private TemplateEngine(string path, ITemplateContext ctx, ICache<string, TemplateAST> cache, ExpressionLanguageEngineConfig cfg)
{
_ctx = ctx ?? new TemplateContext();
_cache = cache ?? NoCache.GetInstance<string, TemplateAST>();
_cfg = cfg ?? ExpressionLanguageEngineConfig.Default;
if (string.IsNullOrEmpty(path))
_path = Runtime.StartupDirectory;
else
_path = System.IO.Path.GetFullPath(path);
}
protected override void DoCheck(IValidateResult result, object instance, object propertyValue)
{
//Extend:use cache to improve performance.
ExpressionLanguageEngineConfig cfg = new ExpressionLanguageEngineConfig(EvalExceptionHandlingPolicy.IgnorePolicy);
ExpressionLanguageEngine engine = ExpressionLanguageEngine.CreateEngine(cfg);
engine.Assign(INSTANCE, instance);
engine.Assign(VALUE, propertyValue);
object b = engine.Eval(_expr);
if (!engine.EvalToBool(b))
{
string msg = string.Format(MSG, _pInfo.Name, instance.GetType().Name, propertyValue, _expr);
this.LogValidateResult(result, msg);
}
}
/// <summary>
/// Build up a template engine.
/// </summary>
/// <param name="path">All template files is supposed in a specified directory(include sub directory).
/// If it is null, will use current app directory.
/// </param>
/// <param name="ctx">Template context, also work as EL context when eval expresion in the template.</param>
/// <param name="cache">Template AST cache.</param>
/// <param name="cfg">the EL engine (which used in eval expression in the template) create config.</param>
/// <returns>Instance of template engine.</returns>
public static TemplateEngine CreateInstance(string path = null, ITemplateContext ctx = null, ICache<string, TemplateAST> cache = null, ExpressionLanguageEngineConfig cfg = null)
{
return new TemplateEngine(path, ctx, cache, cfg);
}
public static ExpressionLanguageEngine CreateEngine(ExpressionLanguageEngineConfig cfg, IEvalContext ctx = null)
{
cfg.ThrowIfNullArgument(nameof(cfg));
return(new ExpressionLanguageEngine(ctx, cfg.Policy, cfg.FallbackValue, cfg.Cache));
}