internet-programming/lab3/node_modules/method-override/index.js

145 lines
3.0 KiB
JavaScript

/*!
* method-override
* Copyright(c) 2010 Sencha Inc.
* Copyright(c) 2011 TJ Holowaychuk
* Copyright(c) 2014 Jonathan Ong
* Copyright(c) 2014 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module dependencies.
*/
var debug = require('debug')('method-override')
var methods = require('methods')
var parseurl = require('parseurl')
var querystring = require('querystring')
var vary = require('vary')
/**
* Method Override:
*
* Provides faux HTTP method support.
*
* Pass an optional `getter` to use when checking for
* a method override.
*
* A string is converted to a getter that will look for
* the method in `req.body[getter]` and a function will be
* called with `req` and expects the method to be returned.
* If the string starts with `X-` then it will look in
* `req.headers[getter]` instead.
*
* The original method is available via `req.originalMethod`.
*
* @param {string|function} [getter=X-HTTP-Method-Override]
* @param {object} [options]
* @return {function}
* @api public
*/
module.exports = function methodOverride (getter, options) {
var opts = options || {}
// get the getter fn
var get = typeof getter === 'function'
? getter
: createGetter(getter || 'X-HTTP-Method-Override')
// get allowed request methods to examine
var methods = opts.methods === undefined
? ['POST']
: opts.methods
return function methodOverride (req, res, next) {
var method
var val
req.originalMethod = req.originalMethod || req.method
// validate request is an allowed method
if (methods && methods.indexOf(req.originalMethod) === -1) {
return next()
}
val = get(req, res)
method = Array.isArray(val)
? val[0]
: val
// replace
if (method !== undefined && supports(method)) {
req.method = method.toUpperCase()
debug('override %s as %s', req.originalMethod, req.method)
}
next()
}
}
/**
* Create a getter for the given string.
*/
function createGetter (str) {
if (str.substr(0, 2).toUpperCase() === 'X-') {
// header getter
return createHeaderGetter(str)
}
return createQueryGetter(str)
}
/**
* Create a getter for the given query key name.
*/
function createQueryGetter (key) {
return function (req, res) {
var url = parseurl(req)
var query = querystring.parse(url.query || '')
return query[key]
}
}
/**
* Create a getter for the given header name.
*/
function createHeaderGetter (str) {
var name = str.toLowerCase()
return function (req, res) {
// set appropriate Vary header
vary(res, str)
// get header
var header = req.headers[name]
if (!header) {
return undefined
}
// multiple headers get joined with comma by node.js core
var index = header.indexOf(',')
// return first value
return index !== -1
? header.substr(0, index).trim()
: header.trim()
}
}
/**
* Check if node supports `method`.
*/
function supports (method) {
return method &&
typeof method === 'string' &&
methods.indexOf(method.toLowerCase()) !== -1
}