“Design depends largely on constraints.” — Charles Eames
Tuesday, 25 October 2011
A lot of bits have been used over on the OpenStack list recently about versioning the HTTP APIs they provide. This over-long and rambling post summarises my current thoughts on the topic, both as background for that discussion, as well...
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Friday, 21 October 2011
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. In that time, interest in ESI has grown, waned and been reborn. As...
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Friday, 2 September 2011
HTTPbis published RFC6266 a little while ago, but the work isn’t finished. This is the RFC that clarifies how the Content-Disposition header is used in HTTP; in a nutshell, while basic file downloads worked OK, there wasn’t any broad interoperability...
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Sunday, 28 August 2011
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; Cache Contexts Most current HTTP caches...
Wednesday, 24 August 2011
It used to be that when you registered a media type, a URI scheme, a HTTP header or another protocol element on the Internet, it was an opaque string that was a unique identifier, nothing more. Sure, there are some...
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Friday, 5 August 2011
Last week, Blaze.io highlighted how mobile browsers use HTTP pipelining. I’ve been active in trying to get pipelining more widely deployed, but to date I haven’t tested mobile browsers much. So, one VM and two test pages (20 images...
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Wednesday, 27 July 2011
FYI, I’ve implemented Content Security Policy on this site. If your’e a Mozilla user, please tell me if you have any problems. (No, I’m not particularly worried about XSS here; I just want to get a feel for it; see...
Monday, 11 July 2011
The explosion of HTTP implementations isn’t just in clients and servers. An oft-overlooked but important part of the Web ecosystem is the intermediary, often called just a “proxy”*. These days, it’s pretty easy for anyone to build a proxy...
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Sunday, 19 June 2011
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
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. In a nutshell, Cache Channels trades off immediacy for reliability; that is, while cache...
Wednesday, 18 May 2011
A lot of people seem to be talking about and performing load tests on HTTP servers, perhaps because there’s a lot more choice of servers these days. That’s great, but I see a lot of the same mistakes being...
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Monday, 4 April 2011
Last week found lots of HTTP-ish folks in Prague for IETF 80. In short, the good bits: HTTPbis HTTPbis had a cracker of a meeting, with three RFC2616 authors and representatives of all five major browsers in the room....
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Wednesday, 9 March 2011
I made a quick and dirty screencast to show off some of the newer features in htracr. htracr demo from mnot on Vimeo. It’s still a work in progress (you can see at least one visible bug if you’re...
Tuesday, 1 March 2011
The IESG has received a request from the Hypertext Transfer Protocol Bis WG (httpbis) to consider the following document: 'Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)' <draft-ietf-httpbis-content-disp-06.txt> as a Proposed Standard The IESG plans...
Saturday, 27 November 2010
There’s a lot of current activity on the binding between HTTP and TCP; from pipelining to SPDY, the frontier of Web performance lives between these layers. To get more visibility in exactly what’s happening down there, I decided to...
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Friday, 1 October 2010
I’m going to try to start blogging more updates (kick me if I don’t!) about what’s happening in the world of HTTP. HTTPbis The effort to revise the core HTTP specification (RFC 2616) is going nicely, albeit slowly. Given...
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Friday, 23 July 2010
Since SPDY has surfaced, one of the oft-repeated topics has been its use of TLS; namely that the SPDY guys have said that they’ll require all traffic to go over it. Mike Belshe dives into all of the details...
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Wednesday, 30 June 2010
Patricia Clausnitzer has kindly translated the Caching Tutorial to Belarusian. Thanks!...
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Thursday, 3 June 2010
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. Overall, we really like...
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Thursday, 6 May 2010
On a bit of a roll, RFC5861: HTTP Stale Controls has (finally) been published as an Informational RFC. As discussed before in “Two HTTP Caching Extensions,” these are very useful ways to hide latency and errors from your end...
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Wednesday, 5 May 2010
Steve Souders and others have been working for a while on HAR, a HTTP Archive format. I love the idea behind HAR, but as I expressed on the mailing list (so far no response), I have a hard time...
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Wednesday, 7 April 2010
One of the nagging theoretical problems in the Web architecture has been finding so-called “site-wide metadata”; i.e., finding something out about a Web site before you access it. We wrestled with this in P3P way back when, and the TAG...
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Wednesday, 10 March 2010
Thomas Hühn has graciously translated the caching tutorial into German. Thanks! See also the Chinese, Czech and French translations. To help the translators keep up with changes, I've started hosting the raw document on Github, which can also be...
Thursday, 18 February 2010
Resource Packages is an interesting proposal from Mozilla folks for binding together bunches of related data (e.g., CSS files, JavaScript and images) and sending it in one HTTP response, rather than many, as browsers typically do. Intuitively, this seems...
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Friday, 15 January 2010
If you haven’t seen it already, check out the Call for Papers for the First International Workshop on RESTful Design (WS-REST 2010), where I’m on the program committee, along with many of the usual suspects. Submissions due February 8, 2010,...
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Wednesday, 16 December 2009
Australia has apparently decided, through its elected leaders, to filter its own Internet connection. Since many, many other people are discussing whether this is advisable or indeed effective, I’ll focus here on what this will do to HTTP, and...
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Friday, 13 November 2009
A couple of nights ago, I had a casual chat with Google’s Mike Belshe, who gave me a preview of how their “Let’s make the Web faster” effort looks at HTTP itself. SPDY (nee FLIP) is an alternate application...
