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464 lines
18 KiB
# body-parser |
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[![NPM Version][npm-image]][npm-url] |
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[![NPM Downloads][downloads-image]][downloads-url] |
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[![Build Status][github-actions-ci-image]][github-actions-ci-url] |
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[![Test Coverage][coveralls-image]][coveralls-url] |
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Node.js body parsing middleware. |
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Parse incoming request bodies in a middleware before your handlers, available |
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under the `req.body` property. |
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**Note** As `req.body`'s shape is based on user-controlled input, all |
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properties and values in this object are untrusted and should be validated |
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before trusting. For example, `req.body.foo.toString()` may fail in multiple |
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ways, for example the `foo` property may not be there or may not be a string, |
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and `toString` may not be a function and instead a string or other user input. |
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[Learn about the anatomy of an HTTP transaction in Node.js](https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/). |
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_This does not handle multipart bodies_, due to their complex and typically |
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large nature. For multipart bodies, you may be interested in the following |
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modules: |
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* [busboy](https://www.npmjs.org/package/busboy#readme) and |
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[connect-busboy](https://www.npmjs.org/package/connect-busboy#readme) |
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* [multiparty](https://www.npmjs.org/package/multiparty#readme) and |
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[connect-multiparty](https://www.npmjs.org/package/connect-multiparty#readme) |
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* [formidable](https://www.npmjs.org/package/formidable#readme) |
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* [multer](https://www.npmjs.org/package/multer#readme) |
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This module provides the following parsers: |
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* [JSON body parser](#bodyparserjsonoptions) |
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* [Raw body parser](#bodyparserrawoptions) |
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* [Text body parser](#bodyparsertextoptions) |
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* [URL-encoded form body parser](#bodyparserurlencodedoptions) |
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Other body parsers you might be interested in: |
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- [body](https://www.npmjs.org/package/body#readme) |
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- [co-body](https://www.npmjs.org/package/co-body#readme) |
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## Installation |
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```sh |
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$ npm install body-parser |
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``` |
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## API |
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```js |
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var bodyParser = require('body-parser') |
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``` |
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The `bodyParser` object exposes various factories to create middlewares. All |
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middlewares will populate the `req.body` property with the parsed body when |
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the `Content-Type` request header matches the `type` option, or an empty |
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object (`{}`) if there was no body to parse, the `Content-Type` was not matched, |
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or an error occurred. |
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The various errors returned by this module are described in the |
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[errors section](#errors). |
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### bodyParser.json([options]) |
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Returns middleware that only parses `json` and only looks at requests where |
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the `Content-Type` header matches the `type` option. This parser accepts any |
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Unicode encoding of the body and supports automatic inflation of `gzip` and |
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`deflate` encodings. |
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A new `body` object containing the parsed data is populated on the `request` |
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object after the middleware (i.e. `req.body`). |
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#### Options |
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The `json` function takes an optional `options` object that may contain any of |
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the following keys: |
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##### inflate |
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When set to `true`, then deflated (compressed) bodies will be inflated; when |
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`false`, deflated bodies are rejected. Defaults to `true`. |
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##### limit |
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Controls the maximum request body size. If this is a number, then the value |
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specifies the number of bytes; if it is a string, the value is passed to the |
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[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults |
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to `'100kb'`. |
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##### reviver |
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The `reviver` option is passed directly to `JSON.parse` as the second |
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argument. You can find more information on this argument |
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[in the MDN documentation about JSON.parse](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#Example.3A_Using_the_reviver_parameter). |
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##### strict |
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When set to `true`, will only accept arrays and objects; when `false` will |
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accept anything `JSON.parse` accepts. Defaults to `true`. |
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##### type |
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The `type` option is used to determine what media type the middleware will |
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parse. This option can be a string, array of strings, or a function. If not a |
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function, `type` option is passed directly to the |
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[type-is](https://www.npmjs.org/package/type-is#readme) library and this can |
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be an extension name (like `json`), a mime type (like `application/json`), or |
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a mime type with a wildcard (like `*/*` or `*/json`). If a function, the `type` |
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option is called as `fn(req)` and the request is parsed if it returns a truthy |
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value. Defaults to `application/json`. |
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##### verify |
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The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`, |
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where `buf` is a `Buffer` of the raw request body and `encoding` is the |
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encoding of the request. The parsing can be aborted by throwing an error. |
