endpoint.php

<?php

if ( isset( $argv[1] ) ) {
	$query = $argv[1];
} else {
	$allowed_tokens = [
	];
	if ( ! in_array( $_POST['token'], $allowed_tokens ) ) {
		die;
	}
	$query = trim( $_POST['text'] );
}

function vipdocs_fetch( $search_query ) {
	$url = 'https://docs.wpvip.com/wp-json/wp/v2/search?search=' . rawurlencode( $search_query );

	$ch = curl_init();
	curl_setopt( $ch, CURLOPT_URL, $url );
	curl_setopt( $ch, CURLOPT_CONNECTTIMEOUT, 2 );
	curl_setopt( $ch, CURLOPT_RETURNTRANSFER, 1 );
	$buffer = curl_exec( $ch );
	curl_close( $ch );

	$json = json_decode( $buffer );
	if ( is_null( $json ) ) {
		no_results( true );
	}
	return $json;

}

function vipdocs_format_results( $json ) {
	if ( empty( $json ) ) {
		no_results();
	}
	foreach ( $json as $match ) {
		$output[] = sprintf( '<%s|%s> %s', $match->url, $match->title, $match->subtype );
	}
	return implode( PHP_EOL, $output );
}

function no_results( $error = false ) {
	$response = [
		"response_type" => "in_channel",
		"blocks" => [
			[
				"type" => "section",
				"text" => [
					"type" => "mrkdwn",
					"text" => $error ? "Error" : "No results"
				]
			],
			[
				"type" => "context",
				"elements" => [
					[
						"type" => "mrkdwn",
						"text" => sprintf( '<%s|Source code>', 'https://gist.github.com/trepmal/7fa4df42bf6ddaa8901bd6d859f9588f' )
					],
					[
						"type" => "plain_text",
						"text" => ':heart: @trepmal'
					]
				]
			],
		]
	];
	header( 'Content-Type: application/json' );
	die( json_encode( $response ) );
}

$response = [
	"response_type" => "in_channel",
	"blocks" => [
		[
			"type" => "section",
			"text" => [
				"type" => "mrkdwn",
				"text" => vipdocs_format_results( vipdocs_fetch( $query ) )
			]
		],
		[
			"type" => "context",
			"elements" => [
				[
					"type" => "mrkdwn",
					"text" => sprintf( 'https://docs.wpvip.com?s=%s', rawurlencode( $query ) )
				],
				[
					"type" => "mrkdwn",
					"text" => sprintf( '<%s|Source code>', 'https://gist.github.com/trepmal/7fa4df42bf6ddaa8901bd6d859f9588f' )
				],
				[
					"type" => "plain_text",
					"text" => ':heart: @trepmal'
				]
			]
		],
	]
];

header( 'Content-Type: application/json' );
die( json_encode( $response ) );