Make web file upload asynchronous

Closes #1

assets/js/fm.js

@@ -1,5 +1,10 @@
 document.addEventListener('DOMContentLoaded', () => {
-    if (!document.getElementById('upload-form')) return;
+    const form = document.getElementById('upload-form');
+    if (!form) return;
+    const upload = document.getElementById('file-upload');
+    const uploadLink = document.getElementById('file-upload-link');
+
+    const uploadField = document.getElementById('field-upload');
 
     const neverExpireCheckbox = document.getElementById('field-never_expire');
     const expireAfterDaysField = document.getElementById('field-expire_after_days');
@@ -14,4 +19,114 @@ document.addEventListener('DOMContentLoaded', () => {
     autogenUrlCheckbox.addEventListener('change', () => {
         slugField.disabled = autogenUrlCheckbox.checked;
     });
-});
+
+    let uploadForm;
+
+    form.addEventListener('submit', e => {
+        e.preventDefault();
+        if (!uploadForm || uploadForm.isFinished()) {
+            uploadForm = new UploadForm(form, upload, uploadLink, uploadField.files[0].name);
+            uploadForm.updateView();
+            uploadForm.start();
+        }
+    });
+});
+
+function UploadForm(form, upload, uploadLink, fileName) {
+    this.form = form;
+    this.upload = upload;
+    this.uploadLink = uploadLink;
+    this.fileName = fileName;
+    this.progressBar = this.upload.querySelector('.progress-bar');
+    this.progressBarContent = this.progressBar.querySelector('.content');
+    this.status = this.upload.querySelector('.status');
+    this.speed = this.status.querySelector('.speed');
+    this.finished = false;
+
+    this.xferSpeed = [];
+    this.lastTransferTime = null;
+
+    this.xhr = new XMLHttpRequest();
+    this.xhr.responseType = 'json';
+    this.xhr.upload.addEventListener('progress', e => {
+        if (e.lengthComputable) {
+            this.progressBar.classList.remove('undefined');
+            let percent = ((e.loaded / e.total) * 100).toFixed(2) + '%';
+            this.progressBar.style = `--progress: ${percent}`;
+            this.progressBarContent.innerText = percent;
+            this.updateSpeed(e.loaded);
+        } else {
+            this.progressBar.classList.add('undefined');
+        }
+    });
+    this.xhr.upload.addEventListener('loadstart', () => {
+        this.status.classList.remove('hidden');
+    });
+    this.xhr.addEventListener('load', () => {
+        this.finished = true;
+        let response = this.xhr.response;
+        console.log('done', response);
+        if (response.status === 'error') {
+            if (response.messages) {
+                this.restoreView();
+                window.applyFormMessages(this.form, response.messages);
+            }
+        } else if (response.url) {
+            this.status.innerHTML = 'Done!';
+            this.uploadLink.querySelector('.content').innerText = response.url;
+            this.uploadLink.classList.remove('hidden');
+        } else {
+            window.location.reload();
+        }
+    });
+    this.xhr.addEventListener('error', (e) => {
+        this.finished = true;
+        console.error('error', e);
+        this.status.innerHTML = 'Error; upload was interrupted.';
+    });
+}
+
+UploadForm.prototype.isFinished = function () {
+    return this.finished;
+}
+
+UploadForm.prototype.updateView = function () {
+    this.upload.querySelector('.name').innerText = this.fileName;
+    this.form.classList.add('hidden');
+    this.upload.classList.remove('hidden');
+    this.status.innerHTML = `Uploading @ <span class="speed">--</span>`;
+    this.speed = this.status.querySelector('.speed');
+}
+
+UploadForm.prototype.restoreView = function () {
+    this.status.classList.add('hidden');
+    this.upload.classList.add('hidden');
+    this.form.classList.remove('hidden');
+};
+
+UploadForm.prototype.start = function () {
+    const formData = new FormData(this.form);
+    this.xhr.open('POST', this.form.action);
+    this.xhr.send(formData);
+}
+
+const units = ['K', 'M', 'G', 'T'];
+UploadForm.prototype.updateSpeed = function (loaded) {
+    console.log(this.xferSpeed);
+    const time = new Date().getTime();
+    if (this.lastTransferTime) {
+        this.xferSpeed.push((loaded - this.lastLoaded) / (time - this.lastTransferTime));
+
+        if (this.xferSpeed.length > 10) this.xferSpeed = this.xferSpeed.slice(1);
+
+        let speed = this.xferSpeed.reduce((v, c) => v + c) / this.xferSpeed.length;
+        let unit = 0;
+        while (speed >= 1000 && unit < units.length - 1) {
+            speed /= 1000;
+            unit++;
+        }
+        this.speed.innerText = (speed).toFixed(2) + units[unit] + 'Bps';
+    }
+    this.lastTransferTime = time;
+    this.lastLoaded = loaded;
+}

assets/sass/app.scss

@@ -1 +1,2 @@
-@import "layout";
+@import "layout";
+@import "fm";

assets/sass/fm.scss

@@ -0,0 +1,11 @@
+@import "vars";
+
+#file-upload {
+	padding: 8px;
+	background: $infoColor;
+	border-radius: 5px;
+
+	.name, .status {
+		text-align: center;
+	}
+}

views/file-upload.njk

@@ -14,7 +14,8 @@
         <section class="panel">
             <h2>Upload a file</h2>
 
-            <form action="{{ route('post-file-frontend') }}" method="POST" enctype="multipart/form-data" id="upload-form">
+            <form action="{{ route('post-file-frontend') }}" method="POST" enctype="multipart/form-data"
+                  id="upload-form">
                 {{ macros.field(_locals, 'file', 'upload', '', 'Choose wisely', 'The maximum upload size is ' + max_upload_size + 'MiB', validation_attributes='required') }}
 
                 {{ macros.field(_locals, 'number', 'expire_after_days', '30', 'How many days to delete this file after', null, validation_attributes='max="1825"') }}
@@ -27,6 +28,18 @@
 
                 <button type="submit"><i data-feather="upload"></i> Upload</button>
             </form>
+
+            <div id="file-upload" class="hidden">
+                <div class="name">photo.jpg</div>
+                <div class="progress-bar" style="--progress: 50%;"><span class="content">50%</span></div>
+                <div class="status hidden"></div>
+            </div>
+
+            <div id="file-upload-link" class="hidden copyable-text">
+                <div class="title">URL</div>
+                <div class="content"></div>
+                <button class="copy-button"><i data-feather="copy"></i></button>
+            </div>
         </section>
 
         <section class="panel">

yarn.lock

@@ -9925,9 +9925,9 @@ widest-line@^3.1.0:
     string-width "^4.0.0"
 
 wms-core@^0:
-  version "0.8.10"
-  resolved "https://registry.toot.party/wms-core/-/wms-core-0.8.10.tgz#8db64926f9bd9eaa61556ad98dcd215361b16950"
-  integrity sha512-1GJkpOX/efoDGK9JOwHnBkD55Q6dEKTQsdHpgMmF3g0h7XxJFAAsZTv0tOyfYHIEpJo5mNdR/+mzdZTPsgtAdw==
+  version "0.8.11"
+  resolved "https://registry.toot.party/wms-core/-/wms-core-0.8.11.tgz#7b33600e3dff864f71e5a8bd57e185cf324b0332"
+  integrity sha512-We+PYb+D80gVj/VWUUYDazZCf/BiEjybi32Z51BEM73ihcmFuCOnD9FUq4Oy3MK/Vl6wVctWdapIb2jVnrSPug==
   dependencies:
     "@types/express" "^4.17.6"
     "@types/express-session" "^1.17.0"