Add server header option to dev and run commands

[smarcelloc]

Security Enhancement: Server Header Control in FastAPI CLI

Problem Context

Uvicorn, by default, includes the "Server: uvicorn" header in all HTTP responses. This information represents a security risk because:

1. It exposes technical details about the infrastructure (Uvicorn server and, by extension, Python)
2. It makes it easier for potential attackers to identify the technology being used
3. It can be used to target specific attacks knowing the underlying technology

Before

Now

Solution Implemented

Added a new --server-header option to the fastapi dev and fastapi run commands, which:

• Is disabled by default (False), removing the "Server: uvicorn" header from responses
• When explicitly enabled (--server-header), maintains the original behavior

How to Use

To maintain the original behavior (show the server header):

fastapi dev --server-header
# or
fastapi run --server-header