MusicBrainz API Module

Module for interacting with the MusicBrainz API.

Αυτός ο κώδικας δεν πρέπει να εγκατασταθεί άμεσα. Είναι μια βιβλιοθήκη για άλλους κώδικες που περιλαμβάνεται μέσω της οδηγίας meta // @require https://update.greatest.deepsurf.us/scripts/552392/1731879/MusicBrainz%20API%20Module.js

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey, το Greasemonkey ή το Violentmonkey για να εγκαταστήσετε αυτόν τον κώδικα.

You will need to install an extension such as Tampermonkey to install this script.

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey ή το Violentmonkey για να εγκαταστήσετε αυτόν τον κώδικα.

θα χρειαστεί να εγκαταστήσετε μια επέκταση όπως το Tampermonkey ή το Userscripts για να εγκαταστήσετε αυτόν τον κώδικα.

You will need to install an extension such as Tampermonkey to install this script.

Θα χρειαστεί να εγκαταστήσετε μια επέκταση διαχείρισης κώδικα χρήστη για να εγκαταστήσετε αυτόν τον κώδικα.

(Έχω ήδη έναν διαχειριστή κώδικα χρήστη, επιτρέψτε μου να τον εγκαταστήσω!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Έχω ήδη έναν διαχειριστή στυλ χρήστη, επιτρέψτε μου να τον εγκαταστήσω!)

// ==UserScript==
// @name         MusicBrainz API Module
// @namespace    https://musicbrainz.org/user/chaban
// @version      0.2.6
// @description  Module for interacting with the MusicBrainz API.
// @author       chaban
// @tag          ai-created
// @license      MIT
// @grant        GM.xmlHttpRequest
// ==/UserScript==

class MusicBrainzAPI {
    constructor(options = {}) {
        let defaultOrigin = 'https://musicbrainz.org';

        if (/(musicbrainz\.(org|eu))$/i.test(window.location.hostname)) {
            defaultOrigin = window.location.origin;
        }

        this.base_url = options.base_url || `${defaultOrigin}/ws/2`;
        this.user_agent = options.user_agent || `UserJS.MusicBrainzAPI/0.2.2 ( https://musicbrainz.org/user/chaban )`;
        this.rate_limit_delay = 1000;
        this.max_retries = options.max_retries || 5;
        this.batch_size = options.batch_size || 100;
        this.cache = new Map();
        this.next_available_request_time = 0;
    }

    _parseHeaders(headerStr) {
        const headers = {};
        if (!headerStr) {
            return headers;
        }
        const headerPairs = headerStr.split('\u000d\u000a');
        for (const headerPair of headerPairs) {
            const index = headerPair.indexOf('\u003a\u0020');
            if (index > 0) {
                const key = headerPair.substring(0, index).toLowerCase();
                const value = headerPair.substring(index + 2);
                headers[key] = value;
            }
        }
        return headers;
    }

    async _request(endpoint, params = {}) {
        const url = new URL(`${this.base_url}/${endpoint}`);
        params.fmt = 'json';
        for (const [key, value] of Object.entries(params)) {
            if (Array.isArray(value)) {
                for (const v of value) {
                    if (v !== undefined && v !== '') {
                        url.searchParams.append(key, v);
                    }
                }
            } else if (value !== undefined && value !== '') {
                url.searchParams.append(key, value);
            }
        }

        for (let i = 0; i < this.max_retries; i++) {
            const now = Date.now();
            const waitTime = this.next_available_request_time - now;
            if (waitTime > 0) {
                await new Promise(resolve => setTimeout(resolve, waitTime));
            }

            try {
                const response = await new Promise((resolve, reject) => {
                    GM.xmlHttpRequest({
                        method: 'GET',
                        url: url.toString(),
                        headers: {
                            'User-Agent': this.user_agent,
                            'Accept': 'application/json',
                            'Origin': location.origin,
                        },
                        anonymous: true,
                        onload: (res) => {
                            const responseTime = Date.now();
                            const headers = this._parseHeaders(res.responseHeaders);
                            const rateLimitReset = parseInt(headers['x-ratelimit-reset'], 10) * 1000;
                            const rateLimitRemaining = parseInt(headers['x-ratelimit-remaining'], 10);
                            const retryAfterSeconds = parseInt(headers['retry-after'], 10);

                            if (!isNaN(retryAfterSeconds) && retryAfterSeconds > 0) {
                                this.next_available_request_time = responseTime + (retryAfterSeconds * 1000);
                            } else if (!isNaN(rateLimitReset) && rateLimitRemaining === 0) {
                                this.next_available_request_time = rateLimitReset;
                            } else {
                                this.next_available_request_time = responseTime + this.rate_limit_delay;
                            }

