/
index.js
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/
index.js
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'use strict'
const absoluteUrl = require('absolute-url')
const hijackResponse = require('hijackresponse')
const URL = require('url').URL
const path = require('path')
const replace = require('string-replace-stream')
const origin = (iri) => {
const parts = new URL(iri)
parts.pathname = '/'
parts.search = ''
parts.username = ''
parts.password = ''
return parts.toString()
}
const storeOriginal = (req) => ({
host: req.headers.host,
forwardedHost: req.headers['x-forwarded-host'],
forwardedProto: req.headers['x-forwarded-proto'],
baseUrl: req.baseUrl,
originalUrl: req.originalUrl,
url: req.url
})
const restoreOriginal = (req, original) => {
req.headers.host = original.host
if (original.forwardedHost) {
req.headers['x-forwarded-host'] = original.forwardedHost
} else {
delete req.headers['x-forwarded-host']
}
if (original.forwardedProto) {
req.headers['x-forwarded-proto'] = original.forwardedProto
} else {
delete req.headers['x-forwarded-proto']
}
req.baseUrl = original.baseUrl
req.originalUrl = original.originalUrl
req.url = original.url
}
const rewrite = (options, req) => {
req.headers.host = options.urlParts.host
req.headers['x-forwarded-host'] = options.urlParts.host
req.headers['x-forwarded-proto'] = options.urlParts.protocol
req.baseUrl = path.join(options.urlParts.pathname, req.baseUrl)
req.originalUrl = path.join(options.urlParts.pathname, req.originalUrl)
}
const middleware = (options, req, res, next) => {
// do nothing if there are no options
if (!options || !options.url) {
return next()
}
// only process configured media types
if (options.mediaTypes) {
const matches = options.mediaTypes.filter((mediaType) => {
return req.accepts(mediaType)
})
if (matches.length === 0) {
return next()
}
}
const ignorePattern = options.ignore && new RegExp(options.ignore)
// store original request parameters
const original = storeOriginal(req)
// allow other middlewares to access the original address (by using `res.locals.camouflageRewriteOriginalUrl`)
absoluteUrl.attach(req)
const originalUrl = new URL(req.absoluteUrl())
originalUrl.search = ''
res.locals.camouflageRewriteOriginalUrl = originalUrl.toString()
// rewrite request parameters
rewrite(options, req)
hijackResponse(res, (err, res) => {
if (err) {
res.unhijack()
return next(err)
}
// restore original request parameters
restoreOriginal(req, original)
absoluteUrl.attach(req)
const url = req.absoluteUrl()
if (ignorePattern && ignorePattern.test(url)) {
return res.pipe(res)
}
// replace url with origin (protocol + host + '/')
const requestOrigin = origin(url)
if (options.rewriteHeaders) {
Object.keys(res.getHeaders()).forEach((field) => {
res.header(field, res.getHeaders()[field].toString().split(options.url).join(requestOrigin))
})
}
if (options.rewriteContent) {
res.removeHeader('content-length')
res.pipe(replace(options.url, requestOrigin)).pipe(res)
} else {
res.pipe(res)
}
})
next()
}
const factory = (options) => {
if (options && options.url) {
options.urlParts = new URL(options.url)
}
return middleware.bind(null, options)
}
factory.origin = origin
factory.storeOriginal = storeOriginal
factory.restoreOriginal = restoreOriginal
factory.rewrite = rewrite
factory.middleware = middleware
module.exports = factory