import type { TimeStamp } from '@datadog/browser-core' import { dateNow, findCommaSeparatedValue, ONE_MINUTE } from '@datadog/browser-core' import { isCommentNode, isTextNode } from '../../browser/htmlDomUtils' interface DocumentTraceData { traceId: string traceTime: TimeStamp } export const INITIAL_DOCUMENT_OUTDATED_TRACE_ID_THRESHOLD = 2 * ONE_MINUTE export function getDocumentTraceId(document: Document): string | undefined { const data = getDocumentTraceDataFromMeta(document) || getDocumentTraceDataFromComment(document) if (!data || data.traceTime <= dateNow() - INITIAL_DOCUMENT_OUTDATED_TRACE_ID_THRESHOLD) { return undefined } return data.traceId } export function getDocumentTraceDataFromMeta(document: Document): DocumentTraceData | undefined { const traceIdMeta = document.querySelector('meta[name=dd-trace-id]') const traceTimeMeta = document.querySelector('meta[name=dd-trace-time]') return createDocumentTraceData(traceIdMeta && traceIdMeta.content, traceTimeMeta && traceTimeMeta.content) } export function getDocumentTraceDataFromComment(document: Document): DocumentTraceData | undefined { const comment = findTraceComment(document) if (!comment) { return undefined } return createDocumentTraceData( findCommaSeparatedValue(comment, 'trace-id'), findCommaSeparatedValue(comment, 'trace-time') ) } export function createDocumentTraceData( traceId: string | undefined | null, rawTraceTime: string | undefined | null ): DocumentTraceData | undefined { const traceTime = rawTraceTime && (Number(rawTraceTime) as TimeStamp) if (!traceId || !traceTime) { return undefined } return { traceId, traceTime, } } export function findTraceComment(document: Document): string | undefined { // 1. Try to find the comment as a direct child of the document // Note: TSLint advises to use a 'for of', but TS doesn't allow to use 'for of' if the iterated // value is not an array or string (here, a NodeList). for (let i = 0; i < document.childNodes.length; i += 1) { const comment = getTraceCommentFromNode(document.childNodes[i]) if (comment) { return comment } } // 2. If the comment is placed after the tag, but have some space or new lines before or // after, the DOM parser will lift it (and the surrounding text) at the end of the tag. // Try to look for the comment at the end of the by by iterating over its child nodes in // reverse order, stopping if we come across a non-text node. if (document.body) { for (let i = document.body.childNodes.length - 1; i >= 0; i -= 1) { const node = document.body.childNodes[i] const comment = getTraceCommentFromNode(node) if (comment) { return comment } if (!isTextNode(node)) { break } } } } function getTraceCommentFromNode(node: Node | null) { if (node && isCommentNode(node)) { const match = /^\s*DATADOG;(.*?)\s*$/.exec(node.data) if (match) { return match[1] } } }