146. Interfacing with RESTful APIs using requests

Interfacing with RESTful APIs using Python's requests module is a common task for sending HTTP requests and handling responses. Here are some basic and advanced examples demonstrating how to interact with RESTful APIs using requests.

1. Making a GET Request

A simple GET request to retrieve data from an API.

import requests

def get_data_from_api(url):
    response = requests.get(url)
    if response.status_code == 200:
        print("Data retrieved successfully:")
        print(response.json())  # Assuming the response is in JSON format
    else:
        print(f"Failed to retrieve data. Status code: {response.status_code}")

# Example usage
get_data_from_api('https://jsonplaceholder.typicode.com/posts')

Explanation:

• requests.get(url) sends a GET request to the provided URL.

• response.json() parses the JSON response into a Python dictionary.

2. Making a POST Request

Sending data to an API using a POST request.

import requests

def send_data_to_api(url, data):
    response = requests.post(url, json=data)
    if response.status_code == 201:
        print("Data posted successfully.")
        print(response.json())  # Assuming the response is in JSON format
    else:
        print(f"Failed to post data. Status code: {response.status_code}")

# Example usage
data = {'title': 'foo', 'body': 'bar', 'userId': 1}
send_data_to_api('https://jsonplaceholder.typicode.com/posts', data)

Explanation:

• requests.post(url, json=data) sends a POST request with JSON data.

• response.status_code == 201 checks if the data was successfully created.

3. Handling Query Parameters in GET Requests

Sending query parameters with a GET request.

import requests

def get_data_with_params(url, params):
    response = requests.get(url, params=params)
    if response.status_code == 200:
        print("Data retrieved successfully:")
        print(response.json())
    else:
        print(f"Failed to retrieve data. Status code: {response.status_code}")

# Example usage
params = {'userId': 1}
get_data_with_params('https://jsonplaceholder.typicode.com/posts', params)

Explanation:

• The params argument in requests.get(url, params=params) adds query parameters to the URL.

• For example, https://jsonplaceholder.typicode.com/posts?userId=1.

4. Handling Headers in Requests

Customizing headers in your HTTP requests.

import requests

def get_data_with_headers(url, headers):
    response = requests.get(url, headers=headers)
    if response.status_code == 200:
        print("Data retrieved successfully:")
        print(response.json())
    else:
        print(f"Failed to retrieve data. Status code: {response.status_code}")

# Example usage
headers = {'Authorization': 'Bearer your_token_here'}
get_data_with_headers('https://jsonplaceholder.typicode.com/posts', headers)

Explanation:

• The headers argument in requests.get(url, headers=headers) allows you to send custom headers, such as authorization tokens.

5. Making PUT Requests to Update Data

Sending data to update an existing resource using a PUT request.

import requests

def update_data_in_api(url, data):
    response = requests.put(url, json=data)
    if response.status_code == 200:
        print("Data updated successfully.")
        print(response.json())
    else:
        print(f"Failed to update data. Status code: {response.status_code}")

# Example usage
data = {'id': 1, 'title': 'updated title', 'body': 'updated body'}
update_data_in_api('https://jsonplaceholder.typicode.com/posts/1', data)

Explanation:

• requests.put(url, json=data) sends a PUT request to update an existing resource at the given URL.

6. Making DELETE Requests

Deleting a resource with a DELETE request.

import requests

def delete_data_from_api(url):
    response = requests.delete(url)
    if response.status_code == 200:
        print("Data deleted successfully.")
    else:
        print(f"Failed to delete data. Status code: {response.status_code}")

# Example usage
delete_data_from_api('https://jsonplaceholder.typicode.com/posts/1')

Explanation:

• requests.delete(url) sends a DELETE request to the specified URL to remove a resource.

7. Handling Timeouts in Requests

Setting a timeout for your HTTP requests to avoid waiting indefinitely.

import requests

def get_data_with_timeout(url, timeout):
    try:
        response = requests.get(url, timeout=timeout)
        if response.status_code == 200:
            print("Data retrieved successfully:")
            print(response.json())
        else:
            print(f"Failed to retrieve data. Status code: {response.status_code}")
    except requests.Timeout:
        print("The request timed out.")
    except requests.RequestException as e:
        print(f"An error occurred: {e}")

# Example usage
get_data_with_timeout('https://jsonplaceholder.typicode.com/posts', timeout=5)

Explanation:

• The timeout parameter in requests.get(url, timeout=timeout) specifies how many seconds to wait before raising a Timeout exception.

8. Handling JSON Response

Parsing a JSON response and handling potential errors.

import requests

def fetch_json_data(url):
    response = requests.get(url)
    try:
        response.raise_for_status()  # Raise HTTPError for bad responses
        data = response.json()
        print("JSON data:", data)
    except requests.exceptions.HTTPError as err:
        print(f"HTTP error occurred: {err}")
    except ValueError:
        print("Error parsing JSON response")

# Example usage
fetch_json_data('https://jsonplaceholder.typicode.com/posts')

Explanation:

• response.raise_for_status() raises an exception if the HTTP request returned an error (status code >= 400).

• response.json() parses the JSON response.

9. Handling Response Status Codes

Checking the status code to handle different API responses.

import requests

def handle_status_code(url):
    response = requests.get(url)
    if response.status_code == 200:
        print("Success!")
    elif response.status_code == 404:
        print("Resource not found.")
    elif response.status_code == 500:
        print("Server error occurred.")
    else:
        print(f"Unexpected status code: {response.status_code}")

# Example usage
handle_status_code('https://jsonplaceholder.typicode.com/posts/1')

Explanation:

• Different status codes (e.g., 404 for "Not Found", 500 for "Internal Server Error") are handled using conditional checks.

10. Sending Form Data with POST Requests

Sending form data using requests.post().

import requests

def send_form_data(url, form_data):
    response = requests.post(url, data=form_data)
    if response.status_code == 200:
        print("Form submitted successfully.")
        print(response.text)
    else:
        print(f"Failed to submit form. Status code: {response.status_code}")

# Example usage
form_data = {'username': 'john_doe', 'password': 'secret'}
send_form_data('https://httpbin.org/post', form_data)

Explanation:

• data=form_data sends form-encoded data in a POST request.

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Conclusion:

The requests library in Python makes interacting with RESTful APIs straightforward. You can handle GET, POST, PUT, DELETE requests, work with query parameters, headers, timeouts, and responses easily. Whether you're interacting with JSON, form data, or handling different HTTP status codes, the requests module provides all the necessary tools to handle API interactions effectively.