brought back 7.5 file-upload as file-upload-multiple-posts; updated to latest API

renamed form-upload to file-upload-html-form
renamed file-upload to file-upload-single-post

examples/file-upload-multiple-posts/web_root/app.js

@@ -0,0 +1,41 @@
+// Copyright (c) 2020 Cesanta Software Limited
+// All rights reserved
+
+// Helper function to display upload status
+var setStatus = function(text) {
+  document.getElementById('el3').innerText = text;
+};
+
+// When user clicks on a button, trigger file selection dialog
+var button = document.getElementById('el2');
+button.onclick = function(ev) {
+  input.click();
+};
+
+// Send a large blob of data chunk by chunk
+var sendFileData = function(name, data, chunkSize) {
+  var sendChunk = function(offset) {
+    var chunk = data.subarray(offset, offset + chunkSize) || '';
+    var opts = {method: 'POST', body: chunk};
+    var url = '/upload?offset=' + offset + '&name=' + encodeURIComponent(name);
+    setStatus(
+        'sending bytes ' + offset + '..' + (offset + chunk.length) + ' of ' +
+        data.length);
+    fetch(url, opts).then(function(res) {
+      if (chunk.length > 0) sendChunk(offset + chunk.length);
+    });
+  };
+  sendChunk(0);
+};
+
+// If user selected a file, read it into memory and trigger sendFileData()
+var input = document.getElementById('el1');
+input.onchange = function(ev) {
+  if (!ev.target.files[0]) return;
+  var f = ev.target.files[0], r = new FileReader();
+  r.readAsArrayBuffer(f);
+  r.onload = function() {
+    ev.target.value = '';
+    sendFileData(f.name, new Uint8Array(r.result), 4096);
+  };
+};