hcard-brainstorming

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The above heuristic (not quite well specified enough to be an algorithm, yet) would allow parsing of the IBM Employee Directory result documented above.
The above heuristic (not quite well specified enough to be an algorithm, yet) would allow parsing of the IBM Employee Directory result documented above.
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There are a lot of existing geocoder APIs that turn unstructured addresses into structured ones - we should examine these for patterns and best practices. eg [http://www.google.com/apis/maps/documentation/#Geocoding_Structured Google's geocoder] [http://exogen.case.edu/projects/geopy/ geopy calls multiple ones]
=== INPUT element handling ===
=== INPUT element handling ===

Revision as of 18:52, 31 July 2007

hCard Brainstorming

This page is for brainstorming about various uses and details of hCard.

Contents


Authors

Contributors

Problems Being Solved

Some of the problems that hCard helps to solve:

FN Nickname semantic

There are many sites (e.g. Flickr, Consumating) which permit the user to both have a multi-word login/handle/alias, and not show their real name (fn, n, given-name, family-name etc.).

For the people represented by the profile pages of these sites, the best we can do is mark-up their login/handle/alias as their "nickname". Originally, we had thought that such handles etc. were single words only, and thus we created the Implied nickname optimization accordingly, where you can markup the handle as an "fn", and have it automatically set a "nickname" property value, and empty values for all the "n" sub-values.

In order to deal with multi-word handles, similar to the hCard Organization contact info method, the following is proposed:

"fn" and "nickname" combination

Due to the use of potentially multi-word nicknames/handles/usernames in content published on the Web, (e.g. on sites like Flickr and Consumating), hCard has a mechanism for specifying a multi-word "fn" that is also a "nickname" without affecting any "n" sub-properties that are otherwise specified, and explicitly implying empty defaults for "n" sub-properties.

Similar to the implied "nickname" optimization, if the "fn" property and a "nickname" property have the exact same value (typically because they are set on the same element, e.g. class="fn nickname"), then

  1. The content of the "fn" is treated as a "nickname" property value.
  2. Parsers should handle the missing "n" property by implying empty values for all the "n" sub-properties.

Implied FN from N

Since the "n" property is more detailed and structured than the "fn" property, and hcard-examples-in-wild have shown that very often what is specified for "n" sub-properties is also specified for the "fn" property, we could add the following implied "fn" optimization which would permit sites to only use "n" and its subproperties.

implied "fn" from "n" optimization

If an hCard has no "fn", yet has an "n" property with one or more subproperties, then the "fn" property value can be implied by concatenating the "n" subproperty values as follows, with a space between each subproperty value, and multiple subproperty instances.

Implied N from its subproperties

Since the "n" subproperties are sufficiently uniquely named (that is, they are not used by any other hCard property), and "n" is one of the hcard-singular-properties, it is possible to consider leaving out the "n" property itself fo the hCard, and simply directlly using the subproperties, as properties of the hCard.

implied "n" from its subproperties

If an hCard has no "fn" nor "n" properties, then the entire scope of the hCard is considered to be inside an implied "n" property.

E.g. this markup:

<span class="vcard">
 <span class="given-name">Tantek</span>
 <span class="family-name">Çelik</span>
</span>

would be treated from a parsing perspective as:

<span class="vcard"><span class="n">
 <span class="given-name">Tantek</span>
 <span class="family-name">Çelik</span>
</span></span>

Which, with the implied "fn" from "n" optimization, would then be effectively treated as:

<span class="vcard"><span class="fn n">
 <span class="given-name">Tantek</span>
 <span class="family-name">Çelik</span>
</span></span>

Examples

Using RFC2806 with hCard

RFC 2806 defines the telephone scheme "tel:", "fax:" and "modem:" to handle phone communications with URIs in the same way, "mailto:" is defined for email. It's part of the list or registered schemes by IANA : Uniform Resource Identifier (URI) SCHEMES

tel   telephone [RFC2806]
fax   fax       [RFC2806]
modem modem     [RFC2806]

It is practical to write your tel number like this.

