thekid/Upload.class.php

## composer.json
{
  "name": "thekid/upload",
  "description": "Upload example",
  "type": "project",
  "require": {
    "xp-forge/handlebars-templates": "^3.3",
    "xp-forge/frontend": "^6.0"
  }
}

## Upload.class.php
<?php

use util\cmd\Console;
use web\Application;
use web\frontend\{Frontend, Handlebars, Get, Post, View, Request};

class Upload extends Application {

  public function routes() {
    $impl= new class() {

      #[Get]
      public function list() {
        return View::named('upload');
      }

      #[Post('/upload')]
      public function upload(#[Request] $req) {
        $uploaded= [];
        if ($multipart= $req->multipart()) {
          foreach ($multipart->files() as $name => $file) {
            Console::write('  Upload ', $file, ' [');

            $transferred= $previous= 0;
            while ($file->available()) {
              $transferred+= strlen($file->read());

              if (($transferred - $previous) > 262144) {
                $display= sprintf('%.1f', $transferred / 1048576);
                Console::write("{$display} MB]\033[".(strlen($display) + 4)."D");
                $previous= $transferred;
              }
            }

            $uploaded[$name]= sprintf('%.1f', $transferred / 1048576);
            Console::writeLine("{$uploaded[$name]} MB]\033[K");
          }
        }
        return View::named('upload')->fragment('success')->with(['uploaded' => $uploaded]);
      }
    };
    return new Frontend($impl, new Handlebars('.'));
  }
}

## upload.handlebars
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Upload</title>
  <link href="https://fonts.googleapis.com/css2?family=Lato:wght@300&display=swap" rel="stylesheet">
  <style type="text/css">
    * {
      font-family: 'Lato', sans-serif;
      padding: 0;
      margin: 0;
    }
    h1, h2, h3 {
      line-height: 1.2;
    }
    p {
      line-height: 1.6;
    }
    ul {
      margin: 1.5rem;
    }
    tt {
      font-family: 'Cascadia Code PL', monospace;
    }
    main {
      padding: 1rem;
    }
    form input, form button {
      font-size: 1rem;
    }
    progress {
      appearance: none;
      display: inline-block;
      width: 10rem;
      height: 1.25rem;
      border: 0;
      visibility: hidden;
    }
    progress::-webkit-progress-bar {
      background: lightgray;
    }
    progress::-webkit-progress-value {
      background: #06c;
      transition: width .25s ease-in-out;
    }
    #drop {
      background: #efefef;
      border: .125rem dashed transparent;
      height: 2rem;
      display: flex;
      align-items: center;
      cursor: pointer;
      margin-block: .25rem;
    }
    #drop.hovering {
      border-color: black;
    }
    #drop input[type='file'] {
      display: none;
    }
  </style>
</head>
<body {{#with request.values.token}}hx-headers='{"X-CSRF-Token": "{{.}}"}'{{/with}}>
  <main class="segments">
    <h1>Upload files</h1>
    <form id="form" hx-encoding="multipart/form-data" hx-post="/upload" hx-target="#message">
      <div id="drop">
        <span class="files"></span>
        <input type="file" name="file" multiple>
      </div>
      <button>Upload</button>

      <progress id="progress" value="0" max="100"></progress>
    </form>
    <div id="message"></div>
  </main>

  {{#*inline "success"}}
    {{#with uploaded}}
      <ul>
        {{#each .}}
          <li>File <tt>{{@key}}</tt> (size: {{.}} MB) uploaded!</li>
        {{/each}}
      </ul>
    {{else}}
      No file uploaded!
    {{/with}}
  {{/inline}}

  <script src="https://unpkg.com/htmx.org@1.9.10/dist/htmx.min.js"></script>
  <script type="module">
    const $progress = document.getElementById('progress');
    const $form = document.getElementById('form');
    const $drop = document.getElementById('drop');
    const $files = $form.elements['file'];

    const filesChanged = e => {
      let list = '';
      for (const file of $files.files) {
        list += ', ' + file.name + ' (' + file.type + ')';
      }
      $drop.querySelector('.files').innerText = list.substring(2);
    };

    $files.addEventListener('change', filesChanged);

    $drop.addEventListener('drop', e => {
      e.preventDefault();
      $drop.classList.remove('hovering');

      // If `Shift` key was pressed, append file
      if (e.shiftKey) {
        const list = new DataTransfer();
        for (const file of $files.files) {
          list.items.add(file);
        }
        for (const file of e.dataTransfer.files) {
          list.items.add(file);
        }
        $files.files = list.files;
      } else {
        $files.files = e.dataTransfer.files;
      }
      filesChanged();
    });

    $drop.addEventListener('click', e => {
      $files.click()
    });

    $drop.addEventListener('dragover', e => {
      e.preventDefault();
    });

    $drop.addEventListener('dragenter', e => {
      e.preventDefault();
      $drop.classList.add('hovering');
    });

    $drop.addEventListener('dragleave', e => {
      e.preventDefault();
      $drop.classList.remove('hovering');
    });

    $form.addEventListener('htmx:beforeRequest', e => {
      $progress.style.visibility = 'visible';
    });

    $form.addEventListener('htmx:afterRequest', e => {
      setTimeout(() => {
        $progress.style.visibility = 'hidden';
        $progress.setAttribute('value', 0);
      }, 1000);
    });

