Serving static files in FastAPI - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output when accessing a static file URL?

Given this FastAPI app code, what will be the HTTP response status code when accessing /static/example.txt if the file exists in the static folder?

FastAPI

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

app = FastAPI()
app.mount("/static", StaticFiles(directory="static"), name="static")

A 500 Internal Server Error

B 200 OK with the contents of example.txt

C 302 Redirect to /static/

D 404 Not Found error

💡 Hint

Think about what happens when a static file exists and is served by StaticFiles.

When a file exists in the mounted static directory, FastAPI serves it with a 200 OK status and the file content.

📝 Syntax

intermediate

Which option correctly mounts a static directory in FastAPI?

Select the code snippet that correctly mounts the 'assets' folder at the URL path '/assets' using FastAPI.

A app.mount("/assets", StaticFiles(directory="assets"))

B app.mount("assets", StaticFiles(directory="/assets"), name="assets")

C app.mount("/assets", StaticFiles(directory="assets"), name="assets")

D app.mount("/assets", StaticFiles(path="assets"), name="assets")

💡 Hint

Check the parameter names and URL path format.

The mount method requires the URL path starting with a slash and the directory parameter to specify the folder.

🔧 Debug

advanced

Why does this FastAPI app return 404 for static files?

Consider this code snippet: from fastapi import FastAPI from fastapi.staticfiles import StaticFiles app = FastAPI() app.mount("/static", StaticFiles(directory="static_files"), name="static") The folder 'static_files' exists and contains 'image.png'. Accessing '/static/image.png' returns 404. What is the most likely cause?

A StaticFiles requires an absolute path, not a relative one.

B The file 'image.png' is not readable by the server.

C The app must include a route to serve static files explicitly.

D The folder name 'static_files' is incorrect or misspelled.

💡 Hint

Check the folder name and path carefully.

If the folder name given to StaticFiles does not match the actual folder name, FastAPI cannot find the files and returns 404.

❓ state_output

advanced

What happens if you mount two static directories on the same path?

Given this FastAPI code: app.mount("/static", StaticFiles(directory="static1"), name="static1") app.mount("/static", StaticFiles(directory="static2"), name="static2") What will be the behavior when accessing '/static/file.txt'?

A The second mount overrides the first; files served from 'static2'.

B Files are served from both directories merged together.

C FastAPI raises an error on app startup due to duplicate mounts.

D Files are served from 'static1' only; second mount ignored.

💡 Hint

Think about how mounting the same path twice works.

Mounting the same path twice causes the second mount to override the first one, so files come from the second directory.

🧠 Conceptual

expert

Which statement about FastAPI StaticFiles is true?

Choose the correct statement about serving static files with FastAPI's StaticFiles.

A StaticFiles automatically sets correct MIME types based on file extensions.

B StaticFiles requires manual setting of Content-Type headers for each file.

C StaticFiles can only serve files from the root directory of the project.

D StaticFiles disables caching by default to always serve fresh files.

💡 Hint

Think about how web servers handle file types.

StaticFiles uses Starlette's implementation which sets MIME types automatically based on file extensions.