<a class="tel"      href="tel:+1-919-555-7878">+1-919-555-7878</a>

or even

<a class="tel"      href="tel:+1-919-555-7878">Mr Smith's phone</a>

You can add support for "tel:" to your desktop and to your browser

On the CSS front… You could for example add automagically an icon. I have put the property !important for those who wants to add it to their own stylesheet in their browsers, so they know type of links when browsing.

a[href^="tel:"]:before {
    content: '\260f  ' !important;
    padding-left: 20px !important; }

a[href^="mailto:"]:before {
    content: '\2709  ' !important;
    padding-left: 20px !important; }



Encoding "modern" attributes

Since vCard was first established, various interactive communication technologies and addressing schemes have been widely adopted. Although there aren't specific properties for these technologies / addressing schemes, they can be captured as URLs or email addresses.

This has now been written up for the most part. See:

http://microformats.org/wiki/hcard-examples#New_Types_of_Contact_Info

Still to be addressed:

Auto-Discovery

Representative hCard discovery

Ways to auto discover the representative hCard for a page, that is the hCard that means the person/owner of the page.

Applications for auto-discovery of the representative hCard for the page

The preferred option is to use only visible semantic HTML (POSH).

Here is a scenario that outlines the proposed auto-discovery process:

  1. I (as user) give the URL of my homepage or hCard or other profile URL, to a site that wants a profile icon
  2. That site goes and gets it (e.g. using hKit), and then:
    1. checks to see if there is an <address> hCard, and uses it if it finds it
    2. otherwise uses the first hCard it finds (which in cases of profile URLs which have a single hCard like on Flickr, Zooomr, and Technorati, will work as expected).
  3. The site looks in the hCard for a "logo" property and uses the first one if it finds any.
  4. Otherwise it looks for a "photo" property and uses the first one if it finds any.
  5. Otherwise the site uses a default icon, but subscribes to the URL with the hCard and checks it for a "logo" or "photo", say, once a day.

vCard link rel auto-discovery

A similar possibility is an auto discovery link in the head of the document could point to a URL (perhaps with transform) to a vCard version of the representative hCard.

On the page with the hCard encoding, the best link would be as follows: <link rel="alternate" type="text/directory" href="..." /> this HTML page is an alternate view of the vCard.

The registered and appropriate type for vCard entities is “text/directory”, as defined in Internet RFC 2425, “A MIME Content-Type for Directory Information”. RFC 2426, “vCard MIME Directory Profile”, specifies the vCard profile for “text/directory” entities, which profile the MIME/HTTP header field “Content-Type” would indicate with a “profile” parameter whose value is “VCARD”.

It is unclear whether the HTML/XHTML “type” attribute allows values with parameters. On 2004-05-23, Björn Höhrmann sent to the HTML Working Group a request for clarification on the issue.

When on a different page, referencing that encoded page in the href would not be an alternate view of the current page. Therefore rel="alternate" may not be appropriate. The problem of what rel value to use is bigger than links to vCards.

hCard to hCard relationships

There are several types of hCard to hCard relationships, that is, one hCard hyperlinking to another hCard which would beneift from the explicit rel values that described the specific relationship.

mini hCard to expanded hCard

Perhaps the most common type of hCard to hCard link is a mini hCard, e.g. from a personal home page or blog to the person's contact/about page, perhaps consisting of only a name and URL, that links to an expanded hCard. Examples in the wild:

In this instance, possible rel values might include:

The following rel values have been suggested, but are not really a good idea due to the fact that they imply a dependence to add a new rel value for any new microformat which might have a mini-version linking to a more expanded version:

Here are some more generic values that have been suggested which perhaps make even less sense:

mini hCard to remote site

Per the instructions in hcard-examples for marking up people in blogrolls, you might have an hCard of your site for another person which then links to that other person's website. Should there be a rel value that indicates this "mini-hCard" to "person" relationship?

mini hCards and nearby expanded hCard links

Some authors include mini-hCards on their pages of themselves (e.g. in their blog posts), and yet those mini-hCards don't actually point to more expanded versions. However, sometimes they have a separate but nearby link on the same page like "about" or "contact" that does link to an expanded hCard.

