Export as a lib

src/pdfy.js

@@ -0,0 +1,133 @@
+import fs from 'node:fs'
+import path from 'node:path'
+import {
+  checkExtension,
+  launchBrowser,
+  discoverExtensionId,
+  getReadabilityPath
+} from './browser.js'
+import {
+  extractArticle,
+  storeArticle,
+  setExtensionPreferences,
+  waitForReaderView,
+  extractRenderedContent,
+  getArticleTitle
+} from './reader.js'
+import { enhanceHtml, generatePdf } from './pdf.js'
+import { VALID_THEMES } from './cli.js'
+import logger from './logger.js'
+
+const EXTENSION_BASE = 'chrome-extension://'
+
+export { launchBrowser, VALID_THEMES }
+
+export class BotProtectionError extends Error {
+  constructor () {
+    super('Bot protection or low-content page detected. Provide the article as HTML.')
+    this.name = 'BotProtectionError'
+  }
+}
+
+export async function convert (url, options = {}) {
+  const {
+    html,
+    theme = 'light',
+    css = null,
+    prefs = {},
+    output = null,
+    browser: externalBrowser = null
+  } = options
+
+  if (!VALID_THEMES.includes(theme)) {
+    throw new Error(`Invalid theme "${theme}". Valid themes: ${VALID_THEMES.join(', ')}`)
+  }
+
+  logger.info(`Theme: ${theme}`)
+
+  await checkExtension()
+
+  let browser = externalBrowser
+  let ownBrowser = false
+  if (!browser) {
+    browser = await launchBrowser()
+    ownBrowser = true
+  }
+
+  try {
+    const extId = await discoverExtensionId(browser)
+
+    logger.info(`Fetching article: "${url}"`)
+    const articlePage = await browser.newPage()
+    if (html) {
+      await articlePage.setContent(html, { waitUntil: 'networkidle0' })
+    } else {
+      await articlePage.goto(url, { waitUntil: 'networkidle0', timeout: 30000 })
+    }
+    const article = await extractArticle(articlePage, getReadabilityPath())
+    await articlePage.close()
+
+    if (article.title === 'Just a moment...' || article.length < 500) {
+      throw new BotProtectionError()
+    }
+
+    const mergedPrefs = { ...prefs, mode: theme }
+    if (css) {
+      mergedPrefs['user-css'] = css
+    }
+
+    const extPage = await browser.newPage()
+    await storeArticle(extPage, extId, 1, article)
+
+    const prefsToSet = Object.fromEntries(
+      Object.entries(mergedPrefs).filter(([_, v]) => v !== undefined && v !== null)
+    )
+    if (Object.keys(prefsToSet).length > 0) {
+      await setExtensionPreferences(extPage, extId, prefsToSet)
+    }
+    await extPage.close()
+
+    const readerUrl = [
+      `${EXTENSION_BASE}${extId}/data/reader/index.html`,
+      '?id=1',
+      `&url=${encodeURIComponent(url)}`
+    ].join('')
+    logger.debug(`Opening Reader View: ${readerUrl}`)
+
+    const readerPage = await browser.newPage()
+    await readerPage.goto(readerUrl, { waitUntil: 'load', timeout: 30000 })
+    await waitForReaderView(readerPage)
+    await new Promise((resolve) => setTimeout(resolve, 1000))
+
+    const title = await getArticleTitle(readerPage)
+
+    let contentHtml = await extractRenderedContent(readerPage)
+    contentHtml = contentHtml.replace(
+      '<head>',
+      `<head><base href="${url}"><meta name="referrer" content="unsafe-url">`
+    )
+    contentHtml = contentHtml.replace(/ loading="lazy"/g, '')
+    await readerPage.close()
+
+    const enhancedHtml = enhanceHtml(contentHtml, css)
+
+    const pdfPage = await browser.newPage()
+    await pdfPage.setViewport({ width: 1280, height: 7200 })
+
+    let outputPath = null
+    if (output) {
+      outputPath = path.resolve(output)
+      fs.mkdirSync(path.dirname(outputPath), { recursive: true })
+    }
+
+    const pdfBuffer = await generatePdf(pdfPage, enhancedHtml, outputPath)
+    await pdfPage.close()
+
+    return { title, pdfBuffer, outputPath }
+  } finally {
+    if (ownBrowser && browser) {
+      await browser.close()
+      logger.info('Browser closed.')
+    }
+  }
+}