Code scaffold to produce valid musicxml examples

src/js/musicxml-examples.js

@@ -6,32 +6,137 @@
  */
 
 const URL_EXAMPLES_ROOT = 'https://www.w3.org/2021/06/musicxml40/musicxml-reference/examples/'
+const MUSICXML_VERSION = '4.0'
 
 import fetch from 'node-fetch'
 import * as cheerio from 'cheerio'
 import fs from 'fs'
 import process from 'process'
 import path from 'path'
+import { parseArgs } from 'node:util'
+import { createRequire } from 'node:module'
 
-const output = process.argv[2] || ''
+const require = createRequire(import.meta.url)
+const { version } = require('../../package.json')
+
+const options = {
+  'xml': {
+    type: 'boolean',
+    short: 'x',
+  },
+  'output': {
+    type: 'string',
+    short: 'o'
+  },
+  'help': {
+    type: 'boolean',
+    short: 'h'
+  },
+  'version': {
+    type: 'boolean',
+    short: 'v'
+  }
+}
+const { values: args } = (function() {
+  try {
+    return parseArgs({ options, allowPositionals: false })
+  }
+  catch (e) {
+    console.error(e.message)
+    process.exit(1)
+  }
+})()
+
+if ('help' in args) {
+  console.log(`
+Usage: musicxml-examples v${version} [--output|-o /path/to/output] [--xml|-x] [--version|-v] [--help|-h]
+
+Extracts MusicXML examples from ${URL_EXAMPLES_ROOT}.
+Use --xml to recreate a valid MusicXML structure around examples that lack it.
+`.trim())
+  process.exit(0)
+}
+
+if ('version' in args) {
+  console.log(`musicxml-examples v${version}`)
+  process.exit(0)
+}
+
+const output = args['output'] || ''
 if (output != '' && !fs.existsSync(output)) {
   console.error(`Missing output dir ${output}`)
   process.exit(1)
 }
 
-async function extractMusicXML(page, title) {
+async function extractMusicXml(page, title) {
   const response = await fetch(page)
   const body = await response.text()
   const $ = cheerio.load(body)
-  const musicxml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" + $('.xmlmarkup').text()
+  const musicxml = scaffoldMusicXml($('.xmlmarkup').text(), title)
   fs.writeFileSync(path.join(output, `${title}.musicxml`), musicxml)
 }
 
+const xmlHeader = `
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE score-partwise PUBLIC
+    "-//Recordare//DTD MusicXML ${MUSICXML_VERSION} Partwise//EN"
+    "http://www.musicxml.org/dtds/partwise.dtd">
+`.trim()
+
+const xmlTemplate = `
+<score-partwise version="${MUSICXML_VERSION}">
+  <part-list>
+    <score-part id="P1">
+      <part-name>Music</part-name>
+    </score-part>
+  </part-list>
+  <part id="P1">
+    <measure number="1">
+      <attributes>
+        <divisions>1</divisions>
+        <key>
+          <fifths>0</fifths>
+        </key>
+        <time>
+          <beats>4</beats>
+          <beat-type>4</beat-type>
+        </time>
+        <clef>
+          <sign>G</sign>
+          <line>2</line>
+        </clef>
+      </attributes>
+      <note>
+        <pitch>
+          <step>C</step>
+          <octave>4</octave>
+        </pitch>
+        <duration>4</duration>
+        <type>whole</type>
+      </note>
+    </measure>
+  </part>
+</score-partwise>
+`.trim()
+
+function scaffoldMusicXml(xml, title) {
+  if (!('xml' in args)) {
+    return "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" + xml
+  }
+
+  // Compare the incoming XML with the template above,
+  // Filling in successive levels from the template if they don't appear in the source.
+  const src = cheerio.load(xml, { xmlMode: true })
+  const tmp = cheerio.load(xmlTemplate, { xmlMode: true })
+
+  return xmlHeader + "\n" + src.html()
+}
+
 const response = await fetch(URL_EXAMPLES_ROOT)
 const main = await response.text()
 const $ = cheerio.load(main)
 for (const example of $('body').find('a:has(img)')) {
   const href = $(example).prop('href')
   console.log(`Extracting ${href}...`)
-  await extractMusicXML(URL_EXAMPLES_ROOT + href, href.replace('/', ''))
+  await extractMusicXml(URL_EXAMPLES_ROOT + href, href.replace('/', ''))
 }