Introduction to Handling APIs

APIs (Application Programming Interfaces) allow applications to communicate with each other. Python’s requests library makes it simple to interact with APIs by sending HTTP requests and handling responses.

In this lesson, you’ll learn how to use the requests library to send API requests and process responses.

Installing requests

To install the requests library, use the following command in your terminal:

pip install requests

Once installed, you can import it in your Python scripts:

# Importing requests
import requests

print("Requests library imported successfully")

Sending a GET Request

The GET method is used to retrieve data from an API. Use the requests.get() function to send a GET request:

# Sending a GET request
import requests

response = requests.get("https://jsonplaceholder.typicode.com/posts/1")
print(response.json())  # Outputs the JSON response

Sending a POST Request

The POST method is used to send data to an API. Use the requests.post() function:

# Sending a POST request
import requests

payload = {"title": "foo", "body": "bar", "userId": 1}
response = requests.post("https://jsonplaceholder.typicode.com/posts", json=payload)
print(response.json())  # Outputs the response

Handling Responses

The requests library provides several attributes to handle responses, such as:

• response.status_code: HTTP status code.
• response.json(): JSON response data.
• response.text: Raw response content.

# Handling responses
response = requests.get("https://jsonplaceholder.typicode.com/posts/1")
if response.status_code == 200:
    print("Success:", response.json())
else:
    print("Failed with status code:", response.status_code)

Adding Query Parameters

You can pass query parameters to APIs using the params argument in a GET request:

# Adding query parameters
params = {"userId": 1}
response = requests.get("https://jsonplaceholder.typicode.com/posts", params=params)
print(response.json())

Adding Headers

Headers allow you to send additional information, such as API keys or content types, with your requests:

# Adding headers
headers = {"Authorization": "Bearer YOUR_API_KEY"}
response = requests.get("https://jsonplaceholder.typicode.com/posts", headers=headers)
print(response.status_code)

Handling Errors

The requests library provides built-in exception handling for network-related errors:

# Handling errors
try:
    response = requests.get("https://jsonplaceholder.typicode.com/invalid")
    response.raise_for_status()
except requests.exceptions.HTTPError as err:
    print("HTTP error occurred:", err)
except requests.exceptions.RequestException as err:
    print("Request error occurred:", err)

Common Mistakes with requests

Here are some mistakes to avoid:

• Not handling HTTP errors with response.raise_for_status().
• Hardcoding sensitive information like API keys in the script.
• Forgetting to specify the correct HTTP method (e.g., GET, POST).

What Did We Learn?

In this lesson, you learned:

• How to install and import the requests library.
• How to send GET and POST requests to APIs.
• How to handle responses, add query parameters, headers, and handle errors.

Great job! Let’s move to the next topic.