Network-shaped failures without fragile parsing

Intermediate Defensive APIs: validation, sanitization & exceptions

Created by Pavel · 29.04.2026 at 19:10 UTC

HTTP layers deliver bytes on the wire; JSON parsers want text; base64 wraps binary inside ASCII. Mixing these causes classic bugs: calling .json() on undecoded bytes, double-decoding UTF-8, or assuming Content-Type matches the body.

Robust clients: read bytes → decode with declared charset → json.loads → validate with Pydantic or manual checks. When scraping or using partner APIs, separate transport, parsing, and validation so failures pinpoint the broken layer.

requests response content vs text: [1].

Sources

[1]https://requests.readthedocs.io/en/latest/user/quickstart/#response-content Return to text

University approvals: 0

Tasks

Question 1

In requests, response.content vs response.text differs because:

Hint

Bytes vs decoded str.

They are identical in all versions

content is raw bytes; text is a decoded Unicode string using encodings

text is always ASCII bytes

content includes HTTP headers

Question 2

You receive base64-encoded UTF-8 JSON inside a string field. The safest layering is:

Hint

Decode then parse then validate.

eval() the inner string

base64-decode to bytes → decode utf-8 → json.loads → validate

json.loads twice without decoding

Use regex alone to extract fields

Question 3

decode_b64_ascii(b: bytes) -> bytes uses base64.b64decode (standard library).

Hint

stdlib base64 only.

import base64


def decode_b64_ascii(b: bytes) -> bytes:
    pass

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Card Info

Topic: Defensive APIs: validation, sanitization & exceptions
Difficulty: Intermediate
Completed: 0 users

Creator

Pavel