public BoundRouteTemplate Bind(
IDictionary <string, object> currentValues,
IDictionary <string, object> values,
HttpRouteValueDictionary defaultValues,
HttpRouteValueDictionary constraints
)
{
if (currentValues == null)
{
currentValues = new HttpRouteValueDictionary();
}
if (values == null)
{
values = new HttpRouteValueDictionary();
}
if (defaultValues == null)
{
defaultValues = new HttpRouteValueDictionary();
}
// The set of values we should be using when generating the URI in this route
HttpRouteValueDictionary acceptedValues = new HttpRouteValueDictionary();
// Keep track of which new values have been used
HashSet <string> unusedNewValues = new HashSet <string>(
values.Keys,
StringComparer.OrdinalIgnoreCase
);
// Step 1: Get the list of values we're going to try to use to match and generate this URI
// Find out which entries in the URI are valid for the URI we want to generate.
// If the URI had ordered parameters a="1", b="2", c="3" and the new values
// specified that b="9", then we need to invalidate everything after it. The new
// values should then be a="1", b="9", c=<no value>.
ForEachParameter(
PathSegments,
delegate(PathParameterSubsegment parameterSubsegment)
{
// If it's a parameter subsegment, examine the current value to see if it matches the new value
string parameterName = parameterSubsegment.ParameterName;
object newParameterValue;
bool hasNewParameterValue = values.TryGetValue(
parameterName,
out newParameterValue
);
if (hasNewParameterValue)
{
unusedNewValues.Remove(parameterName);
}
object currentParameterValue;
bool hasCurrentParameterValue = currentValues.TryGetValue(
parameterName,
out currentParameterValue
);
if (hasNewParameterValue && hasCurrentParameterValue)
{
if (!RoutePartsEqual(currentParameterValue, newParameterValue))
{
// Stop copying current values when we find one that doesn't match
return(false);
}
}
// If the parameter is a match, add it to the list of values we will use for URI generation
if (hasNewParameterValue)
{
if (IsRoutePartNonEmpty(newParameterValue))
{
acceptedValues.Add(parameterName, newParameterValue);
}
}
else
{
if (hasCurrentParameterValue)
{
acceptedValues.Add(parameterName, currentParameterValue);
}
}
return(true);
}
);
// Add all remaining new values to the list of values we will use for URI generation
foreach (var newValue in values)
{
if (IsRoutePartNonEmpty(newValue.Value))
{
if (!acceptedValues.ContainsKey(newValue.Key))
{
acceptedValues.Add(newValue.Key, newValue.Value);
}
}
}
// Add all current values that aren't in the URI at all
foreach (var currentValue in currentValues)
{
string parameterName = currentValue.Key;
if (!acceptedValues.ContainsKey(parameterName))
{
PathParameterSubsegment parameterSubsegment = GetParameterSubsegment(
PathSegments,
parameterName
);
if (parameterSubsegment == null)
{
acceptedValues.Add(parameterName, currentValue.Value);
}
}
}
// Add all remaining default values from the route to the list of values we will use for URI generation
ForEachParameter(
PathSegments,
delegate(PathParameterSubsegment parameterSubsegment)
{
if (!acceptedValues.ContainsKey(parameterSubsegment.ParameterName))
{
object defaultValue;
if (
!IsParameterRequired(
parameterSubsegment,
defaultValues,
out defaultValue
)
)
{
// Add the default value only if there isn't already a new value for it and
// only if it actually has a default value, which we determine based on whether
// the parameter value is required.
acceptedValues.Add(parameterSubsegment.ParameterName, defaultValue);
}
}
return(true);
}
);
// All required parameters in this URI must have values from somewhere (i.e. the accepted values)
bool hasAllRequiredValues = ForEachParameter(
PathSegments,
delegate(PathParameterSubsegment parameterSubsegment)
{
object defaultValue;
if (IsParameterRequired(parameterSubsegment, defaultValues, out defaultValue))
{
if (!acceptedValues.ContainsKey(parameterSubsegment.ParameterName))
{
// If the route parameter value is required that means there's
// no default value, so if there wasn't a new value for it
// either, this route won't match.
return(false);
}
}
return(true);
}
);
if (!hasAllRequiredValues)
{
return(null);
}
// All other default values must match if they are explicitly defined in the new values
HttpRouteValueDictionary otherDefaultValues = new HttpRouteValueDictionary(
defaultValues
);
ForEachParameter(
PathSegments,
delegate(PathParameterSubsegment parameterSubsegment)
{
otherDefaultValues.Remove(parameterSubsegment.ParameterName);
return(true);
}
);
foreach (var defaultValue in otherDefaultValues)
{
object value;
if (values.TryGetValue(defaultValue.Key, out value))
{
unusedNewValues.Remove(defaultValue.Key);
if (!RoutePartsEqual(value, defaultValue.Value))
{
// If there is a non-parameterized value in the route and there is a
// new value for it and it doesn't match, this route won't match.
