path: root/usr/share/kibana/node_modules/subtext/node_modules/wreck/README.md

![wreck Logo](https://raw.github.com/hapijs/wreck/master/images/wreck.png)

### HTTP Client Utilities

[![Npm Version](https://img.shields.io/npm/v/wreck.svg)](https://npmjs.com/package/wreck)
[![Node Version](https://img.shields.io/node/v/wreck.svg)](https://npmjs.com/package/wreck)
[![Build Status](https://secure.travis-ci.org/hapijs/wreck.svg)](http://travis-ci.org/hapijs/wreck)

Lead Maintainer: [Wyatt Preul](https://github.com/geek)

## Usage

### Basic
```javascript
const Wreck = require('wreck');

Wreck.get('https://google.com/', (err, res, payload) => {
    /* do stuff */
});
```

```javascript
const Wreck = require('wreck');

Wreck.post('https://posttestserver.com/post.php', { payload: { hello: 'post' } }, (err, res, payload) => {
    /* do stuff */
});
```

### With Async/Await

```javascript
const Wreck = require('wreck');

async function example () {
  const { req, res, payload } = await Wreck.get('http://example.com');
  console.log(payload.toString());
}

try {
  example();
} catch (ex) {
  console.error(ex);
}
```

### Advanced
```javascript
const Wreck = require('wreck');

const method = 'GET'; // GET, POST, PUT, DELETE
const uri = '/';
const readableStream = Wreck.toReadableStream('foo=bar');

const wreck = Wreck.defaults({
    headers: { 'x-foo-bar': 123 },
    agents: {
        https: new Https.Agent({ maxSockets: 100 }),
        http: new Http.Agent({ maxSockets: 1000 }),
        httpsAllowUnauthorized: new Https.Agent({ maxSockets: 100, rejectUnauthorized: false })
    }
});

// cascading example -- does not alter `wreck`
// inherits `headers` and `agents` specified above
const wreckWithTimeout = wreck.defaults({
    timeout: 5
});

// all attributes are optional
const options = {
    baseUrl: 'https://www.example.com',
    payload: readableStream || 'foo=bar' || new Buffer('foo=bar'),
    headers: { /* http headers */ },
    redirects: 3,
    beforeRedirect: function (redirectMethod, statusCode, location, resHeaders, redirectOptions, next) { return next() },
    redirected: function (statusCode, location, req) {},
    timeout: 1000,    // 1 second, default: unlimited
    maxBytes: 1048576, // 1 MB, default: unlimited
    rejectUnauthorized: true || false,
    downstreamRes: null,
    agent: null,         // Node Core http.Agent
    secureProtocol: 'SSLv3_method', // The SSL method to use
    ciphers: 'DES-CBC3-SHA' // The TLS ciphers to support
};

const optionalCallback = (err, res) => {

    /* handle err if it exists, in which case res will be undefined */

    // buffer the response stream
    Wreck.read(res, null, (err, body) => {
        /* do stuff */
    });
};

const req = wreck.request(method, uri, options, optionalCallback);
```

### `defaults(options)`

Returns a *new* instance of Wreck which merges the provided `options` with those provided on a per-request basis. You can call defaults repeatedly to build up multiple http clients.
- `options` - Config object containing settings for both `request` and `read` operations.

