wip on static cache

begin static file caching
the shed biketh
2025-10-21 22:38:48 -07:00 · 2025-10-21 22:20:24 -07:00 · 2025-10-21 22:16:58 -07:00 · 2025-10-21 22:09:04 -07:00 · 2025-10-21 21:06:35 -07:00 · 2025-10-21 17:12:59 -07:00
14 changed files with 1913 additions and 10 deletions
@@ -4,7 +4,7 @@
         qargs    = undefined :: undefined | #{Key :: binary() := Value :: binary()},
         fragment = undefined :: undefined | none | binary(),
         version  = undefined :: undefined | http10 | http11 | http20,
-         headers  = undefined :: undefined | [{Key :: binary(), Value :: binary()}],
+         headers  = undefined :: undefined | #{Key :: binary() := Value :: binary()},
         cookies  = undefined :: undefined | #{Key :: binary() := Value :: binary()},
         enctype  = undefined :: undefined | none | urlencoded | json | multipart(),
         size     = undefined :: undefined | none | non_neg_integer(),
@@ -0,0 +1,100 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8">
    <title>Chat with Websockets</title>
    <link rel="stylesheet" href="./default.css">
 </head>
 <body>
    <div class="content">
        <h1 class="content-title">Chat with websockets</h1>
        <div class="content-body">
            <input autofocus label="Nick" id="nick"></input>
            <textarea hidden disabled id="wfc-output"></textarea>
            <input hidden id="wfc-input"></input>
        </div>
    </div>
    <script>
        let nelt = document.getElementById('nick');
        let ielt = document.getElementById('wfc-input');
        let oelt = document.getElementById('wfc-output');
        let ws   = new WebSocket("/ws/chat");
        let nick = '';
        // when user hits any key while typing in nick
        function on_nick(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = nelt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    nick = trimmed;
                    let msg_obj = ['nick', nick];
                    let msg_str = JSON.stringify(msg_obj);
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(msg_str);
                    // delete element from dom
                    nelt.remove();
                    oelt.hidden = false;
                    ielt.hidden = false;
                    ielt.autofocus = true;
                }
            }
        }
        // when user hits any key while typing in ielt
        function on_input_key(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = ielt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    let msg_obj = ['chat', trimmed];
                    let msg_str = JSON.stringify(msg_obj);
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(msg_str);
                    // clear input
                    ielt.value = '';
                    // add to output
                    oelt.value += '> ';
                    oelt.value += trimmed;
                    oelt.value += '\n';
                }
            }
        }
        function main() {
            nelt.addEventListener('keydown', on_nick);
            ielt.addEventListener('keydown', on_input_key);
            ws.onmessage =
                function (msg_evt) {
                    console.log('message from server:', msg_evt);
                    let msg_str = msg_evt.data;
                    let msg_obj = JSON.parse(msg_str);
                    oelt.value += msg_obj.nick;
                    oelt.value += '> ';
                    oelt.value += msg_obj.msg;
                    oelt.value += '\n';
                };
        }
        main();
    </script>
 </body>
 </html>
@@ -9,11 +9,14 @@
    <div class="content">
        <h1 class="content-title">WFC Demo</h1>
        <ul>
            <li><a href="/chat.html">Websocket Chatroom</a></li>
            <li><a href="/ws-test-echo.html">Websocket Echo Test</a></li>
        </ul>
        <div class="content-body">
-            <textarea id="wfc-output"
+            <textarea disabled id="wfc-output"></textarea>
-                      disabled
+            <input autofocus id="wfc-input"></input>
            ></textarea>
            <input autofocus id="wfc-input"></textarea>
            <h2>Settings</h2>
            <input type="checkbox" checked id="auto-resize-output">Auto-resize output</input> <br>
@@ -0,0 +1,100 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8">
    <title>Chat with Websockets</title>
    <link rel="stylesheet" href="./default.css">
 </head>
 <body>
    <div class="content">
        <h1 class="content-title">Chat with websockets</h1>
        <div class="content-body">
            <input autofocus label="Nick" id="nick"></input>
            <textarea hidden disabled id="wfc-output"></textarea>
            <input hidden id="wfc-input"></input>
        </div>
    </div>
    <script>
        let nelt = document.getElementById('nick');
        let ielt = document.getElementById('wfc-input');
        let oelt = document.getElementById('wfc-output');
        let ws   = new WebSocket("/ws/chat");
        let nick = '';
        // when user hits any key while typing in nick
        function on_nick(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = nelt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    nick = trimmed;
                    let msg_obj = ['nick', nick];
                    let msg_str = JSON.stringify(msg_obj);
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(msg_str);
                    // delete element from dom
                    nelt.remove();
                    oelt.hidden = false;
                    ielt.hidden = false;
                    ielt.autofocus = true;
                }
            }
        }
        // when user hits any key while typing in ielt
        function on_input_key(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = ielt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    let msg_obj = ['chat', trimmed];
                    let msg_str = JSON.stringify(msg_obj);
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(msg_str);
                    // clear input
                    ielt.value = '';
                    // add to output
                    oelt.value += '> ';
                    oelt.value += trimmed;
                    oelt.value += '\n';
                }
            }
        }
        function main() {
            nelt.addEventListener('keydown', on_nick);
            ielt.addEventListener('keydown', on_input_key);
            ws.onmessage =
                function (msg_evt) {
                    console.log('message from server:', msg_evt);
                    let msg_str = msg_evt.data;
                    let msg_obj = JSON.parse(msg_str);
                    oelt.value += msg_obj.nick;
                    oelt.value += '> ';
                    oelt.value += msg_obj.msg;
                    oelt.value += '\n';
                };
        }
        main();
    </script>
 </body>
 </html>
@@ -0,0 +1,95 @@
 /* color pallette */
 * {
    --white:    #f7f8fb;
    --lgray0:   #f5fbfd;
    --lgray1:   #daddd6;
    --lgray2:   #d3d8d5;
    --mgray1:   #687864;
    --dgreen1:  #21341e;
    --lgreen1:  #e5eef2;
    --black:    #003d27;
    --sans:     Helvetica, Liberation Sans, FreeSans, Roboto, sans-serif;
    --mono:     Liberation Mono, FreeMono, Roboto Mono, monospace;
    --fsdef:    12pt;
 }
 /* body */
 body {
    background:     var(--white);
    color:          var(--dgray1);
    font-size:      var(--fsdef);
    font-family:    var(--sans);
    margin:         0;
    padding:        0;
    line-height:    1.4;
 }
 .content {
    max-width:  800px;
    margin:     0 auto;
    /*
    background:     #ff0;
    */
 }
 /* add some top padding to content */
 .content-title {
    text-align:         center;
    text-decoration:    underline;
 }
 .content-body {
    width:          100%;
    margin:         0 auto;
    /*
    background:     #f00;
    */
    padding-left:   10px;
    padding-right:  10px;
    box-sizing:     border-box;
 }
 /* element-specific styling */
 a {
    color: var(--mgray1);
 }
 #wfc-input {
    font-family:    var(--mono);
    font-size:      var(--fsdef);
    background:     var(--lgreen1);
    width:          100%;
    box-sizing:     border-box;
    border-radius:  6px;
    border:         1px solid var(--lgray1);
    padding:        5px;
 }
 #wfc-output {
    background:     var(--lgray0);
    font-family:    var(--mono);
    font-size:      var(--fsdef);
    width:          100%;
    resize:         vertical;
    box-sizing:     border-box;
    border-radius:  6px;
    border:         1px solid var(--lgray1);
    padding:        5px;
 }
@@ -0,0 +1,138 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8">
    <title>WF Compiler Demo</title>
    <link rel="stylesheet" href="./default.css">
 </head>
 <body>
    <div class="content">
        <h1 class="content-title">WFC Demo</h1>
        <ul>
            <li><a href="/chat.html">Websocket Chatroom</a></li>
            <li><a href="/ws-test-echo.html">Websocket Echo Test</a></li>
        </ul>
        <div class="content-body">
            <textarea disabled id="wfc-output"></textarea>
