Support file: URLs in `fetch` (#3858)

* Support file: URLs in `fetch`

* Update url.zig

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

6 files changed, 281 insertions, 183 deletions

diff --git a/src/bun.js/bindings/BunString.cpp b/src/bun.js/bindings/BunString.cpp
index e044730c4..5eb5f9f9b 100644
--- a/src/bun.js/bindings/BunString.cpp
+++ b/src/bun.js/bindings/BunString.cpp
@@ -315,6 +315,11 @@ extern "C" void BunString__toWTFString(BunString* bunString)
     }
 }
 
+extern "C" BunString URL__getFileURLString(BunString* filePath)
+{
+    return Bun::toStringRef(WTF::URL::fileURLWithFileSystemPath(Bun::toWTFString(*filePath)).stringWithoutFragmentIdentifier());
+}
+
 extern "C" WTF::URL* URL__fromJS(EncodedJSValue encodedValue, JSC::JSGlobalObject* globalObject)
 {
     auto throwScope = DECLARE_THROW_SCOPE(globalObject->vm());
diff --git a/src/bun.js/bindings/bindings.zig b/src/bun.js/bindings/bindings.zig
index 924eb27a1..4f533b9d9 100644
--- a/src/bun.js/bindings/bindings.zig
+++ b/src/bun.js/bindings/bindings.zig
@@ -4751,8 +4751,8 @@ pub const JSValue = enum(JSValueReprInt) {
     /// It knows not to free it
     /// This mimicks the implementation in JavaScriptCore's C++
     pub inline fn ensureStillAlive(this: JSValue) void {
-        if (this.isEmpty() or this.isNumber() or this.isBoolean() or this.isUndefinedOrNull()) return;
-        std.mem.doNotOptimizeAway(@as(C_API.JSObjectRef, @ptrCast(this.asVoid())));
+        if (!this.isCell()) return;
+        std.mem.doNotOptimizeAway(this.asEncoded().asPtr);
     }
 
     pub inline fn asNullableVoid(this: JSValue) ?*anyopaque {
@@ -5391,12 +5391,19 @@ pub const URL = opaque {
     extern fn URL__pathname(*URL) String;
     extern fn URL__getHrefFromJS(JSValue, *JSC.JSGlobalObject) String;
     extern fn URL__getHref(*String) String;
+    extern fn URL__getFileURLString(*String) String;
     pub fn hrefFromString(str: bun.String) String {
         JSC.markBinding(@src());
         var input = str;
         return URL__getHref(&input);
     }
 
+    pub fn fileURLFromString(str: bun.String) String {
+        JSC.markBinding(@src());
+        var input = str;
+        return URL__getFileURLString(&input);
+    }
+
     /// This percent-encodes the URL, punycode-encodes the hostname, and returns the result
     /// If it fails, the tag is marked Dead
     pub fn hrefFromJS(value: JSValue, globalObject: *JSC.JSGlobalObject) String {
diff --git a/src/bun.js/webcore/response.zig b/src/bun.js/webcore/response.zig
index a70a4f0ee..e9ba24fc5 100644
--- a/src/bun.js/webcore/response.zig
+++ b/src/bun.js/webcore/response.zig
@@ -1034,6 +1034,7 @@ pub const Fetch = struct {
         var hostname: ?[]u8 = null;
 
         var url_proxy_buffer: []const u8 = undefined;
+        var is_file_url = false;
 
         // TODO: move this into a DRYer implementation
         // The status quo is very repetitive and very bug prone
@@ -1061,127 +1062,131 @@ pub const Fetch = struct {
                     err,
                 );
             };
+            is_file_url = url.isFile();
             url_proxy_buffer = url.href;
-
-            if (args.nextEat()) |options| {
-                if (options.isObject() or options.jsType() == .DOMWrapper) {
-                    if (options.fastGet(ctx.ptr(), .method)) |method_| {
-                        var slice_ = method_.toSlice(ctx.ptr(), getAllocator(ctx));
-                        defer slice_.deinit();
-                        method = Method.which(slice_.slice()) orelse .GET;
-                    } else {
-                        method = request.method;
-                    }
-
-                    if (options.fastGet(ctx.ptr(), .body)) |body__| {
-                        if (Body.Value.fromJS(ctx.ptr(), body__)) |body_const| {
-                            var body_value = body_const;
-                            // TODO: buffer ReadableStream?
-                            // we have to explicitly check for InternalBlob
-                            body = body_value.useAsAnyBlob();
+            if (!is_file_url) {
+                if (args.nextEat()) |options| {
+                    if (options.isObject() or options.jsType() == .DOMWrapper) {
+                        if (options.fastGet(ctx.ptr(), .method)) |method_| {
+                            var slice_ = method_.toSlice(ctx.ptr(), getAllocator(ctx));
+                            defer slice_.deinit();
+                            method = Method.which(slice_.slice()) orelse .GET;
                         } else {
-                            // clean hostname if any
-                            if (hostname) |host| {
-                                bun.default_allocator.free(host);
-                            }
-                            // an error was thrown
-                            return JSC.JSValue.jsUndefined();
+                            method = request.method;
                         }
-                    } else {
-                        body = request.body.value.useAsAnyBlob();
-                    }
 
