private RoutePatternParameterPart ParseParameter(string routeParameter)
{
// See: #475 - these tests don't pass the 'whole' text.
var templatePart = RouteParameterParser.ParseRouteParameter(routeParameter);
return(templatePart);
}
private static bool ParseParameter(Context context, List <RoutePatternPart> parts)
{
Debug.Assert(context.Current == OpenBrace);
context.Mark();
context.MoveNext();
while (true)
{
if (context.Current == OpenBrace)
{
// This is an open brace inside of a parameter, it has to be escaped
if (context.MoveNext())
{
if (context.Current != OpenBrace)
{
// If we see something like "{p1:regex(^\d{3", we will come here.
context.Error = Resources.TemplateRoute_UnescapedBrace;
return(false);
}
}
else
{
// This is a dangling open-brace, which is not allowed
// Example: "{p1:regex(^\d{"
context.Error = Resources.TemplateRoute_MismatchedParameter;
return(false);
}
}
else if (context.Current == CloseBrace)
{
// When we encounter Closed brace here, it either means end of the parameter or it is a closed
// brace in the parameter, in that case it needs to be escaped.
// Example: {p1:regex(([}}])\w+}. First pair is escaped one and last marks end of the parameter
if (!context.MoveNext())
{
// This is the end of the string -and we have a valid parameter
break;
}
if (context.Current == CloseBrace)
{
// This is an 'escaped' brace in a parameter name
}
else
{
// This is the end of the parameter
break;
}
}
if (!context.MoveNext())
{
// This is a dangling open-brace, which is not allowed
context.Error = Resources.TemplateRoute_MismatchedParameter;
return(false);
}
}
var text = context.Capture();
if (text == "{}")
{
context.Error = Resources.FormatTemplateRoute_InvalidParameterName(string.Empty);
return(false);
}
var inside = text.Substring(1, text.Length - 2);
var decoded = inside.Replace("}}", "}").Replace("{{", "{");
// At this point, we need to parse the raw name for inline constraint,
// default values and optional parameters.
var templatePart = RouteParameterParser.ParseRouteParameter(decoded);
// See #475 - this is here because InlineRouteParameterParser can't return errors
if (decoded.StartsWith("*", StringComparison.Ordinal) && decoded.EndsWith("?", StringComparison.Ordinal))
{
context.Error = Resources.TemplateRoute_CatchAllCannotBeOptional;
return(false);
}
if (templatePart.IsOptional && templatePart.Default != null)
{
// Cannot be optional and have a default value.
// The only way to declare an optional parameter is to have a ? at the end,
// hence we cannot have both default value and optional parameter within the template.
// A workaround is to add it as a separate entry in the defaults argument.
context.Error = Resources.TemplateRoute_OptionalCannotHaveDefaultValue;
return(false);
}
var parameterName = templatePart.Name;
if (IsValidParameterName(context, parameterName))
{
parts.Add(templatePart);
return(true);
}
else
{
return(false);
}
}
private static bool ParseParameter(Context context, List <RoutePatternPart> parts)
{
Debug.Assert(context.Current == OpenBrace);
context.Mark();
context.MoveNext();
while (true)
{
if (context.Current == OpenBrace)
{
// This is an open brace inside of a parameter, it has to be escaped
if (context.MoveNext())
{
if (context.Current != OpenBrace)
{
// If we see something like "{p1:regex(^\d{3", we will come here.
context.Error = "In a route parameter, '{' and '}' must be escaped with '{{' and '}}'.";
return(false);
}
}
else
{
// This is a dangling open-brace, which is not allowed
// Example: "{p1:regex(^\d{"
context.Error = "There is an incomplete parameter in the route template. Check that each '{' character has a matching '}' character.";
return(false);
}
}
else if (context.Current == CloseBrace)
{
// When we encounter Closed brace here, it either means end of the parameter or it is a closed
// brace in the parameter, in that case it needs to be escaped.
// Example: {p1:regex(([}}])\w+}. First pair is escaped one and last marks end of the parameter
if (!context.MoveNext())
{
// This is the end of the string -and we have a valid parameter
break;
}
if (context.Current == CloseBrace)
{
// This is an 'escaped' brace in a parameter name
}
else
{
// This is the end of the parameter
break;
}
}
if (!context.MoveNext())
{
// This is a dangling open-brace, which is not allowed
context.Error = "There is an incomplete parameter in the route template. Check that each '{' character has a matching '}' character.";
return(false);
}
}
var text = context.Capture();
if (text == "{}")
{
context.Error = $"The route parameter name '{string.Empty}' is invalid. Route parameter names must be non-empty and cannot contain these characters: '{{', '}}', '/'. The '?' character marks a parameter as optional, and can occur only at the end of the parameter. The '*' character marks a parameter as catch-all, and can occur only at the start of the parameter.";
return(false);
}
var inside = text.Substring(1, text.Length - 2);
var decoded = inside.Replace("}}", "}").Replace("{{", "{");
// At this point, we need to parse the raw name for inline constraint,
// default values and optional parameters.
var templatePart = RouteParameterParser.ParseRouteParameter(decoded);
// See #475 - this is here because InlineRouteParameterParser can't return errors
if (decoded.StartsWith("*", StringComparison.Ordinal) && decoded.EndsWith("?", StringComparison.Ordinal))
{
context.Error = "A catch-all parameter cannot be marked optional.";
return(false);
}
if (templatePart.IsOptional && templatePart.Default != null)
{
// Cannot be optional and have a default value.
// The only way to declare an optional parameter is to have a ? at the end,
// hence we cannot have both default value and optional parameter within the template.
// A workaround is to add it as a separate entry in the defaults argument.
context.Error = "An optional parameter cannot have default value.";
return(false);
}
var parameterName = templatePart.Name;
if (IsValidParameterName(context, parameterName))
{
parts.Add(templatePart);
return(true);
}
else
{
return(false);
}
}