return(null);
}
}
}
// Step 2: If the route is a match generate the appropriate URI
StringBuilder uri = new StringBuilder();
StringBuilder pendingParts = new StringBuilder();
bool pendingPartsAreAllSafe = false;
bool blockAllUriAppends = false;
for (int i = 0; i < PathSegments.Count; i++)
{
PathSegment pathSegment = PathSegments[i]; // parsedRouteUriPart
if (pathSegment is PathSeparatorSegment)
{
if (pendingPartsAreAllSafe)
{
// Accept
if (pendingParts.Length > 0)
{
if (blockAllUriAppends)
{
return(null);
}
// Append any pending literals to the URI
uri.Append(pendingParts.ToString());
pendingParts.Length = 0;
}
}
pendingPartsAreAllSafe = false;
// Guard against appending multiple separators for empty segments
if (pendingParts.Length > 0 && pendingParts[pendingParts.Length - 1] == '/')
{
// Dev10 676725: Route should not be matched if that causes mismatched tokens
// Dev11 86819: We will allow empty matches if all subsequent segments are null
if (blockAllUriAppends)
{
return(null);
}
// Append any pending literals to the URI (without the trailing slash) and prevent any future appends
uri.Append(pendingParts.ToString(0, pendingParts.Length - 1));
pendingParts.Length = 0;
blockAllUriAppends = true;
}
else
{
pendingParts.Append("/");
}
}
else
{
PathContentSegment contentPathSegment = pathSegment as PathContentSegment;
if (contentPathSegment != null)
{
// Segments are treated as all-or-none. We should never output a partial segment.
// If we add any subsegment of this segment to the generated URI, we have to add
// the complete match. For example, if the subsegment is "{p1}-{p2}.xml" and we
// used a value for {p1}, we have to output the entire segment up to the next "/".
// Otherwise we could end up with the partial segment "v1" instead of the entire
// segment "v1-v2.xml".
bool addedAnySubsegments = false;
for (int j = 0; j < contentPathSegment.Subsegments.Count; j++)
{
PathSubsegment subsegment = contentPathSegment.Subsegments[j];
PathLiteralSubsegment literalSubsegment =
subsegment as PathLiteralSubsegment;
if (literalSubsegment != null)
{
// If it's a literal we hold on to it until we are sure we need to add it
pendingPartsAreAllSafe = true;
pendingParts.Append(literalSubsegment.Literal);
}
else
{
PathParameterSubsegment parameterSubsegment =
subsegment as PathParameterSubsegment;
if (parameterSubsegment != null)
{
if (pendingPartsAreAllSafe)
{
// Accept
if (pendingParts.Length > 0)
{
if (blockAllUriAppends)
{
return(null);
}
// Append any pending literals to the URI
uri.Append(pendingParts.ToString());
pendingParts.Length = 0;
addedAnySubsegments = true;
}
}
pendingPartsAreAllSafe = false;
// If it's a parameter, get its value
object acceptedParameterValue;
bool hasAcceptedParameterValue = acceptedValues.TryGetValue(
parameterSubsegment.ParameterName,
out acceptedParameterValue
);
if (hasAcceptedParameterValue)
{
unusedNewValues.Remove(parameterSubsegment.ParameterName);
}
object defaultParameterValue;
defaultValues.TryGetValue(
parameterSubsegment.ParameterName,
out defaultParameterValue
);
if (
RoutePartsEqual(
acceptedParameterValue,
defaultParameterValue
)
)
{
// If the accepted value is the same as the default value, mark it as pending since
// we won't necessarily add it to the URI we generate.
pendingParts.Append(
Convert.ToString(
acceptedParameterValue,
CultureInfo.InvariantCulture
)
);
}
else
{
if (blockAllUriAppends)
{
return(null);
}
// Add the new part to the URI as well as any pending parts
if (pendingParts.Length > 0)
{
// Append any pending literals to the URI
uri.Append(pendingParts.ToString());
pendingParts.Length = 0;
}
uri.Append(
Convert.ToString(
acceptedParameterValue,
CultureInfo.InvariantCulture
)
);
addedAnySubsegments = true;
}
}
else
{
Contract.Assert(false, "Invalid path subsegment type");
}
}
}
if (addedAnySubsegments)
{
// See comment above about why we add the pending parts
if (pendingParts.Length > 0)
{
if (blockAllUriAppends)
{
return(null);
}
// Append any pending literals to the URI
uri.Append(pendingParts.ToString());
pendingParts.Length = 0;
}
}
}
else
{
Contract.Assert(false, "Invalid path segment type");
}
}
}
if (pendingPartsAreAllSafe)
{
// Accept
if (pendingParts.Length > 0)
{
if (blockAllUriAppends)
{
return(null);
}
// Append any pending literals to the URI
uri.Append(pendingParts.ToString());
}
}
// Process constraints keys
if (constraints != null)
{
// If there are any constraints, mark all the keys as being used so that we don't
// generate query string items for custom constraints that don't appear as parameters
// in the URI format.
foreach (var constraintsItem in constraints)
{
unusedNewValues.Remove(constraintsItem.Key);
}
}
// Encode the URI before we append the query string, otherwise we would double encode the query string
StringBuilder encodedUri = new StringBuilder();
encodedUri.Append(UriEncode(uri.ToString()));
uri = encodedUri;
// Add remaining new values as query string parameters to the URI
if (unusedNewValues.Count > 0)
{
// Generate the query string
bool firstParam = true;
foreach (string unusedNewValue in unusedNewValues)
{
object value;
if (acceptedValues.TryGetValue(unusedNewValue, out value))
{
uri.Append(firstParam ? '?' : '&');
firstParam = false;
uri.Append(Uri.EscapeDataString(unusedNewValue));
uri.Append('=');
uri.Append(
Uri.EscapeDataString(
Convert.ToString(value, CultureInfo.InvariantCulture)
)
);
}
}
}
return(new BoundRouteTemplate
{
BoundTemplate = uri.ToString(),
Values = acceptedValues
});
}