-                    if (options.fastGet(ctx.ptr(), .headers)) |headers_| {
-                        if (headers_.as(FetchHeaders)) |headers__| {
-                            if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                                hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                        if (options.fastGet(ctx.ptr(), .body)) |body__| {
+                            if (Body.Value.fromJS(ctx.ptr(), body__)) |body_const| {
+                                var body_value = body_const;
+                                // TODO: buffer ReadableStream?
+                                // we have to explicitly check for InternalBlob
+                                body = body_value.useAsAnyBlob();
+                            } else {
+                                // clean hostname if any
+                                if (hostname) |host| {
+                                    bun.default_allocator.free(host);
+                                }
+                                // an error was thrown
+                                return JSC.JSValue.jsUndefined();
                             }
-                            headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                            // TODO: make this one pass
-                        } else if (FetchHeaders.createFromJS(ctx.ptr(), headers_)) |headers__| {
-                            if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                                hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                        } else {
+                            body = request.body.value.useAsAnyBlob();
+                        }
+
+                        if (options.fastGet(ctx.ptr(), .headers)) |headers_| {
+                            if (headers_.as(FetchHeaders)) |headers__| {
+                                if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                                    hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                                }
+                                headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
+                                // TODO: make this one pass
+                            } else if (FetchHeaders.createFromJS(ctx.ptr(), headers_)) |headers__| {
+                                if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                                    hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                                }
+                                headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
+                                headers__.deref();
+                            } else if (request.headers) |head| {
+                                if (head.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                                    hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                                }
+                                headers = Headers.from(head, bun.default_allocator, .{ .body = &body }) catch unreachable;
                             }
-                            headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                            headers__.deref();
                         } else if (request.headers) |head| {
-                            if (head.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                                hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
-                            }
                             headers = Headers.from(head, bun.default_allocator, .{ .body = &body }) catch unreachable;
                         }
-                    } else if (request.headers) |head| {
-                        headers = Headers.from(head, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                    }
 
-                    if (options.get(ctx, "timeout")) |timeout_value| {
-                        if (timeout_value.isBoolean()) {
-                            disable_timeout = !timeout_value.asBoolean();
-                        } else if (timeout_value.isNumber()) {
-                            disable_timeout = timeout_value.to(i32) == 0;
+                        if (options.get(ctx, "timeout")) |timeout_value| {
+                            if (timeout_value.isBoolean()) {
+                                disable_timeout = !timeout_value.asBoolean();
+                            } else if (timeout_value.isNumber()) {
+                                disable_timeout = timeout_value.to(i32) == 0;
+                            }
                         }
-                    }
 
-                    if (options.getOptionalEnum(ctx, "redirect", FetchRedirect) catch {
-                        return .zero;
-                    }) |redirect_value| {
-                        redirect_type = redirect_value;
-                    }
+                        if (options.getOptionalEnum(ctx, "redirect", FetchRedirect) catch {
+                            return .zero;
+                        }) |redirect_value| {
+                            redirect_type = redirect_value;
+                        }
 