E.g. on FactoryCity, blog posts have mini-hCards for "published by", e.g. (white space added for readability):

Published by 
<span class="vcard author">
 <a href="http://factoryjoe.com/blog/author/factoryjoe/" class="url fn">
  Chris Messina
 </a>
</span>

On those same blog pages, there is a link labeled "Contact Information" that links to http://factoryjoe.com/blog/hcard/ which has an hCard with more information like phone number, birthday etc.


Auto-Discovery for XFN

An author will typically their XFN information on a specific page, rather than all pages. In particular, a specific page separate from the home page of their blog, and thus it would be useful to have an explicit rel value to assist in auto-discovery of XFN information.

This was suggested by Jens Alfke on 20050606 at the WWDC blogger's dinner.

geo improvements

See geo-brainstorming

Other use cases

Issues with vCard Applications

See vcard-implementations.

Open Questions

Q: since many of the components would be using CSS classes for encoding data, it is possible to MIX two different profiles. (e.g. hCard and XFN) There are no real constraints on where/how to enforce class names, these are based on the html profile, since it is difficult to associate the text within the attribute to a specific profile.

...
<a href="mailto:joe.smith@example.com" class="fn" rel="met">Joe Smith</a>
...

-- Brian Suda

Q: Preserving White space? Should the transforming applications preserve extra white space characters? For example:

<a href="http://mywebsite.com/" class="fn n">
    <span class="given-name">John</span>
    <span class="other-names">Q.</span>
    <span class="family-name">Public</span>
</a>

When transformed into a vCard, the N property will pick apart the span tags and create the value for N correctly seperated by colons. The FN property will take a string and simply display it. There are two possible renderings for FN:

John Q. Public

    John
    Q.
    Public

Either the white-space is preserved or it is not. Which should the transforming applications render?

-- Brian Suda

A: The parsing application should follow the white space collapsing rules of the mime type it retrieves. I.e. if it retrieves a "text/html" document, it should do HTML white space collapsing.

-- Tantek

Many of the Questions and Answers are relevant to both ["hCal"] and hCard.

Q: Would it be appropriate to wrap the name of the vCard owner with ? This may give the hCard some added semantic value in the XHTML document.

<span class="agent"> 
 <span class="vcard">
  <span class="email">
   <a class="internet" href="mailto:jfriday@host.com">
    <dfn>
       <span class="fn">Joe Friday</span>
    </dfn>
   </a>
  </span>
  <span class="tel">+1-919-555-7878</span>
  <span class="title">Area Administrator, Assistant</span>
 </span>
</span>

-- Ben Ward

<dfn class="fn">Joe Friday</dfn>

or

<span class="agent"> 
 <dfn class="vcard">
  <span class="email">
   <a class="internet" href="mailto:jfriday@host.com">
    <span class="fn">Joe Friday</span>
   </a>
  </span>
  <span class="tel">+1-919-555-7878</span>
  <span class="title">Area Administrator, Assistant</span>
 </dfn>
</span>

This would mark the entire hcard as the "defining instance".

Bob Jonkman 10:07, 13 Jul 2007 (PDT)

Applications

Applications that are hCard aware or can convert hCard to vCard formats.

Copy hCards favelet(s)

Distributed Commentor Icons

The URL reffered to in this section is no longer available. The thoughts on using icons are however still relevant. WilleRaab 16:55, 23 Jul 2007 (PDT)

What if we gave each commentor the option of hosting their own icon?

A distributed commentor icon implementation could work like this:

  1. Given the URL of a commentor, look for an <address> element with classname of "vcard" at the commentor's URL. The <address> element is supposed to be the contact information for the page (see hCard FAQ for more info), so this makes sense.
  2. Next, look for the first element inside that hcard that has a classname of "logo".
  3. Hopefully that element is an <img>, and if so, use its src to get the commentor's icon.
  4. Presto. You've got distributed commentor icons!

Spam prevention

hCard uses mailto: links, and therefore it automatically "inherits" the disadvantage of mailto: links: These links can be easily detected by emails spiders (used by spammers).