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Friday, 30 October 2009
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...
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Sunday, 12 July 2009
Just FYI, for those interested: RED now has a blog detailing news and other developments. I’ll still post about it here occaisionally, but most RED-related things are going over there… First (substantial) post: Using RED on a page’s assets....
Thursday, 25 June 2009
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. However, as I’ve got...
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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!). Norwegian should be coming soon......
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Friday, 12 June 2009
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. In that process, I often am...
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Friday, 5 June 2009
HTTP performance is a hot topic these days, so it’s interesting that Opera has announced a “turbo” feature in Opera 10 Beta; Ever felt a Web site was loading slowly? Do you think it will happen again? Think again:...
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Friday, 29 May 2009
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: Did we mention we use Squid? In other words, Google’s hot...
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Tuesday, 14 April 2009
I had a lovely holiday weekend in Canberra with the family, without Web access. Perhaps I’ll blog about that soon — Canberra being in my opinion one of the nicest overlooked cities in the world — but that will...
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Tuesday, 24 February 2009
There’s a rule of thumb about when a HTTP response can be cached; the Caching Tutorial says: If the response’s headers tell the cache not to keep it, it won’t. If the request is authenticated or secure, it won’t...
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Wednesday, 18 February 2009
Sometimes, it seems like every time somebody has a great idea for a new HTTP header, media type, or pretty much any other protocol element, they do the same thing. Rather than trying to figure out how to fit...
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Monday, 27 October 2008
Ryan Tomayko announces Rack::Cache, a HTTP cache for Ruby’s generic Web API; The basic goal is standards-based HTTP caching that scales down to the early stages of a project, development environments, light to medium trafficked sites, stuff like that....
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Thursday, 16 October 2008
Metadata discovery is a nagging problem that’s been hanging around the Web for a while. There have been a few stabs at this problem (including at least one by yours truly), but no real progress. This is both unfortunate...
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Friday, 4 July 2008
Here’s a gem on a little-used mailing list: As most of you know, over the last several years fairly good progress has been made on standardizing Web services. Many Web services specifications have, in fact, been standardized in W3C...
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Thursday, 22 May 2008
Some folks at work were having problems debugging HTTP with LWP’s command-line GET utility; it turned out that it was inserting Link headers — HTTP headers, mind you — for each HTML <link> element present. Blurgh. This brought to...
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Thursday, 20 March 2008
Having complained before about the sad state of HTTP APIs, I’m somewhat happy to say that people seem to be getting it, producing more capable server-side and client-side tools for exposing the full range of the protocol; some frameworks...
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Monday, 3 March 2008
Not many people that I know outside of IETF circles realise that a new *DAV effort has started up; CardDAV. An address book access protocol leveraging the vCard data format. The Internet-draft draft-daboo-carddav will be the starting point. The...
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Wednesday, 6 February 2008
Here’s one that I’ve been wondering about for a while, for the LazyWeb (HTTP Geek Edition); PUTs and POSTs can result in the creation of new resources, or changes to the state of existing ones. The response to both...
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Monday, 21 January 2008
I’m following the discussion of RESTful Web description in general, and WADL in particular, with both difficulty and interest (see Dare, Patrick and Joe’s thoughts for a nice contrast). Difficulty because there’s so much of it, and it’s hard...
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Friday, 4 January 2008
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. In...
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Wednesday, 12 December 2007
We use caching extensively inside Yahoo! to improve scalability, latency and availability for back-end HTTP services, as I’ve discussed before. However, there are a few situations where the plain vanilla HTTP caching model doesn’t quite do the trick. Rather...
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Sunday, 9 December 2007
I haven’t talked about it here much, but I’ve spent a fair amount of time over the last year and a half working with people in the IETF to get RFC2616 — the HTTP specification — revised. That effort...
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Friday, 2 November 2007
I've updated the WADL documentation stylesheet, primarily to; Fix a bug with finding and displaying XML Schema Make it compatible with xsltproc (and hopefully most other XSLT1.0 processors that understand EXSLT node-set) Generate valid XHTML The hard part was...
Saturday, 8 September 2007
Feed Paging and Archiving (nee Feed History) has finally made it to a standards-track RFC. For many non-traditional (read: non-blog) applications of Atom, I think archived feeds in particular are going to be vital. I’m already using it in...
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Tuesday, 7 August 2007
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,...
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Saturday, 28 July 2007
URI Templates -01 is now an Internet-Draft. After sitting on the spec for a while and trying to figure out an elegant solution to the encoding problem, we decided to take the simple route and see how it sticks....
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Wednesday, 20 June 2007
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...
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Tuesday, 15 May 2007
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. Some people claim that Expires is better, because it’s defined by HTTP/1.0,...
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Sunday, 29 April 2007
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...
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Sunday, 15 February 2004
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...
Saturday, 28 June 2003
I feel compelled to respond to Norm Walsh's thoughts on caching. It's important to distinguish between the capabilities of a specific product (such as WWWoffle) and the technology that it implements (caching). I would agree that the general state of...
Monday, 5 May 2003
I've finally gotten sick enough of a project that I've been working on for waaaay too long to release it to the unsuspecting^H^H^H general public. Tarawa is, in short, a HTTP server API that tries to apply some of the...
Tuesday, 8 April 2003
LiveHTTPHeaders for Mozilla is the best HTTP header sniffer I've seen yet; up till now, I've been using WebTee, but for *most* purposes, this is much better. Enjoy....