支持后端解析参数表达式并保留工程JSON

app/main.py

@@ -22,6 +22,11 @@ from fastapi import FastAPI, HTTPException, Request, Response
 from fastapi.responses import FileResponse, HTMLResponse, StreamingResponse
 from pydantic import BaseModel, ConfigDict, Field, ValidationError
 
+from app.parameter_expression import (
+    ParameterExpressionError,
+    evaluate_parameter_expression,
+    expression_value_to_base_unit,
+)
 from app.simulation.performance import performance_span, profile_phase, profile_run
 from app.simulation.property_cache import property_cache_run
 from app.simulation.solvers.solver import SolverActivityTracker
@@ -1100,7 +1105,14 @@ def validate_reactflow_component_contract(
 
     parameter_values: dict[str, float] = {}
     for parameter in component_spec.parameters:
-        value = parameter_float(node, parameter.name, parameter.default)
+        value = parameter_float(
+            node,
+            parameter.name,
+            parameter.default,
+            quantity=parameter.quantity,
+            base_unit=parameter.unit,
+            expressions_allowed=parameter.editor is None,
+        )
         validation_message = parameter.validation_message(value)
         if validation_message is not None:
             raise ValueError(
@@ -1667,14 +1679,45 @@ def parameter_float(
     node: ReactFlowNodePayload | None,
     name: str,
     default: float,
+    *,
+    quantity: str = "dimensionless",
+    base_unit: str = "",
+    expressions_allowed: bool = True,
 ) -> float:
     if node is None:
         return default
     value = node.data.parameters.get(name, default)
     try:
-        return float(value)
+        numeric_value = float(value)
     except (TypeError, ValueError):
-        raise ValueError(f"Parameter '{name}' on component '{node.id}' must be numeric.")
+        if not isinstance(value, str):
+            raise ValueError(
+                f"Parameter '{name}' on component '{node.id}' must be numeric."
+            )
+        if not expressions_allowed:
+            raise ValueError(
+                f"PARAMETER_EXPRESSION_FORBIDDEN: Parameter '{name}' on component "
+                f"'{node.id}' is a discrete selection and cannot use an expression."
+            )
+        try:
+            evaluated = evaluate_parameter_expression(value)
+            selected_unit = node.data.parameterUnits.get(name, base_unit)
+            return expression_value_to_base_unit(
+                evaluated,
+                quantity=quantity,
+                selected_unit=selected_unit,
+            )
+        except ParameterExpressionError as exc:
+            raise ValueError(
+                f"PARAMETER_EXPRESSION_INVALID: Parameter '{name}' on component "
+                f"'{node.id}' contains an invalid expression: {exc}."
+            ) from exc
+    if not isfinite(numeric_value):
+        raise ValueError(
+            f"Parameter '{name}' on component '{node.id}' must be a finite "
+            "numeric value."
+        )
+    return numeric_value
 
 
 def pipe_config_from_node(node: ReactFlowNodePayload | None, pipe_config_type):

