fix: implement correct behaviour for urls with blob: scheme (#5825)

* fix: implement correct behaviour for urls with blob: scheme

Urls using the blob scheme can have special behaviour if their origin itself
is a url.
This fixes that by parsing the subdomain and if valid and the schemes(protocols)
are valid returns its origin.
Ive used node.js here a lot to make sure its behaviour is copied 1:1 and enabled
the automated tests for it.

Fixes https://github.com/oven-sh/bun/issues/5805

* fix: subUrl can be const, we are not modifying it

* style: add spaces after `if` keyword

2 files changed, 12 insertions, 3 deletions

diff --git a/src/bun.js/bindings/URLDecomposition.cpp b/src/bun.js/bindings/URLDecomposition.cpp
index d3f11b27f..21168f70f 100644
--- a/src/bun.js/bindings/URLDecomposition.cpp
+++ b/src/bun.js/bindings/URLDecomposition.cpp
@@ -35,7 +35,14 @@ String URLDecomposition::origin() const
 
     if (fullURL.protocolIsInHTTPFamily() or fullURL.protocolIsInFTPFamily() or fullURL.protocolIs("ws"_s) or fullURL.protocolIs("wss"_s))
         return fullURL.protocolHostAndPort();
-
+    if (fullURL.protocolIsBlob()) {
+        const String& path = fullURL.path().toString();
+        const URL subUrl { URL {}, path };
+        if (subUrl.isValid()) {
+            if (subUrl.protocolIsInHTTPFamily() or subUrl.protocolIsInFTPFamily() or subUrl.protocolIs("ws"_s) or subUrl.protocolIs("wss"_s) or subUrl.protocolIsFile())
+                return subUrl.protocolHostAndPort();
+        }
+    }
     return "null"_s;
 }
 
diff --git a/test/js/web/url/url.test.ts b/test/js/web/url/url.test.ts
index 7ddda80ef..f19a132df 100644
--- a/test/js/web/url/url.test.ts
+++ b/test/js/web/url/url.test.ts
@@ -52,8 +52,7 @@ describe("url", () => {
     expect(url.protocol).toBe("mailto:");
     expect(url.origin).toBe("null");
   });
-  it.skip("should work with blob urls", () => {
-    // TODO
+  it("blob urls", () => {
     var url = new URL("blob:https://example.com/1234-5678");
     expect(url.protocol).toBe("blob:");
     expect(url.origin).toBe("https://example.com");
@@ -72,6 +71,9 @@ describe("url", () => {
     url = new URL("blob:ws://example.com");
     expect(url.protocol).toBe("blob:");
     expect(url.origin).toBe("ws://example.com");
+    url = new URL("blob:file:///folder/else/text.txt");
+    expect(url.protocol).toBe("blob:");
+    expect(url.origin).toBe("file://");
   });
   it("prints", () => {
     expect(Bun.inspect(new URL("https://example.com"))).toBe(`URL {