kinda works, upload, download etc

app/reader.go

@@ -0,0 +1,45 @@
+package app
+
+import (
+	"io"
+	"sync"
+)
+
+type teeReadCloser struct {
+	r io.Reader
+	c io.Closer
+}
+
+func (t *teeReadCloser) Read(p []byte) (int, error) { return t.r.Read(p) }
+func (t *teeReadCloser) Close() error               { return t.c.Close() }
+
+type progressWriter struct {
+	sync.Mutex
+
+	done  int64
+	total int64
+	cb    func(done, total int64)
+}
+
+func (pw *progressWriter) Write(p []byte) (int, error) {
+	n := len(p)
+
+	if pw.cb != nil {
+		pw.Lock()
+		defer pw.Unlock()
+		pw.done += int64(n)
+		pw.cb(pw.done, pw.total)
+	}
+
+	return n, nil
+}
+
+func ReadAllWithProgress(r io.Reader, totalBytes int64, onProgress func(done, total int64)) ([]byte, error) {
+	return io.ReadAll(NewProgressReader(r, totalBytes, onProgress))
+}
+
+func NewProgressReader(r io.Reader, totalBytes int64, onProgress func(done, total int64)) io.ReadCloser {
+	pw := &progressWriter{total: totalBytes, cb: onProgress}
+
+	return &teeReadCloser{r: io.TeeReader(r, pw), c: io.NopCloser(r)}
+}