LiteXiv/include/api.php

<?php
$stream_context = [
	'http' => [
		'header' =>
			'User-Agent: Mozilla/5.0' . PHP_EOL .
			'Cookie: PHPSESSID=' . SESSION_ID,
		'ignore_errors' => true
	]
];
if (HTTP_PROXY) {
	$stream_context['http']['proxy'] = 'tcp://' . HTTP_PROXY;
}
stream_context_set_default($stream_context);

function get_json($url, $associative = false) {
	$response = file_get_contents($url);
	if (!isset($http_response_header)) {
		return [false, 'network-error'];
	}
	$response_code = substr($http_response_header[0], 9, 3);
	if ($response_code == '401') {
		return [false, 'unauthorized'];
	}
	return [json_decode($response, $associative), false];
}

function get_discovery() {
	return get_json(sprintf(
		'https://www.pixiv.net/ajax/discovery/artworks?mode=%s&limit=%s&lang=%s',
		get_closest_mode(), 100, get_string('pixiv-lang')
	));
}

function get_artwork_info($id) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/illust/%s?lang=%s',
		$id, get_string('pixiv-lang')
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'artwork.not-found'];
	return [$response, false];
}

function get_artwork_pages($id) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/illust/%s/pages',
		$id
	), true);
	if ($error) return [false, $error];
	if (empty($response['body'])) return [false, 'artwork.not-found'];
	return [$response, false];
}

function get_artwork_comments($id, $offset, $limit) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/illusts/comments/roots?illust_id=%s&offset=%s&limit=%s',
		$id, $offset, $limit
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'artwork.not-found'];
	if (empty($response->body->comments)) return [false, 'artwork.no-comments'];
	return [$response, false];
}

function get_artwork_comment_replies($id, $page) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/illusts/comments/replies?comment_id=%s&page=%s',
		$id, $page
	));
	if ($error) return [false, $error];
	if (empty($response->body->comments)) return [false, 'artwork.no-replies'];
	return [$response, false];
}

function get_artwork_related($id) {
	return get_json(sprintf(
		'https://www.pixiv.net/ajax/illust/%s/recommend/init?limit=%s&lang=%s',
		$id, 120, get_string('pixiv-lang')
	));
}

function get_search($query, $page) {
	return get_json(sprintf(
		'https://www.pixiv.net/ajax/search/artworks/%s?mode=%s&p=%s&lang=%s',
		urlencode($query), get_closest_mode(), $page, get_string('pixiv-lang')
	));
}

function get_tag_info($query) {
	return get_json(sprintf(
		'https://www.pixiv.net/ajax/search/tags/%s',
		urlencode($query)
	));
}

function get_user_info($id) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/user/%s?full=1',
		$id
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'user.not-found'];
	return [$response, false];
}

function get_user_bookmarks($id, $offset, $limit) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/user/%s/illusts/bookmarks?tag=&offset=%s&limit=%s&rest=show&lang=%s',
		$id, $offset, $limit, get_string('pixiv-lang')
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'user.not-found'];
	return [$response, false];
}

function get_user_artworks_with_tag($id, $category, $tag, $offset, $limit) {
	$request_path = [
		'artworks' => 'illustmanga',
		'illustrations' => 'illusts',
		'manga' => 'manga'
	][$category];
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/user/%s/%s/tag?tag=%s&offset=%s&limit=%s&lang=%s',
		$id, $request_path, urlencode($tag), $offset, $limit, get_string('pixiv-lang')
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'user.not-found'];
	return [$response, false];
}

function get_user_artworks_list($id) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/user/%s/profile/all',
		$id
	), true);
	if ($error) return [false, $error];
	if (empty($response['body'])) return [false, 'user.not-found'];
	return [$response, false];
}

function get_user_artworks($user_id, $artwork_ids) {
	list($response, $error) = get_json(sprintf(
		'https://www.pixiv.net/ajax/user/%s/profile/illusts?work_category=illustManga&is_first_page=0&lang=%s&%s',
		$user_id, get_string('pixiv-lang'), http_build_query(['ids' => $artwork_ids])
	));
	if ($error) return [false, $error];
	if (empty($response->body)) return [false, 'user.not-found'];
	return [$response, false];
}

function get_frequent_tags($artwork_ids) {
	return get_json(sprintf(
		'https://www.pixiv.net/ajax/tags/frequent/illust?lang=%s&%s',
		get_string('pixiv-lang'), http_build_query(['ids' => $artwork_ids])
	));
}