app/parameter_expression.py

@@ -0,0 +1,408 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+import math
+import re
+from typing import Callable
+
+
+MAX_INPUT_LENGTH = 512
+MAX_TOKEN_COUNT = 256
+MAX_OPERATION_COUNT = 256
+MAX_NESTING_DEPTH = 32
+MAX_FUNCTION_ARGUMENTS = 16
+
+_UNSIGNED_NUMBER_PREFIX = re.compile(
+    r"(?:\d+(?:\.\d*)?|\.\d+)(?:[eE][+-]?\d+)?"
+)
+
+
+class ParameterExpressionError(ValueError):
+    """Raised when an editor parameter expression cannot be resolved safely."""
+
+
+@dataclass(frozen=True)
+class _Token:
+    kind: str
+    text: str
+    position: int
+    value: float | None = None
+
+
+def evaluate_parameter_expression(expression: str) -> float:
+    """Evaluate the same bounded arithmetic subset accepted by the frontend.
+
+    The parser never executes Python code and cannot access names other than
+    the constants ``pi`` and ``e`` or the explicitly supported functions.
+    """
+
+    source = expression.strip()
+    if source.startswith("="):
+        source = source[1:].strip()
+    if not source:
+        raise ParameterExpressionError("expression must not be empty")
+    if len(source) > MAX_INPUT_LENGTH:
+        raise ParameterExpressionError(
+            f"expression must not exceed {MAX_INPUT_LENGTH} characters"
+        )
+    return _ParameterExpressionParser(_tokenize(source)).parse()
+
+
+def expression_value_to_base_unit(
+    value: float,
+    *,
+    quantity: str,
+    selected_unit: str,
+) -> float:
+    """Convert an expression result from its editor unit to the SI contract.
+
+    Plain numeric JSON values are already stored in SI and must not pass
+    through this function. Only expression results use the selected display
+    unit, matching the existing frontend behavior.
+    """
+
+    conversions = _UNIT_CONVERSIONS.get(quantity)
+    if not conversions:
+        return _ensure_finite(value, "expression result")
+    conversion = conversions.get(selected_unit)
+    if conversion is None:
+        # The frontend falls back to the first (base) unit for an unknown or
+        # absent selection. Keep the execution boundary behavior identical.
+        conversion = next(iter(conversions.values()))
+    scale, offset = conversion
+    return _ensure_finite(value * scale + offset, "converted expression result")
+
+
+def _tokenize(source: str) -> tuple[_Token, ...]:
+    tokens: list[_Token] = []
+    position = 0
+
+    def append(token: _Token) -> None:
+        tokens.append(token)
+        if len(tokens) > MAX_TOKEN_COUNT:
+            raise ParameterExpressionError(
+                f"expression must not exceed {MAX_TOKEN_COUNT} tokens"
+            )
+
+    while position < len(source):
+        character = source[position]
+        if character.isspace():
+            position += 1
+            continue
+
+        if character.isdigit() or (
+            character == "."
+            and position + 1 < len(source)
+            and source[position + 1].isdigit()
+        ):
+            match = _UNSIGNED_NUMBER_PREFIX.match(source, position)
+            if match is None:
+                raise ParameterExpressionError(
+                    f"invalid number near character {position + 1}"
+                )
+            text = match.group(0)
+            value = _ensure_finite(float(text), f"number {text!r}")
+            append(_Token("number", text, position, value))
+            position = match.end()
+            continue
+
+        if character.isascii() and (character.isalpha() or character == "_"):
+            end = position + 1
+            while end < len(source):
+                candidate = source[end]
+                if not candidate.isascii() or not (
+                    candidate.isalnum() or candidate == "_"
+                ):
+                    break
+                end += 1
+            append(_Token("identifier", source[position:end], position))
+            position = end
+            continue
+
+        if character == "*" and source[position : position + 2] == "**":
+            append(_Token("operator", "**", position))
+            position += 2
+            continue
+        if character in "+-*/^":
+            append(_Token("operator", character, position))
+            position += 1
+            continue
+        if character == "(":
+            append(_Token("left_parenthesis", character, position))
+            position += 1
+            continue
+        if character == ")":
+            append(_Token("right_parenthesis", character, position))
+            position += 1
+            continue
+        if character == ",":
+            append(_Token("comma", character, position))
+            position += 1
+            continue
+
+        raise ParameterExpressionError(
+            f"unsupported symbol {character!r} at character {position + 1}"
+        )
+
+    tokens.append(_Token("end", "", len(source)))
+    return tuple(tokens)
+
+
+class _ParameterExpressionParser:
+    def __init__(self, tokens: tuple[_Token, ...]) -> None:
