| 1 | import json |
| 2 | |
| 1 | 3 | class RestAPI: |
| 2 | 4 | def __init__(self, database: dict | None = None): |
| 3 | | pass |
| 4 | | |
| 5 | # Edge Case: Handle None database by initializing empty structure |
| 6 | if database is None: |
| 7 | self.database = {"users": []} |
| 8 | else: |
| 9 | self.database = database |
| 10 | |
| 5 | 11 | def get(self, url: str, payload: str | None = None) -> str: |
| 6 | | pass |
| 7 | | |
| 12 | # Edge Case: Handle invalid URL |
| 13 | if url != "/users": |
| 14 | return json.dumps({"error": "Invalid URL"}) |
| 15 | |
| 16 | # Edge Case: Handle invalid payload format |
| 17 | if payload is not None: |
| 18 | try: |
| 19 | payload_data = json.loads(payload) |
| 20 | except json.JSONDecodeError: |
| 21 | return json.dumps({"error": "Invalid payload format"}) |
| 22 | |
| 23 | # Edge Case: Handle missing 'users' key in payload |
| 24 | if "users" not in payload_data: |
| 25 | return json.dumps({"error": "Missing 'users' key in payload"}) |
| 26 | |
| 27 | # Edge Case: Handle non-list 'users' value |
| 28 | if not isinstance(payload_data["users"], list): |
| 29 | return json.dumps({"error": "'users' must be a list"}) |
| 30 | |
| 31 | # Edge Case: Filter users based on payload |
| 32 | requested_users = payload_data["users"] |
| 33 | users = [user for user in self.database["users"] if user["name"] in requested_users] |
| 34 | else: |
| 35 | # Edge Case: Return all users when no payload |
| 36 | users = self.database["users"] |
| 37 | |
| 38 | # Sort users by name |
| 39 | users.sort(key=lambda x: x["name"]) |
| 40 | return json.dumps({"users": users}) |
| 41 | |
| 8 | 42 | def post(self, url: str, payload: str | None = None) -> str: |
| 9 | | pass |
| 43 | # Edge Case: Handle invalid URL |
| 44 | if url not in ["/add", "/iou"]: |
| 45 | return json.dumps({"error": "Invalid URL"}) |
| 46 | |
| 47 | # Edge Case: Handle missing payload |
| 48 | if payload is None: |
| 49 | return json.dumps({"error": "Missing payload"}) |
| 50 | |
| 51 | # Edge Case: Handle invalid payload format |
| 52 | try: |
| 53 | payload_data = json.loads(payload) |
| 54 | except json.JSONDecodeError: |
| 55 | return json.dumps({"error": "Invalid payload format"}) |
| 56 | |
| 57 | if url == "/add": |
| 58 | # Edge Case: Handle missing 'user' key |
| 59 | if "user" not in payload_data: |
| 60 | return json.dumps({"error": "Missing 'user' key"}) |
| 61 | |
| 62 | # Edge Case: Handle non-string user name |
| 63 | if not isinstance(payload_data["user"], str): |
| 64 | return json.dumps({"error": "User name must be a string"}) |
| 65 | |
| 66 | # Edge Case: Handle duplicate user |
| 67 | for user in self.database["users"]: |
| 68 | if user["name"] == payload_data["user"]: |
| 69 | return json.dumps({"error": "User already exists"}) |
| 70 | |
| 71 | # Create new user |
| 72 | new_user = { |
| 73 | "name": payload_data["user"], |
| 74 | "owes": {}, |
| 75 | "owed_by": {}, |
| 76 | "balance": 0.0 |
| 77 | } |
| 78 | self.database["users"].append(new_user) |
| 79 | return json.dumps(new_user) |
| 80 | |
| 81 | elif url == "/iou": |
| 82 | # Edge Case: Handle missing required keys |
| 83 | required_keys = ["lender", "borrower", "amount"] |
| 84 | for key in required_keys: |
| 85 | if key not in payload_data: |
| 86 | return json.dumps({"error": f"Missing '{key}' key"}) |
| 87 | |
| 88 | # Edge Case: Handle non-string lender/borrower |
| 89 | if not isinstance(payload_data["lender"], str) or not isinstance(payload_data["borrower"], str): |
| 90 | return json.dumps({"error": "Lender and borrower must be strings"}) |
| 91 | |
| 92 | # Edge Case: Handle non-numeric amount |
| 93 | if not isinstance(payload_data["amount"], (int, float)): |
| 94 | return json.dumps({"error": "Amount must be a number"}) |
| 95 | |
| 96 | # Edge Case: Handle negative amount |
| 97 | if payload_data["amount"] < 0: |
| 98 | return json.dumps({"error": "Amount must be positive"}) |
| 99 | |
| 100 | # Edge Case: Handle lender equals borrower |
| 101 | if payload_data["lender"] == payload_data["borrower"]: |
| 102 | return json.dumps({"error": "Lender and borrower cannot be the same"}) |
| 103 | |
| 104 | # Find lender and borrower |
| 105 | lender = None |
| 106 | borrower = None |
| 107 | for user in self.database["users"]: |
| 108 | if user["name"] == payload_data["lender"]: |
| 109 | lender = user |
| 110 | elif user["name"] == payload_data["borrower"]: |
| 111 | borrower = user |
| 112 | |
| 113 | # Edge Case: Handle lender not found |
| 114 | if lender is None: |
| 115 | return json.dumps({"error": "Lender not found"}) |
| 116 | |
| 117 | # Edge Case: Handle borrower not found |
| 118 | if borrower is None: |
| 119 | return json.dumps({"error": "Borrower not found"}) |
| 120 | |
| 121 | # Update IOUs |
| 122 | # Update lender's owed_by |
| 123 | if payload_data["borrower"] in lender["owed_by"]: |
| 124 | lender["owed_by"][payload_data["borrower"]] += payload_data["amount"] |
| 125 | else: |
| 126 | lender["owed_by"][payload_data["borrower"]] = payload_data["amount"] |
| 127 | |
| 128 | # Update borrower's owes |
| 129 | if payload_data["lender"] in borrower["owes"]: |
| 130 | borrower["owes"][payload_data["lender"]] += payload_data["amount"] |
| 131 | else: |
| 132 | borrower["owes"][payload_data["lender"]] = payload_data["amount"] |
| 133 | |
| 134 | # Update balances |
| 135 | lender["balance"] += payload_data["amount"] |
| 136 | borrower["balance"] -= payload_data["amount"] |
| 137 | |
| 138 | # Return updated users |
| 139 | updated_users = [lender, borrower] |
| 140 | updated_users.sort(key=lambda x: x["name"]) |
| 141 | return json.dumps({"users": updated_users}) |
| 142 | |
| 143 | # Handled Edge Cases: None database, invalid URL, invalid payload format, missing 'users' key, non-list 'users' value, missing payload, missing 'user' key, non-string user name, duplicate user, missing required keys, non-string lender/borrower, non-numeric amount, negative amount, lender equals borrower, lender not found, borrower not found |