-                    if (options.get(ctx, "keepalive")) |keepalive_value| {
-                        if (keepalive_value.isBoolean()) {
-                            disable_keepalive = !keepalive_value.asBoolean();
-                        } else if (keepalive_value.isNumber()) {
-                            disable_keepalive = keepalive_value.to(i32) == 0;
+                        if (options.get(ctx, "keepalive")) |keepalive_value| {
+                            if (keepalive_value.isBoolean()) {
+                                disable_keepalive = !keepalive_value.asBoolean();
+                            } else if (keepalive_value.isNumber()) {
+                                disable_keepalive = keepalive_value.to(i32) == 0;
+                            }
                         }
-                    }
-                    if (options.get(globalThis, "verbose")) |verb| {
-                        verbose = verb.toBoolean();
-                    }
-                    if (options.get(globalThis, "signal")) |signal_arg| {
-                        if (signal_arg.as(JSC.WebCore.AbortSignal)) |signal_| {
-                            _ = signal_.ref();
-                            signal = signal_;
+                        if (options.get(globalThis, "verbose")) |verb| {
+                            verbose = verb.toBoolean();
+                        }
+                        if (options.get(globalThis, "signal")) |signal_arg| {
+                            if (signal_arg.as(JSC.WebCore.AbortSignal)) |signal_| {
+                                _ = signal_.ref();
+                                signal = signal_;
+                            }
                         }
-                    }
 
-                    if (options.get(globalThis, "proxy")) |proxy_arg| {
-                        if (proxy_arg.isString() and proxy_arg.getLength(ctx) > 0) {
-                            var href = JSC.URL.hrefFromJS(proxy_arg, globalThis);
-                            if (href.tag == .Dead) {
-                                const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, "fetch() proxy URL is invalid", .{}, ctx);
-                                // clean hostname if any
-                                if (hostname) |host| {
-                                    bun.default_allocator.free(host);
+                        if (options.get(globalThis, "proxy")) |proxy_arg| {
+                            if (proxy_arg.isString() and proxy_arg.getLength(ctx) > 0) {
+                                var href = JSC.URL.hrefFromJS(proxy_arg, globalThis);
+                                if (href.tag == .Dead) {
+                                    const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, "fetch() proxy URL is invalid", .{}, ctx);
+                                    // clean hostname if any
+                                    if (hostname) |host| {
+                                        bun.default_allocator.free(host);
+                                    }
+                                    bun.default_allocator.free(url_proxy_buffer);
+
+                                    return JSPromise.rejectedPromiseValue(globalThis, err);
                                 }
+                                defer href.deref();
+                                var buffer = std.fmt.allocPrint(bun.default_allocator, "{s}{}", .{ url_proxy_buffer, href }) catch {
+                                    globalThis.throwOutOfMemory();
+                                    return .zero;
+                                };
+                                url = ZigURL.parse(buffer[0..url.href.len]);
+                                is_file_url = url.isFile();
+
+                                proxy = ZigURL.parse(buffer[url.href.len..]);
                                 bun.default_allocator.free(url_proxy_buffer);
-
-                                return JSPromise.rejectedPromiseValue(globalThis, err);
+                                url_proxy_buffer = buffer;
                             }
-                            defer href.deref();
-                            var buffer = std.fmt.allocPrint(bun.default_allocator, "{s}{}", .{ url_proxy_buffer, href }) catch {
-                                globalThis.throwOutOfMemory();
-                                return .zero;
-                            };
-                            url = ZigURL.parse(buffer[0..url.href.len]);
-                            proxy = ZigURL.parse(buffer[url.href.len..]);
-                            bun.default_allocator.free(url_proxy_buffer);
-                            url_proxy_buffer = buffer;
                         }
                     }
-                }
-            } else {
-                method = request.method;
-                body = request.body.value.useAsAnyBlob();
-                if (request.headers) |head| {
-                    if (head.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                        hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                } else {
+                    method = request.method;
+                    body = request.body.value.useAsAnyBlob();
+                    if (request.headers) |head| {
+                        if (head.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                            hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                        }
+                        headers = Headers.from(head, bun.default_allocator, .{ .body = &body }) catch unreachable;
+                    }
+                    if (request.signal) |signal_| {
+                        _ = signal_.ref();
+                        signal = signal_;
                     }
-                    headers = Headers.from(head, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                }
-                if (request.signal) |signal_| {
-                    _ = signal_.ref();
-                    signal = signal_;
                 }
             }
         } else if (bun.String.tryFromJS(first_arg, globalThis)) |str| {
@@ -1203,105 +1208,108 @@ pub const Fetch = struct {
                 return JSPromise.rejectedPromiseValue(globalThis, err);
             };
             url_proxy_buffer = url.href;
+            is_file_url = url.isFile();
+
+            if (!is_file_url) {
+                if (args.nextEat()) |options| {
+                    if (options.isObject() or options.jsType() == .DOMWrapper) {
+                        if (options.fastGet(ctx.ptr(), .method)) |method_| {
+                            var slice_ = method_.toSlice(ctx.ptr(), getAllocator(ctx));
+                            defer slice_.deinit();
+                            method = Method.which(slice_.slice()) orelse .GET;
+                        }
 
