feat(workflow): add workflow engine module (Phase 4)
Implement complete workflow engine with BPMN subset support: Backend (erp-workflow crate): - Token-driven execution engine with exclusive/parallel gateway support - BPMN parser with flow graph validation - Expression evaluator for conditional branching - Process definition CRUD with draft/publish lifecycle - Process instance management (start, suspend, terminate) - Task service (pending, complete, delegate) - PostgreSQL advisory locks for concurrent safety - 5 database tables: process_definitions, process_instances, tokens, tasks, process_variables - 13 API endpoints with RBAC protection - Timeout checker framework (placeholder) Frontend: - Workflow page with 4 tabs (definitions, pending, completed, monitor) - React Flow visual process designer (@xyflow/react) - Process viewer with active node highlighting - 3 API client modules for workflow endpoints - Sidebar menu integration
This commit is contained in:
iven
325
crates/erp-workflow/src/engine/expression.rs
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325
crates/erp-workflow/src/engine/expression.rs
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use std::collections::HashMap;
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use crate::error::{WorkflowError, WorkflowResult};
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/// 简单表达式求值器。
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///
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/// 支持的比较运算符：>, >=, <, <=, ==, !=
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/// 支持 && 和 || 逻辑运算。
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/// 操作数可以是变量名（从 variables map 查找）或字面量（数字、字符串）。
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///
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/// 示例：
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/// - `amount > 1000`
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/// - `status == "approved"`
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/// - `score >= 60 && attendance > 80`
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pub struct ExpressionEvaluator;
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impl ExpressionEvaluator {
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/// 求值单个条件表达式。
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///
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/// 表达式格式: `{left} {op} {right}` 或复合表达式 `{expr1} && {expr2}`
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pub fn eval(expr: &str, variables: &HashMap<String, serde_json::Value>) -> WorkflowResult<bool> {
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let expr = expr.trim();
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// 处理逻辑 OR
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if let Some(idx) = Self::find_logical_op(expr, "||") {
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let left = &expr[..idx];
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let right = &expr[idx + 2..];
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return Ok(Self::eval(left, variables)? || Self::eval(right, variables)?);
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}
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// 处理逻辑 AND
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if let Some(idx) = Self::find_logical_op(expr, "&&") {
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let left = &expr[..idx];
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let right = &expr[idx + 2..];
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return Ok(Self::eval(left, variables)? && Self::eval(right, variables)?);
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}
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// 处理单个比较表达式
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Self::eval_comparison(expr, variables)
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}
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/// 查找逻辑运算符位置，跳过引号内的内容。
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fn find_logical_op(expr: &str, op: &str) -> Option<usize> {
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let mut in_string = false;
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let mut string_char = ' ';
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let chars: Vec<char> = expr.chars().collect();
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let op_chars: Vec<char> = op.chars().collect();
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let op_len = op_chars.len();
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for i in 0..chars.len().saturating_sub(op_len - 1) {
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let c = chars[i];
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if !in_string && (c == '"' || c == '\'') {
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in_string = true;
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string_char = c;
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continue;
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}
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if in_string && c == string_char {
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in_string = false;
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continue;
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}
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if in_string {
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continue;
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}
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if chars[i..].starts_with(&op_chars) {
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return Some(i);
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}
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}
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None
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}
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/// 求值单个比较表达式。
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fn eval_comparison(expr: &str, variables: &HashMap<String, serde_json::Value>) -> WorkflowResult<bool> {
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let operators = [">=", "<=", "!=", "==", ">", "<"];
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for op in &operators {
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if let Some(idx) = Self::find_comparison_op(expr, op) {
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let left = expr[..idx].trim();
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let right = expr[idx + op.len()..].trim();
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let left_val = Self::resolve_value(left, variables)?;
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let right_val = Self::resolve_value(right, variables)?;
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return Self::compare(&left_val, &right_val, op);
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}
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}
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Err(WorkflowError::ExpressionError(format!(
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"无法解析表达式: '{}'",
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expr
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)))
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}
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/// 查找比较运算符位置，跳过引号内的内容。
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fn find_comparison_op(expr: &str, op: &str) -> Option<usize> {
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let mut in_string = false;
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let mut string_char = ' ';
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let bytes = expr.as_bytes();
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let op_bytes = op.as_bytes();
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let op_len = op_bytes.len();
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for i in 0..bytes.len().saturating_sub(op_len - 1) {
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let c = bytes[i] as char;
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if !in_string && (c == '"' || c == '\'') {
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in_string = true;
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string_char = c;
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continue;
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}
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if in_string && c == string_char {
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in_string = false;
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continue;
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}
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if in_string {
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continue;
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}
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if bytes[i..].starts_with(op_bytes) {
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// 确保不是被嵌在其他运算符里（如 != 中的 =）
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// 对于 > 和 < 检查后面不是 = 或 >
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if op == ">" || op == "<" {
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if i + op_len < bytes.len() {
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let next = bytes[i + op_len] as char;
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if next == '=' || (op == ">" && next == '>') {
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continue;
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}
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}
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// 也检查前面不是 ! 或 = 或 < 或 >
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if i > 0 {
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let prev = bytes[i - 1] as char;
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if prev == '!' || prev == '=' || prev == '<' || prev == '>' {
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continue;
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}
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}
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}
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// 对于 ==, >=, <=, != 确保前面不是 ! 或 = (避免匹配到 == 中的第二个 =)
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// 这已经通过从长到短匹配处理了
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return Some(i);
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}
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}
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None
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}
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/// 解析值：字符串字面量、数字字面量或变量引用。
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fn resolve_value(
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token: &str,
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variables: &HashMap<String, serde_json::Value>,