            <input autofocus id="wfc-input"></input>
            <h2>Settings</h2>
            <input type="checkbox" checked id="auto-resize-output">Auto-resize output</input> <br>
            <input type="checkbox" checked id="auto-scroll"       >Auto-scroll output to bottom</input>
        </div>
    </div>
    <script>
        let ielt = document.getElementById('wfc-input');
        let oelt = document.getElementById('wfc-output');
        let MAX_OELT_HEIGHT = 300;
        function auto_resize_output() {
            // if the user has manually resized their output, we do nothing
            if (document.getElementById('auto-resize-output').checked) {
                // resize it automagically up to 500px
                if (oelt.scrollHeight < MAX_OELT_HEIGHT) {
                    oelt.style.height = String(oelt.scrollHeight) + 'px';
                }
                else {
                    oelt.style.height = String(MAX_OELT_HEIGHT) + 'px';
                }
            }
        }
        function auto_scroll_to_bottom() {
            if (document.getElementById('auto-scroll').checked) {
                // scroll to bottom
                oelt.scrollTop = oelt.scrollHeight;
            }
        }
        async function on_server_return(response) {
            console.log('on_server_return:', response);
            if (response.ok) {
                let jsbs = await response.json();
                console.log('jsbs', jsbs);
                // jsbs: {ok: true, result: string} | {ok: false, error: string}
                if (jsbs.ok) {
                    // this means got a result back from server
                    // put it in
                    oelt.value += jsbs.result;
                    oelt.value += '\n';
                }
                else {
                    // this is an error at the WFC level
                    oelt.value += jsbs.error;
                    oelt.value += '\n';
                }
            }
            // this means we sent an invalid request
            else {
                oelt.value += 'HTTP ERROR, SEE BROWSER CONSOLE\n'
            }
        }
        function on_some_bullshit(x) {
            console.log('on_some_bullshit:', x);
            oelt.value += 'NETWORK ERROR, SEE BROWSER CONSOLE\n'
        }
        function fetch_wfcin(user_line) {
            let req_body_obj = {wfcin: user_line};
            // let req_body_str = JSON.stringify(req_body_obj, undefined, 4);
            let req_body_str = JSON.stringify(req_body_obj);
            let req_options  = {method:  'POST',
                                headers: {'content-type': 'application/json'},
                                body:    req_body_str};
            let response_promise = fetch('/wfcin', req_options);
            response_promise.then(on_server_return, on_some_bullshit);
            // this is a promise for a response
            //console.log(response_promise);
        }
        // when user hits any key
        function on_input_key(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = ielt.value;
                // if contents are nonempty
                let nonempty_contents = contents.trim().length > 0;
                if (nonempty_contents) {
                    // put in output
                    // // if it's nonempty add a newline
                    // if (oelt.value.length > 0) {
                    //     oelt.value += '\n';
                    // }
                    oelt.value += '> ' + contents + '\n';
                    oelt.hidden = false;
                    // query backend for result
                    fetch_wfcin(contents.trim());
                    // clear input
                    ielt.value = '';
                    // auto-resize
                    auto_resize_output();
                    auto_scroll_to_bottom();
                }
            }
        }
        function main() {
            ielt.addEventListener('keydown', on_input_key);
        }
        main();
    </script>
 </body>
 </html>
@@ -0,0 +1,56 @@
        /* header */
        div#header {
            background:     var(--lgray2);
            height:         50px;
            width:          100%;
        }
        img#header-logo {
            height:         40px;
            margin-top:     5px;
            margin-bottom:  5px;
            margin-left:    5px;
        }
 .main {
    padding-top: 20px;
 }
 .content-diagram {
    max-width: 100%;
    margin:    0 auto;
    padding:   0 auto;
 }
 /* Pandoc makes some wacky choices with how it lays out code blocks
 *
 * this means all <code> blocks that do not have a <pre> block as an ancestor
 *
 * ie the `inline code`
 */
 code:not(pre *) {
    border-radius:  6px;
    border:         1px solid var(--lgray1);
    padding-left:   3px;
    padding-right:  3px;
    padding-top:    1px;
    padding-bottom: 1px;
    background:     var(--lgreen1);
 }
 /* this is specifically for ```fenced blocks``` */
 pre {
    border-radius:  6px;
    border:         1px solid var(--lgray1);
    padding:        5px;
    background:     var(--lgreen1);
    overflow:       scroll;
 }
 /* All `unfenced` or ```fenced``` blocks */
 code {
    font-family:    Liberation Mono, Roboto Mono, monospace;
    color:          var(--dgreen1);
 }
@@ -0,0 +1,65 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8">
    <title>Websockets echo test</title>
    <link rel="stylesheet" href="./default.css">
 </head>
 <body>
    <div class="content">
        <h1 class="content-title">Websockets echo test</h1>
        <div class="content-body">
            <textarea id="wfc-output"
                      disabled></textarea>
            <input autofocus id="wfc-input"></input>
        </div>
    </div>
    <script>
        let ielt = document.getElementById('wfc-input');
        let oelt = document.getElementById('wfc-output');
        let ws   = new WebSocket("/ws/echo");
        // when user hits any key while typing in ielt
        function on_input_key(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = ielt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(contents.trim());
                    // clear input
                    ielt.value = '';
                    // add to output
                    oelt.value += '> ';
                    oelt.value += trimmed;
                    oelt.value += '\n';
                }
            }
        }
        function main() {
            ielt.addEventListener('keydown', on_input_key);
            ws.onmessage =
                function (msg_evt) {
                    console.log('message from server:', msg_evt);
                    let msg_str = msg_evt.data;
                    oelt.value += '< ';
                    oelt.value += msg_str;
                    oelt.value += '\n';
                };
        }
        main();
    </script>
 </body>
 </html>
@@ -0,0 +1,65 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
    <meta charset="utf-8">
    <title>Websockets echo test</title>
    <link rel="stylesheet" href="./default.css">
 </head>
 <body>
    <div class="content">
        <h1 class="content-title">Websockets echo test</h1>
        <div class="content-body">
            <textarea id="wfc-output"
                      disabled></textarea>
            <input autofocus id="wfc-input"></input>
        </div>
    </div>
    <script>
        let ielt = document.getElementById('wfc-input');
        let oelt = document.getElementById('wfc-output');
        let ws   = new WebSocket("/ws/echo");
        // when user hits any key while typing in ielt
        function on_input_key(evt) {
            if (evt.key === 'Enter') {
                // don't do default thing
                evt.preventDefault();
                // grab contents
                let contents = ielt.value;
                let trimmed = contents.trim();
                // if contents are nonempty
                let nonempty_contents = trimmed.length > 0;
                if (nonempty_contents) {
                    console.log('message to server:', contents.trim());
                    // query backend for result
                    ws.send(contents.trim());
                    // clear input
                    ielt.value = '';
                    // add to output
                    oelt.value += '> ';
                    oelt.value += trimmed;
                    oelt.value += '\n';
                }
            }
        }
        function main() {
            ielt.addEventListener('keydown', on_input_key);
            ws.onmessage =
                function (msg_evt) {
                    console.log('message from server:', msg_evt);
                    let msg_str = msg_evt.data;
                    oelt.value += '< ';
                    oelt.value += msg_str;
                    oelt.value += '\n';
                };
        }
        main();
    </script>
 </body>
 </html>
@@ -0,0 +1,262 @@
 % @doc
 % controller for chat
 -module(fd_chat).
 -vsn("0.1.0").
 -behavior(gen_server).
 -author("Peter Harpending <peterharpending@qpq.swiss>").
