const path = require('path')
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const defu = require('defu')
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const defaults = require('./defaults')
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module.exports = function createServePlaceholder (_options) {
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// Assign default options
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const options = defu(_options, defaults)
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return function servePlaceholderMiddleware (req, res, next) {
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// If response already sent, skip
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if (res.writableEnded) {
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return
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}
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// Get url from req object
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const url = req.url.split('?')[0]
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// Get ext of requst url
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const ext = path.extname(url)
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// Try to find a handler based on ext
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let handler = options.handlers[ext]
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// Skip middleware is handler is explictly set to false
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if (handler === false) {
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return next()
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}
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// In case of no handler guessed
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if (typeof handler === 'undefined') {
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if (options.skipUnknown) {
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// Skip this middleware
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return next()
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} else {
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// Use 'default' handler
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handler = 'default'
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}
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}
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// Set statusCode
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if (options.statusCode) {
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res.statusCode = options.statusCode
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}
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// Try to set appreciate mime type based on handler
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const mime = options.mimes[handler]
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if (mime) {
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res.setHeader('Content-Type', mime)
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}
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// Prevent caching
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if (options.noCache) {
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res.setHeader('Cache-Control', 'no-cache, no-store, must-revalidate') // HTTP 1.1
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res.setHeader('Pragma', 'no-cache') // HTTP 1.0
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res.setHeader('Expires', '0') // Proxies
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}
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// Try to find placeholder based on handler
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const placeholder = options.placeholders[handler]
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// Send placeholder and end response
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res.end(placeholder)
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}
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}
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