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) -> WorkflowResult<serde_json::Value> {
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let token = token.trim();
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// 字符串字面量
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if (token.starts_with('"') && token.ends_with('"'))
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|| (token.starts_with('\'') && token.ends_with('\''))
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{
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return Ok(serde_json::Value::String(
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token[1..token.len() - 1].to_string(),
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));
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}
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// 数字字面量
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if let Ok(n) = token.parse::<i64>() {
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return Ok(serde_json::Value::Number(n.into()));
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}
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if let Ok(f) = token.parse::<f64>() {
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if let Some(n) = serde_json::Number::from_f64(f) {
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return Ok(serde_json::Value::Number(n));
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}
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}
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// 布尔字面量
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if token == "true" {
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return Ok(serde_json::Value::Bool(true));
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}
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if token == "false" {
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return Ok(serde_json::Value::Bool(false));
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}
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// 变量引用
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if let Some(val) = variables.get(token) {
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return Ok(val.clone());
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}
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Err(WorkflowError::ExpressionError(format!(
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"未知的变量或值: '{}'",
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token
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)))
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}
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/// 比较两个 JSON 值。
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fn compare(
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left: &serde_json::Value,
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right: &serde_json::Value,
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op: &str,
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) -> WorkflowResult<bool> {
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match op {
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"==" => Ok(Self::values_equal(left, right)),
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"!=" => Ok(!Self::values_equal(left, right)),
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">" => Ok(Self::values_compare(left, right)? == std::cmp::Ordering::Greater),
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">=" => Ok(Self::values_compare(left, right)? != std::cmp::Ordering::Less),
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"<" => Ok(Self::values_compare(left, right)? == std::cmp::Ordering::Less),
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"<=" => Ok(Self::values_compare(left, right)? != std::cmp::Ordering::Greater),
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_ => Err(WorkflowError::ExpressionError(format!(
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"不支持的比较运算符: '{}'",
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op
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))),
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}
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}
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fn values_equal(left: &serde_json::Value, right: &serde_json::Value) -> bool {
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// 数值比较：允许整数和浮点数互比
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if left.is_number() && right.is_number() {
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return left.as_f64() == right.as_f64();
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}
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left == right
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}
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fn values_compare(
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left: &serde_json::Value,
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right: &serde_json::Value,
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) -> WorkflowResult<std::cmp::Ordering> {
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if left.is_number() && right.is_number() {
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let l = left.as_f64().unwrap_or(0.0);
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let r = right.as_f64().unwrap_or(0.0);
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return Ok(l.partial_cmp(&r).unwrap_or(std::cmp::Ordering::Equal));
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}
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if let (Some(l), Some(r)) = (left.as_str(), right.as_str()) {
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return Ok(l.cmp(r));
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}
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Err(WorkflowError::ExpressionError(format!(
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"无法比较 {:?} 和 {:?}",
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left, right
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)))
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use serde_json::json;
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fn make_vars() -> HashMap<String, serde_json::Value> {
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let mut m = HashMap::new();
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m.insert("amount".to_string(), json!(1500));
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m.insert("status".to_string(), json!("approved"));
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m.insert("score".to_string(), json!(85));
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m.insert("name".to_string(), json!("Alice"));
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m.insert("active".to_string(), json!(true));
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m
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}
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#[test]
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fn test_number_greater_than() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount > 1000", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount > 2000", &vars).unwrap());
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}
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#[test]
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fn test_number_less_than() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount < 2000", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount < 1000", &vars).unwrap());
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}
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#[test]
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fn test_number_equals() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount == 1500", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount == 1000", &vars).unwrap());
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}
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#[test]
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fn test_string_equals() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("status == \"approved\"", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("status == \"rejected\"", &vars).unwrap());
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}
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#[test]
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fn test_string_not_equals() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("status != \"rejected\"", &vars).unwrap());
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}
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#[test]
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fn test_greater_or_equal() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount >= 1500", &vars).unwrap());
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assert!(ExpressionEvaluator::eval("amount >= 1000", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount >= 2000", &vars).unwrap());
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}
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#[test]
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fn test_logical_and() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount > 1000 && score > 80", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount > 2000 && score > 80", &vars).unwrap());
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}
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#[test]
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fn test_logical_or() {
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let vars = make_vars();
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assert!(ExpressionEvaluator::eval("amount > 2000 || score > 80", &vars).unwrap());
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assert!(!ExpressionEvaluator::eval("amount > 2000 || score > 90", &vars).unwrap());
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}
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#[test]
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fn test_unknown_variable() {
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let vars = make_vars();
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let result = ExpressionEvaluator::eval("unknown > 0", &vars);
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assert!(result.is_err());
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}
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#[test]
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fn test_invalid_expression() {
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let vars = make_vars();
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let result = ExpressionEvaluator::eval("justavariable", &vars);
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assert!(result.is_err());
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}
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}
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