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### bodyParser.raw([options]) |
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Returns middleware that parses all bodies as a `Buffer` and only looks at |
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requests where the `Content-Type` header matches the `type` option. This |
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parser supports automatic inflation of `gzip` and `deflate` encodings. |
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A new `body` object containing the parsed data is populated on the `request` |
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object after the middleware (i.e. `req.body`). This will be a `Buffer` object |
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of the body. |
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#### Options |
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The `raw` function takes an optional `options` object that may contain any of |
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the following keys: |
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##### inflate |
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When set to `true`, then deflated (compressed) bodies will be inflated; when |
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`false`, deflated bodies are rejected. Defaults to `true`. |
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##### limit |
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Controls the maximum request body size. If this is a number, then the value |
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specifies the number of bytes; if it is a string, the value is passed to the |
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[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults |
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to `'100kb'`. |
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##### type |
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The `type` option is used to determine what media type the middleware will |
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parse. This option can be a string, array of strings, or a function. |
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If not a function, `type` option is passed directly to the |
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[type-is](https://www.npmjs.org/package/type-is#readme) library and this |
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can be an extension name (like `bin`), a mime type (like |
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`application/octet-stream`), or a mime type with a wildcard (like `*/*` or |
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`application/*`). If a function, the `type` option is called as `fn(req)` |
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and the request is parsed if it returns a truthy value. Defaults to |
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`application/octet-stream`. |
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##### verify |
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The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`, |
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where `buf` is a `Buffer` of the raw request body and `encoding` is the |
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encoding of the request. The parsing can be aborted by throwing an error. |
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### bodyParser.text([options]) |
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Returns middleware that parses all bodies as a string and only looks at |
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requests where the `Content-Type` header matches the `type` option. This |
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parser supports automatic inflation of `gzip` and `deflate` encodings. |
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A new `body` string containing the parsed data is populated on the `request` |
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object after the middleware (i.e. `req.body`). This will be a string of the |
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body. |
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#### Options |
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The `text` function takes an optional `options` object that may contain any of |
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the following keys: |
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##### defaultCharset |
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Specify the default character set for the text content if the charset is not |
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specified in the `Content-Type` header of the request. Defaults to `utf-8`. |
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##### inflate |
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When set to `true`, then deflated (compressed) bodies will be inflated; when |
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`false`, deflated bodies are rejected. Defaults to `true`. |
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##### limit |
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Controls the maximum request body size. If this is a number, then the value |
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specifies the number of bytes; if it is a string, the value is passed to the |
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[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults |
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to `'100kb'`. |
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##### type |
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The `type` option is used to determine what media type the middleware will |
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parse. This option can be a string, array of strings, or a function. If not |
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a function, `type` option is passed directly to the |
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[type-is](https://www.npmjs.org/package/type-is#readme) library and this can |
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be an extension name (like `txt`), a mime type (like `text/plain`), or a mime |
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type with a wildcard (like `*/*` or `text/*`). If a function, the `type` |
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option is called as `fn(req)` and the request is parsed if it returns a |
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truthy value. Defaults to `text/plain`. |
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##### verify |
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The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`, |
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where `buf` is a `Buffer` of the raw request body and `encoding` is the |
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encoding of the request. The parsing can be aborted by throwing an error. |
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### bodyParser.urlencoded([options]) |
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Returns middleware that only parses `urlencoded` bodies and only looks at |
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requests where the `Content-Type` header matches the `type` option. This |
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parser accepts only UTF-8 encoding of the body and supports automatic |
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inflation of `gzip` and `deflate` encodings. |
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A new `body` object containing the parsed data is populated on the `request` |
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object after the middleware (i.e. `req.body`). This object will contain |
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key-value pairs, where the value can be a string or array (when `extended` is |
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`false`), or any type (when `extended` is `true`). |
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#### Options |
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The `urlencoded` function takes an optional `options` object that may contain |
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any of the following keys: |
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##### extended |
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The `extended` option allows to choose between parsing the URL-encoded data |
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with the `querystring` library (when `false`) or the `qs` library (when |
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`true`). The "extended" syntax allows for rich objects and arrays to be |