Email addresses are picked up like any other link crawled by a search engine and trustworthy crawlers may be deterred from adding emphasis while indexing these links by including rel="nofollow" (See rel-nofollow). However, email addresses used for spam are crawled by email spiders which will likely ignore this attribute.

There are ways to prevent email address detection by simple email spiders, while still retaining full compatibility with (X)HTML applications. One common way is to "encode" the the "m" of "mail" and "@" with character entities, yet it's unwise to follow a convention of only encoding specific characters because the email spiders can pick up on this too:

Example of the original link:

<a class="email" href="mailto:john.smith@example.com">john.smith@example.com</a> 

Example of the "encoded" link (with rel-nofollow added):

<a class="e&#109;ail" rel="nofollow" href="&#109;ailto:john.smith&#064;example.com">john.smith&#064;example.com</a>

Simple email spiders which do not do character entity decoding will therefore not be able to find your email address.

Note: Perhaps there are or will be email spiders which can decode entities, so the this technique will only help with some (cheap) email spiders. (See also: http://rbach.priv.at/Misc/2005/EmailSpiderTest)

Other prevention methods to consider

Tutorials

Parsing

See separate hCard parsing page for current hCard parsing rules.

Add thoughts/proposals to improve/add to hCard parsing here in this section in hCard brainstorming, and be sure to include URLs to examples of hCards in the wild which could benefit from parsing rule changes.

fax and modem hyperlink parsing

For the "tel" property in particular, when the element is:

Ambiguous name components

When automatically publishing hCards from pre-existing data, it's not necessarily possible to tell which words in a name map to which hCard properties. When the structure of a name is unknown, it is hard to ensure an automatically published hCard remains valid.

There's currently no easy answer to this.

One implementation suggestion is a 'best-guess' algorithm, something along the lines of:

  1. If the name is one word, attempt implied nickname optimization
  2. If the name is two words, attempt implied n optimization
  3. For three or more words
    1. Perform a lookup against known sub-name combinations (e.g. 'Sarah Jane', 'Vander Wal')
    2. Apply the grammar "given-name additional-name(s) family-name"

The principal behind this suggestion is that it's better to make a good guess and potentially miscategorize an ambiguous name component than to generate an invalid hCard.

ADR with no children

Parsers (Operator, Tails, Almost Universal Microformat Parser) currently expect adr to have one or more sub-properties. It is not clear from the hCard spec that that's mandatory (though the vCard RFC requires it); nor is it always possible for an address field in a templated (or CMS) web site to be defined with such granularity.

Consider Wikipedia, whose templates often have a "locale" or "place" field, used, for example, on these articles about railway stations:

Likewise, the Wikipedia template for organisations, in which a "headquarters" address (for a business, for example) may contain a full or partial postal address, or just a city/county or city/country pair:

I propose that, where adr has content, but no explicit sub-properties, there should be a default sub-property to which that content is allocated, in order that it is captured by user agents, and can later be manually tweaked (in, say, an address book programme) by users if so desired. This would satisfy the vCard requirement for child-of-adr, and adhere to the general principle to "be strict in what you send but generous in what you receive".

Of the available sub-property options:

I suggest that "extended-address" is the most sensible sub-property to use, for this purpose. Andy Mabbett 03:57, 26 Mar 2007 (PDT)

implied adr subproperties

It may be possible for parsers to parse out adr subproperties from a contiguous adr string. This would be an optimization for both adr and hCard.

This may also be too difficult/complex to be dependable or interoperable, but it is worth at least documenting our considerations and analysis either way.

Examples:

IBM's Employee Directory search returns hCards with the "adr" property which contain the "locality" and "country-name" data but unfortunately without being marked up as such, e.g.:

<td class="adr">Austin, USA</td>

We could first define a canonical ordering of how to parse for comma (and perhaps in some cases space) separated adr subproperties within an adr string e.g.:

Given a dictionary of country names and abbreviations, it may be feasible to parse for a country name at the end of the adr string, and then apply country/locale specific parsing rules to the rest of the adr string.

E.g.

The above heuristic (not quite well specified enough to be an algorithm, yet) would allow parsing of the IBM Employee Directory result documented above.