 -copyright("Peter Harpending <peterharpending@qpq.swiss>").
 -license("BSD-2-Clause-FreeBSD").
 -export([
    join/1,
    relay/1,
    nick_available/1
 ]).
 -export([start_link/0]).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
         code_change/3, terminate/2]).
 -include("$zx_include/zx_logger.hrl").
 -record(o, {pid  :: pid(),
            nick :: string()}).
 -type orator() :: #o{}.
 -record(s, {orators = [] :: [orator()]}).
 -type state()   :: #s{}.
 %%% Service Interface
 -spec join(Nick) -> Result
    when Nick   :: string(),
         Result :: ok
                 | {error, Reason :: any()}.
 join(Nick) ->
    gen_server:call(?MODULE, {join, Nick}).
 -spec nick_available(Nick) -> Result
    when Nick   :: string(),
         Result :: boolean().
 nick_available(Nick) ->
    gen_server:call(?MODULE, {nick_available, Nick}).
 -spec relay(Message) -> ok
    when Message :: string().
 relay(Message) ->
    gen_server:cast(?MODULE, {relay, self(), Message}).
 %%% Startup Functions
 -spec start_link() -> Result
    when Result :: {ok, pid()}
                 | {error, Reason :: term()}.
 %% @private
 %% This should only ever be called by fd_chat_orators (the service-level supervisor).
 start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, none, []).
 -spec init(none) -> {ok, state()}.
 %% @private
 %% Called by the supervisor process to give the process a chance to perform any
 %% preparatory work necessary for proper function.
 init(none) ->
    ok = tell("~p Starting.", [?MODULE]),
    State = #s{},
    {ok, State}.
 %%% gen_server Message Handling Callbacks
 -spec handle_call(Message, From, State) -> Result
    when Message  :: term(),
         From     :: {pid(), reference()},
         State    :: state(),
         Result   :: {reply, Response, NewState}
                   | {noreply, State},
         Response :: term(),
         NewState :: state().
 %% @private
 %% The gen_server:handle_call/3 callback.
 %% See: http://erlang.org/doc/man/gen_server.html#Module:handle_call-3
 handle_call({join, Nick}, {Pid, _}, State) ->
    {Reply, NewState} = do_join(Pid, Nick, State),
    {reply, Reply, NewState};
 handle_call({nick_available, Nick}, _, State = #s{orators = Orators}) ->
    Reply = is_nick_available(Nick, Orators),
    {reply, Reply, State};
 handle_call(Unexpected, From, State) ->
    ok = tell("~p Unexpected call from ~tp: ~tp~n", [?MODULE, From, Unexpected]),
    {noreply, State}.
 -spec handle_cast(Message, State) -> {noreply, NewState}
    when Message  :: term(),
         State    :: state(),
         NewState :: state().
 %% @private
 %% The gen_server:handle_cast/2 callback.
 %% See: http://erlang.org/doc/man/gen_server.html#Module:handle_cast-2
 handle_cast({relay, From, Message}, State = #s{orators = Orators}) ->
    do_relay(From, Message, Orators),
    {noreply, State};
 handle_cast(Unexpected, State) ->
    ok = tell("~p Unexpected cast: ~tp~n", [?MODULE, Unexpected]),
    {noreply, State}.
 -spec handle_info(Message, State) -> {noreply, NewState}
    when Message  :: term(),
         State    :: state(),
         NewState :: state().
 %% @private
 %% The gen_server:handle_info/2 callback.
 %% See: http://erlang.org/doc/man/gen_server.html#Module:handle_info-2
 handle_info(Msg = {'DOWN', _Mon, process, _Pid, _Reason}, State) ->
    NewState = handle_down(Msg, State),
    {noreply, NewState};
 handle_info(Unexpected, State) ->
    ok = tell("~p Unexpected info: ~tp~n", [?MODULE, Unexpected]),
    {noreply, State}.
 %%% OTP Service Functions
 -spec code_change(OldVersion, State, Extra) -> Result
    when OldVersion :: {down, Version} | Version,
         Version    :: term(),
         State      :: state(),
         Extra      :: term(),
         Result     :: {ok, NewState}
                     | {error, Reason :: term()},
         NewState   :: state().
 %% @private
 %% The gen_server:code_change/3 callback.
 %% See: http://erlang.org/doc/man/gen_server.html#Module:code_change-3
 code_change(_, State, _) ->
    {ok, State}.
 -spec terminate(Reason, State) -> no_return()
    when Reason :: normal
                 | shutdown
                 | {shutdown, term()}
                 | term(),
         State  :: state().
 %% @private
 %% The gen_server:terminate/2 callback.
 %% See: http://erlang.org/doc/man/gen_server.html#Module:terminate-2
 terminate(_, _) ->
    ok.
 %%% internals
 -spec do_join(Pid, Nick, State) -> {Reply, NewState}
    when Pid      :: pid(),
         Nick     :: string(),
         Reply    :: ok | {error, Reason :: any()},
         NewState :: State.
 do_join(Pid, Nick, State = #s{orators = Orators}) ->
    case ensure_can_join(Pid, Nick, Orators) of
        ok    -> do_join2(Pid, Nick, State);
        Error -> {Error, State}
    end.
 do_join2(Pid, Nick, State = #s{orators = Orators}) ->
    _Monitor   = erlang:monitor(process, Pid),
    NewOrator  = #o{pid = Pid, nick = Nick},
    NewOrators = [NewOrator | Orators],
    NewState   = State#s{orators = NewOrators},
    {ok, NewState}.
 -spec ensure_can_join(Pid, Nick, Orators) -> Result
    when Pid     :: pid(),
         Nick    :: string(),
         Orators :: [orator()],
         Result  :: ok
                  | {error, Reason},
         Reason  :: any().
 % @private
 % ensures both Pid and Nick are unique
 ensure_can_join(Pid, _   , [#o{pid  = Pid}  | _   ]) -> {error, already_joined};
 ensure_can_join(_  , Nick, [#o{nick = Nick} | _   ]) -> {error, {nick_taken, Nick}};
 ensure_can_join(Pid, Nick, [_               | Rest]) -> ensure_can_join(Pid, Nick, Rest);
 ensure_can_join(_  , _   , []                      ) -> ok.
 -spec is_nick_available(Nick, Orators) -> boolean()
    when Nick    :: string(),
         Orators :: [orator()].
 is_nick_available(Nick, [#o{nick = Nick} | _   ]) -> false;
 is_nick_available(Nick, [_               | Rest]) -> is_nick_available(Nick, Rest);
 is_nick_available(_   , []                      ) -> true.
 -spec handle_down(Msg, State) -> NewState
    when Msg      :: {'DOWN', Mon, process, Pid, Reason},
         Mon      :: erlang:monitor(),
         Pid      :: pid(),
         Reason   :: any(),
         State    :: state(),
         NewState :: State.
 handle_down(Msg = {'DOWN', _, process, Pid, _}, State = #s{orators = Orators}) ->
    NewOrators = hdn(Msg, Pid, Orators, []),
    NewState = State#s{orators = NewOrators},
    NewState.
 % encountered item, removing
 hdn(_,   Pid, [#o{pid = Pid} | Rest], Acc) -> Rest ++ Acc;
 hdn(Msg, Pid, [Skip          | Rest], Acc) -> hdn(Msg, Pid, Rest, [Skip | Acc]);
 hdn(Msg, _,   []                    , Acc) ->
    log("~tp: Unexpected message: ~tp", [?MODULE, Msg]),
    Acc.
 do_relay(Pid, Message, Orators) ->
    case lists:keyfind(Pid, #o.pid, Orators) of
        #o{nick = Nick} ->
            do_relay2(Nick, Message, Orators);
        false ->
            tell("~tp: Message received from outsider ~tp: ~tp", [?MODULE, Pid, Message]),
            error
    end.
