Read and Default Query Parameters
Use args.get with fallbacks and type coercion.
Read and Default Query Parameters is a free Flask Academy lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Flask Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Query Params Recap
Query parameters ride in the URL after a question mark, like ?page=2&sort=new. They let clients pass optional tweaks to a request. 🔧
They Live in request.args
Flask parses the query string into request.args, a dict-like object you can read inside any view function.
from flask import request
args = request.argsBracket Access Is Risky
Reading a key with brackets crashes with a 400 when that key is missing. Real users will eventually drop a parameter you expected.
page = request.args["page"]Reach for .get
The .get method returns None instead of raising when a key is absent, so your endpoint stays alive through messy input.
page = request.args.get("page")Give It a Default
Pass a second argument and .get returns that fallback when the key is missing, so the view always has a usable value.
page = request.args.get("page", "1")Everything Is a String
Query values always arrive as text. A page of 2 reads as the string two, so doing math on it directly will surprise you.
request.args.get("page") + 1 # errorCoerce With type
The type keyword converts the value and quietly returns the default if conversion fails, giving you a clean integer.
page = request.args.get("page", 1, type=int)Bad Input Falls Back
If a client sends ?page=oops, the type=int conversion fails and .get hands back your default rather than blowing up.
request.args.get("page", 1, type=int) # 1Booleans Need Care
There is no real bool type here. Compare the raw string yourself to read a flag, since any non empty text is truthy in Python.
active = request.args.get("active") == "1"Combine Several Params
Read each parameter with its own default. Together they shape a filtered list view without ever crashing on absent keys.
page = request.args.get("page", 1, type=int)
sort = request.args.get("sort", "new")A Defensive List View
This products route never errors: missing or invalid query params simply collapse into safe, sensible defaults.
@app.route("/products")
def products():
page = request.args.get("page", 1, type=int)
return f"Page {page}"Quick Check
One question to seal in safe query reading.
Recap: Safe Defaults
You read query params with .get, supplied defaults, coerced types, and handled bad input gracefully. Your views stay crash free. 🎉
Frequently asked questions
Is the “Read and Default Query Parameters” lesson free?
Yes — the full text of “Read and Default Query Parameters” is free to read here on the web, and the Flask Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Flask Academy course, upgrade to CoddyKit PRO.
What will I learn in “Read and Default Query Parameters”?
Use args.get with fallbacks and type coercion. You practise Flask Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Flask Academy?
No prior experience is required. Flask Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Read and Default Query Parameters” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Flask Academy lesson?
Yes. Every Flask Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Build an HTML Form That Posts
- Read and Default Query Parameters
- Validate Required Fields by Hand
- Redirect After Post (PRG Pattern)