private parseHeaders()

in AutoCollection/HttpRequestParser.ts [267:319]
43 lines of code
23 McCabe index (conditional complexity)

    private parseHeaders(request: http.IncomingMessage | HttpRequest, requestId?: string) {

        this.rawHeaders = request.headers || (<any>request).rawHeaders;
        this.userAgent = request.headers && request.headers["user-agent"];
        this.sourceCorrelationId = Util.getCorrelationContextTarget(request, RequestResponseHeaders.requestContextSourceKey);

        if (request.headers) {
            const tracestateHeader = request.headers[RequestResponseHeaders.traceStateHeader] ? request.headers[RequestResponseHeaders.traceStateHeader].toString() : null; // w3c header
            const traceparentHeader = request.headers[RequestResponseHeaders.traceparentHeader] ? request.headers[RequestResponseHeaders.traceparentHeader].toString() : null; // w3c header
            const requestIdHeader = request.headers[RequestResponseHeaders.requestIdHeader] ? request.headers[RequestResponseHeaders.requestIdHeader].toString() : null; // default AI header
            const legacy_parentId = request.headers[RequestResponseHeaders.parentIdHeader] ? request.headers[RequestResponseHeaders.parentIdHeader].toString() : null; // legacy AI header
            const legacy_rootId = request.headers[RequestResponseHeaders.rootIdHeader] ? request.headers[RequestResponseHeaders.rootIdHeader].toString() : null; // legacy AI header

            this.correlationContextHeader = request.headers[RequestResponseHeaders.correlationContextHeader] ? request.headers[RequestResponseHeaders.correlationContextHeader].toString() : null;

            if (CorrelationIdManager.w3cEnabled && (traceparentHeader || tracestateHeader)) {
                // Parse W3C Trace Context headers
                this.traceparent = new Traceparent(traceparentHeader ? traceparentHeader.toString() : null); // new traceparent is always created from this
                this.tracestate = traceparentHeader && tracestateHeader && new Tracestate(tracestateHeader ? tracestateHeader.toString() : null); // discard tracestate if no traceparent is present
                this.setBackCompatFromThisTraceContext();
            } else if (requestIdHeader) {
                // Parse AI headers
                if (CorrelationIdManager.w3cEnabled) {
                    this.traceparent = new Traceparent(null, requestIdHeader);
                    this.setBackCompatFromThisTraceContext();
                } else {
                    this.parentId = requestIdHeader;
                    this.requestId = CorrelationIdManager.generateRequestId(this.parentId);
                    this.operationId = CorrelationIdManager.getRootId(this.requestId);
                }
            } else {
                // Legacy fallback
                if (CorrelationIdManager.w3cEnabled) {
                    this.traceparent = new Traceparent();
                    this.traceparent.parentId = legacy_parentId;
                    this.traceparent.legacyRootId = legacy_rootId || legacy_parentId;
                    this.setBackCompatFromThisTraceContext();
                } else {
                    this.parentId = legacy_parentId;
                    this.requestId = CorrelationIdManager.generateRequestId(legacy_rootId || this.parentId);
                    this.correlationContextHeader = null;
                    this.operationId = CorrelationIdManager.getRootId(this.requestId);
                }
            }

            if (requestId) {
                // For the scenarios that don't guarantee an AI-created context,
                // override the requestId with the provided one.
                this.requestId = requestId;
                this.operationId = CorrelationIdManager.getRootId(this.requestId);
            }
        }
    }