 % skip
 do_relay2(Nick, Msg, [#o{nick = Nick} | Rest]) ->
    do_relay2(Nick, Msg, Rest);
 do_relay2(Nick, Msg, [#o{pid = Pid} | Rest]) ->
    Pid ! {chat, {relay, Nick, Msg}},
    do_relay2(Nick, Msg, Rest);
 do_relay2(_, _, []) ->
    ok.
@@ -222,11 +222,14 @@ handle_request(Sock, R = #request{method = M, path = P}) when M =/= undefined, P
    route(Sock, M, P, R).
-route(Sock, get, Route, _Request) ->
+route(Sock, get, Route, Request) ->
    case Route of
-         <<"/">>            -> home(Sock);
+         <<"/">>                   -> home(Sock);
-         <<"/default.css">> -> default_css(Sock);
+         <<"/default.css">>        -> default_css(Sock);
-         _                  -> http_err(Sock, 404)
+         <<"/chat.html">>          -> chat_html(Sock);
         <<"/ws-test-echo.html">>  -> ws_test_echo_html(Sock);
         <<"/ws/echo">>            -> ws_echo(Sock, Request);
         _                         -> http_err(Sock, 404)
    end;
 route(Sock, post, Route, Request) ->
    case Route of
@@ -237,6 +240,46 @@ route(Sock, _, _, _) ->
    http_err(Sock, 404).
 ws_echo(Sock, Request) ->
    try
        ws_echo2(Sock, Request)
    catch
        X:Y:Z ->
            tell(error, "CRASH ws_echo: ~tp:~tp:~tp", [X, Y, Z]),
            http_err(Sock, 500)
    end.
 ws_echo2(Sock, Request) ->
    tell("~p: ws_echo request: ~tp", [?LINE, Request]),
    case fd_ws:handshake(Request) of
        {ok, Response} ->
            tell("~p: ws_echo response: ~tp", [?LINE, Response]),
            respond(Sock, Response),
            tell("~p: ws_echo: entering loop", [?LINE]),
            ws_echo_loop(Sock);
        Error ->
            tell("ws_echo: error: ~tp", [Error]),
            http_err(Sock, 400)
    end.
 ws_echo_loop(Sock) ->
    ws_echo_loop(Sock, [], <<>>).
 ws_echo_loop(Sock, Frames, Received) ->
    tell("~p: ws_echo_loop: entering loop", [?LINE]),
    case fd_ws:recv(Sock, Received, 5*fd_ws:min(), Frames) of
        Result = {ok, Message, NewFrames, NewReceived} ->
            tell("~p: ws_echo_loop ok: ~tp", [?LINE, Result]),
            % send the same message back
            ok = fd_ws:send(Sock, Message),
            ws_echo_loop(Sock, NewFrames, NewReceived);
        Error ->
            tell("ws_echo_loop: error: ~tp", [Error]),
            fd_ws:send(Sock, {close, <<>>}),
            error(Error)
    end.
 home(Sock) ->
    %% fixme: cache
    Path_IH = filename:join([zx:get_home(), "priv", "index.html"]),
@@ -263,6 +306,32 @@ default_css(Sock) ->
            http_err(Sock, 500)
    end.
 ws_test_echo_html(Sock) ->
    %% fixme: cache
    Path_IH = filename:join([zx:get_home(), "priv", "ws-test-echo.html"]),
    case file:read_file(Path_IH) of
        {ok, Body} ->
            Resp = #response{headers = [{"content-type", "text/html"}],
                             body    = Body},
            respond(Sock, Resp);
        Error ->
            io:format("~p error: ~p~n", [self(), Error]),
            http_err(Sock, 500)
    end.
 chat_html(Sock) ->
    %% fixme: cache
    Path_IH = filename:join([zx:get_home(), "priv", "chat.html"]),
    case file:read_file(Path_IH) of
        {ok, Body} ->
            Resp = #response{headers = [{"content-type", "text/html"}],
                             body    = Body},
            respond(Sock, Resp);
        Error ->
            io:format("~p error: ~p~n", [self(), Error]),
            http_err(Sock, 500)
    end.
 wfcin(Sock, #request{enctype = json,
                     cookies = Cookies,
                     body = #{"wfcin" := Input}}) ->
@@ -0,0 +1,125 @@
 % @doc static file cache
 -module(fd_static_cache).
 -behavior(gen_server).
 -export([
    start_link/0,
    query/1, set/2, unset/1,
    %%---
    %% everything below here runs in process context
    %%--
    %% gen_server callbacks
    init/1, handle_call/3, handle_cast/2, handle_info/2,
    code_change/3, terminate/2
 ]).
 -include("$zx_include/zx_logger.hrl").
 -record(f, {http_path     :: binary(),
            fs_path       :: file:filename(),
            last_modified :: file:date_time(),
            mime_type     :: string(),
            contents      :: binary()}).
 -type context() :: wfc_eval_context:context().
 -record(s,
        {cookies = #{} :: #{Cookie :: binary() := context()}}).
 % -type state() :: #s{}.
 %%--------------------------------
 %% api (runs in context of caller)
 %%--------------------------------
 -spec start_link() -> {ok, pid()} | {error, term()}.
 start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, none, []).
 -spec query(Cookie) -> {ok, Context} | error
    when Cookie  :: binary(),
         Context :: context().
 query(Cookie) ->
    gen_server:call(?MODULE, {query, Cookie}).
 -spec set(Cookie, Context) -> ok
    when Cookie  :: binary(),
         Context :: context().
 set(Cookie, Context) ->
    gen_server:cast(?MODULE, {set, Cookie, Context}).
 -spec unset(Cookie) -> ok
    when Cookie  :: binary().
 unset(Cookie) ->
    gen_server:cast(?MODULE, {unset, Cookie}).
 %%----------------------
 %% gen-server bs
 %%----------------------
 init(none) ->
    log(info, "starting fd_cache"),
    InitState = #s{},
    {ok, InitState}.
 handle_call({query, Cookie}, _, State) ->
    Result = do_query(Cookie, State),
    {reply, Result, State};
 handle_call(Unexpected, From, State) ->
    tell("~tp: unexpected call from ~tp: ~tp", [?MODULE, Unexpected, From]),
    {noreply, State}.
 handle_cast({set, Cookie, Context}, State) ->
    NewState = do_set(Cookie, Context, State),
    {noreply, NewState};
 handle_cast({unset, Cookie}, State) ->
    NewState = do_unset(Cookie, State),
    {noreply, NewState};
 handle_cast(Unexpected, State) ->
    tell("~tp: unexpected cast: ~tp", [?MODULE, Unexpected]),
    {noreply, State}.
 handle_info(Unexpected, State) ->
    tell("~tp: unexpected info: ~tp", [?MODULE, Unexpected]),
    {noreply, State}.
 code_change(_, State, _) ->
    {ok, State}.
 terminate(_, _) ->
    ok.
 %%---------------------
 %% doers
 %%---------------------
 do_set(Cookie, Context, State = #s{cookies = Cookies}) ->
    NewCookies = maps:put(Cookie, Context, Cookies),
    NewState   = State#s{cookies = NewCookies},
    NewState.
 do_unset(Cookie, State = #s{cookies = Cookies}) ->
    NewCookies = maps:remove(Cookie, Cookies),
    NewState   = State#s{cookies = NewCookies},
    NewState.
 do_query(Cookie, _State = #s{cookies = Cookies}) ->
    maps:find(Cookie, Cookies).
@@ -42,11 +42,17 @@ init([]) ->
                 5000,
                 supervisor,
                 [fd_clients]},
    Chat      = {fd_chat,
                 {fd_chat, start_link, []},
                 permanent,
                 5000,
                 worker,
                 [fd_chat]},
    Cache     = {fd_cache,
                 {fd_cache, start_link, []},
                 permanent,
                 5000,
                 worker,
                 [fd_cache]},
-    Children  = [Clients, Cache],
+    Children  = [Clients, Chat, Cache],
    {ok, {RestartStrategy, Children}}.
