Creating URL Queries

Overview

Teaching: 20 min
Exercises: 20 min

Questions

• What are URL query strings?

• How can you make API requests?

• How do you interperet API documentation?

Objectives

• Explain URL query strings

• Explain how to create API queries

• Explain how to read and interperet API documentation

URL Query Strings

YouTube

https://www.youtube.com/watch?v=s7wmiS2mSXY&t=1m45s

Orbis

https://orbis.library.yale.edu/vwebv/searchResults?searchArg=python&searchCode=GKEY&searchType=0&recCount=10

Reading Documentation

• Look through the params
  • What types of search parameters are available?
  • Do they match what you need?
  • What is the Endpoint (Base URL)?
• Look for sample requests & responses
  • What kind of data does it return?
  • Is it what you’re looking for?
• Look for restrictions
  • Is it free?
  • Does it require a key or permissions?
  • Do they impose a limit?

Creating a Query

• National Weather Service API
  • Documentation: https://forecast-v3.weather.gov/documentation?redirect=legacy
  • Endpoint/Base URL: https://api.weather.gov

Let’s create a query

Run this query: https://api.weather.gov/stations?limit=10&state=CT

1. What do the results show?
2. What is the Station Identifier for Tweed-New Haven Airport?
3. Write a query that returns all active weather alerts for California. (Hint: use ‘area’ not ‘state’)

Solution

1. Shows 10 currently-active weather stations in Connecticut and includes metadata about each station.
2. KHVN
3. https://api.weather.gov/alerts?active=1&area=CA or https://api.weather.gov/alerts/active?area=CA or https://api.weather.gov/alerts/active/area/CA

Key Points

• REST APIs use query stings to make requests

• URL queries are found all across the web