There are a lot of existing geocoder APIs that turn unstructured addresses into structured ones - we should examine these for patterns and best practices. eg Google's geocoder geopy calls multiple ones

INPUT element handling

In hcard-parsing, I've defined special-case handling for several elements according to more semantic exceptions, e.g. textual properties on the IMG element use the 'alt' attribute.

One element I forgot at the time was the INPUT element, specifically, <input type="text">. Another I forgot was the TEXTAREA element.


The simple suggestion is to add the following to hcard-parsing, specifically to the all properties sub-section:

Tantek

forms auto-fill

If you go to a site that needs your contact info for something, say an ecommerce site for checkout, and if the form fields are marked up with hCard semantics per the above, then perhaps we could consider having that mean "insert hCard here".

Interactive useragents (e.g. operator on firefox) could detect such "insert hCard here" semantics in forms on pages, and let you "pre-fill" with *your* hCard info, and then all of a sudden we have a standard for forms auto-fill, rather than all the hacks that have gone into browsers since 1999 (starting with IE4.5/Mac which I'm pretty sure was the first to do forms auto-fill of an entire form with a single button press - not just auto-complete of each form field individually).

Obviously this would make sense to build into *existing* forms auto-fill features in Firefox and IE, and any other browsers that support it.

This way new sites could simply conform to the standard, rather than depend on hacks which parse label values etc. and imply things and get them wrong sometimes.

i18n advantages: hCard annotated form inputs would also be more international, thus avoiding the need for each browser to guess what is the "name" and "telephone" field in every language, so they can do forms auto-fill on any site regardless of language, not just English.

Tantek 16:24, 23 Jul 2007 (PDT)

Background discussion:

Key threads:


Somewhat related:

One key summary:

The options discussed in a hypothetical hCard input system so far appear to be:

1) create a new root class other than vcard to indicate a form that's fillable with hCard data.

Proposed markup:

<form class="vcard-input" ...>
   <fieldset class="fn">
      <input type="text" class="given-name" name="first_name" />
      <input type="text" class="family-name" name="last_name" />
   </fieldset>
   ...
</form>
 Benefits:
     Doesn't overcomplicate hCard with new parsing rules,
     doesn't require rewrite of existing parsers to ignore 'unparsable' data.
 Drawbacks:
     Requires completely new parsers to be written.
     Existing parsers would ignore data even if a valid hCard could be extracted.

2) extend hCard's parsing rules to cover form elements and relying on the FORM/INPUT semantics to indicate that stuff is inputtable.

Proposed markup:

<form ...>
<div class="vcard">
   <fieldset class="fn">
      <input type="text" class="given-name" name="first_name" value="Rob" />
      <input type="text" class="family-name" name="last_name" value="Manson" />
   </fieldset>
   ...
</div>
<div class="vcard">
   <fieldset class="fn">
      <input type="text" class="given-name" name="first_name" value="Scott" />
      <input type="text" class="family-name" name="last_name" value="Reynen" />
   </fieldset>
   ...
</div>
</form>
 Benefits:
     Small addition to existing format rather than new one.
     Semantics of an input form and the eventual display format are the same.
 Drawbacks:
     Existing parsers would/could parse forms as invalid hCards, would need re-writing.


Broader question:

Should this be extended beyond just hCard?

Key Issues/discussion points

 - Negative : this require re-coding the existing parsers
 - Positive : this could help to enable uf based auto form filling
 - Negative : this could help to enable uf based auto form filling (e.g. spam automation)
 - Positive : this is in line with the current parsing model
 - Negative : parser doesn't pickup any updated form data after the page has loaded
 - e.g. even though textarea appears to parse ok - it's only ever the initially loaded value that can be exported
 - Positive : this minimises the changes to current parsing rules
 - Examples
   - title select that lists mr/mrs/ms/dr/etc.
   - checkboxes to choose which addresses to use
 - Option : simplify extension to only support input fields and recommend that select's, radio buttons and checkboxes update related hidden input fields with simple javascript (e.g. onChange/Click="this.form.elements[this.className].value = this.value")
 - Positive : this would simplify parsing and server side form processing as only single input fields for each value need to be used/validated
 - Negative : hCard forms then require javascript if they use form elements other than basic <input type="text|hidden">
 - Comment : either way any auto form filling will be more complex beyond simple <input type="text|hidden"> fields

RobManson

Post vCard additions

Keeping hCard properties and values as a 1:1 representation of vCard properties and values has numerous benefits such as simplicity, stability, interoperability with the vast number of existing vCard applications etc.