@@ -0,0 +1,819 @@
 % @doc websockets
 %
 % ref: https://datatracker.ietf.org/doc/html/rfc6455
 -module(fd_ws).
 -export_type([
    opcode/0,
    frame/0,
    ws_msg/0
 ]).
 -export([
    %% time units
    ms/0, sec/0, min/0, hr/0, day/0,
    %% porcelain
    handshake/1,
    recv/3, recv/4,
    send/2
 ]).
 -include("http.hrl").
 -include("$zx_include/zx_logger.hrl").
 -type request()  :: #request{}.
 -type response() :: #response{}.
 -type tcp_error() :: closed
                   | {timeout, RestData :: binary() | erlang:iovec()}
                   | inet:posix().
 -define(MAX_PAYLOAD_SIZE, ((1 bsl 63) - 1)).
 %% Frames
 %% https://datatracker.ietf.org/doc/html/rfc6455#section-5.2
 -type opcode() :: continuation
                | text
                | binary
                | close
                | ping
                | pong.
 -record(frame,
        {fin            = none :: none | boolean(),
         rsv            = none :: none | <<_:3>>,
         opcode         = none :: none | opcode(),
         mask           = none :: none | boolean(),
         payload_length = none :: none | non_neg_integer(),
         masking_key    = none :: none | <<>> | <<_:32>>,
         payload        = none :: none | binary()}).
 -type frame() :: #frame{}.
 %% porcelain messages
 -type ws_msg() :: {text,   Payload :: iodata()}
                | {binary, Payload :: iodata()}
                | {close,  Payload :: iodata()}
                | {ping,   Payload :: iodata()}
                | {pong,   Payload :: iodata()}.
 %% time units
 ms()  -> 1.
 sec() -> 1_000.
 min() -> 60*sec().
 hr()  -> 60*min().
 day() -> 24*hr().
 -spec handshake(Req) -> Result
    when Req              :: request(),
         Result           :: {ok, ClientProtocols, ClientExtensions, DraftResponse}
                           | {error, Reason},
         ClientProtocols  :: [binary()],
         ClientExtensions :: binary(),
         DraftResponse    :: response(),
         Reason           :: any().
 % @doc
 % This mostly just validates that all the 't's have been dotted and 'i's have
 % been crossed.
 %
 % given an HTTP request:
 %
 % - if it is NOT a valid websocket handshake request, error
 % - if it IS a valid websocket handshake request, form an initial candidate
 %   response record with the following fields:
 %
 %       code    = 101
 %       slogan  = "Switching Protocols"
 %       headers = [{"Sec-WebSocket-Accept", ChallengeResponse},
 %                  {"Connection",           "Upgrade"},
 %                  {"Upgrade",              "websocket"}].
 %
 % YOU are responsible for dealing with any cookie logic, authentication logic,
 % validating the Origin field, implementing cross-site-request-forgery, adding
 % the retarded web date, rendering the response, sending it over the socket,
 % etc.
 %
 % The returned ClientExtensions is the result of joining the
 % <<"sec-websocket-extensions">> fields with ", "
 %
 % quoth section 9.1: https://datatracker.ietf.org/doc/html/rfc6455#section-9.1
 %
 % > Note that like other HTTP header fields, this header field MAY be
 % > split or combined across multiple lines.  Ergo, the following are
 % > equivalent:
 % >
 % >       Sec-WebSocket-Extensions: foo
 % >       Sec-WebSocket-Extensions: bar; baz=2
 % >
 % > is exactly equivalent to
 % >
 % >       Sec-WebSocket-Extensions: foo, bar; baz=2
 %
 % Nobody actually uses extensions, so how you choose to parse this is on you.
 handshake(R = #request{method = get, headers = Hs}) ->
    %% downcase the headers because have to match on them
    handshake2(R#request{headers = casefold_headers(Hs)});
 handshake(_) ->
    {error, bad_method}.
 -spec casefold_headers(Headers) -> DowncaseHeaders
    when Headers         :: #{Key := Value},
         Key             :: binary(),
         Value           :: binary(),
         DowncaseHeaders :: Headers.
 % @private
 % casefold all the keys in the header because they're case insensitive
 casefold_headers(Headers) ->
    Downcase =
        fun({K, V}) ->
            NewKey = unicode:characters_to_binary(string:casefold(K)),
            {NewKey, V}
        end,
    maps:from_list(lists:map(Downcase, maps:to_list(Headers))).
 -spec handshake2(DowncaseReq) -> Result
    when DowncaseReq      :: request(),
         Result           :: {ok, DraftResponse}
                           | {error, Reason},
         DraftResponse    :: response(),
         Reason           :: any().
 % @private
 % we may assume (WMA) method=get and headers have all been downcased
 handshake2(#request{headers = DowncaseHeaders}) ->
    % headers MUST contain fields:
    % sec-websocket-key:     _          % arbitrary
    % sec-websocket-version: 13         % must be EXACTLY 13
    % connection:            Upgrade    % must include the token "Upgrade"
    % upgrade:               websocket  % must include the token "websocket"
    MaybeResponseToken = validate_headers(DowncaseHeaders),
    case MaybeResponseToken of
        {ok, ResponseToken} ->
            DraftResponse =
                 #response{code = 101,
                           slogan = "Switching Protocols",
                           headers = [{"Sec-WebSocket-Accept", ResponseToken},
                                      {"Connection",           "Upgrade"},
                                      {"Upgrade",              "websocket"}]},
            {ok, DraftResponse};
        Error ->
            Error
    end.
 -spec validate_headers(HeadersMap) -> Result
    when HeadersMap    :: #{Key :: binary() := Val :: binary()},
         Result        :: {ok, ResponseToken}
                        | {error, Reason},
         ResponseToken :: binary(),
         Reason        :: any().
 % @private
 % validate:
 %   Upgrade: websocket
 %   Connection: Upgrade
 %   Sec-WebSocket-Version: 13
 validate_headers(#{<<"sec-websocket-key">>     := ChallengeToken,
                   <<"sec-websocket-version">> := WS_Vsn,
                   <<"connection">>            := Connection,
                   <<"upgrade">>               := Upgrade}) ->
    BadUpgrade    = bad_upgrade(Upgrade),
    BadConnection = bad_connection(Connection),
    BadVersion    = bad_version(WS_Vsn),
    if
        BadUpgrade    -> {error, {bad_upgrade, Upgrade}};
        BadConnection -> {error, {bad_connection, Connection}};
        BadVersion    -> {error, {bad_version, WS_Vsn}};
        true          -> {ok, response_token(ChallengeToken)}
    end;
 validate_headers(_) ->
    {error, bad_request}.
 -spec bad_upgrade(binary()) -> true | false.
 % @private string must include "websocket" as a token
 bad_upgrade(Str) ->
    case string:find(Str, "websocket") of
        nomatch -> true;
        _       -> false
    end.
 -spec bad_connection(binary()) -> true | false.
 % @private string must include "Upgrade" as a token
 bad_connection(Str) ->
    case string:find(Str, "Upgrade") of
        nomatch -> true;
        _       -> false
    end.
 -spec bad_version(binary()) -> true | false.
 % @private version must be EXACTLY <<"13">>
 bad_version(<<"13">>) -> false;
 bad_version(_)        -> true.
 -spec response_token(binary()) -> binary().
