49 lines
1.7 KiB
C#
49 lines
1.7 KiB
C#
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using Elsa.Expressions.Helpers;
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using Elsa.Expressions.Models;
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using Elsa.Mediator.Contracts;
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using Elsa.Python.Contracts;
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using Elsa.Python.Models;
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using Elsa.Python.Notifications;
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namespace Elsa.Python.Services;
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/// <summary>
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/// Evaluates Python expressions using IronPython.
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/// </summary>
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public class IronPythonEvaluator : IPythonEvaluator
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{
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private readonly INotificationSender _notificationSender;
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/// <summary>
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/// Initializes a new instance of the <see cref="IronPythonEvaluator"/> class.
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/// </summary>
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public IronPythonEvaluator(INotificationSender notificationSender)
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{
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_notificationSender = notificationSender;
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}
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/// <inheritdoc />
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public async Task<object?> EvaluateAsync(string expression, Type returnType, ExpressionExecutionContext context, CancellationToken cancellationToken = default)
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{
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var engine = IronPython.Hosting.Python.CreateEngine();
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var scope = engine.CreateScope();
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var notification = new EvaluatingPython(engine, scope, context);
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// Add imports.
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notification.AppendScript(sb =>
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{
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sb.AppendLine("import System");
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sb.AppendLine("import clr");
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});
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// Add globals.
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scope.SetVariable("execution_context", new ExecutionContextProxy(context));
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scope.SetVariable("input", new InputProxy(context));
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scope.SetVariable("output", new OutputProxy(context));
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scope.SetVariable("outcome", new OutcomeProxy(context));
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await _notificationSender.SendAsync(notification, cancellationToken);
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var result = (object?)engine.Execute(expression, scope);
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return result.ConvertTo(returnType);
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}
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}
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