As noted previously, my page consists of the aggregation of my various feeds and in working on that code recently it was again brought to my attention that everyone has different ways of representing tag metadata in feeds. I made up a list of how my various feed sources represent tags and list that data here so that it might help others in the future.
| Source | Feed Type | Tag Markup Scheme | One Tag Per Element | Tag Scheme URI | Human / Machine Names | Example Markup |
|---|---|---|---|---|---|---|
| LiveJournal | Atom | atom:category | yes | no | no | , (source) |
| LiveJournal | RSS 2.0 | rss2:category | yes | no | no |
technical(soure) |
| WordPress | RSS 2.0 | rss2:category | yes | no | no |
, (source)
|
| Delicious | RSS 1.0 | dc:subject | no | no | no |
photosynth photos 3d tool(source) |
| Delicious | RSS 2.0 | rss2:category | yes | yes | no |
domain="http://delicious.com/SequelGuy/">(source) |
| Flickr | Atom | atom:category | yes | yes | no |
term="seattle"(source) |
| Flickr | RSS 2.0 | media:category | no | yes | no |
scheme="urn:flickr:tags">(source) |
| YouTube | RSS 2.0 | media:category | no | no | no |
label="Tags">(source) |
| LibraryThing | RSS 2.0 | No explicit tag metadata. | no | no | no | n/a, (source) |
| Tag Markup Scheme | Notes | Example |
|---|---|---|
|
Atom Category atom:category xmlns:atom="http://www.w3.org/2005/Atom"
|
|
term="catName"
|
|
RSS 2.0 category rss2:category empty namespace |
|
domain="tag:deletethis.net,2008:tagscheme">
|
|
Yahoo Media RSS Module category media:category xmlns:media="http://search.yahoo.com/mrss/"
|
|
scheme="http://dmoz.org"
|
|
Dublin Core subject dc:subject xmlns:dc="http://purl.org/dc/elements/1.1/"
|
|
humor
|
Update 2009-9-14: Added WordPress to the Tag Markup table and namespaces to the Tag Markup Scheme table.
In my Intro to Algorithms course in college the Fibonacci sequence was used as the example algorithm to which various types of algorithm creation methods were applied. As the course went on we made
better and better performing algorithms to find the nth Fibonacci number. In another course we were told about a matrix that when multiplied successively produced Fibonacci numbers. In my linear
algebra courses I realized I could diagonalize the matrix to find a non-recursive Fibonacci function. To my surprise this worked and I
found a function.
Looking online I found that of course this same function was already well known. Mostly I was irritated that after all the
algorithms we created for faster and faster Fibonacci functions we were never told about a constant time function like this.
I recently found my paper depicting this and thought it would be a good thing to use to try out MathML, a markup language for displaying math. I went to the MathML implementations page and installed a plugin for IE to display MathML and then began writing up my paper in MathML. I wrote the MathML by hand and must say that's not how its intended to be created. The language is very verbose and it took me a long time to get the page of equations transcribed.
MathML has presentation elements and content elements that can be used separately or together. I stuck to content elements and while it looked great in IE with my extension when I tried it in FireFox which has builtin MathML support it didn't render. As it turns out FireFox doesn't support MathML content elements. I had already finished creating this page by hand and wasn't about to switch to content elements. Also, in order to get IE to render a MathML document, the document needs directives at the top for specific IE extensions which is a pain. Thankfully, the W3C has a MathML cross platform stylesheet. You just include this XSL at the top of your XHTML page and it turns content elements into appropriate presentation elements, and inserts all the known IE extension goo required for you. So now my page can look lovely and all the ickiness to get it to render is contained in the W3C's XSL.
The weekend before last was Sarah's birthday and as part of
that, last weekend we took a trip to Victoria, BC. I've got a map of our trip locations and photos. Not all the
photos are on the map but they're all in the trip photo set on Flickr. It turns out there's a lot of tourist intended
activities right around our hotel which was in the inner harbor and downtown Victoria area. As such we didn't get a rental car and did a lot of walking.
On the first day we checked out the Royal British Columbia Museum which had
some interesting exhibits in it and the Undersea Garden which was interesting in that its like a floating aquarium but was a bit grimy. There was a group of Japanese tourists next to us during the
undersea show in which a diver behind the glass in the ocean would pick up and parade various animal life. The group all repeated the word starfish in unison after the show's narrator and one of
the tourists was very excited to see the diver bring over the octopus. The diver made the octopus wave to us while it desperately tried to get away.
We flew in and out of the Victoria International Airport
which is a smaller sized airport. Although we needed our passports we didn't need to take off our shoes -- what convenience! The US dollar was just a bit worse than the Canadian dollar which was
also convenient. The weather was lovely while we were there and I only got slightly sun burned.
I just installed vmcNetFlix which lets you watch your on demand NetFlix movies via your Vista Media Center or any Media Center
Extenders like the Xbox 360. It works well but fails poorly with some cryptic error messages and long timeouts. Be sure to get NetFlix on demand movies working in your browser before installing
this plugin. Once I did that everything worked very well.
To test it out I watched Ong-Bak: The Thai Warrior in which Ting must travel from his country village to Bangkok where he works with his cousin in the city to recover his village's stolen religious artifact. Its a mix of Perfect Strangers, Street Fighter and Pad-See Ew. Martial arts movies, like porn and video games, aren't required to have a strong plot but Ong-Bak has a fine plot line and enjoyable Thai martial arts. I saw the Tiger Knee in there several times. An enjoyable movie that reminded me of watching martial arts movies with my friends in high school.
sequelguy posted a photo:
Kierland Commons shopping center next to the resort had fancy shops, hummers and golf carts.
