Skip to content

Level 2 / Project 10 - Mock API Response Parser

Home: README

Learn Your Way

Read Build Watch Test Review Visualize Try
Concept This project — Quiz Flashcards Diagram Browser

Estimated time: 40 minutes

Focus

  • parse response-like payloads

Why this project exists

This project gives you level-appropriate practice in a realistic operations context. Goal: run the baseline, alter behavior, break one assumption, recover safely, and explain the fix.

Run (copy/paste)

Use <repo-root> as the folder containing this repository's README.md.

cd <repo-root>/projects/level-2/10-mock-api-response-parser
python project.py data/sample_input.txt
python project.py data/sample_input.txt --validate status data message
python project.py data/sample_input.txt --group role
pytest -q

Expected terminal output

Status: {'status': 200, 'category': 'success'}
{"count": 5, "fields": ["active", "id", "name", "role"], ...}
11 passed

Expected artifacts

  • Parsed response summary on stdout
  • Passing tests
  • Updated notes.md

Checkpoint: Baseline code runs and all tests pass. Commit your work before continuing.

Alter it (required) — Extension

  1. Add a --filter flag: --filter active=true to show only matching items.
  2. Add support for paginated responses (read pagination.total_pages).
  3. Add a --status-only flag that just checks and prints the status category.

Break it (required) — Core

  1. Feed a file with a JSON array at the root instead of an object.
  2. Feed a response where data is a string instead of a list.
  3. Pass a response with no status field at all.

Fix it (required) — Core

  1. Handle non-object JSON roots (wrap arrays in a response dict).
  2. Guard against non-list data values in extract_items.
  3. Return a clear message when status code is missing.

Checkpoint: All modifications done, tests still pass. Good time to review your changes.

Explain it (teach-back)

  1. What makes a JSON response "valid" beyond just being parseable JSON?
  2. How do HTTP status code ranges (2xx, 4xx, 5xx) map to outcomes?
  3. Why is dict.get(key, default) safer than dict[key] for API data?
  4. What is the pagination pattern and why do APIs use it?

Mastery check

You can move on when you can: - parse a nested JSON response and extract specific fields, - validate response structure against a schema, - categorise HTTP status codes from memory, - handle missing or malformed API data gracefully.

← Prev Home Next →