    $form.addEventListener('htmx:xhr:progress', e => {
      if (e.detail.lengthComputable) {
        $progress.setAttribute('value', e.detail.loaded / e.detail.total * 100);
      }
    });
  </script>
  </body>
</html>
	{
	"name": "thekid/upload",
	"description": "Upload example",
	"type": "project",
	"require": {
	"xp-forge/handlebars-templates": "^3.3",
	"xp-forge/frontend": "^6.0"
	}
	}
	<?php

	use util\cmd\Console;
	use web\Application;
	use web\frontend\{Frontend, Handlebars, Get, Post, View, Request};

	class Upload extends Application {

	public function routes() {
	$impl= new class() {

	#[Get]
	public function list() {
	return View::named('upload');
	}

	#[Post('/upload')]
	public function upload(#[Request] $req) {
	$uploaded= [];
	if ($multipart= $req->multipart()) {
	foreach ($multipart->files() as $name => $file) {
	Console::write(' Upload ', $file, ' [');

	$transferred= $previous= 0;
	while ($file->available()) {
	$transferred+= strlen($file->read());

	if (($transferred - $previous) > 262144) {
	$display= sprintf('%.1f', $transferred / 1048576);
	Console::write("{$display} MB]\033[".(strlen($display) + 4)."D");
	$previous= $transferred;
	}
	}

	$uploaded[$name]= sprintf('%.1f', $transferred / 1048576);
	Console::writeLine("{$uploaded[$name]} MB]\033[K");
	}
	}
	return View::named('upload')->fragment('success')->with(['uploaded' => $uploaded]);
	}
	};
	return new Frontend($impl, new Handlebars('.'));
	}
	}
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title>Upload</title>
	<link href="https://fonts.googleapis.com/css2?family=Lato:wght@300&display=swap" rel="stylesheet">
	<style type="text/css">
	* {
	font-family: 'Lato', sans-serif;
	padding: 0;
	margin: 0;
	}
	h1, h2, h3 {
	line-height: 1.2;
	}
	p {
	line-height: 1.6;
	}
	ul {
	margin: 1.5rem;
	}
	tt {
	font-family: 'Cascadia Code PL', monospace;
	}
	main {
	padding: 1rem;
	}
	form input, form button {
	font-size: 1rem;
	}
	progress {
	appearance: none;
	display: inline-block;
	width: 10rem;
	height: 1.25rem;
	border: 0;
	visibility: hidden;
	}
	progress::-webkit-progress-bar {
	background: lightgray;
	}
	progress::-webkit-progress-value {
	background: #06c;
	transition: width .25s ease-in-out;
	}
	#drop {
	background: #efefef;
	border: .125rem dashed transparent;
	height: 2rem;
	display: flex;
	align-items: center;
	cursor: pointer;
	margin-block: .25rem;
	}
	#drop.hovering {
	border-color: black;
	}
	#drop input[type='file'] {
	display: none;
	}
	</style>
	</head>
	<body {{#with request.values.token}}hx-headers='{"X-CSRF-Token": "{{.}}"}'{{/with}}>
	<main class="segments">
	<h1>Upload files</h1>
	<form id="form" hx-encoding="multipart/form-data" hx-post="/upload" hx-target="#message">
	<div id="drop">
	<span class="files"></span>
	<input type="file" name="file" multiple>
	</div>
	<button>Upload</button>

	<progress id="progress" value="0" max="100"></progress>
	</form>
	<div id="message"></div>
	</main>

	{{#*inline "success"}}
	{{#with uploaded}}
	<ul>
	{{#each .}}
	<li>File <tt>{{@key}}</tt> (size: {{.}} MB) uploaded!</li>
	{{/each}}
	</ul>
	{{else}}
	No file uploaded!
	{{/with}}
	{{/inline}}

	<script src="https://unpkg.com/htmx.org@1.9.10/dist/htmx.min.js"></script>
	<script type="module">
	const $progress = document.getElementById('progress');
	const $form = document.getElementById('form');
	const $drop = document.getElementById('drop');
	const $files = $form.elements['file'];

	const filesChanged = e => {
	let list = '';
	for (const file of $files.files) {
	list += ', ' + file.name + ' (' + file.type + ')';
	}
	$drop.querySelector('.files').innerText = list.substring(2);
	};

	$files.addEventListener('change', filesChanged);

	$drop.addEventListener('drop', e => {
	e.preventDefault();
	$drop.classList.remove('hovering');

	// If `Shift` key was pressed, append file
	if (e.shiftKey) {
	const list = new DataTransfer();
	for (const file of $files.files) {
	list.items.add(file);
	}
	for (const file of e.dataTransfer.files) {
	list.items.add(file);
	}
	$files.files = list.files;
	} else {
	$files.files = e.dataTransfer.files;
	}
	filesChanged();
	});

	$drop.addEventListener('click', e => {
	$files.click()
	});

	$drop.addEventListener('dragover', e => {
	e.preventDefault();
	});

	$drop.addEventListener('dragenter', e => {
	e.preventDefault();
	$drop.classList.add('hovering');
	});

	$drop.addEventListener('dragleave', e => {
	e.preventDefault();
	$drop.classList.remove('hovering');
	});

	$form.addEventListener('htmx:beforeRequest', e => {
	$progress.style.visibility = 'visible';
	});

	$form.addEventListener('htmx:afterRequest', e => {
	setTimeout(() => {
	$progress.style.visibility = 'hidden';
	$progress.setAttribute('value', 0);
	}, 1000);
	});

	$form.addEventListener('htmx:xhr:progress', e => {
	if (e.detail.lengthComputable) {
	$progress.setAttribute('value', e.detail.loaded / e.detail.total * 100);
	}
	});
	</script>
	</body>
	</html>