### `request(method, uri, [options, [callback]])`

Initiate an HTTP request.
- `method` - A string specifying the HTTP request method, defaulting to 'GET'.
- `uri` - The URI of the requested resource.
- `options` - An optional configuration object. To omit this argument but still
  use a callback, pass `null` in this position. The options object supports the
  following optional keys:
    - `baseUrl` - fully qualified uri string used as the base url. Most useful with `request.defaults`, for example when you want to do many requests to the same domain.
                  If `baseUrl` is `https://example.com/api/`, then requesting `/end/point?test=true` will fetch `https://example.com/api/end/point?test=true`. Any
                  querystring in the `baseUrl` will be overwritten with the querystring in the `uri` When `baseUrl` is given, `uri` must also be a string.
    - `socketPath` - `/path/to/unix/socket` for Server.
    - `payload` - The request body as a string, Buffer, Readable Stream, or an object that can be serialized using `JSON.stringify()`.
    - `headers` - An object containing request headers.
    - `onRequest` - A function that is called when a request is available using the signature `function(req)` where `req` is a [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest).
    - `redirects` - The maximum number of redirects to follow.
    - `redirect303` - if `true`, a HTTP 303 status code will redirect using a GET method. Defaults to no redirection on 303.
    - `beforeRedirect` - A callback function that is called before a redirect is triggered, using the signature
      `function(redirectMethod, statusCode, location, resHeaders, redirectOptions, next)` where:
          - `redirectMethod` - A string specifying the redirect method.
          - `statusCode` - HTTP status code of the response that triggered the redirect.
          - `location` - The redirect location string.
          - `resHeaders` - An object with the headers received as part of the redirection response.
          - `redirectOptions` - Options that will be applied to the redirect request. Changes to this object are applied to the redirection request.
          - `next` - the callback function called to perform the redirection using signature `function()`.
    - `redirected` - A callback function that is called when a redirect was triggered, using the signature `function(statusCode, location, req)` where:
      - `statusCode` - HTTP status code of the response that triggered the redirect.
      - `location` - The redirected location string.
      - `req` - The new [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object which replaces the one initially returned.
    - `timeout` - The number of milliseconds to wait without receiving a response
      before aborting the request. Defaults to unlimited.
    - `maxBytes` - maximum size for response payload. Defaults to unlimited.
    - `rejectUnauthorized` - [TLS](http://nodejs.org/api/tls.html) flag indicating
      whether the client should reject a response from a server with invalid certificates.  This cannot be set at the
      same time as the `agent` option is set.
    - `downstreamRes`: downstream Resource dependency.
    - `agent` - Node Core [http.Agent](http://nodejs.org/api/http.html#http_class_http_agent).
      Defaults to either `wreck.agents.http` or `wreck.agents.https`.  Setting to `false` disables agent pooling.
    - `secureProtocol` - [TLS](http://nodejs.org/api/tls.html) flag indicating the SSL method to use, e.g. `SSLv3_method`
      to force SSL version 3. The possible values depend on your installation of OpenSSL. Read the official OpenSSL docs
      for possible [SSL_METHODS](http://www.openssl.org/docs/ssl/ssl.html#DEALING_WITH_PROTOCOL_METHODS).
    - `ciphers` - [TLS](https://nodejs.org/api/tls.html#tls_modifying_the_default_tls_cipher_suite) list of TLS ciphers to override node's default.  
      The possible values depend on your installation of OpenSSL. Read the official OpenSSL docs
      for possible [TLS_CIPHERS](https://www.openssl.org/docs/man1.0.2/apps/ciphers.html#CIPHER-LIST-FORMAT).
- `callback` - The optional callback function using the signature `function (err, response)` where:
    - `err` - Any error that may have occurred during the handling of the request.
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is also a readable stream.

Returns an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object.


### `read(response, options, callback)`
- `response` - An HTTP Incoming Message object.
- `options` - `null` or a configuration object with the following optional keys:
    - `timeout` - The number of milliseconds to wait while reading data before
    aborting handling of the response. Defaults to unlimited.
    - `json` - A value indicating how to try to parse the payload as JSON. Defaults to `undefined` meaning no parse logic.
        - `true`, 'smart' - only try `JSON.parse` if the response indicates a JSON content-type.
        - `strict` - as 'smart', except returns an error for non-JSON content-type.
        - `force` - try `JSON.parse` regardless of the content-type header.
    - `gunzip` - A value indicating the behavior to adopt when the payload is gzipped. Defaults to `undefined` meaning no gunzipping.
        - `true` - only try to gunzip if the response indicates a gzip content-encoding.
        - `false` - explicitly disable gunzipping.
        - `force` - try to gunzip regardless of the content-encoding header.
    - `maxBytes` - The maximum allowed response payload size. Defaults to unlimited.
- `callback` - The callback function using the signature `function (err, payload)` where:
    - `err` - Any error that may have occurred while reading the response.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

#### Notes about gunzip

When using gunzip, HTTP headers `Content-Encoding`, `Content-Length`, `Content-Range` and `ETag` won't reflect the reality as the payload has been uncompressed.

