/// <summary>
/// Creates a new instance of <see cref="RouteTokenTransformerConvention"/> with the specified <see cref="IOutboundParameterTransformer"/>.
/// </summary>
/// <param name="parameterTransformer">The <see cref="IOutboundParameterTransformer"/> to use with attribute routing token replacement.</param>
public RouteTokenTransformerConvention(IOutboundParameterTransformer parameterTransformer)
{
if (parameterTransformer == null)
{
throw new ArgumentNullException(nameof(parameterTransformer));
}
_parameterTransformer = parameterTransformer;
}
public ControllerRouteTokenTransformerConvention(Type controllerType, IOutboundParameterTransformer parameterTransformer)
{
if (parameterTransformer == null)
{
throw new ArgumentNullException(nameof(parameterTransformer));
}
_controllerType = controllerType;
_parameterTransformer = parameterTransformer;
}
public CustomPageRouteTransformerConvention(IOutboundParameterTransformer parameterTransformer) : base(parameterTransformer)
{
}
public static string ReplaceTokens(string template, IDictionary <string, string> values, IOutboundParameterTransformer routeTokenTransformer)
{
var builder = new StringBuilder();
var state = TemplateParserState.Plaintext;
int?tokenStart = null;
// We'll run the loop one extra time with 'null' to detect the end of the string.
for (var i = 0; i <= template.Length; i++)
{
var c = i < template.Length ? (char?)template[i] : null;
switch (state)
{
case TemplateParserState.Plaintext:
if (c == '[')
{
state = TemplateParserState.SeenLeft;
break;
}
else if (c == ']')
{
state = TemplateParserState.SeenRight;
break;
}
else if (c == null)
{
// We're at the end of the string, nothing left to do.
break;
}
else
{
builder.Append(c);
break;
}
case TemplateParserState.SeenLeft:
if (c == '[')
{
// This is an escaped left-bracket
builder.Append(c);
state = TemplateParserState.Plaintext;
break;
}
else if (c == ']')
{
// This is zero-width parameter - not allowed.
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_EmptyTokenNotAllowed);
throw new InvalidOperationException(message);
}
else if (c == null)
{
// This is a left-bracket at the end of the string.
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_UnclosedToken);
throw new InvalidOperationException(message);
}
else
{
tokenStart = i;
state = TemplateParserState.InsideToken;
break;
}
case TemplateParserState.SeenRight:
if (c == ']')
{
// This is an escaped right-bracket
builder.Append(c);
state = TemplateParserState.Plaintext;
break;
}
else if (c == null)
{
// This is an imbalanced right-bracket at the end of the string.
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_ImbalancedSquareBrackets);
throw new InvalidOperationException(message);
}
else
{
// This is an imbalanced right-bracket.
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_ImbalancedSquareBrackets);
throw new InvalidOperationException(message);
}
case TemplateParserState.InsideToken:
if (c == '[')
{
state = TemplateParserState.InsideToken | TemplateParserState.SeenLeft;
break;
}
else if (c == ']')
{
state = TemplateParserState.InsideToken | TemplateParserState.SeenRight;
break;
}
else if (c == null)
{
// This is an unclosed replacement token
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_UnclosedToken);
throw new InvalidOperationException(message);
}
else
{
// This is a just part of the parameter
break;
}
case TemplateParserState.InsideToken | TemplateParserState.SeenLeft:
if (c == '[')
{
// This is an escaped left-bracket
state = TemplateParserState.InsideToken;
break;
}
else
{
// Unescaped left-bracket is not allowed inside a token.
var message = Resources.FormatAttributeRoute_TokenReplacement_InvalidSyntax(
template,
Resources.AttributeRoute_TokenReplacement_UnescapedBraceInToken);
throw new InvalidOperationException(message);
}
case TemplateParserState.InsideToken | TemplateParserState.SeenRight:
if (c == ']')
{
// This is an escaped right-bracket
state = TemplateParserState.InsideToken;
break;
}
else
{
// This is the end of a replacement token.
var token = template
.Substring(tokenStart.Value, i - tokenStart.Value - 1)
.Replace("[[", "[")
.Replace("]]", "]");
if (!values.TryGetValue(token, out var value))
{
// Value not found
var message = Resources.FormatAttributeRoute_TokenReplacement_ReplacementValueNotFound(
template,
token,
string.Join(", ", values.Keys.OrderBy(k => k, StringComparer.OrdinalIgnoreCase)));
throw new InvalidOperationException(message);
}
if (routeTokenTransformer != null)
{
value = routeTokenTransformer.TransformOutbound(value);
}
builder.Append(value);
if (c == '[')
{
state = TemplateParserState.SeenLeft;
}
else if (c == ']')
{
state = TemplateParserState.SeenRight;
}
else if (c == null)
{
state = TemplateParserState.Plaintext;
}
else
{
builder.Append(c);
state = TemplateParserState.Plaintext;
}
tokenStart = null;
break;
}
}
}
return(builder.ToString());
}