API 1

desktop/src/main/stream.ts

@@ -43,6 +43,16 @@ export const registerStreamProtocol = () => {
         // Convert e.g. "%20" to spaces.
         const path = decodeURIComponent(pathname);
         switch (host) {
+            case "read":
+                try {
+                    return net.fetch(pathToFileURL(path).toString());
+                } catch (e) {
+                    log.error(`Failed to read stream for ${url}`, e);
+                    return new Response(`Failed to read stream: ${e.message}`, {
+                        status: 500,
+                    });
+                }
+
             case "write":
                 try {
                     await writeStream(path, request.body);
@@ -55,16 +65,6 @@ export const registerStreamProtocol = () => {
                     );
                 }
 
-            case "read":
-                try {
-                    return net.fetch(pathToFileURL(path).toString());
-                } catch (e) {
-                    log.error(`Failed to read stream for ${url}`, e);
-                    return new Response(`Failed to read stream: ${e.message}`, {
-                        status: 500,
-                    });
-                }
-
             default:
                 return new Response("", { status: 404 });
         }

web/apps/photos/src/utils/native-stream.ts

@@ -4,6 +4,34 @@
  * NOTE: These functions only work when we're running in our desktop app.
  */
 
+/**
+ * Stream the given file from the user's local filesystem.
+ *
+ * **This only works when we're running in our desktop app**. It uses the
+ * "stream://" protocol handler exposed by our custom code in the Node.js layer.
+ * See: [Note: IPC streams].
+ *
+ * @param path The path on the file on the user's local filesystem whose
+ * contents we want to stream.
+ *
+ * @return A standard web {@link Response} object that contains the contents of
+ * the file. In particular, `response.body` will be a {@link ReadableStream}
+ * that can be used to read the files contents in a streaming, chunked, manner.
+ */
+export const readStream = async (path: string) => {
+    const req = new Request(`stream://read${path}`, {
+        method: "GET",
+    });
+
+    const res = await fetch(req);
+    if (!res.ok)
+        throw new Error(
+            `Failed to read stream from ${path}: HTTP ${res.status}`,
+        );
+
+    return res;
+};
+
 /**
  * Write the given stream to a file on the local machine.
  *