With fhook, you could easily implement functionality to:
- Cache requests in memory, localStorage, etc.
- Insert authentication headers
- S3 Request Signing, see S3 Hook
- Simulate responses
- Create fake transparent backends for testing purposes
- Sending Error statistics to Google Analytics
- Create a client-side alternative to CORS by offloading requests to an iframe then splicing the response back in, see XDomain
- Devious practical jokes
- Supports RequiresJS and Browserify
- Preflight GZip compression, see XZip (Incomplete)
- Intercept and modify XMLHttpRequest ("AJAX") request and response
- Simulate responses transparently
- Backwards compatible
addEventListenerremoveEventListener - Backwards compatible user controlled progress (download/upload) events
Support Modern Browser.
XMLHttpRequest before fhook can patch it
Using script link to load fhook and use it, like so:
<script src="//unpkg.com/fhook@latest/dist/fhook.min.js"></script>
<script>
fhook.after(function (request, response) {
if (request.url.match(/example\.txt$/))
response.text = response.text.replace(/[aeiou]/g, "z");
});
</script>- Development fhook.js
- Production fhook.min.js
- CDN (Use
latestor lock to one of the available versions)
We can also install fhook via npm.
npm install fhookThen use ESM syntax to load fhook.
import fhook from "fhook";
//modify 'responseText' of 'example2.txt'
fhook.after(function (request, response) {
if (request.url.match(/example\.txt$/))
response.text = response.text.replace(/[aeiou]/g, "z");
});Modifying any property of the request object will modify the underlying XHR before it is sent.
To make the handler is asynchronous, just include the optional callback function, which accepts an optional response object.
To provide a fake response, return or callback() a response object.
Modifying any property of the response object will modify the underlying XHR before it is received.
To make the handler is asynchronous, just include the optional callback function.
Enables fhook (swaps out the native XMLHttpRequest class). fhook is enabled be default.
Disables fhook (swaps the native XMLHttpRequest class back in)
method(String) (open(method,url))url(String) (open(method,url))body(String) (send(body))headers(Object) (Contains Name-Value pairs set withsetRequestHeader(name,value))timeout(Number) (timeout)type(String) (responseType)withCredentials(String) (withCredentials)
status(Number) Required when for fakeresponses (status)statusText(String) (statusText)text(String) (responseText)headers(Object) (Contains Name-Value pairs retrieved withgetAllResponseHeaders())xml(XML) (responseXML)data(Varies) (response)
The dark red before hook is returning a response object, which will trigger the after
hooks, then trigger the appropriate events, so it appears as if response came from
the server.
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest
http://www.w3.org/TR/XMLHttpRequest/
http://www.w3.org/TR/XMLHttpRequest2/
-
fhook does not attempt to resolve any browser compatibility issues. Libraries like jQuery and https://github.com/ilinsky/xmlhttprequest will attempt to do this. fhook simply proxies to and from
XMLHttpRequest, so you may use any library conjunction with fhook, just make sure to load fhook first. -
You may use synchronous XHR, though this will cause asynchronous hooks to be skipped.
See CONTRIBUTING for instructions on how to build and run fhook locally.
MIT License Copyright © 2022 Jaime Pillora dev@jpillora.com