Rewrote the server in cpp with the frontend in svelte

frontend/src/components/FileViewer.svelte

@@ -0,0 +1,57 @@
+<script lang="ts">
+    import {Button, Spinner} from 'flowbite-svelte';
+    import {Download} from 'carbon-icons-svelte';
+    import {api, rpc, token, workingWrapperR} from '../store';
+    import {onDestroy} from 'svelte';
+
+    export let node: api.Node;
+
+    let src = '';
+    let loading = false;
+
+    let mime: string|null;
+    let image: boolean, video: boolean, audio: boolean, pdf: boolean, can_display: boolean;
+    $: workingWrapperR<string>(() => rpc.FS_get_mime($token ?? '', node.id)).then(v => mime = v);
+    $: image = mime?.startsWith('image/') ?? false;
+    $: video = mime?.startsWith('video/') ?? false;
+    $: audio = mime?.startsWith('audio/') ?? false;
+    $: pdf = mime === 'application/pdf';
+    $: can_display = image || video || audio || pdf;
+
+    async function load() {
+        loading = true;
+        if (src.startsWith('blob'))
+            URL.revokeObjectURL(src);
+        const resp = await fetch('/download', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+            body: `token=${$token ?? ''}&node=${node.id}`
+        });
+        if (resp.status != 200)
+            return;
+        src = URL.createObjectURL(await resp.blob());
+        loading = false;
+    }
+
+    $: if (image || pdf) load();
+
+    onDestroy(() => { if (src.startsWith('blob')) URL.revokeObjectURL(src); });
+</script>
+
+<Button class="w-full mb-6"><Download />Download</Button>
+{#if can_display && !loading && src === ''}
+    <Button class="w-full" outline on:click={load}>Load</Button>
+{:else if loading}
+    <Spinner class="w-full" />
+{:else if can_display && src !== ''}
+    {#if image}
+        <img class="w-full" alt="img" src={src} />
+    {:else if video}
+        <!-- svelte-ignore a11y-media-has-caption -->
+        <video class="w-full" src={src} controls autoplay />
+    {:else if audio}
+        <audio class="w-full" src={src} controls autoplay />
+    {:else if pdf}
+        <embed class="w-full" style="height: 75vh" src={src} type="application/pdf" />
+    {/if}
+{/if}