What is xhr2?
The xhr2 npm package is a server-side implementation of the XMLHttpRequest API, which is commonly used in web browsers for making HTTP requests. This package allows Node.js applications to make HTTP requests using the familiar XMLHttpRequest interface.
What are xhr2's main functionalities?
Basic GET Request
This feature allows you to make a basic GET request to a specified URL. The code sample demonstrates how to open a connection, send the request, and handle the response.
const XMLHttpRequest = require('xhr2');
const xhr = new XMLHttpRequest();
xhr.open('GET', 'https://jsonplaceholder.typicode.com/posts/1', true);
xhr.onload = function () {
if (xhr.status >= 200 && xhr.status < 300) {
console.log(xhr.responseText);
} else {
console.error('Request failed with status:', xhr.status);
}
};
xhr.send();
POST Request with Data
This feature allows you to make a POST request with data. The code sample demonstrates how to set the request method to POST, set the appropriate headers, and send JSON data in the request body.
const XMLHttpRequest = require('xhr2');
const xhr = new XMLHttpRequest();
xhr.open('POST', 'https://jsonplaceholder.typicode.com/posts', true);
xhr.setRequestHeader('Content-Type', 'application/json;charset=UTF-8');
xhr.onload = function () {
if (xhr.status >= 200 && xhr.status < 300) {
console.log(xhr.responseText);
} else {
console.error('Request failed with status:', xhr.status);
}
};
xhr.send(JSON.stringify({ title: 'foo', body: 'bar', userId: 1 }));
Handling Errors
This feature allows you to handle errors that may occur during the request. The code sample demonstrates how to handle both HTTP status errors and network errors.
const XMLHttpRequest = require('xhr2');
const xhr = new XMLHttpRequest();
xhr.open('GET', 'https://jsonplaceholder.typicode.com/invalid-url', true);
xhr.onload = function () {
if (xhr.status >= 200 && xhr.status < 300) {
console.log(xhr.responseText);
} else {
console.error('Request failed with status:', xhr.status);
}
};
xhr.onerror = function () {
console.error('Network error occurred');
};
xhr.send();
Other packages similar to xhr2
axios
Axios is a promise-based HTTP client for the browser and Node.js. It provides a more modern and flexible API compared to xhr2, including support for promises and async/await, which makes it easier to handle asynchronous operations.
node-fetch
Node-fetch is a lightweight module that brings the Fetch API to Node.js. It is similar to xhr2 in that it allows you to make HTTP requests, but it uses the modern Fetch API, which is more widely used in modern web development.
request
Request is a simplified HTTP client for Node.js. It provides a more user-friendly API compared to xhr2 and supports features like cookies, redirects, and multipart form data. However, it has been deprecated in favor of more modern alternatives like axios and node-fetch.
XMLHttpRequest Emulation for node.js
This is an npm package that implements the
W3C XMLHttpRequest specification on top
of the node.js APIs.
Supported Platforms
This library is tested against the following platforms.
Keep in mind that the versions above are not hard requirements.
Installation and Usage
The preferred installation method is to add the library to the dependencies
section in your package.json
.
{
"dependencies": {
"xhr2": "*"
}
}
Alternatively, npm
can be used to install the library directly.
npm install xhr2
Once the library is installed, require
-ing it returns the XMLHttpRequest
constructor.
var XMLHttpRequest = require('xhr2');
The other objects that are usually defined in an XHR environment are hanging
off of XMLHttpRequest
.
var XMLHttpRequestUpload = XMLHttpRequest.XMLHttpRequestUpload;
MDN (the Mozilla Developer Network) has a
great intro to XMLHttpRequest.
This library's CoffeeDocs can
be used as quick reference to the XMLHttpRequest specification parts that were
implemented.
Features
The following standard features are implemented.
http
and https
URI protocols- Basic authentication according to the XMLHttpRequest specification
- request and response header management
send()
accepts the following data types: String, ArrayBufferView,
ArrayBuffer (deprecated in the standard)responseType
values: text
, json
, arraybuffer
readystatechange
and download progress eventsoverrideMimeType()
abort()
timeout
- automated redirection following
The following node.js extensions are implemented.
send()
accepts a node.js Buffer- Setting
responseType
to buffer
produces a node.js Buffer nodejsSet
does XHR network configuration that is not exposed in browsers,
for security reasons
The following standard features are not implemented.
- FormData
- Blob
file://
URIsdata:
URIs- upload progress events
- synchronous operation
- Same-origin policy checks and CORS
- cookie processing
Versioning
The library aims to implement the
W3C XMLHttpRequest specification, so
the library's API will always be a (hopefully growing) subset of the API in the
specification.
Development
The following commands will get the source tree in a node-xhr2/
directory and
build the library.
git clone git://github.com/pwnall/node-xhr2.git
cd node-xhr2
npm install
npm pack
Installing CoffeeScript globally will let you type cake
instead of
node_modules/.bin/cake
npm install -g coffee-script
The library comes with unit tests that exercise the XMLHttpRequest API.
cake test
The tests themselves can be tested by running them in a browser environment,
where a different XMLHttpRequest implementation is available. Both Google
Chrome and Firefox deviate from the specification in small ways, so it's best
to run the tests in both browsers and mentally compute an intersection of the
failing tests.
cake webtest
BROWSER=firefox cake webtest
Copyright and License
The library is Copyright (c) 2013 Victor Costan, and distributed under the MIT
License.