http-client
v4.3.1
Published
Compose HTTP clients using JavaScript's fetch API
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http-client
http-client lets you compose HTTP clients using JavaScript's fetch API. This library has the following goals:
- Preserve the full capabilities of the fetch API
- Provide an extendable middleware API
- Use the same API on both client and server
Installation
Using npm:
$ npm install --save http-client
http-client requires you to bring your own global fetch
function (for convenience when using the top-level createFetch
function). isomorphic-fetch is a great polyfill if you need to support environments that don't already have a global fetch
function.
Then, use as you would anything else:
// using ES6 modules
import { createFetch } from 'http-client'
// using CommonJS modules
var createFetch = require('http-client').createFetch
The UMD build is also available on unpkg:
<script src="https://unpkg.com/http-client/umd/http-client.min.js"></script>
You can find the library on window.HTTPClient
.
Usage
http-client simplifies the process of creating flexible HTTP clients that work in both node and the browser. You create your own fetch
function using the createFetch
method, optionally passing middleware as arguments.
import { createFetch, base, accept, parse } from 'http-client'
const fetch = createFetch(
base('https://api.stripe.com/v1'), // Prefix all request URLs
accept('application/json'), // Set "Accept: application/json" in the request headers
parse('json') // Read the response as JSON and put it in response.body
)
fetch('/customers/5').then(response => {
console.log(response.jsonData)
})
Top-level API
createFetch(...middleware)
Creates a fetch
function that uses some middleware. Uses the global fetch
function to actually make the request.
createStack(...middleware)
Combines several middleware into one, in the same order they are provided as arguments. Use this function to create re-usable middleware stacks or if you don't want to use a global fetch
function.
enableRecv(fetch)
Returns an "enhanced" version of the given fetch
function that knows how to run response handlers registered using recv
. This is only really useful when using stacks directly instead of createFetch
.
Middleware
http-client provides a variety of middleware that may be used to extend the functionality of the client. Out of the box, http-client ships with the following middleware:
accept(contentType)
Adds an Accept
header to the request.
import { createFetch, accept } from 'http-client'
const fetch = createFetch(
accept('application/json')
)
auth(value)
Adds an Authorization
header to the request.
import { createFetch, auth } from 'http-client'
const fetch = createFetch(
auth('Bearer ' + oauth2Token)
)
base(baseURL)
Adds the given baseURL
to the beginning of the request URL.
import { createFetch, base } from 'http-client'
const fetch = createFetch(
base('https://api.stripe.com/v1')
)
fetch('/customers/5') // GET https://api.stripe.com/v1/customers/5
body(content, contentType)
Sets the given content
string as the request body.
import { createFetch, body } from 'http-client'
const fetch = createFetch(
body(JSON.stringify(data), 'application/json')
)
debug()
Adds a debug
property to the response or error object so you can inspect them. Mainly useful for testing/debugging (should run after all other middleware).
import { createFetch, debug } from 'http-client'
const fetch = createFetch(
// ... other middleware
debug()
)
fetch(input).then(response => {
console.log(response.debug.input, response.debug.options)
})
header(name, value)
Adds a header to the request.
import { createFetch, header } from 'http-client'
const fetch = createFetch(
header('Content-Type', 'application/json')
)
init(propertyName, value)
Sets the value of an arbitrary property in the options object.
import { createFetch, init } from 'http-client'
const fetch = createFetch(
init('credentials', 'include')
)
json(object)
Adds the data in the given object as JSON to the request body.
method(verb)
Sets the request method.
import { createFetch, method } from 'http-client'
const fetch = createFetch(
method('POST')
)
params(object)
Adds the given object to the query string of GET
/HEAD
requests and as a x-www-form-urlencoded
payload on all others.
import { createFetch, method, params } from 'http-client'
// Create a client that will append hello=world to the URL in the query string
const fetch = createFetch(
params({ hello: 'world' })
)
// Create a client that will send hello=world as POST data
const fetch = createFetch(
method('POST'),
params({ hello: 'world' })
)
parse(parser, as = 'body')
Reads the response body to completion, parses the response, and puts the result on response.body
(or whatever as
is). parser
must be the name of a valid Body parsing method. The following parsers are available in the spec:
arrayBuffer
blob
formData
json
text
import { createFetch, parse } from 'http-client'
const fetch = createFetch(
parse('json')
)
fetch(input).then(response => {
console.log(response.body)
})
Note: Some parsers may not be available when using a fetch
polyfill. In particular if you're using node-fetch
, you should be aware of its limitations.
query(object)
Adds the data in the given object (or string) to the query string of the request URL.
recv(handler)
Used to handle the response
in some way. The handler
function should return the new response value, or a promise for it. Response handlers run in the order they are defined.
import { createFetch, recv } from 'http-client'
const fetch = createFetch(
recv(response => (console.log('runs first'), response)),
recv(response => (console.log('runs second'), response))
)
Stacks
Middleware may be combined together into re-usable middleware "stacks" using createStack
. A stack is itself a middleware that is composed of one or more other pieces of middleware. Thus, you can pass a stack directly to createFetch
as if it were any other piece of middleware.
This is useful when you have a common set of functionality that you'd like to share between several different fetch
methods, e.g.:
import { createFetch, createStack, header, base, parse, query } from 'http-client'
const commonStack = createStack(
header('X-Auth-Key', key),
header('X-Auth-Email', email),
base('https://api.cloudflare.com/client/v4'),
parse('json')
)
// This fetch function can be used standalone...
const fetch = createFetch(commonStack)
// ...or we can add further middleware to create another fetch function!
const fetchSinceBeginningOf2015 = createFetch(
commonStack,
query({ since: '2015-01-01T00:00:00Z' })
)
Stacks are also useful when you don't have a global fetch
function, e.g. in node. In those cases, you can still use http-client middleware and supply your own fetch
(we recommend node-fetch) function directly, but make sure you "enhance" it first:
const { createStack, enableRecv, header, base } = require('http-client')
// We need to "enhance" node-fetch so it knows how to
// handle responses correctly. Specifically, enableRecv
// gives a fetch function the ability to run response
// handlers registered with recv (which parse, used below,
// uses behind the scenes).
const fetch = enableRecv(
require('node-fetch')
)
const stack = createStack(
header('X-Auth-Key', key),
header('X-Auth-Email', email),
base('https://api.cloudflare.com/client/v4'),
parse('json')
)
stack(fetch, input, options)