Node v4 does not detect premature ending of gzipped content, if the payload is partial, you will not get an error on this specific version of node.js.

### `get(uri, [options, [callback]])`

Convenience method for GET operations.
- `uri` - The URI of the requested resource.
- `options` - Optional config object containing settings for both `request` and
  `read` operations.
- `callback` - Optional callback function using the signature `function (err, response, payload)` where:
    - `err` - Any error that may have occurred during handling of the request or a Boom error object if the response has an error status code (i.e. 4xx or 5xx). If the error is a boom error object it will have the following properties in addition to the standard boom properties.
        - `data.isResponseError` - boolean, indicates if the error is a result of an error response status code
        - `data.headers` - object containing the response headers
        - `data.payload` - the payload in the form of a Buffer or as a parsed object
        - `data.response` - the [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is a readable stream that has "ended" and contains no more data to read.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

If a callback function is provided then an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object is returned.
If no callback function is provided then a Promise is returned that resolves an object with the following structure: `{ req, res, payload }`;


### `post(uri, [options, [callback]])`

Convenience method for POST operations.
- `uri` - The URI of the requested resource.
- `options` - Optional config object containing settings for both `request` and
  `read` operations.
- `callback` - Optional callback function using the signature `function (err, response, payload)` where:
    - `err` - Any error that may have occurred during handling of the request or a Boom error object if the response has an error status code (i.e. 4xx or 5xx). If the error is a boom error object it will have the following properties in addition to the standard boom properties.
        - `data.isResponseError` - boolean, indicates if the error is a result of an error response status code
        - `data.headers` - object containing the response headers
        - `data.payload` - the payload in the form of a Buffer or as a parsed object
        - `data.response` - the [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is a readable stream that has "ended" and contains no more data to read.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

If a callback function is provided then an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object is returned.
If no callback function is provided then a Promise is returned that resolves an object with the following structure: `{ req, res, payload }`;


### `patch(uri, [options, [callback]])`

Convenience method for PATCH operations.
- `uri` - The URI of the requested resource.
- `options` - Optional config object containing settings for both `request` and
  `read` operations.
- `callback` - Optional callback function using the signature `function (err, response, payload)` where:
    - `err` - Any error that may have occurred during handling of the request or a Boom error object if the response has an error status code (i.e. 4xx or 5xx). If the error is a boom error object it will have the following properties in addition to the standard boom properties.
        - `data.isResponseError` - boolean, indicates if the error is a result of an error response status code
        - `data.headers` - object containing the response headers
        - `data.payload` - the payload in the form of a Buffer or as a parsed object
        - `data.response` - the [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is a readable stream that has "ended" and contains no more data to read.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

If a callback function is provided then an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object is returned.
If no callback function is provided then a Promise is returned that resolves an object with the following structure: `{ req, res, payload }`;


### `put(uri, [options, [callback]])`

Convenience method for PUT operations.
- `uri` - The URI of the requested resource.
- `options` - Optional config object containing settings for both `request` and
  `read` operations.
- `callback` - Optional callback function using the signature `function (err, response, payload)` where:
    - `err` - Any error that may have occurred during handling of the request or a Boom error object if the response has an error status code (i.e. 4xx or 5xx). If the error is a boom error object it will have the following properties in addition to the standard boom properties.
        - `data.isResponseError` - boolean, indicates if the error is a result of an error response status code
        - `data.headers` - object containing the response headers
        - `data.payload` - the payload in the form of a Buffer or as a parsed object
        - `data.response` - the [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is a readable stream that has "ended" and contains no more data to read.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

If a callback function is provided then an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object is returned.
If no callback function is provided then a Promise is returned that resolves an object with the following structure: `{ req, res, payload }`;