 % @doc
 % Quoth the RFC:
 %
 % >    Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 % >
 % > For this header field, the server has to take the value (as present
 % > in the header field, e.g., the base64-encoded [RFC4648] version minus
 % > any leading and trailing whitespace) and concatenate this with the
 % > Globally Unique Identifier (GUID, [RFC4122]) "258EAFA5-E914-47DA-
 % > 95CA-C5AB0DC85B11" in string form, which is unlikely to be used by
 % > network endpoints that do not understand the WebSocket Protocol.  A
 % > SHA-1 hash (160 bits) [FIPS.180-3], base64-encoded (see Section 4 of
 % > [RFC4648]), of this concatenation is then returned in the server's
 % > handshake.
 % >
 % >  Concretely, if as in the example above, the |Sec-WebSocket-Key|
 % >  header field had the value "dGhlIHNhbXBsZSBub25jZQ==", the server
 % >  would concatenate the string "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
 % >  to form the string "dGhlIHNhbXBsZSBub25jZQ==258EAFA5-E914-47DA-95CA-
 % >  C5AB0DC85B11".  The server would then take the SHA-1 hash of this,
 % >  giving the value 0xb3 0x7a 0x4f 0x2c 0xc0 0x62 0x4f 0x16 0x90 0xf6
 % >  0x46 0x06 0xcf 0x38 0x59 0x45 0xb2 0xbe 0xc4 0xea.  This value is
 % >  then base64-encoded (see Section 4 of [RFC4648]), to give the value
 % >  "s3pPLMBiTxaQ9kYGzzhZRbK+xOo=".  This value would then be echoed in
 % >  the |Sec-WebSocket-Accept| header field.
 response_token(ChallengeToken) when is_binary(ChallengeToken) ->
    MagicString  = <<"258EAFA5-E914-47DA-95CA-C5AB0DC85B11">>,
    ConcatString = <<ChallengeToken/binary, MagicString/binary>>,
    Sha1         = crypto:hash(sha, ConcatString),
    base64:encode(Sha1).
 -spec recv(Socket, Received, TimeoutMS) -> Result
    when Socket    :: gen_tcp:socket(),
         Received  :: binary(),
         TimeoutMS :: non_neg_integer(),
         Result    :: {ok, Message, Frames, Remainder}
                    | {error, Reason},
         Message   :: ws_msg(),
         Frames    :: [frame()],
         Remainder :: binary(),
         Reason    :: any().
 % @doc
 % Equivalent to recv(Socket, Received, [])
 recv(Sock, Recv, TimeoutMS) ->
    recv(Sock, Recv, TimeoutMS, []).
 -spec recv(Socket, Received, TimeoutMS, Frames) -> Result
    when Socket    :: gen_tcp:socket(),
         Received  :: binary(),
         TimeoutMS :: non_neg_integer(),
         Frames    :: [frame()],
         Result    :: {ok, Message, NewFrames, Remainder}
                    | {error, Reason},
         Message   :: ws_msg(),
         NewFrames :: Frames,
         Remainder :: binary(),
         Reason    :: any().
 % @doc
 % Pull a message off the socket
 recv(Sock, Received, Timeout, Frames) ->
    case maybe_pop_msg(Frames) of
        {ok, Message, NewFrames} ->
            {ok, Message, NewFrames, Received};
        incomplete ->
            case recv_frame(#frame{}, Sock, Received, Timeout) of
                {ok, Frame, NewReceived} ->
                    NewFrames = [Frame | Frames],
                    recv(Sock, NewReceived, Timeout, NewFrames);
                Error ->
                    Error
            end;
        Error ->
            Error
    end.
 -spec maybe_pop_msg(Frames) -> Result
    when Frames    :: [frame()],
         Result    :: {ok, Message, NewFrames}
                    | incomplete
                    | {error, Reason},
         Message   :: ws_msg(),
         NewFrames :: Frames,
         Reason    :: any().
 % @private
 % try to parse the stack of frames into a single message
 %
 % ignores RSV bits
 % @end
 maybe_pop_msg([]) ->
    incomplete;
 % case 1: control frames
 % note that maybe_control_msg checks that the fin bit is true
 %
 % meaning if the client sends a malicious control frame with fin=false, that
 % error will be caught in maybe_control_msg
 maybe_pop_msg([Frame = #frame{opcode = ControlOpcode} | Frames])
        when (ControlOpcode =:= close)
             orelse (ControlOpcode =:= ping)
             orelse (ControlOpcode =:= pong) ->
    case maybe_control_msg(Frame) of
        {ok, Msg} -> {ok, Msg, Frames};
        Error     -> Error
    end;
 % case 2: messages
 % finished message in a single frame, just pull here
 maybe_pop_msg([Frame = #frame{fin         = true,
                              opcode      = DataOpcode,
                              mask        = Mask,
                              masking_key = Key,
                              payload     = Payload}
              | Rest])
        when DataOpcode =:= text; DataOpcode =:= binary ->
    case maybe_unmask(Frame, Mask, Key, Payload) of
        {ok, Unmasked} ->
            Message = {DataOpcode, Unmasked},
            {ok, Message, Rest};
        Error ->
            Error
    end;
 % end of a long message
 maybe_pop_msg(Frames = [#frame{fin    = true,
                               opcode = continuation} | _]) ->
    maybe_long_data_msg(Frames);
 % unfinished message, say we need more
 maybe_pop_msg([#frame{fin    = false,
                      opcode = continuation}
               | _]) ->
    incomplete;
 % wtf... this case should be impossible
 maybe_pop_msg([Frame | _]) ->
    {error, {wtf_frame, Frame}}.
 -spec maybe_long_data_msg(Frames) -> Result
    when Frames    :: [frame()],
         Result    :: {ok, Message, NewFrames}
                    | {error, Reason},
         Message   :: ws_msg(),
         NewFrames :: Frames,
         Reason    :: any().
 % @private
 % assumes:
 % 1. top of stack is a finished frame
 % 2. top opcode is continuation
 % 3. the stack corresponds to a linear sequence of frames all corresponding to
 %    one message, until we get to the leading frame of the message, which must
 %    have opcode text|binary
 %
 %    the reason we can make this assumption is because anterior in the call
 %    chain is recv/3, which eagerly consumes control messages
 %
 %    meaning if we encounter a control frame in the middle here, we can assume
 %    there is some sort of bug
 %
 % TODO: I am NOT enforcing that the data message consumes the entire stack of
 % frames. Given that the context here is eager consumption, this might be a
 % point of enforcement. Need to think about this.
 % @end
 maybe_long_data_msg(Frames) ->
    mldm(Frames, Frames, <<>>).
 % general case: decode the payload in this frame
 mldm(OrigFrames, [Frame | Rest], Acc) ->
    Opcode  = Frame#frame.opcode,
    Mask    = Frame#frame.mask,
    Key     = Frame#frame.masking_key,
    Payload = Frame#frame.payload,
    case maybe_unmask(Frame, Mask, Key, Payload) of
        {ok, Unmasked} ->
            NewAcc = <<Unmasked/binary, Acc/binary>>,
            case Opcode of
                continuation -> mldm(OrigFrames, Rest, NewAcc);
                text         -> {ok, {text, NewAcc}, Rest};
                binary       -> {ok, {binary, NewAcc}, Rest};
                _            -> {error, {illegal_data_frame, Frame, OrigFrames, Acc}}
            end;
        Error ->
            Error
    end;
 % out of frames
 mldm(OrigFrames, [], Acc) ->
    {error, {no_start_frame, Acc, OrigFrames}}.
 -spec maybe_control_msg(Frame) -> Result
    when Frame   :: frame(),
         Result  :: {ok, Message}
                  | {error, Reason},
         Message :: ws_msg(),
         Reason  :: any().
