/// <summary>
/// Sets the correlation id on IOwinRequest and IOwinResponse. If the Owin.RequestId already exists a new one will not be generated.
/// Only if the Owin.RequestId is null, empty, whitespace, or non-existent will it be overriden.
/// </summary>
/// <param name="context">The <see cref="IOwinContext"/>.</param>
/// <param name="createCorrelationId">The Func to build a correlation ID.</param>
/// <param name="requestIdName">The name of the Http Header to place the request correlation id.</param>
public static void SetCorrelationId(this IOwinContext context, CorrelationIdProperties properties)
{
var correlationId = properties.GenerateId();
var requestIdName = properties.CorrelationIdHeaderName;
var environment = context.Environment;
// Update IOwinContext.Environment if it doesn't have a value.
var hasCorrelationId = environment.ContainsKey(OwinRequestIdKey) && !string.IsNullOrWhiteSpace(environment[OwinRequestIdKey].ToString());
if (hasCorrelationId)
{
correlationId = environment[OwinRequestIdKey].ToString();
}
else
{
environment[OwinRequestIdKey] = correlationId;
}
// Apply correlation ID to Request and Response.
var headerValue = new[] { correlationId };
if (context.Request.Headers.ContainsKey(correlationId))
{
context.Request.Headers[requestIdName] = correlationId;
}
else
{
context.Request.Headers.Add(requestIdName, headerValue);
}
context.Response.Headers.Add(requestIdName, headerValue);
}
/// <summary>
/// Use request correlation middleware. Adds a Request ID to the Request and Response.
/// </summary>
/// <param name="app">The app.</param>
/// <param name="properties">The properties for the request correlation.</param>
/// <returns>The <see cref="IAppBuilder"/>.</returns>
public static IAppBuilder UseRequestIds(this IAppBuilder app, CorrelationIdProperties properties = null)
{
if (properties == null)
{
properties = new CorrelationIdProperties();
}
app.Use <RequestIdMiddleware>(properties);
return(app);
}
/// <summary>
/// Initializes a new instance of <see cref="RequestIdMiddleware"/>.
/// </summary>
/// <param name="next">The next owin middleware to execute.</param>
/// <param name="properties">The <see cref="CorrelationIdProperties"/> used to configure the middleware.</param>
public RequestIdMiddleware(OwinMiddleware next, CorrelationIdProperties properties) : base(next)
{
_properties = properties;
}