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encoded into the URL-encoded format, allowing for a JSON-like experience |
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with URL-encoded. For more information, please |
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[see the qs library](https://www.npmjs.org/package/qs#readme). |
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Defaults to `true`, but using the default has been deprecated. Please |
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research into the difference between `qs` and `querystring` and choose the |
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appropriate setting. |
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##### inflate |
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When set to `true`, then deflated (compressed) bodies will be inflated; when |
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`false`, deflated bodies are rejected. Defaults to `true`. |
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##### limit |
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Controls the maximum request body size. If this is a number, then the value |
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specifies the number of bytes; if it is a string, the value is passed to the |
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[bytes](https://www.npmjs.com/package/bytes) library for parsing. Defaults |
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to `'100kb'`. |
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##### parameterLimit |
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The `parameterLimit` option controls the maximum number of parameters that |
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are allowed in the URL-encoded data. If a request contains more parameters |
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than this value, a 413 will be returned to the client. Defaults to `1000`. |
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##### type |
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The `type` option is used to determine what media type the middleware will |
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parse. This option can be a string, array of strings, or a function. If not |
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a function, `type` option is passed directly to the |
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[type-is](https://www.npmjs.org/package/type-is#readme) library and this can |
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be an extension name (like `urlencoded`), a mime type (like |
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`application/x-www-form-urlencoded`), or a mime type with a wildcard (like |
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`*/x-www-form-urlencoded`). If a function, the `type` option is called as |
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`fn(req)` and the request is parsed if it returns a truthy value. Defaults |
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to `application/x-www-form-urlencoded`. |
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##### verify |
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The `verify` option, if supplied, is called as `verify(req, res, buf, encoding)`, |
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where `buf` is a `Buffer` of the raw request body and `encoding` is the |
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encoding of the request. The parsing can be aborted by throwing an error. |
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## Errors |
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The middlewares provided by this module create errors using the |
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[`http-errors` module](https://www.npmjs.com/package/http-errors). The errors |
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will typically have a `status`/`statusCode` property that contains the suggested |
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HTTP response code, an `expose` property to determine if the `message` property |
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should be displayed to the client, a `type` property to determine the type of |
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error without matching against the `message`, and a `body` property containing |
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the read body, if available. |
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The following are the common errors created, though any error can come through |
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for various reasons. |
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### content encoding unsupported |
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This error will occur when the request had a `Content-Encoding` header that |
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contained an encoding but the "inflation" option was set to `false`. The |
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`status` property is set to `415`, the `type` property is set to |
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`'encoding.unsupported'`, and the `charset` property will be set to the |
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encoding that is unsupported. |
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### entity parse failed |
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This error will occur when the request contained an entity that could not be |
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parsed by the middleware. The `status` property is set to `400`, the `type` |
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property is set to `'entity.parse.failed'`, and the `body` property is set to |
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the entity value that failed parsing. |
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### entity verify failed |
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This error will occur when the request contained an entity that could not be |
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failed verification by the defined `verify` option. The `status` property is |
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set to `403`, the `type` property is set to `'entity.verify.failed'`, and the |
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`body` property is set to the entity value that failed verification. |
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### request aborted |
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This error will occur when the request is aborted by the client before reading |
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the body has finished. The `received` property will be set to the number of |
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bytes received before the request was aborted and the `expected` property is |
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set to the number of expected bytes. The `status` property is set to `400` |
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and `type` property is set to `'request.aborted'`. |
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### request entity too large |
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This error will occur when the request body's size is larger than the "limit" |
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option. The `limit` property will be set to the byte limit and the `length` |
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property will be set to the request body's length. The `status` property is |
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set to `413` and the `type` property is set to `'entity.too.large'`. |
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### request size did not match content length |
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This error will occur when the request's length did not match the length from |
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the `Content-Length` header. This typically occurs when the request is malformed, |
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typically when the `Content-Length` header was calculated based on characters |
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instead of bytes. The `status` property is set to `400` and the `type` property |
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is set to `'request.size.invalid'`. |
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### stream encoding should not be set |
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This error will occur when something called the `req.setEncoding` method prior |
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to this middleware. This module operates directly on bytes only and you cannot |
