Python class and calling code to retrieve US Consumer Price Index data from the Bureau of Labor Statistics (BLS) V2.0 Data API.

c_bls_data_api.py

import requests
import json

class c_bls_data_api:
    
    """
        File name:      c_bls_data_api.py
        Class name:     c_bls_data_api
        Author:         Randy Runtsch
        Date:           August 12, 2021
        Description:    Call BLS Data API with a query and handle the results.
        Reference:      https://www.bls.gov/developers/api_python.htm
    """

    def __init__(self, parameters, json_file_nm):

        # Open the output JSON file, get the report from api.bls.gov, and close the output file.

        json_file = open(json_file_nm, 'w', encoding='utf-8')
        self.get_report(parameters, json_file)
        json_file.close()

    def get_report(self, parameters, json_file):

        # Call the API to get the report. Write it to a JSON file.

        headers = {'Content-type': 'application/json'}
 
        response = requests.post('https://api.bls.gov/publicAPI/v2/timeseries/data/', data = parameters, headers = headers)

        if response.status_code != 200:
            # Something went wrong.
            raise ApiError('GET /tasks/ {}'.format(resp.status_code))
       
        json.dump(response.json(), json_file, indent = 6)

get_bls_cpi_data.py

import json
from c_bls_data_api import c_bls_data_api

# Call c_bls_data_api.py with a request for CPI data from 2002 through 2021
# and the name of the file to store the returned JSON data structure in.

print("Program started.")

# Set the register, series ID for CPI, start year, end year, and calculations. Note that setting calculations to true
# returns CPI percentages as well as the raw CPI.

parameters = json.dumps({"registrationkey":"PasteYourKeyHere", "seriesid":['CUUR0000SA0'], "startyear":"2002", "endyear":"2021", "calculations":"true"})

# Call the bls data api class with the parameters and the name of the data output file.
c_bls_data_api(parameters, 'D:/project_data/cpi/cpi_data_report.json')

print("Program completed")