+        self._tokens = tokens
+        self._index = 0
+        self._operation_count = 0
+
+    def parse(self) -> float:
+        value = self._parse_additive(0)
+        trailing = self._current()
+        if trailing.kind != "end":
+            raise ParameterExpressionError(
+                f"unexpected content {trailing.text!r} near character "
+                f"{trailing.position + 1}"
+            )
+        return _ensure_finite(value, "expression result")
+
+    def _parse_additive(self, depth: int) -> float:
+        value = self._parse_multiplicative(depth)
+        while self._is_operator("+") or self._is_operator("-"):
+            operator = self._advance().text
+            right = self._parse_multiplicative(depth)
+            self._count_operation()
+            value = _safe_operation(
+                lambda: value + right if operator == "+" else value - right,
+                f"operation {operator!r}",
+            )
+        return value
+
+    def _parse_multiplicative(self, depth: int) -> float:
+        value = self._parse_unary(depth)
+        while self._is_operator("*") or self._is_operator("/"):
+            operator = self._advance().text
+            right = self._parse_unary(depth)
+            self._count_operation()
+            if operator == "/" and right == 0:
+                raise ParameterExpressionError("division by zero is not allowed")
+            value = _safe_operation(
+                lambda: value * right if operator == "*" else value / right,
+                f"operation {operator!r}",
+            )
+        return value
+
+    def _parse_unary(self, depth: int) -> float:
+        self._assert_depth(depth)
+        if self._is_operator("+") or self._is_operator("-"):
+            operator = self._advance().text
+            self._count_operation()
+            operand = self._parse_unary(depth + 1)
+            return _ensure_finite(
+                operand if operator == "+" else -operand,
+                f"unary operation {operator!r}",
+            )
+        return self._parse_power(depth)
+
+    def _parse_power(self, depth: int) -> float:
+        self._assert_depth(depth)
+        base = self._parse_primary(depth)
+        if not self._is_operator("^") and not self._is_operator("**"):
+            return base
+        operator = self._advance().text
+        exponent = self._parse_unary(depth + 1)
+        self._count_operation()
+        return _safe_operation(
+            lambda: math.pow(base, exponent),
+            f"operation {operator!r}",
+        )
+
+    def _parse_primary(self, depth: int) -> float:
+        self._assert_depth(depth)
+        token = self._current()
+        if token.kind == "number":
+            self._advance()
+            return _ensure_finite(
+                token.value if token.value is not None else math.nan,
+                f"number {token.text!r}",
+            )
+
+        if token.kind == "identifier":
+            self._advance()
+            normalized_name = token.text.casefold()
+            if self._current().kind == "left_parenthesis":
+                return self._parse_function_call(
+                    normalized_name,
+                    token.text,
+                    depth + 1,
+                )
+            if normalized_name == "pi":
+                return math.pi
+            if normalized_name == "e":
+                return math.e
+            raise ParameterExpressionError(f"unknown identifier {token.text!r}")
+
+        if token.kind == "left_parenthesis":
+            self._advance()
+            value = self._parse_additive(depth + 1)
+            self._expect("right_parenthesis", "missing closing parenthesis")
+            return value
+
+        if token.kind == "end":
+            raise ParameterExpressionError(
+                "expression ends before a number, constant, or function"
+            )
+        raise ParameterExpressionError(
+            f"expected a number, constant, or function near character "
+            f"{token.position + 1}"
+        )
+
+    def _parse_function_call(
+        self,
+        normalized_name: str,
+        source_name: str,
+        depth: int,
+    ) -> float:
+        self._assert_depth(depth)
+        self._expect(
+            "left_parenthesis",
+            f"function {source_name} is missing an opening parenthesis",
+        )
+        arguments: list[float] = []
+        if self._current().kind != "right_parenthesis":
+            while True:
+                if len(arguments) >= MAX_FUNCTION_ARGUMENTS:
+                    raise ParameterExpressionError(
+                        f"function {source_name} accepts at most "
+                        f"{MAX_FUNCTION_ARGUMENTS} arguments"
+                    )
+                arguments.append(self._parse_additive(depth))
+                if self._current().kind != "comma":
+                    break
+                self._advance()
+                if self._current().kind == "right_parenthesis":
