85 lines
3.4 KiB
TypeScript
85 lines
3.4 KiB
TypeScript
import { inflateRawSync } from 'node:zlib'
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export interface SpotXml {
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title: string
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category: number | null
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subcats: string[]
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size: number
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website: string
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/** Message ids (without <>) of the compressed NZB in alt.binaries.ftd. */
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nzbSegments: string[]
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created: number | null
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}
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const ENTITIES: Record<string, string> = { amp: '&', lt: '<', gt: '>', quot: '"', apos: "'" }
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function text(value: string | undefined): string {
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if (value === undefined) return ''
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const cdata = /^\s*<!\[CDATA\[([\s\S]*)\]\]>\s*$/.exec(value)
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if (cdata) return cdata[1]
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return value.replace(/&(#x[0-9a-f]+|#\d+|[a-z]+);/gi, (match, entity: string) => {
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if (entity[0] === '#') {
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const code = entity[1].toLowerCase() === 'x' ? Number.parseInt(entity.slice(2), 16) : Number.parseInt(entity.slice(1), 10)
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return Number.isFinite(code) && code > 0 && code <= 0x10ffff ? String.fromCodePoint(code) : match
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}
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return ENTITIES[entity.toLowerCase()] ?? match
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})
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}
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const element = (xml: string, name: string) => new RegExp(`<${name}(?:\\s[^>]*)?>([\\s\\S]*?)</${name}>`, 'i').exec(xml)?.[1]
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/** The spot XML from the X-XML header lines (a tolerant scanner, as spots are often invalid XML). */
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export function parseSpotXml(xml: string): SpotXml | null {
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const posting = element(xml, 'Posting')
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if (!posting) return null
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const categoryXml = element(posting, 'Category') ?? ''
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const key = Number.parseInt(element(posting, 'Key') ?? '', 10)
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const rawCategory = Number.parseInt(categoryXml.replace(/<[\s\S]*$/, ''), 10)
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const nzb = element(posting, 'NZB') ?? ''
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return {
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title: text(element(posting, 'Title')).trim(),
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// Newer keys number categories from 1.
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category: Number.isNaN(rawCategory) ? null : key !== 1 ? rawCategory - 1 : rawCategory,
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subcats: [...categoryXml.matchAll(/<(?:Sub|SubCat)>([^<]*)<\/(?:Sub|SubCat)>/gi)].map((m) => m[1].trim()),
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size: Number.parseInt(element(posting, 'Size') ?? '', 10) || 0,
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website: text(element(posting, 'Website')).trim(),
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nzbSegments: [...nzb.matchAll(/<Segment>([^<>]*)<\/Segment>/gi)].map((m) => m[1].trim()).filter(Boolean),
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created: Number.parseInt(element(posting, 'Created') ?? '', 10) || null,
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}
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}
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/** Header lines of a raw HEAD response; X-XML (split over many lines) joined. */
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export function parseSpotArticleHeaders(raw: string): { headers: Record<string, string>; xml: string } {
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const headers: Record<string, string> = {}
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let xml = ''
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for (const line of raw.split(/\r?\n/)) {
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const colon = line.indexOf(':')
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if (colon <= 0) continue
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const name = line.slice(0, colon).toLowerCase()
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const value = line.slice(colon + 1).replace(/^ /, '')
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if (name === 'x-xml') xml += value
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else headers[name] ??= value
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}
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return { headers, xml }
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}
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/**
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* Spot binaries (the NZB, images): article bodies joined without line
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* breaks, Spotnet's escapes undone (=A NUL, =B CR, =C LF, =D =), then raw
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* deflate (PHP gzinflate).
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*/
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export function decodeSpotBinary(bodies: Buffer[], compressed = true): Buffer {
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const joined = bodies
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.map((body) =>
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body
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.toString('latin1')
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.split('\r\n')
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// NNTP dot-stuffing.
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.map((line) => (line.startsWith('..') ? line.slice(1) : line))
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.join('')
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)
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.join('')
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const unescaped = Buffer.from(joined.replace(/=([ABCD])/g, (_, c: string) => ({ A: '\0', B: '\r', C: '\n', D: '=' })[c]!), 'latin1')
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return compressed ? inflateRawSync(unescaped) : unescaped
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}
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