When should one develop HATEOAS server RESTful API instead of using HTML (resource links, forms, etc.)?
Isn't HTML and a browser good enough as hypermedia engine?
Isn't HTML and a browser good enough as hypermedia engine?
HTML + HTTP + URI + Browser === The world wide web. So it's pretty good, no joke.
It's not without fault.
HTML's understanding of links is disappointingly limited. No support for idempotent writes. Uri Template support for GET only. I'm not super keen on how many different spellings there are for "link".
It's kind of verbose for a hypermedia format; don't get me wrong - built in text markup is brilliant when you are trying to document what is going on for a human being. But my impression thus far is that same structure starts to get in the way when as a human being you want to quickly review the semantic content that your automated agent is consuming.
I call your attention to this quote from RFC-4287
The primary use case that Atom addresses is the syndication of Web content such as weblogs and news headlines to Web sites as well as directly to user agents.
So a bunch of really smart guys, specifically trying to address use cases directly related to the web, decided to invest a bunch of effort into standardizing a new hypermedia format rather than using the one that was already ubiquitous in their problem domain.
And over the past 10+ years, that format has been widely adopted.
Without adoption, I'm not sure that HATEOAS has much benefit. You don't need a hypermedia api if you are controlling both sides of the conversation (example: javascript on the web -- hypermedia with code on demand capability downloading a client that has learned the protocol of a web api via some out of band channel).
Evidence would seem to suggest that HTML is not nearly as convenient a format as, for example, any of the JSON based hypermedia formats.
In conclusion: no, it's not good enough. It might be an acceptable place holder for the moment; but the JSON hypermedia tool sets are soon going to be sufficiently mature that HTML will be seen as a giant step in the wrong direction.
Do front-end developers need any special considerations for the Amazon Silk Browser because of it's split architecture and it's re-sizing of images? Or can it be considered as just another webkit browser from a developer's perspective?
In general, you can develop content for Amazon Silk as you would for any other browser. The EC2 backend follows all standard caching semantics, and the media handling is as you'd expect.
In general, it's a good idea to set the height and width attributes explicitly on images and other page elements, and to design responsively for the form factor. In other words, the standard web development best practices apply.
In general I've found Silk - especially the newer versions - to behave as a pretty standard WebKit browser. Some of the Apple specific tuning isn't there so testing against Chrome on the desktop has been the closest experience (though one caveat there is that Chrome does seem to take webkit fixes faster than anyone else)
I've not seen anything that would indicate that accelerated browsing does anything different for EC2 hosted content - As hosted content often comes from a number of sources I don't expect they'd split traffic on internal and external networks though it sounds like something worth asking in the forums at forums.developer.amazon.com/forums/category.jspa?categoryID=3 to get an official answer
I know the DLNA is subset of UPnP. I read this post : What's the difference between UPnP AV and DLNA?
But, i still can't understand clearly. Are there any features inside DLNA? how to define this device is DLNA or UPnP? Why make people confused about DLNA & UPnP?
Please advice!!
There are two main differences, I would say: scope and organisation.
UPnP's scope is limited to the UPnP standards and protocols. As long as a device has the protocols done right, it is UPnP compatible. But that's not the whole truth, as for instance, the media may be incompatible. The result is that the end user expects the system to work, but it does not.
DLNA on the other hand does not limit to UPnP standards as it places requirements for ALL standards in use. UPnP AV happens to be one of those standards but others are included, for instance:
media (ensuring media in devices is compatible, and devices recognise is media compatible instead of trying and failing)
mediaservers (exact requirements to HTTP headers and timeouts)
etc
As an organization, UPnP is essentially a collection of protocols and a number of people working on developing that protocol. DLNA on the other hand (as the name suggests) is an alliance of companies that saw that they need to do something that their devices start talking to each other - without errors.
A rough analog to mobile phone world:
UPnP: phone has correctly implemented GSM/3G stack
DLNA: you can actually call from one phone to another and have a conversation :-)
From this analogue you can assume that DLNA specs are more complex.
This spec http://www.w3.org/TR/webdatabase/ says:
This document was on the W3C Recommendation track but specification work has stopped. The specification reached an impasse: all interested implementors have used the same SQL backend (Sqlite), but we need multiple independent implementations to proceed along a standardisation path.
Does this mean that HTML5 database is going away, and for some time we will have a de-facto standard using SQLite, possibly with browser differences? Or has the W3C published a plan of attack for finishing the standard?
