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https://github.com/expressjs/method-override

Override HTTP verbs.
https://github.com/expressjs/method-override

expressjs javascript method-override middleware nodejs

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Override HTTP verbs.

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README 

        
# method-override



[![NPM Version][npm-image]][npm-url]

[![NPM Downloads][downloads-image]][downloads-url]

[![Build Status][travis-image]][travis-url]

[![Test Coverage][coveralls-image]][coveralls-url]



Lets you use HTTP verbs such as PUT or DELETE in places where the client doesn't support it.



## Install



This is a [Node.js](https://nodejs.org/en/) module available through the

[npm registry](https://www.npmjs.com/). Installation is done using the

[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally):



```sh

$ npm install method-override

```



## API



**NOTE** It is very important that this module is used **before** any module that

needs to know the method of the request (for example, it _must_ be used prior to

the `csurf` module).



### methodOverride(getter, options)



Create a new middleware function to override the `req.method` property with a new

value. This value will be pulled from the provided `getter`.



- `getter` - The getter to use to look up the overridden request method for the request. (default: `X-HTTP-Method-Override`)

- `options.methods` - The allowed methods the original request must be in to check for a method override value. (default: `['POST']`)



If the found method is supported by node.js core, then `req.method` will be set to

this value, as if it has originally been that value. The previous `req.method`

value will be stored in `req.originalMethod`.



#### getter



This is the method of getting the override value from the request. If a function is provided,

the `req` is passed as the first argument, the `res` as the second argument and the method is

expected to be returned. If a string is provided, the string is used to look up the method

with the following rules:



- If the string starts with `X-`, then it is treated as the name of a header and that header

  is used for the method override. If the request contains the same header multiple times, the

  first occurrence is used.

- All other strings are treated as a key in the URL query string.



#### options.methods



This allows the specification of what methods(s) the request *MUST* be in in order to check for

the method override value. This defaults to only `POST` methods, which is the only method the

override should arrive in. More methods may be specified here, but it may introduce security

issues and cause weird behavior when requests travel through caches. This value is an array

of methods in upper-case. `null` can be specified to allow all methods.



## Examples



### override using a header



To use a header to override the method, specify the header name

as a string argument to the `methodOverride` function. To then make

the call, send  a `POST` request to a URL with the overridden method

as the value of that header. This method of using a header would

typically be used in conjunction with `XMLHttpRequest` on implementations

that do not support the method you are trying to use.



```js

var express = require('express')

var methodOverride = require('method-override')

var app = express()



// override with the X-HTTP-Method-Override header in the request

app.use(methodOverride('X-HTTP-Method-Override'))

```



Example call with header override using `XMLHttpRequest`:



```js

var xhr = new XMLHttpRequest()

xhr.onload = onload

xhr.open('post', '/resource', true)

xhr.setRequestHeader('X-HTTP-Method-Override', 'DELETE')

xhr.send()



function onload () {

  alert('got response: ' + this.responseText)

}

```



### override using a query value



To use a query string value to override the method, specify the query

string key as a string argument to the `methodOverride` function. To

then make the call, send  a `POST` request to a URL with the overridden

method as the value of that query string key. This method of using a

query value would typically be used in conjunction with plain HTML

`` elements when trying to support legacy browsers but still use

newer methods.



```js

var express = require('express')

var methodOverride = require('method-override')

var app = express()



// override with POST having ?_method=DELETE

app.use(methodOverride('_method'))

```



Example call with query override using HTML ``:



```html



  Delete resource



```



### multiple format support



```js

var express = require('express')

var methodOverride = require('method-override')

var app = express()



// override with different headers; last one takes precedence

app.use(methodOverride('X-HTTP-Method')) //          Microsoft

app.use(methodOverride('X-HTTP-Method-Override')) // Google/GData

app.use(methodOverride('X-Method-Override')) //      IBM

```



### custom logic



You can implement any kind of custom logic with a function for the `getter`. The following

implements the logic for looking in `req.body` that was in `method-override@1`:



```js

var bodyParser = require('body-parser')

var express = require('express')

var methodOverride = require('method-override')

var app = express()



// NOTE: when using req.body, you must fully parse the request body

//       before you call methodOverride() in your middleware stack,

//       otherwise req.body will not be populated.

app.use(bodyParser.urlencoded())

app.use(methodOverride(function (req, res) {

  if (req.body && typeof req.body === 'object' && '_method' in req.body) {

    // look in urlencoded POST bodies and delete it

    var method = req.body._method

    delete req.body._method

    return method

  }

}))

```



Example call with query override using HTML ``:



```html



  

  Delete resource



```



## License



[MIT](LICENSE)



[npm-image]: https://img.shields.io/npm/v/method-override.svg

[npm-url]: https://npmjs.org/package/method-override

[travis-image]: https://img.shields.io/travis/expressjs/method-override/master.svg

[travis-url]: https://travis-ci.org/expressjs/method-override

[coveralls-image]: https://img.shields.io/coveralls/expressjs/method-override/master.svg

[coveralls-url]: https://coveralls.io/r/expressjs/method-override?branch=master

[downloads-image]: https://img.shields.io/npm/dm/method-override.svg

[downloads-url]: https://npmjs.org/package/method-override