File Upload Gateway

const [file, setFile] = useState<File | null>(null)
const [uploading, setUploading] = useState(false)

const handleFileChange = (e: ChangeEvent<HTMLInputElement>) => {
  const selected = e.target.files?.[0]
  if (!selected) return
  
  // Validate file type
  const allowed = ['application/pdf', 'application/vnd...']
  if (!allowed.includes(selected.type)) {
    alert('Only PDF, DOCX, TXT allowed')
    return
  }
  
  // Validate file size (10MB max)
  if (selected.size > 10 * 1024 * 1024) {
    alert('File too large (max 10MB)')
    return
  }
  
  setFile(selected)
}

const handleUpload = async () => {
  if (!file) return
  
  setUploading(true)
  
  const formData = new FormData()
  formData.append('file', file)
  
  try {
    const response = await fetch('/api/documents', {
      method: 'POST',
      body: formData,
    })
    
    const result = await response.json()
    console.log('Uploaded:', result)
    alert(`Success: ${result.filename}`)
  } catch (error) {
    console.error('Upload failed:', error)
    alert('Upload failed')
  } finally {
    setUploading(false)
  }
}

from fastapi import FastAPI, File, UploadFile
from pathlib import Path
import shutil

app = FastAPI()

UPLOAD_DIR = Path("./uploads")
UPLOAD_DIR.mkdir(exist_ok=True)

@app.post("/ingest/file")
async def ingest_file(file: UploadFile = File(...)):
    # Save file
    file_path = UPLOAD_DIR / file.filename
    
    with file_path.open("wb") as buffer:
        shutil.copyfileobj(file.file, buffer)
    
    # Get metadata
    file_size = file_path.stat().st_size
    
    return {
        "filename": file.filename,
        "size": file_size,
        "contentType": file.content_type,
        "storagePath": str(file_path)
    }