some code for streamed downloads

1 files changed, 57 insertions, 0 deletions

diff --git a/client-web/source/sw/download_stream.ts b/client-web/source/sw/download_stream.ts
new file mode 100644
index 0000000..4eaf382
--- /dev/null
+++ b/client-web/source/sw/download_stream.ts
@@ -0,0 +1,57 @@
+import { SW } from "./init.ts"
+
+// export function StreamDownload(size: number, filename?: string, progress?: (position: number) => void) {
+//     let position = 0
+//     const buffer = new Uint8Array(size)
+//     return {
+//         close() {
+//             const a = document.createElement("a")
+//             a.href = URL.createObjectURL(new Blob([buffer], { type: "text/plain" }))
+//             a.download = filename ?? "file"
+//             a.click()
+//         },
+//         write(chunk: Blob) {
+//             const reader = new FileReader();
+//             reader.onload = function (event) {
+//                 const arr = new Uint8Array(event.target!.result as ArrayBuffer);
+//                 for (let i = 0; i < arr.length; i++, position++) {
+//                     buffer[position] = arr[i]
+//                 }
+//                 if (progress) progress(position)
+//             };
+//             reader.readAsArrayBuffer(chunk);
+//         }
+//     }
+// }
+
+export function StreamDownload(size: number, filename?: string, progress?: (position: number) => void) {
+    let position = 0
+
+    const path = `/download/${encodeURIComponent(filename ?? "file")}`
+
+    const { port1, port2 } = new MessageChannel()
+    SW!.postMessage({ path, size }, [port2])
+
+    const a = document.createElement("a")
+    a.href = path
+    a.download = filename ?? "file"
+    a.target = "_blank"
+    a.click()
+
+    return {
+        close() {
+            port1.postMessage("end")
+        },
+        write(chunk: Blob) {
+            const reader = new FileReader();
+            reader.onload = function (event) {
+                const arr = new Uint8Array(event.target!.result as ArrayBuffer);
+                console.log("send", arr);
+                port1.postMessage(arr)
+                position += arr.length
+                if (progress) progress(position)
+            };
+            reader.readAsArrayBuffer(chunk);
+        }
+    }
+}