# Upr - Upload Progress for Rack (initial release)

**URL:** <https://www.ruby-forum.com/t/upr-upload-progress-for-rack-initial-release/178771>\
**Category:** Ruby\
**Created:** [November 11, 2009, 2:39am UTC](https://www.ruby-forum.com/t/upr-upload-progress-for-rack-initial-release/178771 "2009-11-11T02:39:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ericw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/97f17d/32.png) [@ericw](https://www.ruby-forum.com/u/ericw)\
**Post date:** [November 11, 2009, 2:39am UTC](https://www.ruby-forum.com/t/upr-upload-progress-for-rack-initial-release/178771/1 "2009-11-11T02:39:33Z")

</div>

upr is Rack middleware that allows browser-side upload progress  
monitoring. It is based-on the “mongrel\_upload\_progress” module, but  
allows any Moneta backing store in addition to DRb. There is also a  
packaged example for using an ActiveRecord model for Rails.

- [http://upr.bogomips.org/](http://upr.bogomips.org/)
- removed\_email\_address@domain.invalid
- git://git.bogomips.org/upr.git

You can see upr it in action at [http://upr-demo.bogomips.org/](http://upr-demo.bogomips.org/)  
It will report the size and SHA1 of the file you’ve uploaded.  
Much of the demo was stolen from mongrel\_upload\_progress.

== Web Server Compatibility

While upr is completely Rack::Lint-compatible, upr is only compatible  
with Rack web servers that support a streaming “rack.input”. Currently  
this is limited to {Rainbows!}[[http://rainbows.rubyforge.org/](http://rainbows.rubyforge.org/)] with a  
handful of concurrency models:

- ThreadSpawn
- ThreadPool
- Revactor\*

For use with Revactor, the use of network-based Moneta stores or DRb is  
only advised if those stores are using Revactor-aware sockets.

== JavaScript/HTML Compatibility

The current developer does not react well with GUIs. Thus all (R)HTML  
and Prototype JavaScript code was stolen from mongrel\_upload\_progress.

Contributions to add compatibility for more modern things like JQuery  
and HTML5 are very welcome.

== Backend Compatibility

We depend on {Moneta}[[GitHub - wycats/moneta: a unified interface to key/value stores](http://github.com/wycats/moneta)], which allows the  
use of a multitude of key-value stores. We also provide a  
DRb+Moneta::Memory server to ease transitions from  
mongrel\_upload\_progress.

Additionally, there is an example for using Rails ActiveRecord as a  
backend storage mechanism. Cookie-based upload tracking may eventually  
be used, too (contributions very welcome).

== Proxy Compatibility

No proxy is required when used with Rainbows!

The only incompatible HTTP proxy we know of is nginx. nginx will buffer  
large requests to the filesystem before sending them to the backend.  
nginx has its own 3rd-party module for  
{upload progress}[[http://wiki.nginx.org/NginxHttpUploadProgressModule](http://wiki.nginx.org/NginxHttpUploadProgressModule)]  
and may be used instead of upr.

Most other HTTP-aware and all TCP-only proxies should be compatible.  
Disabling Nagle’s algorithm in both the Rack web server and proxy is  
advised for lower latency, especially with stunnel.

== Unicorn Compatibility

While {Unicorn}[[http://unicorn.bogomips.org/](http://unicorn.bogomips.org/)] provides the streaming  
“rack.input” for Rainbows!, using Unicorn with upr is generally NOT  
recommended. Unicorn only supports fast clients and progress reporting  
is unnecessary unless clients are uploading files that are hundreds of  
megabyte in size or larger.

== Getting Started

gem install upr

For Rails, look at the Rails application  
{example}[[Upload Progress for Rack](http://git.bogomips.org/cgit/upr.git/tree/examples/rails_app-2.3.4)]  
and RDoc. More documentation is on the way.