private void ProcessHTTPRequest()

in sdk/src/Handlers/AspNetCore/Internal/AWSXRayMiddleware.cs [194:254]
52 lines of code
9 McCabe index (conditional complexity)

        private void ProcessHTTPRequest(HttpContext context)
        {
            HttpRequest request = context.Request;
            string headerString = null;

            if (request.Headers.TryGetValue(TraceHeader.HeaderKey, out StringValues headerValue))
            {
                if (headerValue.ToArray().Length >= 1)
                    headerString = headerValue.ToArray()[0];
            }

            // Trace header doesn't exist, which means this is the root node. Create a new traceId and inject the trace header.
            if (!TraceHeader.TryParse(headerString, out TraceHeader traceHeader))
            {
                _logger.DebugFormat("Trace header doesn't exist or not valid : ({0}). Injecting a new one.", headerString);
                traceHeader = new TraceHeader
                {
                    RootTraceId = TraceId.NewId(),
                    ParentId = null,
                    Sampled = SampleDecision.Unknown
                };
            }

            var segmentName = SegmentNamingStrategy.GetSegmentName(request);
            bool isSampleDecisionRequested = traceHeader.Sampled == SampleDecision.Requested;

            string ruleName = null;
            // Make sample decision
            if (traceHeader.Sampled == SampleDecision.Unknown || traceHeader.Sampled == SampleDecision.Requested)
            {
                string host = request.Host.Host;
                string url = request.Path;
                string method = request.Method;
                SamplingInput samplingInput = new SamplingInput(host, url, method, segmentName, _recorder.Origin);
                SamplingResponse sampleResponse = _recorder.SamplingStrategy.ShouldTrace(samplingInput);
                traceHeader.Sampled = sampleResponse.SampleDecision;
                ruleName = sampleResponse.RuleName;
            }

            if (AWSXRayRecorder.IsLambda())
            {
                _recorder.BeginSubsegment(segmentName);
            }
            else
            {
                SamplingResponse samplingResponse = new SamplingResponse(ruleName, traceHeader.Sampled); // get final ruleName and SampleDecision
                _recorder.BeginSegment(SegmentNamingStrategy.GetSegmentName(request), traceHeader.RootTraceId, traceHeader.ParentId, samplingResponse);
            }

            if (!AWSXRayRecorder.Instance.IsTracingDisabled())
            {
                var requestAttributes = new Dictionary<string, object>();
                PopulateRequestAttributes(request, requestAttributes);
                _recorder.AddHttpInformation("request", requestAttributes);
            }

            if (isSampleDecisionRequested)
            {
                context.Response.Headers.Add(TraceHeader.HeaderKey, traceHeader.ToString()); // Its recommended not to modify response header after _next.Invoke() call
            }
        }