uses fetch.body

app/api.js

@@ -197,6 +197,69 @@ export function uploadWs(encrypted, info, metadata, verifierB64, onprogress) {
   };
 }
 
+////////////////////////
+
+async function downloadS(id, keychain, onprogress, signal) {
+  const auth = await keychain.authHeader();
+  try {
+    const response = await fetch(`/api/download/${id}`, {
+      signal: signal ,
+      method: 'GET',
+      headers: {'Authorization': auth}
+    });
+
+    if (response.status !== 200) { 
+      throw new Error(response.status);
+    }
+
+    const authHeader = response.headers.get('WWW-Authenticate');
+    if (authHeader) {
+      keychain.nonce = parseNonce(authHeader);
+    }
+
+    const fileSize = response.headers.get('Content-Length');
+    onprogress([0, fileSize]);
+    
+    console.log(response.body);
+    if (response.body) {
+      return response.body;
+    }
+    return response.blob();
+
+  } catch (err) {
+    if (err.name === 'AbortError') {
+      throw new Error('0');
+    } else {
+      throw err;
+    }
+  }
+}
+
+async function tryDownloadStream(id, keychain, onprogress, signal, tries = 1) {
+  try {
+    const result = await downloadS(id, keychain, onprogress, signal);
+    return result;
+  } catch (e) {
+    if (e.message === '401' && --tries > 0) {
+      return tryDownloadStream(id, keychain, onprogress, signal, tries);
+    }
+    throw e;
+  }
+}
+
+export function downloadStream(id, keychain, onprogress) {
+  const controller = new AbortController();
+  function cancel() {
+    controller.abort();
+  }
+  return {
+    cancel,
+    result: tryDownloadStream(id, keychain, onprogress, controller.signal, 2)
+  };
+}
+
+//////////////////
+
 function download(id, keychain, onprogress, canceller) {
   const xhr = new XMLHttpRequest();
   canceller.oncancel = function() {