superagent

What is superagent?

The superagent npm package is a small progressive client-side HTTP request library, and Node.js module with the same API, sporting many high-level HTTP client features. It is designed to make HTTP requests from both Node.js and browsers.

What are superagent's main functionalities?

GET requests

This feature allows you to make GET requests to retrieve data from a server. You can include query parameters and handle the response asynchronously.

superagent.get('/search').query({ query: 'Manny' }).end(function(err, res){ /* handling response */ });

POST requests

This feature is used to send POST requests to a server. You can send data as part of the request body and set custom headers.

superagent.post('/api/pets').send({ name: 'Manny', species: 'cat' }).set('X-API-Key', 'foobar').end(function(err, res){ /* handling response */ });

Handling responses

This feature allows you to handle responses from the server, checking if the request was successful and then acting on the data received.

superagent.get('/some-url').end(function(err, res){ if (res.ok) { console.log('yay got ' + JSON.stringify(res.body)); } else { console.log('Oh no! error ' + res.text); } });

Promises and async/await

Superagent can be used with promises and async/await syntax for better asynchronous control flow.

async function getData() { try { const res = await superagent.get('/some-url'); console.log(res.body); } catch (err) { console.error(err); } }

Pipelining requests

This feature allows you to pipe the response stream directly to a file or another writable stream.

superagent.get('/some-url').pipe(fs.createWriteStream('result.txt'))

Other packages similar to superagent

axios

Axios is a promise-based HTTP client for the browser and Node.js. It provides a simple API and handles requests and responses in JSON format. Compared to superagent, it has built-in CSRF protection and supports interceptors for request and response transformation.

fetch

The Fetch API provides a more modern alternative to XMLHttpRequest for making HTTP requests in the browser. It is not an npm package but a built-in browser API. It returns promises and works with async/await. Unlike superagent, it is not Node.js compatible without polyfills.

got

Got is a Node.js HTTP request library that is designed to be a simpler and more user-friendly alternative to Node's native 'http' module. It supports promises and async/await, streams, and advanced features like retries and timeouts. It is often compared to superagent for its simplicity and feature set.

node-fetch

node-fetch is a light-weight module that brings the browser Fetch API to Node.js. It is similar to superagent but is designed to mimic the Fetch API as closely as possible. It is promise-based and supports stream consumption.

request

Request is a simplified HTTP request client for Node.js, but it has been deprecated. It was known for its simplicity and wide adoption. Superagent offers a similar feature set but continues to be maintained and updated.

README

SuperAgent

SuperAgent is a small progressive client-side and Node.js HTTP request library, sporting many high-level HTTP client features. View the docs.

Installation

node:

$ npm install superagent

Works with browserify and webpack.

const res = await request
  .post('/api/pet')
  .send({ name: 'Manny', species: 'cat' }) // sends a JSON post body
  .set('X-API-Key', 'foobar')
  .set('accept', 'json');

Supported browsers and Node versions

Tested browsers:

• Latest Firefox, Chrome, Safari
• Latest Android, iPhone
• IE10 through latest. IE9 with polyfills. Even though IE9 is supported, a polyfill for window.FormData is required for .field().

Node 6 or later is required. For older browsers ES6-to-ES5 translation (like Babel) is required.

Plugins

SuperAgent is easily extended via plugins.

const nocache = require('superagent-no-cache');
const request = require('superagent');
const prefix = require('superagent-prefix')('/static');

request
  .get('/some-url')
  .query({ action: 'edit', city: 'London' }) // query string
  .use(prefix) // Prefixes *only* this request
  .use(nocache) // Prevents caching of *only* this request
  .end((err, res) => {
    // Do something
  });

Existing plugins:

• superagent-no-cache - prevents caching by including Cache-Control header
• superagent-prefix - prefixes absolute URLs (useful in test environment)
• superagent-suffix - suffix URLs with a given path
• superagent-mock - simulate HTTP calls by returning data fixtures based on the requested URL
• superagent-mocker — simulate REST API
• superagent-cache - A global SuperAgent patch with built-in, flexible caching
• superagent-cache-plugin - A SuperAgent plugin with built-in, flexible caching
• superagent-jsonapify - A lightweight json-api client addon for superagent
• superagent-serializer - Converts server payload into different cases
• superagent-httpbackend - stub out requests using AngularJS' $httpBackend syntax
• superagent-throttle - queues and intelligently throttles requests
• superagent-charset - add charset support for node's SuperAgent
• superagent-verbose-errors - include response body in error messages for failed requests
• superagent-cheerio - include cheerio as res.$ on html responses

Please prefix your plugin with superagent-* so that it can easily be found by others.

For SuperAgent extensions such as couchdb and oauth visit the wiki.

Upgrading from previous versions:

Our breaking changes are mostly in rarely used functionality and from stricter error handling.

• 3.x to 4.x:
  • Ensure you're running Node 6 or later. We've dropped support for Node 4.
  • We've started using ES6 and for compatibility with Internet Explorer you may need to use Babel.
  • We suggest migrating from .end() callbacks to .then() or await.
• 2.x to 3.x:
  • Ensure you're running Node 4 or later. We've dropped support for Node 0.x.
  • Test code that calls .send() multiple times. Invalid calls to .send() will now throw instead of sending garbage.
• 1.x to 2.x:
  • If you use .parse() in the browser version, rename it to .serialize().
  • If you rely on undefined in query-string values being sent literally as the text "undefined", switch to checking for missing value instead. ?key=undefined is now ?key (without a value).
  • If you use .then() in Internet Explorer, ensure that you have a polyfill that adds a global Promise object.
• 0.x to 1.x:
  • Instead of 1-argument callback .end(function(res){}) use .then(res => {}).

Running node tests

Install dependencies:

$ npm install

Run em!

$ make test

Running browser tests

Install dependencies:

$ npm install

Start the test runner:

$ make test-browser-local

Visit http://localhost:4000/__zuul in your browser.

Edit tests and refresh your browser. You do not have to restart the test runner.

Packaging Notes for Developers

npm (for node) is configured via the package.json file and the .npmignore file. Key metadata in the package.json file is the version field which should be changed according to semantic versioning and have a 1-1 correspondence with git tags. So for example, if you were to git show v1.5.0:package.json | grep version, you should see "version": "1.5.0", and this should hold true for every release. This can be handled via the npm version command. Be aware that when publishing, npm will presume the version being published should also be tagged in npm as latest, which is OK for normal incremental releases. For betas and minor/patch releases to older versions, be sure to include --tag appropriately to avoid an older release getting tagged as latest.

npm (for browser standalone) When we publish versions to npm, we run make superagent.js which generates the standalone superagent.js file via browserify, and this file is included in the package published to npm (but this file is never checked into the git repository). If users want to install via npm but serve a single .js file directly to the browser, the node_modules/superagent/superagent.js is a standalone browserified file ready to go for that purpose. It is not minified.

npm (for browserify) is handled via the package.json browser field which allows users to install SuperAgent via npm, reference it from their browser code with require('superagent'), and then build their own application bundle via browserify, which will use lib/client.js as the SuperAgent entrypoint.

bower is configured via the bower.json file. Bower installs files directly from git/github without any transformation, so you must use Browserify or Webpack (or use npm).

License

MIT

Changelog

4.1.0 (2018-12-26)

• .connect() IP/DNS override option (Kornel)
• .trustLocalhost() option for allowing broken HTTPS on localhost
• .abort() used with promises rejects the promise.