                            if (res.status >= 200 && res.status < 300) {
                                resolve(JSON.parse(res.responseText));
                            } else if (res.status === 503) {
                                reject(new Error('Rate limit hit or server overloaded'));
                            } else {
                                const ErrorClass = (res.status >= 400 && res.status < 500) ? PermanentError : Error;
                                reject(new ErrorClass(`HTTP Error ${res.status}: ${res.statusText}`));
                            }
                        },
                        onerror: (err) => {
                            this.next_available_request_time = Date.now() + 5000;
                            reject(new Error('Network error'));
                        },
                        ontimeout: () => {
                            this.next_available_request_time = Date.now() + 5000;
                            reject(new Error('Request timed out'));
                        },
                    });
                });

                return response;
            } catch (error) {
                if (error instanceof PermanentError) {
                    throw error; // Stop retrying and propagate the error.
                }

                if (!navigator.onLine) {
                    console.log(`[MusicBrainzAPI] Offline detected. Waiting for network...`);
                    await new Promise(resolve => {
                        const handler = () => {
                            window.removeEventListener('online', handler);
                            resolve();
                        };
                        window.addEventListener('online', handler);
                    });
                    i--; // Don't count this attempt
                    continue;
                }

                if (i === this.max_retries - 1) throw error;
                const delay = this.rate_limit_delay * Math.pow(2, i);
                await new Promise(resolve => setTimeout(resolve, delay));
            }
        }
    }

    async lookupUrl(urls, inc = []) {
        const isInputArray = Array.isArray(urls);
        const urlArray = isInputArray ? [...new Set(urls)] : [urls];

        if (urlArray.length === 0) {
            return isInputArray ? {} : null;
        }

        const results = new Map();
        const uncachedUrls = [];

        for (const url of urlArray) {
            if (this.cache.has(url)) {
                results.set(url, this.cache.get(url));
            } else {
                uncachedUrls.push(url);
            }
        }

        if (uncachedUrls.length > 0) {
            const urlChunks = [];
            for (let i = 0; i < uncachedUrls.length; i += this.batch_size) {
                urlChunks.push(uncachedUrls.slice(i, i + this.batch_size));
            }

            const promises = urlChunks.map(chunk =>
                this._request('url', {
                    resource: chunk,
                    inc: inc.join('+')
                })
            );

            // Use Promise.allSettled to ensure all batches are processed, even if some fail.
            const settledResults = await Promise.allSettled(promises);

            settledResults.forEach((result, index) => {
                const chunk = urlChunks[index]; // Get the corresponding chunk of URLs for this result.

                if (result.status === 'fulfilled') {
                    const response = result.value;

                    // The API returns a single object for a 1-item request, and an object with a `urls` array for multi-item requests.
                    if (chunk.length === 1) {
                        const url = chunk[0];
                        const mbData = response && response.resource === url ? response : null;
                        this.cache.set(url, mbData);
                        results.set(url, mbData);
                    } else {
                        const responseMap = new Map(response.urls?.map(u => [u.resource, u]) || []);
                        for (const url of chunk) {
                            const mbData = responseMap.get(url) || null;
                            this.cache.set(url, mbData);
                            results.set(url, mbData);
                        }
                    }
                } else { // status === 'rejected'
                    console.error(`MusicBrainz API batch lookup failed for chunk starting with ${chunk[0]}`, result.reason);

                    // Only cache as null if it's a permanent error (like 404), not for network errors
                    const isPermanent = result.reason && result.reason.name === 'PermanentError';

                    for (const url of chunk) {
                        if (isPermanent) {
                            this.cache.set(url, null);
                        }
                        results.set(url, null);
                    }
                }
            });
        }

        return isInputArray ? results : results.get(urlArray[0]);
    }

    async search(entity, query, limit = 100, inc = [], fetch_all = false) {
        if (!fetch_all) {
            return this._request(entity, { query, limit, inc: inc.join('+') });
        }

        let results = [];
        let offset = 0;
        let total;

        do {
            const data = await this._request(entity, { query, limit, offset, inc: inc.join('+') });
            const entities = data[entity + 's'] || [];
            results.push(...entities);
            total = data.count;
            offset += entities.length;
            if (entities.length === 0) break;
        } while (offset < total);

        return results;
    }

    get(entity, mbid, inc = []) {
        return this._request(`${entity}/${mbid}`, { inc: inc.join('+') });
    }

    clearCache() {
        this.cache.clear();
    }


    invalidateCacheForUrl(url) {
        const urls = Array.isArray(url) ? url : [url];
        urls.forEach(u => this.cache.delete(u));
    }

    /**
     * Synchronously retrieves a value from the cache if available.
     * @param {string} url - The URL to check.
     * @returns {object|undefined} The cached response or undefined if not cached.
     */
    getFromCache(url) {
        return this.cache.get(url);
    }
}

class PermanentError extends Error {
    constructor(message) {
        super(message);
        this.name = 'PermanentError';
    }
}