 % @private
 % assume the frame is a control frame, validate it, and unmask the payload
 %
 % TODO: this doesn't enforce that messages from the client HAVE to be masked,
 % which strictly speaking is part of the protocol.
 maybe_control_msg(F = #frame{fin            = true,
                             opcode         = Opcode,
                             mask           = Mask,
                             payload_length = Len,
                             masking_key    = Key,
                             payload        = Payload})
        when ((Opcode =:= close) orelse (Opcode =:= ping) orelse (Opcode =:= pong))
             andalso (Len =< 125) ->
    case maybe_unmask(F, Mask, Key, Payload) of
        {ok, UnmaskedPayload} ->
            Msg = {Opcode, UnmaskedPayload},
            {ok, Msg};
        Error ->
            Error
    end;
 maybe_control_msg(F) ->
    {error, {illegal_frame, F}}.
 -spec maybe_unmask(Frame, Mask, Key, Payload) -> Result
    when Frame    :: frame(),
         Mask     :: boolean(),
         Key      :: <<>> | <<_:32>>,
         Payload  :: binary(),
         Result   :: {ok, Unmasked}
                   | {error, Reason},
         Unmasked :: binary(),
         Reason   :: any().
 % @private
 % unmask the payload
 % @end
 % eliminate invalid pairs of {mask, masking_key}
 maybe_unmask(_, true,  <<Key:4/bytes>>, Payload) -> {ok, mask_unmask(Key, Payload)};
 maybe_unmask(_, false, <<>>,            Payload) -> {ok, Payload};
 maybe_unmask(F, true,  <<>>,            _)       -> {error, {illegal_frame, F}};
 maybe_unmask(F, false, <<_:4/bytes>>,   _)       -> {error, {illegal_frame, F}}.
 %% invertible
 %% see: https://datatracker.ietf.org/doc/html/rfc6455#section-5.3
 mask_unmask(Key = <<_:4/bytes>>, Payload) ->
    mu(Key, Key, Payload, <<>>).
 % essentially this is a modular zipWith xor of the masking key with the payload
 mu(Key, <<KeyByte:8, KeyRest/binary>>, <<PayloadByte:8, PayloadRest/binary>>, Acc) ->
    NewByte = KeyByte bxor PayloadByte,
    NewAcc  = <<Acc/binary, NewByte:8>>,
    mu(Key, KeyRest, PayloadRest, NewAcc);
 % this is the case where we need to refresh the active key
 mu(Key, <<>>, Payload, Acc) ->
    mu(Key, Key, Payload, Acc);
 % done
 mu(_, _, <<>>, Acc) ->
    Acc.
 -spec recv_frame(Parsed, Socket, Received, TimeoutMS) -> Result
    when Parsed    :: frame(),
         Socket    :: gen_tcp:socket(),
         Received  :: bitstring(),
         TimeoutMS :: non_neg_integer(),
         Result    :: {ok, frame(), Remainder}
                    | {error, Reason},
         Remainder :: bitstring(),
         Reason    :: any().
 % @private
 % parse a single frame off the socket
 % @end
 %% frame: 1 bit
 recv_frame(Frame = #frame{fin = none}, Sock, <<FinBit:1, Rest/bits>>, Timeout) ->
    NewFin =
        case FinBit of
            0 -> false;
            1 -> true
        end,
    NewFrame = Frame#frame{fin = NewFin},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 recv_frame(Frame = #frame{fin = none}, Sock, Received = <<>>, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% rsv: 3 bits
 recv_frame(Frame = #frame{rsv = none}, Sock, <<RSV:3/bits, Rest/bits>>, Timeout) ->
    NewFrame = Frame#frame{rsv = RSV},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 recv_frame(Frame = #frame{rsv = none}, Sock, Received, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% opcode: 4 bits
 recv_frame(Frame = #frame{opcode = none}, Sock, <<OpcodeInt:4, Rest/bits>>, Timeout) ->
    Opcode =
        case OpcodeInt of
            0  -> continuation;
            1  -> text;
            2  -> binary;
            8  -> close;
            9  -> ping;
            10 -> pong;
            _  -> bad_opcode
        end,
    case Opcode of
        bad_opcode ->
            {error, {bad_opcode, OpcodeInt}};
        _ ->
            NewFrame = Frame#frame{opcode = Opcode},
            recv_frame(NewFrame, Sock, Rest, Timeout)
    end;
 recv_frame(Frame = #frame{opcode = none}, Sock, Received, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% mask: 1 bit
 recv_frame(Frame = #frame{mask = none}, Sock, <<MaskBit:1, Rest/bits>>, Timeout) ->
    NewMask =
        case MaskBit of
            0 -> false;
            1 -> true
        end,
    NewFrame = Frame#frame{mask = NewMask},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 recv_frame(Frame = #frame{mask = none}, Sock, Received = <<>>, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% payload length: variable (yay)
 % first case: short length 0..125
 recv_frame(Frame = #frame{payload_length = none}, Sock, <<Len:7, Rest/bits>>, Timeout) when Len =< 125 ->
    NewFrame = Frame#frame{payload_length = Len},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 % second case: 126 -> 2 bytes to follow
 recv_frame(Frame = #frame{payload_length = none}, Sock, <<126:7, Len:16, Rest/bits>>, Timeout) ->
    NewFrame = Frame#frame{payload_length = Len},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 % third case: 127 -> 8 bytes to follow
 % bytes must start with a 0 bit
 recv_frame(_Frame = #frame{payload_length = none}, _Sock, <<127:7, 1:1, _/bits>>, _Timeout) ->
    {error, {illegal_frame, "payload length >= 1 bsl 63"}};
 % 127, next is a legal length, continue
 recv_frame(Frame = #frame{payload_length = none}, Sock, <<127:7, Len:64, Rest/bits>>, Timeout) ->
    NewFrame = Frame#frame{payload_length = Len},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 % otherwise wait
 recv_frame(Frame = #frame{payload_length = none}, Sock, Received, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% masking key: 0 or 4 bits
 % not expecting a masking key, fill in that field here
 recv_frame(Frame = #frame{mask = false, masking_key = none}, Sock, Received, Timeout) ->
    NewFrame = Frame#frame{masking_key = <<>>},
    recv_frame(NewFrame, Sock, Received, Timeout);
 % expecting one
 recv_frame(Frame = #frame{mask = true, masking_key = none}, Sock, <<Key:4/bytes, Rest/bits>>, Timeout) ->
    NewFrame = Frame#frame{masking_key = Key},
    recv_frame(NewFrame, Sock, Rest, Timeout);
 % not found
 recv_frame(Frame = #frame{mask = true, masking_key = none}, Sock, Received, Timeout) ->
    recv_frame_await(Frame, Sock, Received, Timeout);
 %% payload
 recv_frame(Frame = #frame{payload_length = Len, payload = none}, Sock, Received, Timeout) when is_integer(Len) ->
    case Received of
        % we have enough bytes
        <<Payload:Len/bytes, Rest/bits>> ->
            FinalFrame = Frame#frame{payload = Payload},
            {ok, FinalFrame, Rest};
        % we do not have enough bytes
        _ ->
            recv_frame_await(Frame, Sock, Received, Timeout)
    end.
 %% factoring this out into a function to reduce repetition
 recv_frame_await(Frame, Sock, Received, Timeout) ->
    case inet:setopts(Sock, [{active, once}]) of
        ok ->
            receive
                {tcp, Sock, Bin}          -> recv_frame(Frame, Sock, <<Received/bits, Bin/binary>>, Timeout);
                {tcp_closed, Sock}        -> {error, tcp_closed};
                {tcp_error, Sock, Reason} -> {error, {tcp_error, Reason}}
            after Timeout ->
                {error, timeout}
            end;
        {error, Reason} ->
            {error, {inet, Reason}}
    end.
 -spec send(Socket, Message) -> Result
    when Socket  :: gen_tcp:socket(),
         Message :: ws_msg(),
         Result  :: ok
                  | {error, Reason},
         Reason  :: any().
