Requests - Handling GET Requests

Requests - Handling GET Requests

This chapter focuses on HTTP GET requests, one of the most common methods used to retrieve data from a specified resource. The requests library makes sending GET requests straightforward.

Making a Simple GET Request

To make a GET request, you use the requests.get() function, passing the URL of the resource you want to fetch.

Example: Fetching User Data

import requests
import json # For pretty printing JSON

url = 'https://jsonplaceholder.typicode.com/users/1' # API endpoint for a single user

try:
    response = requests.get(url)
    response.raise_for_status()  # Raise an exception for bad status codes (4xx or 5xx)

    # Accessing response data
    print(f"Status Code: {response.status_code}")
    print(f"Content-Type Header: {response.headers['Content-Type']}")

    # For JSON responses, use response.json()
    user_data = response.json()
    print("\nUser Data (parsed JSON):")
    # Pretty print the JSON data
    print(json.dumps(user_data, indent=2))

    # For text content (like HTML or plain text), use response.text
    # print(f"\nRaw Text Content (first 100 chars): {response.text[:100]}...")

except requests.exceptions.HTTPError as http_err:
    print(f"HTTP error occurred: {http_err}")
except requests.exceptions.RequestException as err:
    print(f"Other error occurred: {err}")

Output (Example)

Status Code: 200
Content-Type Header: application/json; charset=utf-8

User Data (parsed JSON):
{
  "id": 1,
  "name": "Leanne Graham",
  "username": "Bret",
  "email": "Sincere@april.biz",
  "address": {
    "street": "Kulas Light",
    "suite": "Apt. 556",
    "city": "Gwenborough",
    "zipcode": "92998-3874",
    "geo": {
      "lat": "-37.3159",
      "lng": "81.1496"
    }
  },
  "phone": "1-770-736-8031 x56442",
  "website": "hildegard.org",
  "company": {
    "name": "Romaguera-Crona",
    "catchPhrase": "Multi-layered client-server neural-net",
    "bs": "harness real-time e-markets"
  }
}

Key takeaways from the response object: response.status_code: The HTTP status code (e.g., 200 for OK, 404 for Not Found). response.headers: A dictionary-like object of response headers. response.json(): Parses JSON response content into a Python dictionary or list. Raises JSONDecodeError if parsing fails. response.text: The response content as a Unicode string. response.content: The response content as bytes (useful for images or other binary files).

Passing URL Parameters

You can pass URL parameters (also known as query strings) to a GET request using the params argument. Provide a dictionary of key-value pairs, and requests will correctly encode and append them to the URL.

Example: Fetching Posts by User ID

import requests
import json

url = 'https://jsonplaceholder.typicode.com/posts'
params = {
    'userId': 1,    # Filter posts for userId = 1
    '_limit': 2     # Limit results to 2 posts (some APIs support this)
}

try:
    response = requests.get(url, params=params)
    response.raise_for_status()

    print(f"Request URL: {response.url}") # Shows the full URL with parameters
    posts_data = response.json()
    print("\nFiltered Posts Data:")
    print(json.dumps(posts_data, indent=2))

except requests.exceptions.HTTPError as http_err:
    print(f"HTTP error occurred: {http_err}")
except requests.exceptions.RequestException as err:
    print(f"Other error occurred: {err}")

The params dictionary {'userId': 1, '_limit': 2} will be converted to the query string ?userId=1&_limit=2 and appended to the base URL.

Output (Example)

Request URL: https://jsonplaceholder.typicode.com/posts?userId=1&_limit=2

Filtered Posts Data:
[
  {
    "userId": 1,
    "id": 1,
    "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
    "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
  },
  {
    "userId": 1,
    "id": 2,
    "title": "qui est esse",
    "body": "est rerum tempore vitae\nsequi sint nihil reprehenderit dolor beatae ea dolores neque\nfugiat blanditiis voluptate porro vel nihil molestiae ut reiciendis\nqui aperiam non debitis possimus qui neque nisi nulla"
  }
]

Practical Applications

GET requests are fundamental for: - Fetching web pages (HTML content). - Consuming RESTful APIs to retrieve data (often in JSON or XML format). - Checking the availability or status of a web resource. - Downloading files where the entire resource is identified by the URL.