Requests and responses

Asking a server for something

An HTTP request has a method, a URL, and optional headers and parameters. The answer has a status code, headers, and a body.

In this course you will use fake_requests, which behaves like the requests library but answers from a scripted service instead of the network — Python compiled to WebAssembly has no sockets. Everything you learn transfers unchanged.

import fake_requests as requests

r = requests.get("https://api.pylearn.dev/weather?city=London")
r.status_code    # 200
r.ok             # True for 2xx and 3xx
r.json()         # {"city": "London", "temp_c": 14, ...}
r.text           # the body as a string

Query parameters are better passed separately than glued onto the URL, because the library escapes them for you:

r = requests.get("https://api.pylearn.dev/weather", params={"city": "Tokyo"})

Your turn: fetch the weather for Lisbon and pull out the status code, the temperature and the condition.

Turning a response into your own shape

An API gives you its structure; your program usually wants a different one. Doing that conversion at the boundary — rather than passing raw response dictionaries through your whole codebase — is what keeps a change at the API from rippling everywhere.

Your turn: write get_summary(city) returning {"city": ..., "temp_c": ..., "summary": "London: 14C, cloudy"} for a city that exists.