add structure for `Oracles' (special answers depending on queries + a few implementations (#10)

incl. a calculator, a hash encoder + rot13 and b64!, and a "what time is it" with timezone selection

frontend injected in $payload["left"] in web.php

you can see this live [on my instance](https://4get.silly.computer/web?s=7%2B8(9%5E2)&scraper=brave&nsfw=yes) (there are some issues that aren't related to this PR. favicons, etc. I'll fix them later.)

Reviewed-on: #10
Co-authored-by: cynic <admin@cynic.moe>
Co-committed-by: cynic <admin@cynic.moe>
This commit is contained in:
cynic 2023-09-13 22:24:02 -05:00 committed by lolcat
parent d312674df7
commit 8762d68466
6 changed files with 349 additions and 0 deletions

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oracles/base.php Normal file
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<?php
abstract class oracle {
// some info to spit out alongside the result, so the user knows
// what exactly is giving out the answer. prevents confusion
// about what oracle is answering them for ambiguous queries.
public $info = [
"name" => "some oracle"
];
// this function should take in a query string search from $_GET,
// and return a bool determining whether or not it is a question
// intended for the oracle.
public function check_query($q) {
return false;
}
// produce the correct answer for the query using the oracle.
// note: if it becomes apparent /during generation/ that the
// query is not in fact for the oracle, returning an empty
// string will kill the oracle pane.
// answer format: ["ans1 title" => "ans1", ...]
public function generate_response($q) {
return "";
}
}
?>

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<?php
include_once("oracles/base.php");
class calculator extends oracle {
public $info = [
"name" => "calculator"
];
public function check_query($q) {
// straight numerics should go to that oracle
if (is_numeric($q)) {
return false;
}
// all chars should be number-y or operator-y
$char_whitelist = str_split("1234567890.+-/*^%() ");
foreach (str_split($q) as $char) {
if (!in_array($char, $char_whitelist)) {
return false;
}
}
return true;
}
// a custom parser and calculator because FUCK YUO, libraries are
// gay.
public function generate_response($q)
{
$nums = str_split("1234567890.");
$ops = str_split("+-/*^%;");
$grouping = str_split("()");
$q = str_replace(" ", "", $q);
// backstop for the parser so it catches the last
// numeric token
$q .= ";";
// the following comments refer to this example input:
// 21+9*(3+2^9)+1
// 2-length lists of the following patterns:
// ["n" (umeric), <some number>]
// ["o" (perator), "<some operator>"]
// ["g" (roup explicit), <"(" or ")">]
// e.g. [["n", 21], ["o", "+"], ["n", 9], ["o", *],
// ["g", "("], ["n", 3], ["o", "+"], ["n", 2],
// ["o", "^"], ["n", 9], ["g", ")"], ["o", "+"],
// ["n", "1"]]
$tokens = array();
$dragline = 0;
foreach(str_split($q) as $i=>$char) {
if (in_array($char, $nums)) {
continue;
}
elseif (in_array($char, $ops) || in_array($char, $grouping)) {
// hitting a non-numeric implies everything since the
// last hit has been part of a number
$capture = substr($q, $dragline, $i - $dragline);
// prevent the int cast from creating imaginary
// ["n", 0] tokens
if ($capture != "") {
if (substr_count($capture, ".") > 1) {
return "";
}
array_push($tokens, ["n", (float)$capture]);
}
// reset to one past the current (non-numeric) char
$dragline = $i + 1;
// the `;' backstop is not a real token and this should
// never be present in the token list
if ($char != ";") {
array_push($tokens, [
($char == "(" || $char == ")") ? "g" : "o",
$char
]);
}
}
else {
return "";
}
}
// two operators back to back should fail
for ($i = 1; $i < count($tokens); $i++) {
if ($tokens[$i][0] == "o" && $tokens[$i-1][0] == "o") {
return "";
}
}
//strategy:
// traverse to group open (if there is one)
// - return to start with the internals
// traverse to ^, attack token previous and after
// same but for *, then / then + then -
// poppers all teh way down
try {
return [
substr($q, 0, strlen($q)-1)." = " => $this->executeBlock($tokens)[0][1]
];
}
catch (\Throwable $e) {
if (get_class($e) == "DivisionByZeroError") {
return [
$q." = " => "Division by Zero Error!!"
];
}
return "";
}
}
public function executeBlock($tokens) {
if (count($tokens) >= 2 && $tokens[0][0] == "o" && $tokens[0][1] == "-" && $tokens[1][0] == "n") {
array_splice($tokens, 0, 2, [["n", -1 * (float)$tokens[1][1]]]);
}
if (count($tokens) > 0 && $tokens[0][0] == "o" || $tokens[count($tokens)-1][0] == "o") {
throw new Exception("Error Processing Request", 1);
}
if (in_array(["g", "("], $tokens)) {
$first_open = array_search(["g", "("], $tokens);
$enclosedality = 1;
for ($i = $first_open+1; $i < count($tokens); $i++) {
if ($tokens[$i][0] == "g") {
$enclosedality += ($tokens[$i][1] == "(") ? 1 : -1;
}
if ($enclosedality == 0) {
array_splice($tokens,
$first_open,
$i+1 - $first_open,
$this->executeBlock(
array_slice($tokens, $first_open+1, $i-1 - $first_open)
)
);
break;
}
}
}
$operators_in_pemdas_order = [
"^" => (fn($x, $y) => $x ** $y),
"*" => (fn($x, $y) => $x * $y),
"/" => (fn($x, $y) => $x / $y),
"%" => (fn($x, $y) => $x % $y),
"+" => (fn($x, $y) => $x + $y),
"-" => (fn($x, $y) => $x - $y)
];
foreach ($operators_in_pemdas_order as $op=>$func) {
while (in_array(["o", $op], $tokens)) {
for ($i = 0; $i < count($tokens); $i++) {
if ($tokens[$i] == ["o", $op]) {
array_splice(
$tokens,
$i-1,
3,
[["n", (string)($func((float)$tokens[$i-1][1], (float)$tokens[$i+1][1]))]]
);
}
}
}
}
return $tokens;
}
}
?>

