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@shanefulmer
Created November 30, 2012 04:49
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CorsHandler
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
namespace DotNetOpenAuth.WebAPI {
public class CorsHandler : DelegatingHandler {
const string Origin = "Origin";
const string AccessControlRequestMethod = "Access-Control-Request-Method";
const string AccessControlRequestHeaders = "Access-Control-Request-Headers";
const string AccessControlAllowOrigin = "Access-Control-Allow-Origin";
const string AccessControlAllowMethods = "Access-Control-Allow-Methods";
const string AccessControlAllowHeaders = "Access-Control-Allow-Headers";
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) {
bool isCorsRequest = request.Headers.Contains(Origin);
bool isPreflightRequest = request.Method == HttpMethod.Options;
if (isCorsRequest) {
if (isPreflightRequest) {
return Task.Factory.StartNew<HttpResponseMessage>(() => {
HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
response.Headers.Add(AccessControlAllowOrigin, request.Headers.GetValues(Origin).First());
string accessControlRequestMethod = request.Headers.GetValues(AccessControlRequestMethod).FirstOrDefault();
if (accessControlRequestMethod != null) {
response.Headers.Add(AccessControlAllowMethods, accessControlRequestMethod);
}
string requestedHeaders = string.Join(", ", request.Headers.GetValues(AccessControlRequestHeaders));
if (!string.IsNullOrEmpty(requestedHeaders)) {
response.Headers.Add(AccessControlAllowHeaders, requestedHeaders);
}
return response;
}, cancellationToken);
} else {
return base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>(t => {
HttpResponseMessage resp = t.Result;
resp.Headers.Add(AccessControlAllowOrigin, request.Headers.GetValues(Origin).First());
return resp;
});
}
} else {
return base.SendAsync(request, cancellationToken);
}
}
}
}
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