| 1 | | class RestAPI: |
| 2 | | def __init__(self, database: dict | None = None): |
| 3 | | pass |
| 4 | | |
| 5 | | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 1 | import json |
| 2 | from typing import Dict, List, Optional, Any |
| 7 | 3 | |
| 8 | | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 4 | class RestAPI: |
| 5 | """ |
| 6 | A RESTful API for tracking IOUs between users. |
| 7 | |
| 8 | This class manages user data and IOU transactions in memory. |
| 9 | It supports creating users, creating IOUs, and retrieving user information. |
| 10 | """ |
| 11 | |
| 12 | def __init__(self, database: Optional[Dict[str, Any]] = None): |
| 13 | """ |
| 14 | Initialize the RestAPI with an optional database. |
| 15 | |
| 16 | Args: |
| 17 | database: Optional dictionary containing initial user data |
| 18 | """ |
| 19 | if database is None: |
| 20 | self.database = {'users': []} |
| 21 | else: |
| 22 | self.database = database |
| 23 | |
| 24 | def get(self, url: str, payload: Optional[str] = None) -> str: |
| 25 | """ |
| 26 | Handle GET requests to the API. |
| 27 | |
| 28 | Args: |
| 29 | url: The endpoint URL |
| 30 | payload: Optional JSON payload |
| 31 | |
| 32 | Returns: |
| 33 | JSON string response |
| 34 | """ |
| 35 | if url == '/users': |
| 36 | # Edge Case: Handle request with no payload (list all users) |
| 37 | if payload is None: |
| 38 | return json.dumps({ |
| 39 | 'users': sorted(self.database['users'], key=lambda x: x['name']) |
| 40 | }) |
| 41 | |
| 42 | # Edge Case: Handle request with payload (list specific users) |
| 43 | try: |
| 44 | data = json.loads(payload) |
| 45 | user_names = data.get('users', []) |
| 46 | |
| 47 | # Filter users by the provided names |
| 48 | filtered_users = [user for user in self.database['users'] if user['name'] in user_names] |
| 49 | |
| 50 | # Sort by name |
| 51 | filtered_users.sort(key=lambda x: x['name']) |
| 52 | |
| 53 | return json.dumps({'users': filtered_users}) |
| 54 | except json.JSONDecodeError: |
| 55 | # Edge Case: Handle invalid JSON payload |
| 56 | return json.dumps({'users': []}) |
| 57 | |
| 58 | # Edge Case: Handle unknown URL |
| 59 | return json.dumps({}) |
| 60 | |
| 61 | def post(self, url: str, payload: Optional[str] = None) -> str: |
| 62 | """ |
| 63 | Handle POST requests to the API. |
| 64 | |
| 65 | Args: |
| 66 | url: The endpoint URL |
| 67 | payload: Optional JSON payload |
| 68 | |
| 69 | Returns: |
| 70 | JSON string response |
| 71 | """ |
| 72 | if payload is None: |
| 73 | # Edge Case: Handle missing payload |
| 74 | return json.dumps({}) |
| 75 | |
| 76 | try: |
| 77 | data = json.loads(payload) |
| 78 | except json.JSONDecodeError: |
| 79 | # Edge Case: Handle invalid JSON payload |
| 80 | return json.dumps({}) |
| 81 | |
| 82 | if url == '/add': |
| 83 | # Edge Case: Handle missing user field |
| 84 | if 'user' not in data: |
| 85 | return json.dumps({}) |
| 86 | |
| 87 | user_name = data['user'] |
| 88 | |
| 89 | # Edge Case: Handle duplicate user creation |
| 90 | for user in self.database['users']: |
| 91 | if user['name'] == user_name: |
| 92 | return json.dumps({}) |
| 93 | |
| 94 | # Create new user |
| 95 | new_user = { |
| 96 | 'name': user_name, |
| 97 | 'owes': {}, |
| 98 | 'owed_by': {}, |
| 99 | 'balance': 0.0 |
| 100 | } |
| 101 | |
| 102 | self.database['users'].append(new_user) |
| 103 | |
| 104 | # Sort users by name |
| 105 | self.database['users'].sort(key=lambda x: x['name']) |
| 106 | |
| 107 | return json.dumps(new_user) |
| 108 | |
| 109 | elif url == '/iou': |
| 110 | # Edge Case: Handle missing required fields |
| 111 | if 'lender' not in data or 'borrower' not in data or 'amount' not in data: |
| 112 | return json.dumps({}) |
| 113 | |
| 114 | lender_name = data['lender'] |
| 115 | borrower_name = data['borrower'] |
| 116 | amount = data['amount'] |
| 117 | |
| 118 | # Edge Case: Handle invalid amount type |
| 119 | if not isinstance(amount, (int, float)): |
| 120 | return json.dumps({}) |
| 121 | |
| 122 | # Edge Case: Handle negative amount |
| 123 | if amount < 0: |
| 124 | return json.dumps({}) |
| 125 | |
| 126 | # Edge Case: Handle same lender and borrower |
| 127 | if lender_name == borrower_name: |
| 128 | return json.dumps({}) |
| 129 | |
| 130 | # Find lender and borrower |
| 131 | lender = None |
| 132 | borrower = None |
| 133 | |
| 134 | for user in self.database['users']: |
| 135 | if user['name'] == lender_name: |
| 136 | lender = user |
| 137 | elif user['name'] == borrower_name: |
| 138 | borrower = user |
| 139 | |
| 140 | # Edge Case: Handle non-existent lender or borrower |
| 141 | if lender is None or borrower is None: |
| 142 | return json.dumps({}) |
| 143 | |
| 144 | # Update lender's owed_by |
| 145 | if borrower_name in lender['owed_by']: |
| 146 | lender['owed_by'][borrower_name] += amount |
| 147 | else: |
| 148 | lender['owed_by'][borrower_name] = amount |
| 149 | |
| 150 | # Update borrower's owes |
| 151 | if lender_name in borrower['owes']: |
| 152 | borrower['owes'][lender_name] += amount |
| 153 | else: |
| 154 | borrower['owes'][lender_name] = amount |
| 155 | |
| 156 | # Recalculate balances |
| 157 | lender_owes_total = sum(lender['owes'].values()) |
| 158 | lender_owed_by_total = sum(lender['owed_by'].values()) |
| 159 | lender['balance'] = lender_owed_by_total - lender_owes_total |
| 160 | |
| 161 | borrower_owes_total = sum(borrower['owes'].values()) |
| 162 | borrower_owed_by_total = sum(borrower['owed_by'].values()) |
| 163 | borrower['balance'] = borrower_owed_by_total - borrower_owes_total |
| 164 | |
| 165 | # Return updated users sorted by name |
| 166 | result_users = [lender, borrower] |
| 167 | result_users.sort(key=lambda x: x['name']) |
| 168 | |
| 169 | return json.dumps({'users': result_users}) |
| 170 | |
| 171 | # Edge Case: Handle unknown URL |
| 172 | return json.dumps({}) |
| 173 | |
| 174 | # Handled Edge Cases: Missing payload, invalid JSON payload, unknown URL, missing user field, |
| 175 | # duplicate user creation, missing required fields, invalid amount type, negative amount, |
| 176 | # same lender and borrower, non-existent lender or borrower |