-            if (args.nextEat()) |options| {
-                if (options.isObject() or options.jsType() == .DOMWrapper) {
-                    if (options.fastGet(ctx.ptr(), .method)) |method_| {
-                        var slice_ = method_.toSlice(ctx.ptr(), getAllocator(ctx));
-                        defer slice_.deinit();
-                        method = Method.which(slice_.slice()) orelse .GET;
-                    }
-
-                    if (options.fastGet(ctx.ptr(), .body)) |body__| {
-                        if (Body.Value.fromJS(ctx.ptr(), body__)) |body_const| {
-                            var body_value = body_const;
-                            // TODO: buffer ReadableStream?
-                            // we have to explicitly check for InternalBlob
-                            body = body_value.useAsAnyBlob();
-                        } else {
-                            // clean hostname if any
-                            if (hostname) |host| {
-                                bun.default_allocator.free(host);
+                        if (options.fastGet(ctx.ptr(), .body)) |body__| {
+                            if (Body.Value.fromJS(ctx.ptr(), body__)) |body_const| {
+                                var body_value = body_const;
+                                // TODO: buffer ReadableStream?
+                                // we have to explicitly check for InternalBlob
+                                body = body_value.useAsAnyBlob();
+                            } else {
+                                // clean hostname if any
+                                if (hostname) |host| {
+                                    bun.default_allocator.free(host);
+                                }
+                                // an error was thrown
+                                return JSC.JSValue.jsUndefined();
                             }
-                            // an error was thrown
-                            return JSC.JSValue.jsUndefined();
                         }
-                    }
 
-                    if (options.fastGet(ctx.ptr(), .headers)) |headers_| {
-                        if (headers_.as(FetchHeaders)) |headers__| {
-                            if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                                hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
-                            }
-                            headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                            // TODO: make this one pass
-                        } else if (FetchHeaders.createFromJS(ctx.ptr(), headers_)) |headers__| {
-                            defer headers__.deref();
-                            if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
-                                hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                        if (options.fastGet(ctx.ptr(), .headers)) |headers_| {
+                            if (headers_.as(FetchHeaders)) |headers__| {
+                                if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                                    hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                                }
+                                headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
+                                // TODO: make this one pass
+                            } else if (FetchHeaders.createFromJS(ctx.ptr(), headers_)) |headers__| {
+                                defer headers__.deref();
+                                if (headers__.fastGet(JSC.FetchHeaders.HTTPHeaderName.Host)) |_hostname| {
+                                    hostname = _hostname.toOwnedSliceZ(bun.default_allocator) catch unreachable;
+                                }
+                                headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
+                            } else {
+                                // Converting the headers failed; return null and
+                                //  let the set exception get thrown
+                                return .zero;
                             }
-                            headers = Headers.from(headers__, bun.default_allocator, .{ .body = &body }) catch unreachable;
-                        } else {
-                            // Converting the headers failed; return null and
-                            //  let the set exception get thrown
-                            return .zero;
                         }
-                    }
 
-                    if (options.get(ctx, "timeout")) |timeout_value| {
-                        if (timeout_value.isBoolean()) {
-                            disable_timeout = !timeout_value.asBoolean();
-                        } else if (timeout_value.isNumber()) {
-                            disable_timeout = timeout_value.to(i32) == 0;
+                        if (options.get(ctx, "timeout")) |timeout_value| {
+                            if (timeout_value.isBoolean()) {
+                                disable_timeout = !timeout_value.asBoolean();
+                            } else if (timeout_value.isNumber()) {
+                                disable_timeout = timeout_value.to(i32) == 0;
+                            }
                         }
-                    }
 
-                    if (options.getOptionalEnum(ctx, "redirect", FetchRedirect) catch {
-                        return .zero;
-                    }) |redirect_value| {
-                        redirect_type = redirect_value;
-                    }
+                        if (options.getOptionalEnum(ctx, "redirect", FetchRedirect) catch {
+                            return .zero;
+                        }) |redirect_value| {
+                            redirect_type = redirect_value;
+                        }
 
