/// <summary>
/// Adds a new inbound route to the <see cref="TreeRouter"/>.
/// </summary>
/// <param name="handler">The <see cref="IRouter"/> for handling the route.</param>
/// <param name="routeTemplate">The <see cref="RouteTemplate"/> of the route.</param>
/// <param name="routeName">The route name.</param>
/// <param name="order">The route order.</param>
/// <returns>The <see cref="InboundRouteEntry"/>.</returns>
public InboundRouteEntry MapInbound(
IRouter handler,
RouteTemplate routeTemplate,
string routeName,
int order)
{
if (handler == null)
{
throw new ArgumentNullException(nameof(handler));
}
if (routeTemplate == null)
{
throw new ArgumentNullException(nameof(routeTemplate));
}
var entry = new InboundRouteEntry()
{
Handler = handler,
Order = order,
Precedence = RoutePrecedence.ComputeInbound(routeTemplate),
RouteName = routeName,
RouteTemplate = routeTemplate,
};
var constraintBuilder = new RouteConstraintBuilder(_constraintResolver, routeTemplate.TemplateText);
foreach (var parameter in routeTemplate.Parameters)
{
if (parameter.InlineConstraints != null)
{
if (parameter.IsOptional)
{
constraintBuilder.SetOptional(parameter.Name);
}
foreach (var constraint in parameter.InlineConstraints)
{
constraintBuilder.AddResolvedConstraint(parameter.Name, constraint.Constraint);
}
}
}
entry.Constraints = constraintBuilder.Build();
entry.Defaults = new RouteValueDictionary();
foreach (var parameter in entry.RouteTemplate.Parameters)
{
if (parameter.DefaultValue != null)
{
entry.Defaults.Add(parameter.Name, parameter.DefaultValue);
}
}
InboundEntries.Add(entry);
return(entry);
}
internal void AddEntry(InboundRouteEntry entry)
{
// The url matching tree represents all the routes asociated with a given
// order. Each node in the tree represents all the different categories
// a segment can have for which there is a defined inbound route entry.
// Each node contains a set of Matches that indicate all the routes for which
// a URL is a potential match. This list contains the routes with the same
// number of segments and the routes with the same number of segments plus an
// additional catch all parameter (as it can be empty).
// For example, for a set of routes like:
// 'Customer/Index/{id}'
// '{Controller}/{Action}/{*parameters}'
//
// The route tree will look like:
// Root ->
// Literals: Customer ->
// Literals: Index ->
// Parameters: {id}
// Matches: 'Customer/Index/{id}'
// Parameters: {Controller} ->
// Parameters: {Action} ->
// Matches: '{Controller}/{Action}/{*parameters}'
// CatchAlls: {*parameters}
// Matches: '{Controller}/{Action}/{*parameters}'
//
// When the tree router tries to match a route, it iterates the list of url matching trees
// in ascending order. For each tree it traverses each node starting from the root in the
// following order: Literals, constrained parameters, parameters, constrained catch all routes, catch alls.
// When it gets to a node of the same length as the route its trying to match, it simply looks at the list of
// candidates (which is in precence order) and tries to match the url against it.
//
var current = Root;
var matcher = new TemplateMatcher(entry.RouteTemplate, entry.Defaults);
for (var i = 0; i < entry.RouteTemplate.Segments.Count; i++)
{
var segment = entry.RouteTemplate.Segments[i];
if (!segment.IsSimple)
{
// Treat complex segments as a constrained parameter
if (current.ConstrainedParameters == null)
{
current.ConstrainedParameters = new UrlMatchingNode(length: i + 1);
}
current = current.ConstrainedParameters;
continue;
}
Debug.Assert(segment.Parts.Count == 1);
var part = segment.Parts[0];
if (part.IsLiteral)
{
if (!current.Literals.TryGetValue(part.Text, out var next))
{
next = new UrlMatchingNode(length: i + 1);
current.Literals.Add(part.Text, next);
}
current = next;
continue;
}
// We accept templates that have intermediate optional values, but we ignore
// those values for route matching. For that reason, we need to add the entry
// to the list of matches, only if the remaining segments are optional. For example:
// /{controller}/{action=Index}/{id} will be equivalent to /{controller}/{action}/{id}
// for the purposes of route matching.
if (part.IsParameter &&
RemainingSegmentsAreOptional(entry.RouteTemplate.Segments, i))
{
current.Matches.Add(new InboundMatch()
{
Entry = entry, TemplateMatcher = matcher
});
}
if (part.IsParameter && part.InlineConstraints.Any() && !part.IsCatchAll)
{
if (current.ConstrainedParameters == null)
{
current.ConstrainedParameters = new UrlMatchingNode(length: i + 1);
}
current = current.ConstrainedParameters;
continue;
}
if (part.IsParameter && !part.IsCatchAll)
{
if (current.Parameters == null)
{
current.Parameters = new UrlMatchingNode(length: i + 1);
}
current = current.Parameters;
continue;
}
if (part.IsParameter && part.InlineConstraints.Any() && part.IsCatchAll)
{
if (current.ConstrainedCatchAlls == null)
{
current.ConstrainedCatchAlls = new UrlMatchingNode(length: i + 1)
{
IsCatchAll = true
};
}
current = current.ConstrainedCatchAlls;
continue;
}
if (part.IsParameter && part.IsCatchAll)
{
if (current.CatchAlls == null)
{
current.CatchAlls = new UrlMatchingNode(length: i + 1)
{
IsCatchAll = true
};
}
current = current.CatchAlls;
continue;
}
Debug.Fail("We shouldn't get here.");
}
current.Matches.Add(new InboundMatch()
{
Entry = entry, TemplateMatcher = matcher
});
current.Matches.Sort((x, y) =>
{
var result = x.Entry.Precedence.CompareTo(y.Entry.Precedence);
return(result == 0 ? x.Entry.RouteTemplate.TemplateText.CompareTo(y.Entry.RouteTemplate.TemplateText) : result);
});
}
