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Local SoundCloud Downloader

Download SoundCloud without external service.

  1. // ==UserScript==
  2. // @name         Local SoundCloud Downloader
  3. // @namespace    https://blog.maple3142.net/
  4. // @version      0.1.5
  5. // @description  Download SoundCloud without external service.
  6. // @author       maple3142
  7. // @match        https://soundcloud.com/*
  8. // @require      https://cdn.jsdelivr.net/npm/web-streams-polyfill@2.0.2/dist/ponyfill.min.js
  9. // @require      https://cdn.jsdelivr.net/npm/streamsaver@2.0.3/StreamSaver.min.js
  10. // @grant        none
  11. // @icon         https://a-v2.sndcdn.com/assets/images/sc-icons/favicon-2cadd14bdb.ico
  12. // ==/UserScript==
  13.  
  14. streamSaver.mitm = 'https://maple3142.github.io/StreamSaver.js/mitm.html'
  15. function hook(obj, name, callback, type) {
  16. 	const fn = obj[name]
  17. 	obj[name] = function (...args) {
  18. 		if (type === 'before') callback.apply(this, args)
  19. 		fn.apply(this, args)
  20. 		if (type === 'after') callback.apply(this, args)
  21. 	}
  22. 	return () => {
  23. 		// restore
  24. 		obj[name] = fn
  25. 	}
  26. }
  27. function triggerDownload(url, name) {
  28. 	const a = document.createElement('a')
  29. 	document.body.appendChild(a)
  30. 	a.href = url
  31. 	a.download = name
  32. 	a.click()
  33. 	a.remove()
  34. }
  35. const btn = {
  36. 	init() {
  37. 		this.el = document.createElement('button')
  38. 		this.el.textContent = 'Download'
  39. 		this.el.classList.add('sc-button')
  40. 		this.el.classList.add('sc-button-medium')
  41. 		this.el.classList.add('sc-button-icon')
  42. 		this.el.classList.add('sc-button-responsive')
  43. 		this.el.classList.add('sc-button-secondary')
  44. 		this.el.classList.add('sc-button-download')
  45. 	},
  46. 	cb() {
  47. 		const par = document.querySelector('.sc-button-toolbar .sc-button-group')
  48. 		if (par && this.el.parentElement !== par) par.insertAdjacentElement('beforeend', this.el)
  49. 	},
  50. 	attach() {
  51. 		this.detach()
  52. 		this.observer = new MutationObserver(this.cb.bind(this))
  53. 		this.observer.observe(document.body, { childList: true, subtree: true })
  54. 		this.cb()
  55. 	},
  56. 	detach() {
  57. 		if (this.observer) this.observer.disconnect()
  58. 	}
  59. }
  60. btn.init()
  61. async function getClientId() {
  62. 	return new Promise(resolve => {
  63. 		const restore = hook(
  64. 			XMLHttpRequest.prototype,
  65. 			'open',
  66. 			async (method, url) => {
  67. 				const u = new URL(url, document.baseURI)
  68. 				const clientId = u.searchParams.get('client_id')
  69. 				if (!clientId) return
  70. 				console.log('got clientId', clientId)
  71. 				restore()
  72. 				resolve(clientId)
  73. 			},
  74. 			'after'
  75. 		)
  76. 	})
  77. }
  78. const clientIdPromise = getClientId()
  79. let controller = null
  80. async function load(by) {
  81. 	btn.detach()
  82. 	console.log('load by', by, location.href)
  83. 	if (/^(\/(you|stations|discover|stream|upload|search|settings))/.test(location.pathname)) return
  84. 	const clientId = await clientIdPromise
  85. 	if (controller) {
  86. 		controller.abort()
  87. 		controller = null
  88. 	}
  89. 	controller = new AbortController()
  90. 	const result = await fetch(
  91. 		`https://api-v2.soundcloud.com/resolve?url=${encodeURIComponent(location.href)}&client_id=${clientId}`,
  92. 		{ signal: controller.signal }
  93. 	).then(r => r.json())
  94. 	console.log('result', result)
  95. 	if (result.kind !== 'track') return
  96. 	btn.el.onclick = async () => {
  97. 		const progressive = result.media.transcodings.find(t => t.format.protocol === 'progressive')
  98. 		if (progressive) {
  99. 			const { url } = await fetch(progressive.url + `?client_id=${clientId}`).then(r => r.json())
  100. 			const resp = await fetch(url)
  101. 			const ws = streamSaver.createWriteStream(result.title + '.mp3', {
  102. 				size: resp.headers.get('Content-Length')
  103. 			})
  104. 			const rs = resp.body
  105. 			if (rs.pipeTo) {
  106. 				console.log(rs, ws)
  107. 				return rs.pipeTo(ws)
  108. 			}
  109. 			const reader = rs.getReader()
  110. 			const writer = ws.getWriter()
  111. 			const pump = () =>
  112. 				reader.read().then(res => (res.done ? writer.close() : writer.write(res.value).then(pump)))
  113.  
  114. 			return pump()
  115. 		}
  116. 		alert('Sorry, downloading this music is currently unsupported.')
  117. 	}
  118. 	btn.attach()
  119. 	console.log('attached')
  120. }
  121. load('init')
  122. hook(history, 'pushState', () => load('pushState'), 'after')
  123. window.addEventListener('popstate', () => load('popstate'))