HTTP Client Utilities

Lead Maintainer: Wyatt Preul

Usage

Basic

const Wreck = require('wreck');

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

const Wreck = require('wreck');

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

Advanced

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 }
});

// cascading example -- does not alter `wreck`
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
};

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.
  • redirects - The maximum number of redirects to follow.
  • redirect303 - if true, treats HTTP 303 status code the same way as a 301/302. 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 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 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. Defaults to either wreck.agents.http or wreck.agents.https. Setting to false disables agent pooling.
  • secureProtocol - TLS 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.
• 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 object, which is also a readable stream.

Returns an instance of the node.js 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.
    • force - try JSON.parse regardless of the content-type 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).

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 - The callback function using the signature function (err, response, payload) where:
  • err - Any error that may have occurred during handling of the request.
  • response - The HTTP Incoming Message object, which is also a readable stream.
  • payload - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

Returns an instance of the node.js ClientRequest object.

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 - The callback function using the signature function (err, response, payload) where:
  • err - Any error that may have occurred during handling of the request.
  • response - The HTTP Incoming Message object, which is also a readable stream.
  • payload - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

Returns an instance of the node.js ClientRequest object.

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 - The callback function using the signature function (err, response, payload) where:
  • err - Any error that may have occurred during handling of the request.
  • response - The HTTP Incoming Message object, which is also a readable stream.
  • payload - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

Returns an instance of the node.js ClientRequest object.

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 - The callback function using the signature function (err, response, payload) where:
  • err - Any error that may have occurred during handling of the request.
  • response - The HTTP Incoming Message object, which is also a readable stream.
  • payload - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

Returns an instance of the node.js ClientRequest object.

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 - The callback function using the signature function (err, response, payload) where:
  • err - Any error that may have occurred during handling of the request.
  • response - The HTTP Incoming Message object, which is also a readable stream.
  • payload - The payload in the form of a Buffer or (optionally) parsed JavaScript object (JSON).

Returns an instance of the node.js ClientRequest object.

toReadableStream(payload, [encoding])

Creates a readable stream 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'.

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.

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 true. All agents have maxSockets configured to Infinity. They are each instances of the node.js Agent and expose the standard properties.

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

const Wreck = require('wreck');

Wreck.agents.http.maxSockets = 20;

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 (error, request, response, start, uri) where:

• error - a Boom error
• request - the raw ClientHttp request object
• response - 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 error and response 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 argument 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:

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

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