mark nottingham


Wednesday, 7 June 2017

How (Not) to Control Your CDN

In February, Omer Gil described the Web Cache Deception Attack.

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Thursday, 16 March 2017

The State of Browser Caching, Revisited

A long, long time ago, I wrote some tests using XmlHttpRequest to figure out how well browser caches behaved, and wrote up the results.

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Sunday, 1 June 2014

Chrome and Stale-While-Revalidate

Chrome is looking at adding support for RFC5861’s stale-while-revalidate, which is really cool. I wrote about the details of SwR when it first became an RFC, but its application to browsers is something that’s a new. Seems like a good time to answer a few potential questions.

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Monday, 24 September 2012

Caching POST

One of the changes in Apple’s release of iOS6 last week was a surprising new ability to cache POST responses.

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Friday, 21 October 2011

Why ESI is Still Important, and How to Make it Better

More than ten years ago, I was working at Akamai and got involved in the specification of Edge Side Includes (ESI), sort of a templating language for intermediaries.

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Sunday, 28 August 2011

Better Browser Caching

In discussing my whinge about AppCache offline with a few browser vendory folks, I ending up writing down my longstanding wishlist for making browser caches better. Without further ado, a bunch of blue-sky ideas;

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Sunday, 19 June 2011

Fixing AppCache

HTML5’s AppCache mechanism is one confused little puppy. Purporting to be for taking web applications offline — a compelling and useful thing — it’s more often used by performance-hungry sites that want to use it as an online cache.

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Friday, 27 May 2011

Linked Cache Invalidation

After designing and deploying Cache Channels, it quickly became apparent that one Web cache invalidation mechanism wasn’t able to cover the breadth of use cases.

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Wednesday, 30 June 2010

Падручнік па кэшаванню

Patricia Clausnitzer has kindly translated the Caching Tutorial to Belarusian. Thanks!

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Thursday, 3 June 2010

Why Our New TV Doesn't Like the Web

A while back we used an absurd amount of reward points from our credit card to get some Myer gift certificates, and on the weekend these miraculously turned into a new TV, the Sony 32EX600.

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Wednesday, 10 March 2010

Caching-Tutorial für Webautoren und Webmaster

Thomas Hühn has graciously translated the caching tutorial into German. Thanks!

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Friday, 30 October 2009

Traffic Server

A long time ago*, the word in high-performance proxy-caching was Inktomi’s Traffic Server. It was so fast it was referred to being “carrier grade” and this could be said without people smirking, and it was deployed by the likes of AOL, when AOL was still how most people accessed the Internet.

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Thursday, 25 June 2009

The Resource Expert Droid

A (very) long time ago, I wrote the Cacheability Engine to help people figure out how a Web cache would treat their sites. It has a few bugs, but is generally useful for that purpose.

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Wednesday, 17 June 2009


The caching tutorial is now available in Chinese, courtesy of Che Dong (and apologies for taking so long in linking to it!).

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Friday, 12 June 2009

What to Look For in a HTTP Proxy/Cache

Part of my job is maintaining Yahoo!’s build of Squid and supporting its users, which use it to serve everything from the internal Web services that make sites go to serving Flickr’s images.

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Friday, 29 May 2009

Most Revealing Google Wave Comment

Everybody’s atwitter (yeah, sue me) about the Google Wave developer preview. Lots of new stuff there, but for me the most revealing comment, almost a throwaway, was here:

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Tuesday, 24 February 2009

Caching When You Least Expect it

There’s a rule of thumb about when a HTTP response can be cached; the Caching Tutorial says:

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Monday, 27 October 2008

Dev-Friendly Web Caching

Ryan Tomayko announces Rack::Cache, a HTTP cache for Ruby’s generic Web API;

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Friday, 4 January 2008

Cache Channels

The stale-while-revalidate and stale-if-error extensions aren’t the only fiddling we’ve been doing with the HTTP caching model. Now that Squid 2.7 is starting to see daylight, I can explain about a much more ambitious project — Cache Channels.

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Wednesday, 12 December 2007

Two HTTP Caching Extensions

We use caching extensively inside Yahoo! to improve scalability, latency and availability for back-end HTTP services, as I’ve discussed before.

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Tuesday, 7 August 2007

ETags, ETags, ETags

I’ve been hoping to avoid this, but ETags seem to be popping up more and more often recently. For whatever reason, people latch onto them as a litmus test for RESTfulness, as the defining factor of HTTP’s caching model, and much more.

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Wednesday, 20 June 2007

The State of Proxy Caching

A while back I wrote up the state of browser caching, after writing a quick-and-dirty XHR-based test page, with the idea that if people know how their content is handled by common implementations, they’d be able to trust caches a bit more.

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Tuesday, 15 May 2007

Expires vs. max-age

I occasionally get a question from readers of the caching tutorial about whether to use the Expires header or Cache-Control: max-age to control a response’s freshness lifetime.

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Sunday, 29 April 2007

Squid is My Service Bus

The QCon presentation ( slides) was ostensibly about how we use HTTP for services within Yahoo’s Media Group. When I started thinking about the talk, however, I quickly concluded that everyone’s heard enough about the high-level benefits of HTTP and not nearly enough details of what it does on the ground. So, I decided to concentrate on one aspect of the value that we get from using HTTP for services; intermediation, as an example.

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Monday, 21 August 2006

Caching Performance Notes

There have been some interesting developments in Web caching lately, from a performance perspective; event loops are becoming mainstream, and there are lots of new contenders on the scene.

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Tuesday, 16 May 2006

Caching Web 2.0

I just finished my XTech presentation, “ Web 2.0 on Speed”. here are the slides [pdf]; I’m going to try to s5 them soon. There isn’t much new in this talk; it’s just a synthesis of a few different observations;

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Thursday, 11 May 2006

The State of Browser Caching

Updated 2006-06-03

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Saturday, 18 February 2006

Invalidating Caches with POST

Have you ever posted a comment to a blog, found it missing, so you re-posted it, only to find two entries? Annoying, huh?

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Saturday, 26 November 2005

Leveraging the Web: Caching

The first in an occasional series about the real-world benefits of REST and the Web architecture, as applied to HTTP.

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Sunday, 22 May 2005

Prefetching (again)

There’s been quite a kerfuffle over Google’s Web Accelerator, because it prefetches Web content.

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Thursday, 12 May 2005

Google's Cache-Control Extensions

I happened to look at the HTTP headers returned from Google News just now (what can I say, I’m a HTTP geek), and I noticed something unusual;

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Sunday, 15 February 2004

Caching Tutorial Update

I’ve published a revision of the Caching Tutorial for Web Authors and Webmasters, the first non-trivial edit in some time almost since I wrote it in 1998. That said, there aren’t any substantial changes; this is mostly tweaking and incorporation of new information.

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Saturday, 28 June 2003

Caching is often enough

I feel compelled to respond to Norm Walsh’s thoughts on caching.

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