Show HN: Crapify, a proxy for simulating slow, spotty HTTP connections

Nice! There was a different tool in the same category, aptly named "Comcast", featured on HN a few weeks ago: https://github.com/tylertreat/Comcast

At work we've been running into problems performing npm installs over a VPN. I'm suspicious that it relates to executing too many concurrent HTTP requests. This motivated me to create crapify, a tool which lets us experiment with throttling connection speed and concurrency.

On OS X you can achieve something similar using ipfw

For example,

sudo ipfw pipe 1 config bw 500KByte/s

Limits all network on your box to 500kb/s

sudo ipfw add 1 pipe 1 src-port 443

To direct all traffic through port 443 through your slow pipe

sudo ipfw delete 1

When you are all done delete

This is cool. If it could add random NATing between various VLANs and occasionally not open firewall ports as configured, it would be a simulation of my work environment!

For linux there is tool 'tc'

A more complete version of this: https://github.com/lightbody/browsermob-proxy

    * captures performance data in the HAR format.
    * blacklisting and whitelisting certain URL patterns
    * simulating various bandwidth and latency
    * remapping DNS lookups
    * flushing DNS caching
    * controlling DNS and request timeouts
    * automatic BASIC authorization
    * REST API

If you simply need to test a website on a simulated slow connection, then Chrome Devtools. For all other purposes, this looks great!

Why not use DummyNet, Clumsy or Network Link Conditioner (depending on your OS of choice)?

If you really need a HTTP proxy there are tools like Charles (although the low RTT to a proxy may change the nature of the testing)