11 - API

Study Guide for Python Programming: Unit on APIs

POOF WAFFLE!

API Syntax

Here’s Poof Waffle’s bulleted summary of the specified API functions and attributes commonly used with the Python requests library:

  • json()
    • Converts the JSON response content into a Python dictionary.
    • Syntax: response.json()
    • Used when the server response is in JSON format.
  • raise_for_status()
    • Raises an HTTPError exception for certain types of HTTP responses, such as 4xx or 5xx errors.
    • Syntax: response.raise_for_status()
    • Useful for error handling and ensuring the HTTP request was successful.
  • get()
    • Sends an HTTP GET request to the specified URL.
    • Syntax: requests.get(url, params=None, **kwargs)
    • Retrieves data from the URL and can accept parameters and other keyword arguments like headers, cookies, etc.
  • headers
    • Contains the HTTP headers that the server sent with the response.
    • Accessed as: response.headers
    • A dictionary-like object allowing access to header values, such as Content-Type or Date.
  • query string/params
    • Used to pass query parameters in an HTTP GET request.
    • Syntax within get(): requests.get(url, params={key: value})
    • params can be a dictionary, a list of tuples, or bytes, sent as a query string in the URL.
  • response.url
    • Contains the URL of the response.
    • Accessed as: response.url
    • Useful for debugging or logging, showing the URL after any redirections.

Study Guide for Python Programming: Unit on APIs

Key Concepts

Introduction to Web APIs

  • Web API: An Application Program Interface (API) that works over HTTP, allowing remote function calls and service access.
  • Evolution from User-Consumption to Device-Consumption: Transition from browsing the internet to using web services in applications and devices.

Basic Principles of Web APIs

  • API: A set of functions and procedures that allow the creation of applications accessing features or data of an operating system, application, or other services.
  • HTTP Protocol: The foundation for data communication on the Web, used by Web APIs.
  • JSON Responses: Most Web APIs return data in JSON (JavaScript Object Notation) format.

Finding and Using APIs

  • Research: Use search engines, API registries, and documentation to find relevant APIs.
  • API Registries: Websites like ProgrammableWeb, Mashape Marketplace, and GitHub public APIs list.
  • Cloud Providers: Amazon AWS, Google Cloud, Microsoft Azure, IBM Cloud offer a variety of APIs.
  • Mobile Apps: Many have associated APIs, often listed on their developer pages.

API Authentication

  • Common Methods: OAuth2, API keys (in headers or query strings).
  • Registration: Many APIs require registration to obtain an API key or token.
  • Access Control: Not all APIs are public or free; some require paid access.

Python and APIs

  • Requests Module: A Python library for making HTTP requests to APIs.
  • Handling API Responses: Parsing JSON responses, handling errors, and working with data.

Practical Applications

  • Service Integration: Combining multiple APIs to create new applications or services.
  • Data Retrieval and Analysis: Fetching data from APIs for analysis or display.

Practice Questions

  1. What is the standard authentication method used by most modern Web APIs? A. Basic Auth B. OAuth2 C. API Keys D. SSH Keys

  2. In Python, which module is primarily used for making HTTP requests to APIs? A. urllib B. http C. requests D. api

  3. Which HTTP method is commonly used for retrieving data from a Web API? A. POST B. GET C. PUT D. DELETE

  4. What format is most commonly used for Web API responses? A. XML B. HTML C. JSON D. CSV

  5. Where is the best place to find documentation for a specific Web API? A. The API’s official website B. Generic programming forums C. Python’s official documentation D. Textbooks on Python programming

Correct Answers and Explanations

  1. Answer: B. OAuth2
    • Explanation: OAuth2 is a common authentication standard used by many modern Web APIs for secure authorization.
  2. Answer: C. requests
    • Explanation: The requests module in Python is widely used for making HTTP requests to web APIs.
  3. Answer: B. GET
    • Explanation: The HTTP GET method is typically used for retrieving data from a Web API.
  4. Answer: C. JSON
    • Explanation: JSON is the most common format for Web API responses due to its lightweight and ease of use in web applications.
  5. Answer: A. The API’s official website
    • Explanation: The most reliable and up-to-date documentation for a Web API can usually be found on its official website.