-                    if (options.get(ctx, "keepalive")) |keepalive_value| {
-                        if (keepalive_value.isBoolean()) {
-                            disable_keepalive = !keepalive_value.asBoolean();
-                        } else if (keepalive_value.isNumber()) {
-                            disable_keepalive = keepalive_value.to(i32) == 0;
+                        if (options.get(ctx, "keepalive")) |keepalive_value| {
+                            if (keepalive_value.isBoolean()) {
+                                disable_keepalive = !keepalive_value.asBoolean();
+                            } else if (keepalive_value.isNumber()) {
+                                disable_keepalive = keepalive_value.to(i32) == 0;
+                            }
                         }
-                    }
 
-                    if (options.get(globalThis, "verbose")) |verb| {
-                        verbose = verb.toBoolean();
-                    }
-                    if (options.get(globalThis, "signal")) |signal_arg| {
-                        if (signal_arg.as(JSC.WebCore.AbortSignal)) |signal_| {
-                            _ = signal_.ref();
-                            signal = signal_;
+                        if (options.get(globalThis, "verbose")) |verb| {
+                            verbose = verb.toBoolean();
+                        }
+                        if (options.get(globalThis, "signal")) |signal_arg| {
+                            if (signal_arg.as(JSC.WebCore.AbortSignal)) |signal_| {
+                                _ = signal_.ref();
+                                signal = signal_;
+                            }
                         }
-                    }
 
-                    if (options.getTruthy(globalThis, "proxy")) |proxy_arg| {
-                        if (proxy_arg.isString() and proxy_arg.getLength(globalThis) > 0) {
-                            var href = JSC.URL.hrefFromJS(proxy_arg, globalThis);
-                            if (href.tag == .Dead) {
-                                const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, "fetch() proxy URL is invalid", .{}, ctx);
-                                // clean hostname if any
-                                if (hostname) |host| {
-                                    bun.default_allocator.free(host);
+                        if (options.getTruthy(globalThis, "proxy")) |proxy_arg| {
+                            if (proxy_arg.isString() and proxy_arg.getLength(globalThis) > 0) {
+                                var href = JSC.URL.hrefFromJS(proxy_arg, globalThis);
+                                if (href.tag == .Dead) {
+                                    const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, "fetch() proxy URL is invalid", .{}, ctx);
+                                    // clean hostname if any
+                                    if (hostname) |host| {
+                                        bun.default_allocator.free(host);
+                                    }
+                                    bun.default_allocator.free(url_proxy_buffer);
+
+                                    return JSPromise.rejectedPromiseValue(globalThis, err);
                                 }
+                                defer href.deref();
+                                var buffer = std.fmt.allocPrint(bun.default_allocator, "{s}{}", .{ url_proxy_buffer, href }) catch {
+                                    globalThis.throwOutOfMemory();
+                                    return .zero;
+                                };
+                                url = ZigURL.parse(buffer[0..url.href.len]);
+                                proxy = ZigURL.parse(buffer[url.href.len..]);
                                 bun.default_allocator.free(url_proxy_buffer);
-
-                                return JSPromise.rejectedPromiseValue(globalThis, err);
+                                url_proxy_buffer = buffer;
                             }
-                            defer href.deref();
-                            var buffer = std.fmt.allocPrint(bun.default_allocator, "{s}{}", .{ url_proxy_buffer, href }) catch {
-                                globalThis.throwOutOfMemory();
-                                return .zero;
-                            };
-                            url = ZigURL.parse(buffer[0..url.href.len]);
-                            proxy = ZigURL.parse(buffer[url.href.len..]);
-                            bun.default_allocator.free(url_proxy_buffer);
-                            url_proxy_buffer = buffer;
                         }
                     }
                 }
@@ -1318,14 +1326,73 @@ pub const Fetch = struct {
             return JSPromise.rejectedPromiseValue(globalThis, err);
         }
 
