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- const {
- URL_MATCHER,
- TYPE_URL,
- TYPE_REGEX,
- TYPE_PATH,
- } = require('./matchers')
- /**
- * creates a string of asterisks,
- * this forces a minimum asterisk for security purposes
- */
- const asterisk = (length = 0) => {
- length = typeof length === 'string' ? length.length : length
- if (length < 8) {
- return '*'.repeat(8)
- }
- return '*'.repeat(length)
- }
- /**
- * escapes all special regex chars
- * @see https://stackoverflow.com/a/9310752
- * @see https://github.com/tc39/proposal-regex-escaping
- */
- const escapeRegExp = (text) => {
- return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, `\\$&`)
- }
- /**
- * provieds a regex "or" of the url versions of a string
- */
- const urlEncodeRegexGroup = (value) => {
- const decoded = decodeURIComponent(value)
- const encoded = encodeURIComponent(value)
- const union = [...new Set([encoded, decoded, value])].map(escapeRegExp).join('|')
- return union
- }
- /**
- * a tagged template literal that returns a regex ensures all variables are excaped
- */
- const urlEncodeRegexTag = (strings, ...values) => {
- let pattern = ''
- for (let i = 0; i < values.length; i++) {
- pattern += strings[i] + `(${urlEncodeRegexGroup(values[i])})`
- }
- pattern += strings[strings.length - 1]
- return new RegExp(pattern)
- }
- /**
- * creates a matcher for redacting url hostname
- */
- const redactUrlHostnameMatcher = ({ hostname, replacement } = {}) => ({
- type: TYPE_URL,
- predicate: ({ url }) => url.hostname === hostname,
- pattern: ({ url }) => {
- return urlEncodeRegexTag`(^${url.protocol}//${url.username}:.+@)?${url.hostname}`
- },
- replacement: `$1${replacement || asterisk()}`,
- })
- /**
- * creates a matcher for redacting url search / query parameter values
- */
- const redactUrlSearchParamsMatcher = ({ param, replacement } = {}) => ({
- type: TYPE_URL,
- predicate: ({ url }) => url.searchParams.has(param),
- pattern: ({ url }) => urlEncodeRegexTag`(${param}=)${url.searchParams.get(param)}`,
- replacement: `$1${replacement || asterisk()}`,
- })
- /** creates a matcher for redacting the url password */
- const redactUrlPasswordMatcher = ({ replacement } = {}) => ({
- type: TYPE_URL,
- predicate: ({ url }) => url.password,
- pattern: ({ url }) => urlEncodeRegexTag`(^${url.protocol}//${url.username}:)${url.password}`,
- replacement: `$1${replacement || asterisk()}`,
- })
- const redactUrlReplacement = (...matchers) => (subValue) => {
- try {
- const url = new URL(subValue)
- return redactMatchers(...matchers)(subValue, { url })
- } catch (err) {
- return subValue
- }
- }
- /**
- * creates a matcher / submatcher for urls, this function allows you to first
- * collect all urls within a larger string and then pass those urls to a
- * submatcher
- *
- * @example
- * console.log("this will first match all urls, then pass those urls to the password patcher")
- * redactMatchers(redactUrlMatcher(redactUrlPasswordMatcher()))
- *
- * @example
- * console.log(
- * "this will assume you are passing in a string that is a url, and will redact the password"
- * )
- * redactMatchers(redactUrlPasswordMatcher())
- *
- */
- const redactUrlMatcher = (...matchers) => {
- return {
- ...URL_MATCHER,
- replacement: redactUrlReplacement(...matchers),
- }
- }
- const matcherFunctions = {
- [TYPE_REGEX]: (matcher) => (value) => {
- if (typeof value === 'string') {
- value = value.replace(matcher.pattern, matcher.replacement)
- }
- return value
- },
- [TYPE_URL]: (matcher) => (value, ctx) => {
- if (typeof value === 'string') {
- try {
- const url = ctx?.url || new URL(value)
- const { predicate, pattern } = matcher
- const predicateValue = predicate({ url })
- if (predicateValue) {
- value = value.replace(pattern({ url }), matcher.replacement)
- }
- } catch (_e) {
- return value
- }
- }
- return value
- },
- [TYPE_PATH]: (matcher) => (value, ctx) => {
- const rawPath = ctx?.path
- const path = rawPath.join('.').toLowerCase()
- const { predicate, replacement } = matcher
- const replace = typeof replacement === 'function' ? replacement : () => replacement
- const shouldRun = predicate({ rawPath, path })
- if (shouldRun) {
- value = replace(value, { rawPath, path })
- }
- return value
- },
- }
- /** converts a matcher to a function */
- const redactMatcher = (matcher) => {
- return matcherFunctions[matcher.type](matcher)
- }
- /** converts a series of matchers to a function */
- const redactMatchers = (...matchers) => (value, ctx) => {
- const flatMatchers = matchers.flat()
- return flatMatchers.reduce((result, matcher) => {
- const fn = (typeof matcher === 'function') ? matcher : redactMatcher(matcher)
- return fn(result, ctx)
- }, value)
- }
- /**
- * replacement handler, keeping $1 (if it exists) and replacing the
- * rest of the string with asterisks, maintaining string length
- */
- const redactDynamicReplacement = () => (value, start) => {
- if (typeof start === 'number') {
- return asterisk(value)
- }
- return start + asterisk(value.substring(start.length).length)
- }
- /**
- * replacement handler, keeping $1 (if it exists) and replacing the
- * rest of the string with a fixed number of asterisks
- */
- const redactFixedReplacement = (length) => (_value, start) => {
- if (typeof start === 'number') {
- return asterisk(length)
- }
- return start + asterisk(length)
- }
- const redactUrlPassword = (value, replacement) => {
- return redactMatchers(redactUrlPasswordMatcher({ replacement }))(value)
- }
- module.exports = {
- asterisk,
- escapeRegExp,
- urlEncodeRegexGroup,
- urlEncodeRegexTag,
- redactUrlHostnameMatcher,
- redactUrlSearchParamsMatcher,
- redactUrlPasswordMatcher,
- redactUrlMatcher,
- redactUrlReplacement,
- redactDynamicReplacement,
- redactFixedReplacement,
- redactMatchers,
- redactUrlPassword,
- }
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