feat: add file-sharing example with shareable download links

apps/file-sharing/.env.example

@@ -0,0 +1,4 @@
+SHELBY_ACCOUNT_PRIVATE_KEY=your_private_key_here
+SHELBY_API_KEY=your_api_key_here
+SHELBY_ACCOUNT_ADDRESS=your_account_address_here
+PORT=3000

apps/file-sharing/README.md

@@ -0,0 +1,67 @@
+# Shelby File Sharing Example
+
+A full-stack example demonstrating decentralized file sharing built on the Shelby SDK. Upload any file, receive a unique shareable link, and let anyone download it — every file is SHA-256 hashed and stored on Shelby decentralized hot storage with Aptos blockchain provenance.
+
+Think of it as a decentralized alternative to WeTransfer.
+
+## Prerequisites
+
+- Node.js >= 22
+- pnpm
+- A Shelby account with testnet tokens
+- Shelby API key
+
+## Installation
+
+Navigate to the file-sharing directory and install dependencies:
+
+    cd apps/file-sharing
+    pnpm install
+
+## Environment Variables
+
+Copy the example file and fill in your credentials:
+
+    cp .env.example .env
+
+Required variables:
+
+    SHELBY_ACCOUNT_PRIVATE_KEY=your_private_key_here
+    SHELBY_API_KEY=your_api_key_here
+    SHELBY_ACCOUNT_ADDRESS=your_account_address_here
+    PORT=3000
+
+## Usage
+
+    pnpm dev
+
+Open http://localhost:3000 in your browser.
+
+## How It Works
+
+1. Upload — User selects a file; the server pushes it to Shelby via client.upload()
+2. Hash — A SHA-256 digest is computed locally before upload for integrity verification
+3. Link — A unique drop ID is generated and stored in drops.json
+4. Share — Anyone with the link can hit /drop/:id/download to stream the file from Shelby via client.download()
+5. Verify — The SHA-256 hash is displayed on the download page so recipients can verify file integrity
+
+## API
+
+| Method | Path | Description |
+|--------|------|-------------|
+| POST | /upload | Upload a file multipart/form-data |
+| GET | /drop/:id | Get drop metadata |
+| GET | /drop/:id/download | Download file from Shelby |
+| GET | /drops | List all drops |
+
+## Project Structure
+
+    apps/file-sharing/
+    src/
+        server.ts      # Express server + Shelby SDK integration
+    public/
+        index.html     # Upload page, and the download page served for /d/:id links
+    .env.example
+    package.json
+    README.md
+    tsconfig.json

apps/file-sharing/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "@shelby-protocol/file-sharing-example",
+  "version": "1.0.0",
+  "description": "An example app demonstrating decentralized file sharing with shareable download links using the Shelby SDK",
+  "type": "module",
+  "scripts": {
+    "dev": "tsx --env-file=.env src/server.ts",
+    "lint": "biome check .",
+    "fmt": "biome check . --write"
+  },
+  "keywords": [
+    "shelby",
+    "sdk",
+    "blob",
+    "storage",
+    "file-sharing"
+  ],
+  "author": "erhnysr",
+  "license": "MIT",
+  "dependencies": {
+    "@aptos-labs/ts-sdk": "^5.1.1",
+    "@shelby-protocol/sdk": "latest",
+    "express": "^4.21.2",
+    "multer": "^2.0.1",
+    "uuid": "^11.1.0"
+  },
+  "devDependencies": {
+    "@biomejs/biome": "2.2.4",
+    "@types/express": "^5.0.3",
+    "@types/multer": "^1.4.12",
+    "@types/uuid": "^10.0.0",
+    "tsx": "^4.20.5",
+    "typescript": "^5.9.2"
+  },
+  "engines": {
+    "node": ">=22"
+  }
+}

apps/file-sharing/public/index.html

@@ -0,0 +1,120 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <title>Shelby File Sharing</title>
+    <style>
+      body {
+        font-family: system-ui, sans-serif;
+        max-width: 560px;
+        margin: 48px auto;
+        padding: 0 16px;
+        color: #1a1a1a;
+      }
+      h1 {
+        font-size: 1.4rem;
+      }
+      .card {
+        border: 1px solid #ddd;
+        border-radius: 8px;
+        padding: 16px;
+        margin-top: 16px;
+      }
+      .hash {
+        font-family: ui-monospace, monospace;
+        font-size: 0.8rem;
+        word-break: break-all;
+      }
+      .error {
+        color: #b00020;
+      }
+      [hidden] {
+        display: none;
+      }
+    </style>
+  </head>
+  <body>
+    <h1>Shelby File Sharing</h1>
+
+    <section id="upload-view" hidden>
+      <form id="upload-form" class="card">
+        <input type="file" name="file" required />
+        <button type="submit">Upload</button>
+      </form>
+      <div id="upload-result" class="card" hidden>
+        <p>Share this link:</p>
+        <p><a id="share-link"></a></p>
+        <p>SHA-256: <span id="upload-hash" class="hash"></span></p>
+        <p>Expires: <span id="upload-expires"></span></p>
+      </div>
+    </section>
+
+    <section id="drop-view" class="card" hidden>
+      <p><strong id="drop-name"></strong> (<span id="drop-size"></span>)</p>
+      <p>SHA-256: <span id="drop-hash" class="hash"></span></p>
+      <p>Expires: <span id="drop-expires"></span></p>
+      <p><a id="drop-download">Download</a></p>
+    </section>
+
+    <p id="error" class="error" hidden></p>
+
+    <script>
+      const $ = (id) => document.getElementById(id);
+
+      function showError(message) {
+        $("error").textContent = message;
+        $("error").hidden = false;
+      }
+
+      function formatSize(bytes) {
+        if (bytes < 1024) return `${bytes} B`;
+        if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
+        return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
+      }
+
+      async function showDrop(id) {
+        $("drop-view").hidden = false;
+        const res = await fetch(`/drop/${encodeURIComponent(id)}`);
+        if (!res.ok) {
+          $("drop-view").hidden = true;
+          showError("This drop was not found.");
+          return;
+        }
+        const drop = await res.json();
+        $("drop-name").textContent = drop.fileName;
+        $("drop-size").textContent = formatSize(drop.fileSize);
+        $("drop-hash").textContent = drop.sha256;
+        $("drop-expires").textContent = new Date(drop.expiresAt).toLocaleString();
+        $("drop-download").href = `/drop/${encodeURIComponent(id)}/download`;
+      }
+
+      function showUpload() {
+        $("upload-view").hidden = false;
+        $("upload-form").addEventListener("submit", async (event) => {
+          event.preventDefault();
+          $("error").hidden = true;
+          const res = await fetch("/upload", {
+            method: "POST",
+            body: new FormData(event.target),
+          });
+          const body = await res.json();
+          if (!res.ok) {
+            showError(body.error ?? "Upload failed.");
+            return;
+          }
+          const link = `${location.origin}/d/${body.id}`;
+          $("share-link").href = link;
+          $("share-link").textContent = link;
+          $("upload-hash").textContent = body.sha256;
+          $("upload-expires").textContent = new Date(body.expiresAt).toLocaleString();
+          $("upload-result").hidden = false;
+        });
+      }
+
+      const match = location.pathname.match(/^\/d\/([^/]+)\/?$/);
+      if (match) showDrop(decodeURIComponent(match[1]));
+      else showUpload();
+    </script>
+  </body>
+</html>