### `delete(uri, [options, [callback]])`

Convenience method for DELETE operations.
- `uri` - The URI of the requested resource.
- `options` - Optional config object containing settings for both `request` and
  `read` operations.
- `callback` - Optional callback function using the signature `function (err, response, payload)` where:
    - `err` - Any error that may have occurred during handling of the request or a Boom error object if the response has an error status code (i.e. 4xx or 5xx). If the error is a boom error object it will have the following properties in addition to the standard boom properties.
        - `data.isResponseError` - boolean, indicates if the error is a result of an error response status code
        - `data.headers` - object containing the response headers
        - `data.payload` - the payload in the form of a Buffer or as a parsed object
        - `data.response` - the [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object
    - `response` - The [HTTP Incoming Message](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
       object, which is a readable stream that has "ended" and contains no more data to read.
    - `payload` - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

If a callback function is provided then an instance of the node.js [ClientRequest](http://nodejs.org/api/http.html#http_class_http_clientrequest) object is returned.
If no callback function is provided then a Promise is returned that resolves an object with the following structure: `{ req, res, payload }`;


### `toReadableStream(payload, [encoding])`

Creates a [readable stream](http://nodejs.org/api/stream.html#stream_class_stream_readable)
for the provided payload and encoding.
- `payload` - The Buffer or string to be wrapped in a readable stream.
- `encoding` - The encoding to use. Must be a valid Buffer encoding, such as 'utf8' or 'ascii'.

```javascript
const stream = Wreck.toReadableStream(new Buffer('Hello', 'ascii'), 'ascii');
const read = stream.read();
// read -> 'Hello'
```

### `parseCacheControl(field)`

Parses the provided *cache-control* request header value into an object containing
a property for each directive and it's value. Boolean directives, such as "private"
or "no-cache" will be set to the boolean `true`.
- `field` - The header cache control value to be parsed.

```javascript
const result = Wreck.parseCacheControl('private, max-age=0, no-cache');
// result.private -> true
// result['max-age'] -> 0
// result['no-cache'] -> true
```

### `agents`

Object that contains the agents for pooling connections for `http` and `https`.
The properties are `http`, `https`, and `httpsAllowUnauthorized` which is an
`https` agent with `rejectUnauthorized` set to false.  All agents have
`maxSockets` configured to `Infinity`.  They are each instances of the Node.js
[Agent](http://nodejs.org/api/http.html#http_class_http_agent) and expose the
standard properties.

For example, the following code demonstrates changing `maxSockets` on the `http`
agent.

 ```js
 const Wreck = require('wreck');

 Wreck.agents.http.maxSockets = 20;
 ```

Below is another example that sets the certificate details for all HTTPS requests.

```js
const HTTPS = require('https');
const Wreck = require('wreck');

Wreck.agents.https = new HTTPS.Agent({
    cert,
    key,
    ca
});
```

### Events

#### `request`

The request event is emitted just before *wreck* makes a request.  The
handler should accept the following arguments `(uri, options)` where:

  - `uri` - the result of `Url.parse(uri)`. This will provide information about
  the resource requested.  Also includes the headers and method.
  - `options` - the options passed into the request function.  This will include
  a payload if there is one.

Since the `request` event executes on a global event handler, you can intercept
and decorate a request before its sent.


#### `response`

The response event is always emitted for any request that *wreck* makes.  The
handler should accept the following arguments `(err, details)` where:

  - `err` - a Boom error
  - `details` - object with the following properties
    - `req` - the raw `ClientHttp` request object
    - `res` - the raw `IncomingMessage` response object
    - `start` - the time that the request was initiated
    - `uri` - the result of `Url.parse(uri)`. This will provide information about
    the resource requested.  Also includes the headers and method.

This event is useful for logging all requests that go through *wreck*. The `err`
and `res` arguments can be undefined depending on if an error occurs.  Please
be aware that if multiple modules are depending on the same cached *wreck*
module that this event can fire for each request made across all modules.  The
`start` property is the timestamp when the request was started.  This can be
useful for determining how long it takes *wreck* to get a response back and
processed.

The `EventEmitter` is attached to the `process` object under a `Symbol` with the
value of `'wreck'`.  Therefore, if you want to capture a wreck event, after
wreck has been loaded, but in a module that doesn't require wreck, you can
handle events in the following way:

```js
const symbol = Symbol.for('wreck');
process[symbol].on('response', (err, details) => {

    if (err) {
      console.error(err);
    }
});
```