HTTP Status 411 - Length Required

POST /api/files HTTP/1.1
Host: api.example.com
Content-Type: application/octet-stream
Transfer-Encoding: chunked

HTTP/1.1 411 Length Required
Content-Type: application/json

{
  "error": "length_required",
  "message": "Content-Length header is required for file uploads",
  "reason": "Server needs to validate upload size against quota before accepting data"
}

POST /api/files HTTP/1.1
Host: api.example.com
Content-Type: application/octet-stream
Content-Length: 1048576

[1MB binary data]

HTTP/1.1 201 Created
Location: /api/files/file-abc-123

PUT /api/documents/doc-1 HTTP/1.1
Host: api.example.com
Content-Type: application/pdf

[PDF data without Content-Length]

HTTP/1.1 411 Length Required
Content-Type: application/json

{
  "error": "length_required",
  "message": "Content-Length required for size validation",
  "max_file_size": 52428800,
  "reason": "Server must validate size before allocating storage"
}