I can able to log the request message body in Application Insights using a method mentioned in this link https://stackoverflow.com/a/42772603/1094140 but I can’t able to log in the response message body. I am interested in logging the response message body as well. I am already logging the Post, Put, Delete Request message body.
When I tried to access the response body in the TelemetryInitializer I keep getting an exception with an error message saying that “stream was not readable. When I researched more I found that AzureInitializer is running as part of HttpModule(ApplicationInsightsWebTracking) so by the time it gets control response object is disposed of.
My idea is to record the response using a delegate handler since the response object is not disposed at the stage of the message handler. The message handler is part of the Web API life cycle i.e. similar to the HTTP module but confined to Web API Life cycle. When I developed and tested this idea, fortunately, It worked I recorded the response in the request message using message handler and retrieved it at the AzureInitializer (HTTP module whose execution happens later than the message handler i.e ASP.NET Web API Life cycle order). Here is the sample code.
public class AzureRequestResponseInitializer : ITelemetryInitializer
{
public void Initialize(ITelemetry telemetry)
{
var requestTelemetry = telemetry as RequestTelemetry;
if (requestTelemetry != null && HttpContext.Current != null && HttpContext.Current.Request != null)
{
if ((HttpContext.Current.Request.HttpMethod == HttpMethod.Post.ToString()
|| HttpContext.Current.Request.HttpMethod == HttpMethod.Put.ToString()) &&
HttpContext.Current.Request.Url.AbsoluteUri.Contains("api"))
using (var reader = new StreamReader(HttpContext.Current.Request.InputStream))
{
HttpContext.Current.Request.InputStream.Position = 0;
string requestBody = reader.ReadToEnd();
if (requestTelemetry.Properties.Keys.Contains("requestbody"))
{
requestTelemetry.Properties["requestbody"] = requestBody;
}
else
{
requestTelemetry.Properties.Add("requestbody", requestBody);
}
}
else if (HttpContext.Current.Request.HttpMethod == HttpMethod.Get.ToString()
&& HttpContext.Current.Response.ContentType.Contains("application/json"))
{
var netHttpRequestMessage = HttpContext.Current.Items["MS_HttpRequestMessage"] as HttpRequestMessage;
if (netHttpRequestMessage.Properties.Keys.Contains("responsejson"))
{
var responseJson = netHttpRequestMessage.Properties["responsejson"].ToString();
if (requestTelemetry.Properties.Keys.Contains("responsebody"))
{
requestTelemetry.Properties["responsebody"] = responseJson;
}
else
{
requestTelemetry.Properties.Add("responsebody", responseJson);
}
}
}
}
}
} config.MessageHandlers.Add(new LoggingHandler());
public class LoggingHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
return base.SendAsync(request, cancellationToken).ContinueWith(task =>
{
var response = task.Result;
StoreResponse(response);
return response;
});
}
private void StoreResponse(HttpResponseMessage response)
{
var request = response.RequestMessage;
(response.Content ?? new StringContent("")).ReadAsStringAsync().ContinueWith(x =>
{
var ctx = request.Properties["MS_HttpContext"] as HttpContextWrapper;
if (request.Properties.ContainsKey("responseJson"))
{
request.Properties["responsejson"] = x.Result;
}
else
{
request.Properties.Add("responsejson", x.Result);
}
});
}
} 
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