private void addRule(IEnumerable <string> tokens, RoutingTreeNode currentNode, Func <Parameters, ApiResponse> method)
{
if (tokens.Count() == 0)
{
if (currentNode.Method != null)
{
// there is action already
throw new ArgumentException("Rule with this route was added before. Last token: " + currentNode.Token);
}
else
{
// add method
currentNode.Method = method;
}
return;
}
else
{
string currentToken = tokens.First();
// go deeper
RoutingTreeNode nextNode =
currentNode.Children.Where(ch => ch.Token == currentToken).FirstOrDefault();
if (nextNode == null)
{
// create next node
nextNode = NodeFactory.Create(currentToken);
// add it to tree
currentNode.Children.Add(nextNode);
}
// go to next node
addRule(tokens.Skip(1), nextNode, method);
}
}
private ApiResponse route(IEnumerable <string> tokens, RoutingTreeNode currentNode, Parameters parameters)
{
if (tokens.Count() == 0)
{
// it's last token in route, execute method
if (currentNode.IsAction)
{
// if node contains api call
return(currentNode.Method(parameters));
}
else
{
// if node doesn't contain api call
// check its children to be optional parameters
// for that, try to check it by passing empty string as token
RoutingTreeNode nextNode;
object param;
if (tryCheckParameter(String.Empty, currentNode.Children, out nextNode, out param, requireMethod: true))
{
// add param to route parameters
parameters.Add(nextNode.Token, param);
// finally, execute method
return(nextNode.Method(parameters));
}
else
{
// error, bad url
return(new ApiResponse(System.Net.HttpStatusCode.BadRequest));
}
}
}
else
{
// go deeper
var currentToken = tokens.First();
// firstly, check non-param tokens
var nextNode = currentNode.Children
.Where(ch => !ch.IsParam &&
ch.Token == currentToken)
.FirstOrDefault();
if (nextNode == null)
{
// if required token was not found,
// try to validate it as parameter
object param;
if (tryCheckParameter(currentToken, currentNode.Children, out nextNode, out param))
{
// add param to route parameters
parameters.Add(nextNode.Token, param);
// next node is initialized by out-keyword
}
else
{
// error, bad url
return(new ApiResponse("Error parsing url at: " + currentToken + ".", System.Net.HttpStatusCode.BadRequest));
}
}
// process remaining tokens from next node
return(route(tokens.Skip(1), nextNode, parameters));
}
}
public RoutingTree()
{
this.head = NodeFactory.Create(String.Empty);
}
private bool tryCheckParameter(string token, List <RoutingTreeNode> children, out RoutingTreeNode nextNode, out object parameter, bool requireMethod = false)
{
parameter = null;
nextNode = null;
foreach (var ch in children)
{
// check all child parameters
// if method is not reuiqred, (!requireMethod || ch.IsAction) == (!false || ..) == true
if (ch.IsParam && (!requireMethod || ch.IsAction))
{
parameter = ch.CheckConstraint(token);
// if parameter is valid (not null), return
if (parameter != null)
{
// set next node to node with valid parameter
nextNode = ch;
return(true);
}
}
}
// there are no parameters for this token
return(false);
}
