usenet-indexer/lib/newznab/xml.ts

import { create } from 'xmlbuilder2'
import { CATEGORIES, categoryLabel, parentCategory } from './categories.js'

const NEWZNAB_NS = 'http://www.newznab.com/DTD/2010/feeds/attributes/'

export interface NewznabItem {
  id: number
  title: string
  category: number
  size: number
  files: number
  postedAt: Date | null
  poster: string | null
  groups: string[]
  password: boolean
  /** Longer text than the title, e.g. a Spotnet spot's description (UBB markup). */
  description?: string
  season?: string
  episode?: string
}

export interface NewznabServer {
  title: string
  /** Absolute base URL, e.g. http://homelab:3333 */
  baseUrl: string
  /** Appended to download links so a client can fetch without extra config. */
  apiKey?: string
}

/** Newznab error codes: 100 credentials, 101 suspended, 102 privileges, 200/201 parameters, 202 function, 300 item, 500/501 request/download limit. */
/** Spotnet UBB markup (or the HTML of old spots) as plain text: [br] as line breaks, other tags dropped. */
export function ubbToText(ubb: string): string {
  return ubb
    .replace(/<br\s*\/?>|\[br\]/gi, '\n')
    .replace(/<\/?[a-z][^>]*>/gi, '')
    .replace(/\[url=([^\]]*)\]([\s\S]*?)\[\/url\]/gi, (_, url: string, label: string) => (label.trim() ? `${label} (${url.trim()})` : url.trim()))
    .replace(/\[\/?[a-z]+(?:=[^\]]*)?\]/gi, '')
    .trim()
}

export function errorXml(code: number, description: string): string {
  return create({ version: '1.0', encoding: 'UTF-8' })
    .ele('error', { code: String(code), description })
    .end({ prettyPrint: true })
}

/** A caller's day so far and its limits (null: none), as nZEDb-style indexers report them. */
export interface ApiLimits {
  apiCurrent: number
  apiMax: number | null
  grabCurrent: number
  grabMax: number | null
}

export function capsXml(
  server: NewznabServer,
  limits: { max: number; default: number },
  registration = { available: false, open: false }
): string {
  const caps = create({ version: '1.0', encoding: 'UTF-8' }).ele('caps')
  caps.ele('server', { version: '1.0', title: server.title, strapline: 'Usenet indexer', url: `${server.baseUrl}/` })
  caps.ele('limits', { max: String(limits.max), default: String(limits.default) })
  caps.ele('registration', { available: registration.available ? 'yes' : 'no', open: registration.open ? 'yes' : 'no' })
  const searching = caps.ele('searching')
  searching.ele('search', { available: 'yes', supportedParams: 'q' })
  searching.ele('tv-search', { available: 'yes', supportedParams: 'q,season,ep' })
  searching.ele('movie-search', { available: 'yes', supportedParams: 'q' })
  searching.ele('audio-search', { available: 'yes', supportedParams: 'q' })
  searching.ele('book-search', { available: 'yes', supportedParams: 'q' })
  const categories = caps.ele('categories')
  for (const category of CATEGORIES) {
    const element = categories.ele('category', { id: String(category.id), name: category.name })
    for (const sub of category.subcats) element.ele('subcat', { id: String(sub.id), name: sub.name })
  }
  return caps.end({ prettyPrint: true })
}

export function resultsXml(server: NewznabServer, items: NewznabItem[], offset: number, total: number, limits?: ApiLimits): string {
  const rss = create({ version: '1.0', encoding: 'UTF-8' }).ele('rss', {
    'version': '2.0',
    'xmlns:atom': 'http://www.w3.org/2005/Atom',
    'xmlns:newznab': NEWZNAB_NS,
  })
  const channel = rss.ele('channel')
  channel.ele('title').txt(server.title)
  channel.ele('description').txt(`${server.title} API results`)
  channel.ele('link').txt(`${server.baseUrl}/`)
  channel.ele('newznab:response', { offset: String(offset), total: String(total) })
  if (limits) {
    channel.ele('newznab:apilimits', {
      apicurrent: String(limits.apiCurrent),
      ...(limits.apiMax !== null && { apimax: String(limits.apiMax) }),
      grabcurrent: String(limits.grabCurrent),
      ...(limits.grabMax !== null && { grabmax: String(limits.grabMax) }),
    })
  }

  const key = server.apiKey ? `&apikey=${encodeURIComponent(server.apiKey)}` : ''
  for (const item of items) {
    const getUrl = `${server.baseUrl}/api?t=get&id=${item.id}${key}`
    const pubDate = (item.postedAt ?? new Date()).toUTCString()
    const element = channel.ele('item')
    element.ele('title').txt(item.title)
    element.ele('guid', { isPermaLink: 'false' }).txt(String(item.id))
    element.ele('link').txt(getUrl)
    element.ele('comments').txt(`${server.baseUrl}/?release=${item.id}`)
    element.ele('pubDate').txt(pubDate)
    element.ele('category').txt(categoryLabel(item.category))
    element.ele('description').txt(item.description ? ubbToText(item.description) : item.title)
    element.ele('enclosure', { url: getUrl, length: String(item.size), type: 'application/x-nzb' })

    const attr = (name: string, value: string | number) =>
      element.ele('newznab:attr', { name, value: String(value) })
    attr('category', parentCategory(item.category))
    if (item.category !== parentCategory(item.category)) attr('category', item.category)
    attr('size', item.size)
    attr('files', item.files)
    attr('grabs', 0)
    attr('password', item.password ? 1 : 0)
    if (item.poster) attr('poster', item.poster)
    if (item.groups.length) attr('group', item.groups[0])
    attr('usenetdate', pubDate)
    if (item.season) attr('season', item.season)
    if (item.episode) attr('episode', item.episode)
  }
  return rss.end({ prettyPrint: true })
}