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call `req.setEncoding` when using this module. The `status` property is set to |
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`500` and the `type` property is set to `'stream.encoding.set'`. |
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### stream is not readable |
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This error will occur when the request is no longer readable when this middleware |
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attempts to read it. This typically means something other than a middleware from |
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this module read the request body already and the middleware was also configured to |
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read the same request. The `status` property is set to `500` and the `type` |
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property is set to `'stream.not.readable'`. |
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### too many parameters |
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This error will occur when the content of the request exceeds the configured |
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`parameterLimit` for the `urlencoded` parser. The `status` property is set to |
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`413` and the `type` property is set to `'parameters.too.many'`. |
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### unsupported charset "BOGUS" |
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This error will occur when the request had a charset parameter in the |
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`Content-Type` header, but the `iconv-lite` module does not support it OR the |
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parser does not support it. The charset is contained in the message as well |
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as in the `charset` property. The `status` property is set to `415`, the |
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`type` property is set to `'charset.unsupported'`, and the `charset` property |
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is set to the charset that is unsupported. |
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### unsupported content encoding "bogus" |
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This error will occur when the request had a `Content-Encoding` header that |
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contained an unsupported encoding. The encoding is contained in the message |
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as well as in the `encoding` property. The `status` property is set to `415`, |
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the `type` property is set to `'encoding.unsupported'`, and the `encoding` |
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property is set to the encoding that is unsupported. |
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## Examples |
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### Express/Connect top-level generic |
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This example demonstrates adding a generic JSON and URL-encoded parser as a |
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top-level middleware, which will parse the bodies of all incoming requests. |
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This is the simplest setup. |
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```js |
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var express = require('express') |
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var bodyParser = require('body-parser') |
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var app = express() |
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// parse application/x-www-form-urlencoded |
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app.use(bodyParser.urlencoded({ extended: false })) |
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// parse application/json |
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app.use(bodyParser.json()) |
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app.use(function (req, res) { |
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res.setHeader('Content-Type', 'text/plain') |
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res.write('you posted:\n') |
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res.end(JSON.stringify(req.body, null, 2)) |
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}) |
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``` |
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### Express route-specific |
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This example demonstrates adding body parsers specifically to the routes that |
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need them. In general, this is the most recommended way to use body-parser with |
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Express. |
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```js |
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var express = require('express') |
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var bodyParser = require('body-parser') |
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var app = express() |
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// create application/json parser |
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var jsonParser = bodyParser.json() |
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// create application/x-www-form-urlencoded parser |
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var urlencodedParser = bodyParser.urlencoded({ extended: false }) |
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// POST /login gets urlencoded bodies |
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app.post('/login', urlencodedParser, function (req, res) { |
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res.send('welcome, ' + req.body.username) |
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}) |
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// POST /api/users gets JSON bodies |
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app.post('/api/users', jsonParser, function (req, res) { |
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// create user in req.body |
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}) |
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``` |
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### Change accepted type for parsers |
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All the parsers accept a `type` option which allows you to change the |
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`Content-Type` that the middleware will parse. |
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```js |
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var express = require('express') |
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var bodyParser = require('body-parser') |
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var app = express() |
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// parse various different custom JSON types as JSON |
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app.use(bodyParser.json({ type: 'application/*+json' })) |
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// parse some custom thing into a Buffer |
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app.use(bodyParser.raw({ type: 'application/vnd.custom-type' })) |
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// parse an HTML body into a string |
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app.use(bodyParser.text({ type: 'text/html' })) |
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``` |
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## License |
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[MIT](LICENSE) |
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[npm-image]: https://img.shields.io/npm/v/body-parser.svg |
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[npm-url]: https://npmjs.org/package/body-parser |
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[coveralls-image]: https://img.shields.io/coveralls/expressjs/body-parser/master.svg |
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[coveralls-url]: https://coveralls.io/r/expressjs/body-parser?branch=master |
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[downloads-image]: https://img.shields.io/npm/dm/body-parser.svg |
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[downloads-url]: https://npmjs.org/package/body-parser |
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[github-actions-ci-image]: https://img.shields.io/github/workflow/status/expressjs/body-parser/ci/master?label=ci |
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[github-actions-ci-url]: https://github.com/expressjs/body-parser/actions/workflows/ci.yml
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