 % @doc
 % send message to client over Socket. handles frame nonsense
 %
 % max payload size is 2^63 - 1 bytes
 % @end
 send(Socket, {Type, Payload}) ->
    tell("fd_ws: send(~tp, {~tp, ~tp})", [Socket, Type, Payload]),
    BPayload = payload_to_binary(Payload),
    tell("fd_ws: BPayload = ~tp", [BPayload]),
    Frame = message_to_frame(Type, BPayload),
    tell("fd_ws: Frame = ~tp", [Frame]),
    send_frame(Socket, Frame).
 payload_to_binary(Bin) when is_binary(Bin) -> Bin;
 payload_to_binary(X)                       -> unicode:characters_to_binary(X).
 % data messages
 message_to_frame(Data, Payload)
        when ((Data =:= text) orelse (Data =:= binary)),
             is_binary(Payload),
             (byte_size(Payload) =< ?MAX_PAYLOAD_SIZE) ->
    #frame{fin            = true,
           opcode         = Data,
           payload_length = byte_size(Payload),
           payload        = Payload};
 message_to_frame(Control, Payload)
        when ((Control =:= close) orelse (Control =:= ping) orelse (Control =:= pong)),
             is_binary(Payload),
             (byte_size(Payload) =< 125) ->
    #frame{fin            = true,
           opcode         = Control,
           payload_length = byte_size(Payload),
           payload        = Payload}.
 -spec send_frame(Sock, Frame) -> Result
    when Sock     :: gen_tcp:socket(),
         Frame    :: frame(),
         Result   :: ok
                   | {error, Reason},
         Reason   :: tcp_error().
 % @private
 % send a frame on the socket
 % @end
 send_frame(Sock, Frame) ->
    Binary = render_frame(Frame),
    tell("send_frame: rendered frame: ~tp", [Binary]),
    gen_tcp:send(Sock, Binary).
 -spec render_frame(Frame) -> Binary
    when Frame  :: frame(),
         Binary :: binary().
 % @private
 % render a frame
 %
 % All fields in a `#frame{}` record have default values of `none`.
 %
 % ```erlang
 % -record(frame,
 %         {fin            = none :: none | boolean(),
 %          rsv            = none :: none | <<_:3>>,
 %          opcode         = none :: none | opcode(),
 %          mask           = none :: none | boolean(),
 %          payload_length = none :: none | non_neg_integer(),
 %          masking_key    = none :: none | <<>> | <<_:32>>,
 %          payload        = none :: none | binary()}).
 % ```
 %
 % Given a value of `none`, some of these fields are inferred, some cannot be
 % inferred.
 %
 % Inference cases:
 %
 % ```
 % rsv            = none     -> <<0:3>>
 % mask           = none     -> false
 % masking_key    = none     -> <<>>
 % payload_length = none     -> byte_size(Payload)
 % ```
 %
 % Non-inference:
 %
 % ```
 % fin
 % opcode
 % payload
 % ```
 % @end
 render_frame(#frame{fin            = Fin,
                    rsv            = RSV,
                    opcode         = Opcode,
                    mask           = Mask,
                    payload_length = Len,
                    masking_key    = MaskingKey,
                    payload        = Payload}) ->
    BFin =
        case Fin of
            true  -> <<1:1>>;
            false -> <<0:1>>
        end,
    BRSV =
        case RSV of
            none    -> <<0:3>>;
            <<_:3>> -> RSV;
            _       -> error({illegal_rsv, RSV})
        end,
    BOpcode =
        case Opcode of
            continuation -> << 0:4>>;
            text         -> << 1:4>>;
            binary       -> << 2:4>>;
            close        -> << 8:4>>;
            ping         -> << 9:4>>;
            pong         -> <<10:4>>
        end,
    BoolMask =
        case Mask of
            none  -> false;
            false -> false;
            true  -> true
        end,
    BMask =
        case BoolMask of
            true  -> <<1:1>>;
            false -> <<0:1>>
        end,
    IntPayloadLength =
        case Len of
            none -> byte_size(Payload);
            _    -> Len
        end,
    BPayloadLength = render_payload_length(IntPayloadLength),
    BMaskingKey =
        case {BoolMask, MaskingKey} of
            {false, none}             -> <<>>;
            {false, <<>>}             -> <<>>;
            {true,  <<BKey:4/bytes>>} -> BKey;
            {false, _}                -> error({not_masking_but_have_masking_key, {Mask, MaskingKey}});
            {true,  _}                -> error({illegal_masking_key, MaskingKey})
        end,
    % failure case here is same as error case just above, so no need to worry
    % about cryptic "illegal frame" message
    %
    % masking = unmasking, so `maybe_unmask` is a bit of a misnomer
    {ok, BPayload} = maybe_unmask(#frame{}, BoolMask, BMaskingKey, Payload),
    <<BFin/bits,
      BRSV/bits,
      BOpcode/bits,
      BMask/bits,
      BPayloadLength/bits,
      BMaskingKey/binary,
      BPayload/binary>>.
 -spec render_payload_length(non_neg_integer()) -> binary().
 % @private
 % > Payload length:  7 bits, 7+16 bits, or 7+64 bits
 % >
 % >    The length of the "Payload data", in bytes: if 0-125, that is the
 % >    payload length.  If 126, the following 2 bytes interpreted as a
 % >    16-bit unsigned integer are the payload length.  If 127, the
 % >    following 8 bytes interpreted as a 64-bit unsigned integer (the
 % >    most significant bit MUST be 0) are the payload length.  Multibyte
 % >    length quantities are expressed in network byte order.  Note that
 % >    in all cases, the minimal number of bytes MUST be used to encode
 % >    the length, for example, the length of a 124-byte-long string
 % >    can't be encoded as the sequence 126, 0, 124.  The payload length
 % >    is the length of the "Extension data" + the length of the
 % >    "Application data".  The length of the "Extension data" may be
 % >    zero, in which case the payload length is the length of the
 % >    "Application data".
 render_payload_length(Len) when 0 =< Len, Len =< 125 ->
    <<Len:7>>;
 render_payload_length(Len) when 126 =< Len, Len =< 2#1111_1111_1111_1111 ->
    <<126:7, Len:16>>;
 render_payload_length(Len) when (1 bsl 16) =< Len, Len =< ?MAX_PAYLOAD_SIZE ->
    <<127:7, Len:64>>.
Author	SHA1	Message	Date
pharpend	2151fff0fa	wip on static cache	2025-10-21 22:38:48 -07:00
pharpend	73fc38b7ad	begin static file caching	2025-10-21 22:20:24 -07:00
pharpend	a0418788c5	the shed biketh	2025-10-21 22:16:58 -07:00
pharpend	cb600dc0da	starting chat service	2025-10-21 22:09:04 -07:00
pharpend	027c020a34	begin to add chat function	2025-10-21 21:06:35 -07:00
Peter Harpending	079c47962a	websockets work	2025-10-21 17:12:59 -07:00
Peter Harpending	7ed8b12c4e	painting bike shed	2025-10-21 14:55:51 -07:00
Peter Harpending	4509a328a8	fix type error	2025-10-21 13:22:37 -07:00
Peter Harpending	04970142aa	painting the bike shed	2025-10-21 12:37:33 -07:00
Peter Harpending	b44292a790	websockets I think are done	2025-10-21 12:28:45 -07:00
Peter Harpending	1865f03085	Almost done... have to fix send and then of course test it there will be no bugs, right?	2025-10-21 12:10:28 -07:00
Peter Harpending	5824aaaf36	continuing with websockets am now working on popping messages off the frame stack	2025-10-21 11:17:27 -07:00
Peter Harpending	35dbf06a55	wip: websocket frame parsing	2025-10-20 22:07:53 -07:00
Peter Harpending	62d0710fcf	committing brain-damaged websocket extensions bs this is just retarded, i'm just going to ignore	2025-10-20 20:02:02 -07:00
Peter Harpending	9107679dfc	start websocket stuff	2025-10-20 15:43:52 -07:00