Delete backend.py

backend.py

@@ -1,60 +0,0 @@
-from fastapi import APIRouter, HTTPException
-from pydantic import BaseModel, field_validator
-import math
-import re
-
-router = APIRouter()
-
-ALLOWED_FUNCTIONS = {'sin', 'cos', 'tan', 'log', 'ln', 'sqrt', 'abs', 'pow'}
-ALLOWED_CONSTANTS = {'pi', 'e'}
-
-class Expression(BaseModel):
-    expr: str
-
-    @field_validator('expr')
-    @classmethod
-    def validate_expression(cls, v: str) -> str:
-        if not v:
-            raise ValueError("Expression cannot be empty")
-        
-        # Check for invalid characters
-        valid_chars = set('0123456789.+-*/()^ \t\nabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
-        invalid_chars = set(v) - valid_chars
-        if invalid_chars:
-            raise ValueError(f"Invalid characters found: {', '.join(invalid_chars)}")
-        
-        # Check for invalid function names or constants
-        tokens = re.findall(r'\b[a-zA-Z_]\w*\b', v)
-        invalid_tokens = [token for token in tokens if token not in ALLOWED_FUNCTIONS and token not in ALLOWED_CONSTANTS]
-        if invalid_tokens:
-            raise ValueError(f"Invalid function or constant names: {', '.join(invalid_tokens)}")
-        
-        return v
-
-@router.post("/calculate")
-async def calculate_api(expression: Expression):
-    try:
-        result = evaluate_expression(expression.expr)
-        return {"result": result}
-    except ValueError as e:
-        raise HTTPException(status_code=400, detail=str(e))
-    except Exception as e:
-        raise HTTPException(status_code=500, detail=f"An unexpected error occurred: {str(e)}")
-
-def evaluate_expression(expr: str) -> float:
-    safe_dict = {
-        'sin': math.sin, 'cos': math.cos, 'tan': math.tan,
-        'log': math.log10, 'ln': math.log, 'sqrt': math.sqrt,
-        'pi': math.pi, 'e': math.e,
-        'abs': abs, 'pow': pow
-    }
-    try:
-        # Replace '^' with '**' for exponentiation
-        expr = expr.replace('^', '**')
-        return eval(expr, {"__builtins__": None}, safe_dict)
-    except ZeroDivisionError:
-        raise ValueError("Division by zero is not allowed")
-    except ValueError as e:
-        raise ValueError(f"Math domain error: {str(e)}")
-    except Exception as e:
-        raise ValueError(f"Invalid expression: {str(e)}")