According to this article:
[...] we think it is worth explaining our design choices, and why we think IndexedDB is a better solution for the web than Web SQL Database.
In another article, we compare IndexedDB with Web SQL Database, and note that the former provides much syntactic simplicity over the latter. IndexedDB leaves room for a third-party JavaScript library to straddle the underlying primitives with a BTree API, and we look forward to seeing initiatives like BrowserCouch built on top of IndexedDB. Intrepid web developers can even build a SQL API on top of IndexedDB. We’d particularly welcome an implementation of the Web SQL Database API on top of IndexedDB, since we think that this is technically feasible. Starting with a SQL-based API for use with browser primitives wasn’t the right first step, but certainly there’s room for SQL-based APIs on top of IndexedDB.
I'm not personally swayed by the arguments put forth in the article, but it seems clear that (for the time being) Mozilla has decided that Web SQL Database is dead.
Further interesting comments about this article may be found on Hacker News.
My understanding is that this is now called "IndexedDB"
http://www.w3.org/TR/IndexedDB/
Apparently the Firefox team has started implementing this:
http://hacks.mozilla.org/2011/01/indexeddb-in-firefox-4/
I don't know if anyone knows the answer. Mozilla doesn't like the dependence upon SQLite and has decided to go a different way. However, all WebKit based browsers already have it implemented and I don't see them removing it as any websites built to take advantage of the spec would be broken.
This means that at least in certain contexts, mostly within the mobile sphere where most browsers have a webkit implementation, it can still makes sense to use the HTML5 Web SQL spec. I see this as especially true for developers who are looking to create mobile applications using a framework like phonegap.
There are some times where as an application developer you want to provide users with access to data even if they aren't connected to the internet or if the connection is slow and some types of data is just more efficiently stored in a database than in a cookie or JSON cashe. For example, if you have data that has relationships it is much easier and quicker to do a join query to pull the data you need than it is to search a json map.
I don't think the spec is dead, and I actually hope that Mozilla will reverse their stance so that developers can use it to solve problems outside of the mobile webkit world.
The recent article of steve jobs link
made me think about the future of flash. I'm learning actionscript 3.0 in my studies but is it the right decision still to go for it? I was pretty sure that I will be able to build application in as3 for iphones/ipads in the near future. It seems to me, while I would stay with flash, the market will be polarized by apple and adobe and you will always work double for both clientele, or just lose half of them.
Which decision would you take as a designer, if you were still at university and you intend to become a freelancer?
This question has been around a lot of times. For my opinion on flash's future please look at this answer: Should I Abandon Adobe Flash for HTML5 and <canvas>?
If you are a designer, you will probably actually feel good working with Adobe's Creative Suite, including Flash CS3/CS4/CS5. CS5 will be able to export HTML5 in the near future: http://www.9to5mac.com/Flash-html5-canvas-35409730 . You shouldn't be too worried. OTOH you should consider, that whatever CS5 exports is likely to perform poorer in HTML5, than on flash player.
From my perspective as a developer, I think there is no harm in learning any language, altough ActionScript 3 is relatively boring and easy to grasp. However this makes it a good language to learn programming, including many best practices. The most important things you learn as a programmer transcend languages. The more languages you try to really fully understand and exploit, the better you become by understanding the approaches they promote.
My personal advice to web developers is to have a look at Haxe. It is a much more powerful, elegant and expressive language than ActionScript and it allows you to target many platforms. Enough to build a whole web app on 'classic' platforms with only one language. Haxe's C++ backend allows building native iPhone apps using an SDL based port of the flash player API, although currently it's not very clear whether Apple's policy will allow distribution. Nonetheless it is an open source language with an enthusiastic community, that moves really fast and adapts to changes rapidly (e.g. unlike ActionScript Haxe can leverage flash player 10's alchemy opcodes for fast memory access) making you as a developer independant.
edit: I have personally dropped any plans of targetting the platform until Apple is willing to ease its very restictive policies, since I find this kind of behaviour intollerable. Nonetheless, I think Objective-C is a great and inspiring language, so you may actually wanna have a look at it.
I think that reports of the death of flash have been greatly exaggerated. Flash has always been "the bad guy" - self-proclaimed experts have always loudly declared that Flash sucks and is on its way out, but oddly enough I've never had any trouble finding lots of Flash work. There are things that you can do quickly and easily in Flash that are either much harder or flat-out impossible without it. It's an amazing tool and it's going to be in use at least in some capacity for the foreseeable future.
