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Add extensibility point to resolve descriptors in assembly. 

- Modified our default TagHelperDescriptorResolver to provide a protected virtual method that it uses under the covers to resolve descriptors for an entire assembly. This will enable tooling to cache descriptors on a per-assembly basis.

#214
This commit is contained in:
N. Taylor Mullen 2014-10-30 14:46:28 -07:00
parent 829faaaa4b
commit bad8b16a2a
1 changed files with 33 additions and 23 deletions
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56
src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperDescriptorResolver.cs
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@ -45,34 +45,44 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
nameof(lookupText));
}
var tagHelperTypes = ResolveTagHelperTypes(lookupStrings);
// Grab the assembly name from the lookup text strings. Due to our supported lookupText formats it will
// always be the last element provided.
var assemblyName = lookupStrings.Last().Trim();
// Retrieve all TagHelperDescriptors that exist within the given assemblyName.
var descriptors = ResolveDescriptorsInAssembly(assemblyName);
// Check if the lookupText specifies a type to search for.
if (lookupStrings.Length == 2)
{
// The user provided a type name retrieve it so we can prune our descriptors.
var typeName = lookupStrings[0].Trim();
descriptors = descriptors.Where(descriptor =>
string.Equals(descriptor.TagHelperName, typeName, StringComparison.Ordinal));
}
return descriptors;
}
/// <summary>
/// Resolves all <see cref="TagHelperDescriptor"/>s for <see cref="ITagHelper"/>s from the given
/// <paramref name="assemblyName"/>.
/// </summary>
/// <param name="assemblyName">
/// The name of the assembly to resolve <see cref="TagHelperDescriptor"/>s from.
/// </param>
/// <returns><see cref="TagHelperDescriptor"/>s that represent <see cref="ITagHelper"/>s from the given
/// <paramref name="assemblyName"/>.</returns>
protected virtual IEnumerable<TagHelperDescriptor> ResolveDescriptorsInAssembly(string assemblyName)
{
// Resolve valid tag helper types from the assembly.
var tagHelperTypes = _typeResolver.Resolve(assemblyName);
// Convert types to TagHelperDescriptors
var descriptors = tagHelperTypes.SelectMany(TagHelperDescriptorFactory.CreateDescriptors);
return descriptors;
}
private IEnumerable<Type> ResolveTagHelperTypes(string[] lookupStrings)
{
// Grab the assembly name from the lookup text strings. Due to our supported lookupText formats it will
// always be the last element provided.
var assemblyName = lookupStrings.Last().Trim();
// Resolve valid tag helper types from the assembly.
var types = _typeResolver.Resolve(assemblyName);
// Check if the lookupText specifies a type to search for.
if (lookupStrings.Length == 2)
{
// The user provided a type name retrieve the value and trim it.
var typeName = lookupStrings[0].Trim();
types = types.Where(type =>
string.Equals(type.Namespace + "." + type.Name, typeName, StringComparison.Ordinal));
}
return types;
}
}
}