From 6837c964284da00edf8515c3b5691e989d5bae45 Mon Sep 17 00:00:00 2001
From: Jelle De Loecker <jelle@elevenways.be>
Date: Thu, 10 Oct 2024 20:10:13 +0200
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20Add=20support=20for=20downloading?=
 =?UTF-8?q?=20`data:`=20uris=20with=20`Alchemy#download()`?=
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---
 CHANGELOG.md                  |  1 +
 lib/core/alchemy_functions.js | 56 +++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 09b9ecd..431778a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 * End requests with an error when parsing posted body contents fail
 * Make the max body & file size of a request configurable (per route)
+* Add support for downloading `data:` uris with `Alchemy#download()`
 
 ## 1.4.0-alpha.6 (2024-09-11)
 
diff --git a/lib/core/alchemy_functions.js b/lib/core/alchemy_functions.js
index b80b251..b3b3b6e 100644
--- a/lib/core/alchemy_functions.js
+++ b/lib/core/alchemy_functions.js
@@ -1,6 +1,7 @@
 let mkdirp       = alchemy.use('mkdirp')?.mkdirp,
     ncp          = alchemy.use('ncp').ncp,
     fs           = alchemy.use('fs'),
+    fsp          = fs.promises,
     libpath      = alchemy.use('path'),
     child        = alchemy.use('child_process'),
     crypto       = alchemy.use('crypto'),
@@ -1106,6 +1107,53 @@ Alchemy.setMethod(function request(url, options, callback) {
 	return Blast.fetch(options, callback);
 });
 
+/**
+ * Turn a `data:` uri into a file
+ *
+ * @author   Jelle De Loecker <jelle@elevenways.be>
+ * @since    1.4.0
+ * @version  1.4.0
+ *
+ * @param    {string}   data_uri
+ *
+ * @return   {Pledge<File>}
+ */
+function convertDataUriToFile(data_uri) {
+
+	// Split the data uri into its 2 parts
+	let pieces = data_uri.slice(5).split(',');
+
+	// Split the info bit
+	let info = pieces[0].split(';');
+
+	// Get the expected mime type
+	let mime_type = info[0];
+
+	// And is it base64?
+	let is_b64 = info[1] && info[1].toLowerCase() == 'base64';
+
+	let buffer;
+
+	if (is_b64) {
+		buffer = Buffer.from(pieces[1], 'base64');
+	} else {
+		buffer = Buffer.from(String.decodeURI(pieces[1]));
+	}
+
+	return Pledge.Swift.waterfall(
+		() => Blast.createTempDir({prefix: 'aldl'}),
+		async (temp_dir) => {
+			let full_path = libpath.resolve(temp_dir, 'buffer_' + alchemy.ObjectId());
+			
+			await fsp.writeFile(full_path, buffer);
+
+			return full_path;
+		},
+		(full_path) => Classes.Alchemy.Inode.Inode.from(full_path)
+	);
+
+}
+
 /**
  * Download a file
  *
@@ -1119,6 +1167,14 @@ Alchemy.setMethod(function request(url, options, callback) {
  */
 Alchemy.setMethod(function download(url, options) {
 
+	if (url.startsWith('data:')) {
+		try {
+			return convertDataUriToFile(url, options);
+		} catch (err) {
+			return Pledge.reject(err);
+		}
+	}
+
 	const pledge = new Pledge();
 
 	// Get the file