You can also stream a file to a PUT or POST request. This method will also check the file extension against a mapping of file extensions to content-types (in this case `application/json`) and use the proper `content-type` in the PUT request (if the headers don’t already provide one).
Request emits a "response" event when a response is received. The `response` argument will be an instance of [http.IncomingMessage](http://nodejs.org/api/http.html#http_http_incomingmessage).
You can also `pipe()` from `http.ServerRequest` instances, as well as to `http.ServerResponse` instances. The HTTP method, headers, and entity-body data will be sent. Which means that, if you don't really care about security, you can do:
### Controlling proxy behaviour using environment variables
The following environment variables are respected by `request`:
*`HTTP_PROXY` / `http_proxy`
*`HTTPS_PROXY` / `https_proxy`
*`NO_PROXY` / `no_proxy`
When `HTTP_PROXY` / `http_proxy` are set, they will be used to proxy non-SSL requests that do not have an explicit `proxy` configuration option present. Similarly, `HTTPS_PROXY` / `https_proxy` will be respected for SSL requests that do not have an explicit `proxy` configuration option. It is valid to define a proxy in one of the environment variables, but then override it for a specific request, using the `proxy` configuration option. Furthermore, the `proxy` configuration option can be explicitly set to false / null to opt out of proxying altogether for that request.
`request` is also aware of the `NO_PROXY`/`no_proxy` environment variables. These variables provide a granular way to opt out of proxying, on a per-host basis. It should contain a comma separated list of hosts to opt out of proxying. It is also possible to opt of proxying when a particular destination port is used. Finally, the variable may be set to `*` to opt out of the implicit proxy configuration of the other environment variables.
`request` supports making requests to [UNIX Domain Sockets](http://en.wikipedia.org/wiki/Unix_domain_socket). To make one, use the following URL scheme:
For `multipart/form-data` we use the [form-data](https://github.com/felixge/node-form-data) library by [@felixge](https://github.com/felixge). For the most cases, you can pass your upload form data via the `formData` option.
For advanced cases, you can access the form-data object itself via `r.form()`. This can be modified until the request is fired on the next cycle of the event-loop. (Note that this calling `form()` will clear the currently set form data for that request.)
See the [form-data README](https://github.com/felixge/node-form-data) for more information & examples.
#### multipart/related
Some variations in different HTTP implementations require a newline/CRLF before, after, or both before and after the boundary of a `multipart/related` request (using the multipart option). This has been observed in the .NET WebAPI version 4.0. You can turn on a boundary preambleCRLF or postamble by passing them as `true` to your request options.
If passed as an option, `auth` should be a hash containing values `user` || `username`, `pass` || `password`, and `sendImmediately` (optional). The method form takes parameters `auth(username, password, sendImmediately)`.
`sendImmediately` defaults to `true`, which causes a basic authentication header to be sent. If `sendImmediately` is `false`, then `request` will retry with a proper authentication header after receiving a `401` response from the server (which must contain a `WWW-Authenticate` header indicating the required authentication method).
Digest authentication is supported, but it only works with `sendImmediately` set to `false`; otherwise `request` will send basic authentication on the initial request, which will probably cause the request to fail.
Bearer authentication is supported, and is activated when the `bearer` value is available. The value may be either a `String` or a `Function` returning a `String`. Using a function to supply the bearer token is particularly useful if used in conjuction with `defaults` to allow a single function to supply the last known token at the time or sending a request or to compute one on the fly.
*`body` - entity body for PATCH, POST and PUT requests. Must be a `Buffer` or `String`, unless `json` is `true`. If `json` is `true`, then `body` must be a JSON-serializable object.
*`form` - when passed an object or a querystring, this sets `body` to a querystring representation of value, and adds `Content-type: application/x-www-form-urlencoded` header. When passed no options, a `FormData` instance is returned (and is piped to request). See "Forms" section above.
*`json` - sets `body` but to JSON representation of value and adds `Content-type: application/json` header. Additionally, parses the response body as JSON.
*`jsonReviver` - a [reviver function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse) that will be passed to `JSON.parse()` when parsing a JSON response body.
*`followRedirect` - follow HTTP 3xx responses as redirects (default: `true`). This property can also be implemented as function which gets `response` object as a single argument and should return `true` if redirects should continue or `false` otherwise.
*`encoding` - Encoding to be used on `setEncoding` of response data. If `null`, the `body` is returned as a `Buffer`. Anything else **(including the default value of `undefined`)** will be passed as the [encoding](http://nodejs.org/api/buffer.html#buffer_buffer) parameter to `toString()` (meaning this is effectively `utf8` by default).
*`pool` - An object describing which agents to use for the request. If this option is omitted the request will use the global agent (as long as [your options allow for it](request.js#L747)). Otherwise, request will search the pool for your custom agent. If no custom agent is found, a new agent will be created and added to the pool.
* A `maxSockets` property can also be provided on the `pool` object to set the max number of sockets for all agents created (ex: `pool: {maxSockets: Infinity}`).
*`proxy` - An HTTP proxy to be used. Supports proxy Auth with Basic Auth, identical to support for the `url` parameter (by embedding the auth info in the `uri`)
*`oauth` - Options for OAuth HMAC-SHA1 signing. See documentation above.
*`hawk` - Options for [Hawk signing](https://github.com/hueniverse/hawk). The `credentials` key must contain the necessary signing info, [see hawk docs for details](https://github.com/hueniverse/hawk#usage-example).
*`strictSSL` - If `true`, requires SSL certificates be valid. **Note:** to use your own certificate authority, you need to specify an agent that was created with that CA as an option.
*`agentOptions` - Object containing user agent options. See documentation above. **Note:** [see tls API doc for TLS/SSL options](http://nodejs.org/api/tls.html#tls_tls_connect_options_callback).
*`aws` - `object` containing AWS signing information. Should have the properties `key`, `secret`. Also requires the property `bucket`, unless you’re specifying your `bucket` as part of the path, or the request doesn’t use a bucket (i.e. GET Services)
*`httpSignature` - Options for the [HTTP Signature Scheme](https://github.com/joyent/node-http-signature/blob/master/http_signing.md) using [Joyent's library](https://github.com/joyent/node-http-signature). The `keyId` and `key` properties must be specified. See the docs for other options.
*`localAddress` - Local interface to bind for network connections.
*`gzip` - If `true`, add an `Accept-Encoding` header to request compressed content encodings from the server (if not already present) and decode supported content encodings in the response. **Note:** Automatic decoding of the response content is performed on the body data returned through `request` (both through the `request` stream and passed to the callback function) but is not performed on the `response` stream (available from the `response` event) which is the unmodified `http.IncomingMessage` object which may contain compressed data. See example below.
Cookies are disabled by default (else, they would be used in subsequent requests). To enable cookies, set `jar` to `true` (either in `defaults` or `options`) and install `tough-cookie`.