That said, even if Flash on the web goes the way of the dodo in two years (which won't happen) it's still a valuable tool. It's a wonderful way to learn Object Oriented Programming, and its uses go far beyond shiny websites. You can use something like Flash Builder in Eclipse to get accustomed to working in a code-oriented IDE, you can build AIR apps to deploy across platforms, you will soon be able to publish saleable apps to every major phone including the iPhone, etc. I've been having a lot of fun with it lately getting it to work with Arduino - it's just a hobby project but I'm trying to build a little helicopter that I can control from an AIR app. I'd be curious to see someone do that in HTML5. ;)
Flash is amazingly powerful - your abilities are in many respects limited only by your imagination and willingness to figure out how to make it work. It's really bizarre to read all of this stuff about how (some) browsers can now play (certain types of) video one their own, ergo Flash is Dead. How unimaginative. :)
This is a tough call. Flash is a fairly dominant technology at this point when it comes to media-intensive web sites. Flash is also very popular for delivering mini-games. I do think that Flash video, which is currently also dominant, will gradually be replaced by HTML5 technologies. I'm not so sure that Flash can be replaced easily when it comes to those media-intensive sites. There is a large number of very talented people comfortable with Flash that might be reluctant to adopt other technologies. I would probably hedge my bets and get comfortable with Javascript and other HTML5 technologies.
Apple vs. Adobe controversy reveals two opposite views of mobile computing.
Apple wants that its developers make the best of its devices by excluding middleware. The aim is to deliver the best possible user experience.
Adobe wants that its developers publish their work on as many platforms as possible. The aim is to reach the widest audience.
Nobody knows which view will win in the future. The mobile war is just beginning...
I think it depends on how far into the future you want to look, and what you think is most important. Flash on the desktop will not die for a long time, if ever. If that is good enough, keep going with where you're going. If not using flash on iPhone/iPad is a deal breaker, you only really have two choices - Objective-C or HTML5.
HTML5 is definitely gaining momentum, but it can't be used directly in all browsers yet, and likely for a while. However, in the mobile space, there is pretty excellent support in the major smart phones.
There isn't a single platform/technology/language that can hit everything. If I were going to bet money on the future, though, I would say HTML5 is going to win for the most reach across platforms. And given it is on the rise, I would bet that in the next few years, there will be a lot of demand for good developers in this area, but don't expect the path to be fully paved for you. You'll have to get your hands a little dirty. If you're looking for a decent editor, I use Netbeans, but I also do Java development, so that makes sense for me. Search around, though, and you'll probably find a decent set of tools that work well for you. It is a very active space.
As far as I'm concerned, Actionscript is a pretty good language to learn OOP. Javascript is a bit shit. Eitherway, I would expect you'd learn a certain set of (frontend/2d graphics) skills which will come in handy regardless of the vehicle you'll eventually use to deploy your work.
Personally, I like the flexscript language used by Flash, it's more structured and object oriented than Javascript. Also it has real inheritance, not the prototype based crap, and compiles to bytecode. For the artist, Flash is easier to use in many ways due to the available tools.
I do hope for better integration into browsers. The current flash plugin is clunky and causes crashes for many users, also the plugin system makes it integrate badly into the flow of pages.
With HTML5, I think the browser plugin idiom is dying in general. Everything from video playback to fancy vector animations can be done with just HTML + Javascript. Even a standard for 3D graphics in webpages is on the way (O3D).
Also I wonder how Adobe will cope with the current explosion of platforms/operating sytems/browsers, especially in the mobile realm. At the moment, the Flash support for systems except for Windows on PC isn't much good.
Just as projects like SVGWeb brings SVG capabilities to browsers that don't have native SVG, I would expect that if/when HTML5 gains traction against Flash there will be conversion capabilities from existing Flash to browsers without Flash. In fact, Adobe already has a conversion from Flash to iPhone using Flash Professional CS5. IMHO, there's too much Flash content in the wild for this not to happen eventually, and there are too many people for which Actionscript is their primary (or only) language for some conversion not to happen.
Career-wise, the clear long-term trend is away from Flash, and I agree with Tom that hedging your bets is wise. However, HTML5 is still fairly new, and you might do yourself a disservice to ignore Flash at this point. With conversion technologies, a Flash skillset will likely be usable for at least several years.