FileMetadata

interface FileMetadata {
  mimeType: string;
  size: number;
  isBinary: boolean;
  encoding: 'utf-8' | 'base64';
}

import { getSandbox } from '@cloudflare/sandbox';

const sandbox = getSandbox(env.SANDBOX, 'my-sandbox');

// Stream a file and get metadata
const stream = await sandbox.readFileStream('/workspace/image.png');
const reader = stream.getReader();
const decoder = new TextDecoder();

let metadata: FileMetadata | null = null;
const chunks: Uint8Array[] = [];

while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  
  const text = decoder.decode(value, { stream: true });
  const lines = text.split('\n');
  
  for (const line of lines) {
    if (!line.startsWith('data: ')) continue;
    
    const event = JSON.parse(line.substring(6));
    
    if (event.type === 'metadata') {
      metadata = {
        mimeType: event.mimeType,
        size: event.size,
        isBinary: event.isBinary,
        encoding: event.encoding
      };
      
      console.log('File metadata:', metadata);
      // mimeType: "image/png"
      // size: 52431
      // isBinary: true
      // encoding: "base64"
    }
    
    if (event.type === 'chunk' && metadata) {
      if (metadata.isBinary) {
        // Decode base64 chunk
        const binary = atob(event.data);
        const bytes = new Uint8Array(binary.length);
        for (let i = 0; i < binary.length; i++) {
          bytes[i] = binary.charCodeAt(i);
        }
        chunks.push(bytes);
      } else {
        // UTF-8 text chunk
        chunks.push(new TextEncoder().encode(event.data));
      }
    }
  }
}

// Reconstruct file
if (metadata) {
  const blob = new Blob(chunks, { type: metadata.mimeType });
  console.log('Reconstructed file size:', blob.size);
}

const stream = await sandbox.readFileStream(filePath);
const reader = stream.getReader();

let metadata: FileMetadata | null = null;

while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  
  const text = new TextDecoder().decode(value);
  const event = JSON.parse(text.substring(6)); // Skip "data: "
  
  if (event.type === 'metadata') {
    metadata = event as FileMetadata;
    
    // Choose processing based on file type
    if (metadata.mimeType.startsWith('text/')) {
      console.log('Processing text file...');
    } else if (metadata.mimeType.startsWith('image/')) {
      console.log('Processing image file...');
    } else {
      console.log('Unknown file type:', metadata.mimeType);
    }
    
    // Check file size
    if (metadata.size > 10_000_000) {
      console.warn('Large file detected:', metadata.size, 'bytes');
      reader.cancel();
      break;
    }
  }
}