While re-reading Cryptonomicon I thought about what kind of information I'm leaking by posting links on Delicious. At work I don't post any Intranet websites for fear of revealing anything but I wondered if not posting would reveal anything. For instance, if I'm particularly busy at work might I post less indicating something about the state of the things I work on? I got an archive of my Delicious posts via the Delicious API and then ran it through a tool I made to create a couple of tables which I've graphed on Many Eyes
![['Neverending story' by Alexandre Duret-Lutz. A framed photo of books with the droste effect applied. Licensed under creative commons.]](http://farm1.static.flickr.com/90/252757784_3de44cbeb4_m_d.jpg)
Information about URI Fragments, the portion of URIs
that follow the '#' at the end and that are used to navigate within a document, is scattered throughout various documents which I usually have to hunt down. Instead I'll link to them all here.
Definitions. Fragments are defined in the URI RFC which states that they're used to identify a secondary resource that is related to the primary resource identified by the URI as a subset of the primary, a view of the primary, or some other resource described by the primary. The interpretation of a fragment is based on the mime type of the primary resource. Tim Berners-Lee notes that determining fragment meaning from mime type is a problem because a single URI may contain a single fragment, however over HTTP a single URI can result in the same logical resource represented in different mime types. So there's one fragment but multiple mime types and so multiple interpretations of the one fragment. The URI RFC says that if an author has a single resource available in multiple mime types then the author must ensure that the various representations of a single resource must all resolve fragments to the same logical secondary resource. Depending on which mime types you're dealing with this is either not easy or not possible.
HTTP. In HTTP when URIs are used, the fragment is not included. The General Syntax section of the HTTP standard says it uses the definitions of 'URI-reference' (which includes the fragment), 'absoluteURI', and 'relativeURI' (which don't include the fragment) from the URI RFC. However, the 'URI-reference' term doesn't actually appear in the BNF for the protocol. Accordingly the headers like 'Request-URI', 'Content-Location', 'Location', and 'Referer' which include URIs are defined with 'absoluteURI' or 'relativeURI' and don't include the fragment. This is in keeping with the original fragment definition which says that the fragment is used as a view of the original resource and consequently only needed for resolution on the client. Additionally, the URI RFC explicitly notes that not including the fragment is a privacy feature such that page authors won't be able to stop clients from viewing whatever fragments the client chooses. This seems like an odd claim given that if the author wanted to selectively restrict access to portions of documents there are other options for them like breaking out the parts of a single resource to which the author wishes to restrict access into separate resources.
HTML. In HTML, the HTML mime type RFC defines HTML's fragment use which consists of fragments referring to elements with a corresponding 'id' attribute or one of a particular set of elements with a corresponding 'name' attribute. The HTML spec discusses fragment use additionally noting that the names and ids must be unique in the document and that they must consist of only US-ASCII characters. The ID and NAME attributes are further restricted in section 6 to only consist of alphanumerics, the hyphen, period, colon, and underscore. This is a subset of the characters allowed in the URI fragment so no encoding is discussed since technically its not needed. However, practically speaking, browsers like FireFox and Internet Explorer allow for names and ids containing characters outside of the defined set including characters that must be percent-encoded to appear in a URI fragment. The interpretation of percent-encoded characters in fragments for HTML documents is not consistent across browsers (or in some cases within the same browser) especially for the percent-encoded percent.
Text. Text/plain recently got a fragment definition that allows fragments to refer to particular lines or characters within a text document. The scheme no longer includes regular expressions, which disappointed me at first, but in retrospect is probably good idea for increasing the adoption of this fragment scheme and for avoiding the potential for ubiquitous DoS via regex. One of the authors also notes this on his blog. I look forward to the day when this scheme is widely implemented.
XML. XML has the XPointer framework to define its fragment structure as noted by the XML mime type definition. XPointer consists of a general scheme that contains subschemes that identify a subset of an XML document. Its too bad such a thing wasn't adopted for URI fragments in general to solve the problem of a single resource with multiple mime type representations. I wrote more about XPointer when I worked on hacking XPointer into IE.
SVG and MPEG. Through the Media Fragments Working Group I found a couple more fragment scheme definitions. SVG's fragment scheme is defined in the SVG documentation and looks similar to XML's. MPEG has one defined but I could only find it as an ISO document "Text of ISO/IEC FCD 21000-17 MPEG-12 FID" and not as an RFC which is a little disturbing.
AJAX. AJAX websites have used fragments as an escape hatch for two issues that I've seen. The first is getting a unique URL for versions of a page that are produced on the client by script. The fragment may be changed by script without forcing the page to reload. This goes outside the rules of the standards by using HTML fragments in a fashion not called out by the HTML spec. but it does seem to be inline with the spirit of the fragment in that it is a subview of the original resource and interpretted client side. The other hack-ier use of the fragment in AJAX is for cross domain communication. The basic idea is that different frames or windows may not communicate in normal fashions if they have different domains but they can view each other's URLs and accordingly can change their own fragments in order to send a message out to those who know where to look. IMO this is not inline with the spirit of the fragment but is rather a cool hack.
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