However some have found vCard to be limiting in terms of the data/properties/fields they want to express in contact information. Some implementations use vCard extensions to express such information [citation needed].

This section is for documentation of such suggested additions. Empirical evidence of actual *real world* examples on the Web of people publishing this information would be a good step towards considering any such additions/extensions.

Thus see (and add to): vcard-suggestions

Another path to consider is the development of another microformat which includes an hCard and then extends it with additional properties for a particular domain. In many ways hResume has already done this. Other related efforts:

Using hCard as a stable building block for additional microformats may seem more desirable than incrementally growing hCard itself.

Of course if vCard were extended itself, that may provide impetus to add such extensions to hCard in order to maintain the 1:1 representation of properties/values.

Wikipedia's Persondata

Wikipedia's Persondata aligns very closely with hCard, but has additional date and place of birth & death fields. Andy Mabbett 13:02, 28 Jan 2007 (PST)

TODO

CSS Styles

Not only can you create semantics with the hCard values, but you can add CSS styles to them as well. You are free to style the terms in any way you want, but here we can list a few ideas for how to style terms.

If you want to encode hCard data, but do NOT want to display it in the HTML code (WARNING: This is very much recommended AGAINST, and in general against the microformat principle of marking up visible data), then you can hide that tag in CSS with the following code:

<span style="display: none">Hidden Data</span>

Transforming applications will still find the data and use it when converting hCards to vCards.


Other Implementations/Ideas

Accepted Suggestions

Encoding Company data as a Business Card (proposal)

( Accepted: http://microformats.org/wiki/hcard#Organization_Contact_Info )

In the wild there are several hCards that do not currently validate because they are businesses that have omitted the "fn" property in favor of the "org" property.

Proposal: hCards representing a business or organization MUST set fn AND org to the same value. Parsers may then use this equivalence, if detected, to treat an hCard as the contact info for a business or organization rather than an individual.

Note that Apple Address Book supports this semantic when importing vCards.

See the Technorati Contact Info for an example.

Implied "FN and N" Optimization (proposal)

Right now a parser first looks for an "n" element.

And then if no "n" is present, look for an "fn" element to use to imply an "n" element per the "implied n property" rules in the spec.

BACKGROUND:

Due to the prevalence of the use of "nicknames" or "handles" on the Web, in actual content published on the Web (e.g. authors of reviews), there has been a discussion about adding a "fn" shortcut to the "n" shortcut that used the "nickname" as a fallback.

PROPOSAL:

We should consider adding one more implied optimization after the steps documented above and that is:

If no "fn" is present either, then look for a "nickname" element to use to imply both the "fn", and the "n/given-name", leaving the "n/family-name" as empty.

This would enable "nickname" only hCards for denoting and individual on a website, which is quite common on blogs and reviews published on the Web.


Rejected Suggestions

Suggestion: The use of class="url" on an <a> tag to represent an hCard URL property is redundant. By virtue of the <a> tag you know this is a URL.

Rejected. This is a bad suggestion because although it appears to reduce redunancy and keep things cleaner, it also creates a few problems. Without explicitly noting that this is a URL then any <a> tags within a 'vcard' would be considered a URL, for example:

<span class="vcard">
...
<ul class="categories">
<li><a href="http://w3c.org">W3C</a></li>
</ul>
...
</span>

There is no way to "turn-off" the encoding of the W3C URL, whereas if "url" needed to be explicitly listed in the class attribute list, then by NOT listing it you could effectively turn it off.

References

Normative References

Informative References

Related Pages

The hCard specification is a work in progress. As additional aspects are discussed, understood, and written, they will be added. These thoughts, issues, and questions are kept in separate pages.

hcard-brainstorming was last modified: Wednesday, December 31st, 1969

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