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oracles/encoder.php Normal file
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<?php
include_once("oracles/base.php");
class encoder extends oracle {
public $info = [
"name" => "text encoder/hasher"
];
private $special_types = [
"rot13",
"base64"
];
public function check_query($q) {
$types = array_merge($this->special_types, hash_algos());
foreach ($types as $type) {
$type .= " ";
if (str_starts_with($q, $type)) {
return true;
}
}
return false;
}
public function generate_response($q)
{
$type = explode(" ", $q)[0];
$victim = substr($q, strlen($type)+1);
if (in_array($type, hash_algos())) {
return [$type." hash" => hash($type, $victim)];
}
switch ($type) {
case "rot13":
return ["rot13 encoded" => str_rot13($victim)];
case "base64":
return [
"base64 encoded" => base64_encode($victim),
"base64 decoded" => base64_decode($victim)
];
}
return "";
}
}
?>

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<?php
include_once("oracles/base.php");
class numerics extends oracle {
public $info = [
"name" => "numeric base conversion"
];
public function check_query($q) {
if (str_contains($q, " ")) {
return false;
}
$q = strtolower($q);
$profiles = [
["0x", str_split("0123456789abcdef")],
["", str_split("1234567890")],
["b", str_split("10")]
];
foreach ($profiles as $profile) {
$good = true;
$good &= str_starts_with($q, $profile[0]);
$nq = substr($q, strlen($profile[0]));
foreach (str_split($nq) as $c) {
$good &= in_array($c, $profile[1]);
}
if ($good) {
return true;
}
}
return false;
}
public function generate_response($q) {
$n = 0;
if (str_starts_with($q, "0x")) {
$nq = substr($q, strlen("0x"));
$n = hexdec($nq);
}
elseif (str_starts_with($q, "b")) {
$nq = substr($q, strlen("b"));
$n = bindec($nq);
}
else {
$n = (int)$q;
}
return [
"decimal (base 10)" => (string)$n,
"hexadecimal (base 16)" => "0x".(string)dechex($n),
"binary (base 2)" => "b".(string)decbin($n),
"" => "binary inputs should be prefixed with 'b', hex with '0x'."
];
}
}
?>

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<?php
include_once("oracles/base.php");
class time extends oracle {
public $info = [
"name" => "what time is it?"
];
public function check_query($q) {
$prompts = [
"what", "time", "is", "it",
"right", "now", "the", "current",
"get"
];
$q = str_replace(",", "", $q);
$q = str_replace("?", "", $q);
$q = str_replace("what's", "what is", $q);
$oq = $q;
$q = explode(" ", $q);
$count = 0;
foreach ($q as $word) {
if (in_array($word, $prompts)) {
$count++;
}
}
// remove one from total count if a timezone is specified
return ($count/(count($q) + (str_contains($oq, "tz:") ? -1 : 0))) > 3/4;
}
public function generate_response($q) {
$timezone = timezone_name_from_abbr("UTC");
foreach (explode(" ", $q) as $word) {
if (str_starts_with($word, "tz:")) {
$decltz = timezone_name_from_abbr(substr($word, 3, 3));
if ($decltz) {
$timezone = $decltz;
}
}
}
date_default_timezone_set($timezone);
return [
"The time in ".$timezone => date("H:i:s"),
"" => "include the string \"tz:XXX\" to use timezone XXX"
];
}
}
?>

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web.php
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$payload["left"] .= '</table>';
}
/*
Prepend Oracle output, if applicable
*/
include_once("oracles/encoder.php");
include_once("oracles/calc.php");
include_once("oracles/time.php");
include_once("oracles/numerics.php");
$oracles = [new calculator(), new encoder(), new time(), new numerics()];
$fortune = "";
foreach ($oracles as $oracle) {
if ($oracle->check_query($_GET["s"])) {
$resp = $oracle->generate_response($_GET["s"]);
if ($resp != "") {
$fortune .= "<div class=\"infobox\">";
foreach ($resp as $title => $r) {
if ($title) {
$fortune .= "<h3>".htmlspecialchars($title)."</h3><div class=\"code\">".htmlspecialchars($r)."</div>";
}
else {
$fortune .= "<i>".$r."</i><br>";
}
}
$fortune .= "<small>Answer provided by oracle: ".$oracle->info["name"]."</small></div>";
}
break;
}
}
$payload["left"] = $fortune . $payload["left"];
/*
Load next page
*/