+                    raise ParameterExpressionError(
+                        f"function {source_name} has no argument after its comma"
+                    )
+        self._expect(
+            "right_parenthesis",
+            f"function {source_name} is missing a closing parenthesis",
+        )
+        self._count_operation()
+        return _evaluate_function(normalized_name, source_name, arguments)
+
+    def _current(self) -> _Token:
+        return self._tokens[min(self._index, len(self._tokens) - 1)]
+
+    def _advance(self) -> _Token:
+        token = self._current()
+        if token.kind != "end":
+            self._index += 1
+        return token
+
+    def _expect(self, kind: str, message: str) -> _Token:
+        if self._current().kind != kind:
+            raise ParameterExpressionError(message)
+        return self._advance()
+
+    def _is_operator(self, operator: str) -> bool:
+        token = self._current()
+        return token.kind == "operator" and token.text == operator
+
+    def _assert_depth(self, depth: int) -> None:
+        if depth > MAX_NESTING_DEPTH:
+            raise ParameterExpressionError(
+                f"expression nesting must not exceed {MAX_NESTING_DEPTH} levels"
+            )
+
+    def _count_operation(self) -> None:
+        self._operation_count += 1
+        if self._operation_count > MAX_OPERATION_COUNT:
+            raise ParameterExpressionError(
+                f"expression must not exceed {MAX_OPERATION_COUNT} operations"
+            )
+
+
+def _evaluate_function(
+    normalized_name: str,
+    source_name: str,
+    arguments: list[float],
+) -> float:
+    def require_count(expected: int) -> None:
+        if len(arguments) != expected:
+            raise ParameterExpressionError(
+                f"function {source_name} requires {expected} arguments, "
+                f"received {len(arguments)}"
+            )
+
+    if normalized_name == "sqrt":
+        require_count(1)
+        if arguments[0] < 0:
+            raise ParameterExpressionError("sqrt argument must not be negative")
+        operation = lambda: math.sqrt(arguments[0])
+    elif normalized_name == "abs":
+        require_count(1)
+        operation = lambda: abs(arguments[0])
+    elif normalized_name in {"sin", "cos", "tan", "asin", "acos", "atan"}:
+        require_count(1)
+        if normalized_name in {"asin", "acos"} and not -1 <= arguments[0] <= 1:
+            raise ParameterExpressionError(
+                f"{source_name} argument must be between -1 and 1"
+            )
+        function = getattr(math, normalized_name)
+        operation = lambda: function(arguments[0])
+    elif normalized_name == "exp":
+        require_count(1)
+        operation = lambda: math.exp(arguments[0])
+    elif normalized_name in {"ln", "log"}:
+        require_count(1)
+        if arguments[0] <= 0:
+            raise ParameterExpressionError(f"{source_name} argument must be positive")
+        operation = lambda: math.log(arguments[0])
+    elif normalized_name == "log10":
+        require_count(1)
+        if arguments[0] <= 0:
+            raise ParameterExpressionError("log10 argument must be positive")
+        operation = lambda: math.log10(arguments[0])
+    elif normalized_name in {"min", "max"}:
+        if not arguments:
+            raise ParameterExpressionError(
+                f"function {source_name} requires at least one argument"
+            )
+        function = min if normalized_name == "min" else max
+        operation = lambda: float(function(arguments))
+    elif normalized_name == "pow":
+        require_count(2)
+        operation = lambda: math.pow(arguments[0], arguments[1])
+    else:
+        raise ParameterExpressionError(f"unsupported function {source_name!r}")
+    return _safe_operation(operation, f"function {source_name}")
+
+
+def _safe_operation(operation: Callable[[], float], context: str) -> float:
+    try:
+        value = operation()
+    except (ArithmeticError, ValueError) as exc:
+        raise ParameterExpressionError(f"{context} has no finite real result") from exc
+    return _ensure_finite(float(value), context)
+
+
+def _ensure_finite(value: float, context: str) -> float:
+    if not math.isfinite(value):
+        raise ParameterExpressionError(f"{context} is not finite")
+    return value
+
+
+# Ordered exactly like the editor's unit selector. The first entry is the
+# fallback SI unit when a persisted selection is absent or unknown.
+_UNIT_CONVERSIONS: dict[str, dict[str, tuple[float, float]]] = {
+    "area": {"m2": (1.0, 0.0), "cm2": (1.0e-4, 0.0), "mm2": (1.0e-6, 0.0)},
+    "heat_transfer_coefficient": {"W/(m2*K)": (1.0, 0.0)},
+    "pressure": {
+        "Pa": (1.0, 0.0),
+        "kPa": (1.0e3, 0.0),
+        "MPa": (1.0e6, 0.0),
+        "bar": (1.0e5, 0.0),
+    },
+    "volume": {"m3": (1.0, 0.0), "L": (1.0e-3, 0.0), "mL": (1.0e-6, 0.0)},
+    "temperature": {"K": (1.0, 0.0), "degC": (1.0, 273.15)},
+    "length": {"m": (1.0, 0.0), "cm": (1.0e-2, 0.0), "mm": (1.0e-3, 0.0)},
+}