Configure the Advanced I/O Function

Next, we will begin coding the to-do list application by configuring the function component.

The function’s directory, functions/to_do_list_function contains:

• The main.py main function file

• The catalyst-config.json configuration file

• The requirements.txt file to mention any external libraries that you might add.

You will be adding code in the main.py file.

The three APIs in the Advanced I/O function that handle the routing between the server and the Data Store are:

• GET /todo: To obtain the to-do list items from the TodoItems table in the Data Store

• POST /todo: To create and save a new list item in the Data Store

• DELETE /todo: To delete a list item from the Data Store

Next, let’s add the code in the function file. Copy the Python code and paste it in main.py in the functions/to_do_list_function directory of your project, and save the file. You can use any IDE of your choice to work with the application’s files.

    

        
main.py
        

            
copy
            

                

            
        
    
    

    

         import json
import zcatalyst_sdk
import logging
from flask import Request, make_response, jsonify
logger = logging.getLogger()

def handler(request: Request):
    try:
        app = zcatalyst_sdk.initialize()
        logger = logging.getLogger()
        if request.path == "/add" and request.method == 'POST': 
            req_data = request.get_json()
            notes = req_data.get("notes")           
            table = app.datastore().table('TodoItems')
            row = table.insert_row({
            'Notes': notes
            })
            todo_item = {'id': row['ROWID'], 'notes': notes}        
            response_data = {
                'status': 'success',
                'data': {
                    'todoItem': todo_item
                }
            }
            return make_response(jsonify(response_data), 200)
        elif request.path == "/all" and request.method == 'GET':
            page = request.args.get('page')
            per_page = request.args.get('perPage')
            page = int(page)
            logger.info(page)
            per_page = int(per_page)
            logger.info(per_page)
            zcql_service = app.zcql()     
            row_count = zcql_service.execute_query('SELECT COUNT(ROWID) FROM TodoItems')
            row_id = int(row_count[0]['TodoItems']['ROWID'])
            has_more = int(row_id) > (page) * (per_page)
            logger.info(has_more)
            query_result = zcql_service.execute_query(f'SELECT ROWID, Notes FROM TodoItems LIMIT {(page - 1) * per_page + 1},{per_page}')
            todo_items = [{'id': item['TodoItems']['ROWID'], 'notes': item['TodoItems']['Notes']} for item in query_result]
            get_resp = {
                'status': 'success',
                'data': {
                    'todoItems': todo_items,
                    'hasMore': has_more
                }
            }
            return make_response(jsonify(get_resp), 200)
        elif request.method == 'DELETE':
            row_id = request.path[1:]
            if row_id:
                datastore_service = app.datastore()
                table_service = datastore_service.table("ToDoItems")
                table_service.delete_row(row_id)
                row_response = {
                'status': 'success',
                'data': {
                    'todoItem': {
                        'id': row_id
                    }
                }}         
                logging.info(row_response)
                return make_response(jsonify(row_response), 200)
            else:
                message = {
                'status': 'failure',
                'error': 'Please provide a valid rowid in the request path'
                }
                return make_response(jsonify(message), 400)
        else:
            print('working')
    except Exception as err:
        logger.error(f"Exception in to_do_list_function :{err}")
        response = make_response(jsonify({
                 "error": "Internal server error occurred. Please try again in some time."
        }), 500)
        return response

         
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The functions directory is now configured.