+        // This is not 100% correct.
+        // We don't pass along headers, we ignore method, we ignore status code...
+        // But it's better than status quo.
+        if (is_file_url) {
+            defer bun.default_allocator.free(url_proxy_buffer);
+            var path_buf: [bun.MAX_PATH_BYTES]u8 = undefined;
+            const PercentEncoding = @import("../../url.zig").PercentEncoding;
+            var path_buf2: [bun.MAX_PATH_BYTES]u8 = undefined;
+            var stream = std.io.fixedBufferStream(&path_buf2);
+            const url_path_decoded = path_buf2[0 .. PercentEncoding.decode(
+                @TypeOf(&stream.writer()),
+                &stream.writer(),
+                url.path,
+            ) catch {
+                globalThis.throwOutOfMemory();
+                return .zero;
+            }];
+            const temp_file_path = bun.path.joinAbsStringBuf(
+                globalThis.bunVM().bundler.fs.top_level_dir,
+                &path_buf,
+                &[_]string{
+                    globalThis.bunVM().main,
+                    "../",
+                    url_path_decoded,
+                },
+                .auto,
+            );
+            var file_url_string = JSC.URL.fileURLFromString(bun.String.fromUTF8(temp_file_path));
+            defer file_url_string.deref();
+
+            const bun_file = Blob.findOrCreateFileFromPath(
+                .{
+                    .path = .{
+                        .string = bun.PathString.init(
+                            temp_file_path,
+                        ),
+                    },
+                },
+                globalThis,
+            );
+
+            var response = bun.default_allocator.create(Response) catch @panic("out of memory");
+
+            response.* = Response{
+                .body = Body{
+                    .init = Body.Init{
+                        .status_code = 200,
+                    },
+                    .value = .{ .Blob = bun_file },
+                },
+                .allocator = bun.default_allocator,
+                .url = file_url_string.toOwnedSlice(bun.default_allocator) catch @panic("out of memory"),
+            };
+
+            return JSPromise.resolvedPromiseValue(globalThis, response.toJS(globalThis));
+        }
+
         if (url.protocol.len > 0) {
             if (!(url.isHTTP() or url.isHTTPS())) {
+                defer bun.default_allocator.free(url_proxy_buffer);
                 const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, "protocol must be http: or https:", .{}, ctx);
                 return JSPromise.rejectedPromiseValue(globalThis, err);
             }
         }
 
         if (!method.hasRequestBody() and body.size() > 0) {
+            defer bun.default_allocator.free(url_proxy_buffer);
             const err = JSC.toTypeError(.ERR_INVALID_ARG_VALUE, fetch_error_unexpected_body, .{}, ctx);
             return JSPromise.rejectedPromiseValue(globalThis, err);
         }
diff --git a/src/url.zig b/src/url.zig
index dcb1e91cd..064481257 100644
--- a/src/url.zig
+++ b/src/url.zig
@@ -36,6 +36,10 @@ pub const URL = struct {
     username: string = "",
     port_was_automatically_set: bool = false,
 
+    pub fn isFile(this: *const URL) bool {
+        return strings.eqlComptime(this.protocol, "file");
+    }
+
     pub fn fromJS(js_value: JSC.JSValue, globalObject: *JSC.JSGlobalObject, allocator: std.mem.Allocator) !URL {
         var href = JSC.URL.hrefFromJS(globalObject, js_value);
         if (href.tag == .Dead) {
@@ -63,6 +67,10 @@ pub const URL = struct {
         return this.hostname.len == 0 or strings.eqlComptime(this.hostname, "localhost") or strings.eqlComptime(this.hostname, "0.0.0.0");
     }
 
+    pub inline fn isUnix(this: *const URL) bool {
+        return strings.hasPrefixComptime(this.protocol, "unix");
+    }
+
     pub fn displayProtocol(this: *const URL) string {
         if (this.protocol.len > 0) {
             return this.protocol;
diff --git a/test/js/web/fetch/fetch.test.ts b/test/js/web/fetch/fetch.test.ts
index 768818420..d7fc87ade 100644
--- a/test/js/web/fetch/fetch.test.ts
+++ b/test/js/web/fetch/fetch.test.ts
@@ -1203,3 +1203,13 @@ it("new Request(https://example.com, otherRequest) uses url from left instead of
   expect(req2.url).toBe("http://localhost/def");
   expect(req2.headers.get("foo")).toBe("bar");
 });
+
+it("fetch() file:// works", async () => {
+  expect(await (await fetch(import.meta.url)).text()).toEqual(await Bun.file(import.meta.path).text());
+  expect(await (await fetch(new URL("fetch.test.ts", import.meta.url))).text()).toEqual(
+    await Bun.file(Bun.fileURLToPath(new URL("fetch.test.ts", import.meta.url))).text(),
+  );
+  expect(await (await fetch(new URL("file with space in the name.txt", import.meta.url))).text()).toEqual(
+    await Bun.file(Bun.fileURLToPath(new URL("file with space in the name.txt", import.meta.url))).text(),
+  );
+});
diff --git a/test/js/web/fetch/file with space in the name.txt b/test/js/web/fetch/file with space in the name.txt
new file mode 100644
index 000000000..3462721fd
--- /dev/null
+++ b/test/js/web/fetch/file with space in the name.txt
@@ -0,0 +1 @@
+hello!
\ No newline at end of file