby.quit("Argh!");
$gatsby.done;

my $gatsby = Supplier.new;

# version 2
start react whenever $gatsby.Supply
{   say "got $_";
    LAST { say "bye" }
    QUIT { say "quitting: $_" }
}

$gatsby.emit('wine');
$gatsby.quit("Argh!");
$gatsby.done;

my $gatsby = Supplier.new;
start react whenever IO::Socket::Async.listen($.host,$.port) {
    self.handle-connection($^connection);
    QUIT { debug "socket quit"; }
    LAST { debug "socket done"; }
}

sub handle-connection {
  whenever $conn.Supply(:bin) {
     if self.generate-response($bytes,$^buf) { ... }
     QUIT { debug "connection quit"; }
     LAST { debug "connection done"; }
  }
}

Promises

my $timeout = Promise.in(5).then({
  $connection.close unless $closed;
});

Numeric Parameters

self.render: $res, status => 404

self.render: $res, :status<404> 

self.render: $res, :404status

Implicit Parameters

sub handle($req,$res) {
  self.render($res, text => "hello, { $req.json<name> }")
}

sub ($req,$res) {
  self.render: $res, text => "hello, { $req.json<name> }"
}

-> $req,$res { self.render: $res, text => "hello, { $req.json<name> }" }

{ self.render: $^res, text => "hello, { $req.json<name> }"  }

Signature Objects

$cb.signature.count == 1 ?? $cb($res) !! $cb($req,$res);

$cb.count == 1 ?? $cb($res) !! $cb($req,$res);

Multi-dispatch

multi method render($res, :$text!, :$status=200) {

multi method render($res, :$json!, :$status=200) {

multi method render($res, :$template!, :$status=200) {

multi method render($res, Pair $p) {

Topicalizing

$_ = $dog;

given $dog { ...

with $dog { ...

for $dog { ...

.bark

Match Object ($/)

$/{"day"}

$/<day>

$<day>

No DSL

method setup {
    with self {
      .get: '/', { self.redirect_to: $^res, '/wiki' }
      .get: '/cal/range/Δfrom/Δto', -> $req, $/
          { ...$<from>...$<to>... }
      .post: '/cal/', { ...$^req...$^res...}
      ...
    }

Types

my Buf $buf = Buf.new(65,66,67);

my Buf[uint8] $buf = Buf[uint8].new(65,66,67);

my Str $body = $buf.decode('UTF-8');

my UInt $content-length = $body.encode('UTF-8').elems;

Object Hierarchies

unit class Utiaji::App;
has $.router handles <get post put> = Utiaji::Router.new;

Object Hierarchies

class Utiaji::Model::Pim { .. }

Set Operations

for ( @new (-) @old ).keys { ...save... }
for ( @old (-) @new ).keys { ..remove.. }

method !header_valid(Buf[] $header) {
   return $header ⊂ (10,13,32..127);
}

⚠️ Rakudo to-json

say to-json( "🍺")

"\u1f37a"

use JSON::Fast;
say to-json( "🍺")'

"🍺"

⚠️ Single Argument R ule

say [ { a => 1 } ]  eqv [ a => 1 ];
say [ { a => 1 }, ] eqv [ a => 1 ];

True
False

Testing

cache:
  directories:
    - $HOME/.rakudobrew

dependencies:
  cache_directories:
    - ../.rakudobrew

panda --notests install DBIish
panda install HTTP::Tinyish

Wishlist

• Better dependency management
• Coercion (dates to strings, matches to strings)
• leave

$ perl6 -e '{leave}'
leave not yet implemented. Sorry.
  in block  at -e line 1