I know that some big players have embraced it and are actually exposing some of their services in APP compliant way, already. However, I haven't found many other (smaller) players in this field. Do you know any web application/service that uses APP as its public API protocol? What is your own take on AtomPub? Do you have any practical experiences using it? What are its limitations and drawbacks? Do you prefer AtomPub as your REST style or do you have some other favourite one? And why?
I know, these are many questions, not just one. The thing I'm interested here in is simple, though - how did the APP standard hit the market and particularly how does it seem with its adoption among web developers?
The company that I work for, is developing a lot of RESTful services.
However none of them expose public APIs.(In the sense that all services are internally consumed by our own clients). The reason why we went for REST architectural style was that we wanted our services to be easily consumable and more importantly scale well.
From my own practical experience I have come to the conclusion that HTTP + ATOM syndication format is a good idea, provided you want to keep things flexible(In terms of different content model, attaching and extending meta data associated with payloads, uniform parsing etc). ATOM ensures that everybody interprets the payload in an uniform manner without any scope for ambiguity.
However if one does not have any such complex requirements or does not forsee such requirements then the ATOM format could be a bit of an overhead. (For instance elements like Author,Title etc make sense more in the blogging/RSS world and may not make sense in your particular problem domain).
Also if the goal is to just serialize data structures at one end and reconstruct it at the other end, then most web frameworks(like WCF) have custom formats which are more appealing.
So in my opinion ATOM Pub is good if you need flexiblity in terms of data representation and if the playing field is huge with different kind of client.
However if you have a good knowledge of potential clients and server/client usage patterns then custom formats might be a good idea.
If the client is browser based then formats like JSON are very appealing.
Hope this answers your question.
My own research so far:
Wordpress supports AtomPub as its API protocol since version 2.3
GData is probably the biggest shot in the AtomPub field so far
Habari - new promising blogging system promotes APP as one of its main features
BlogSvc.net - an AtomPub
server, blog engine for .NET
platform, written in C#
Jangle - an open source project
designed to facilitate API access to
Library Systems
There's also mod_atom - an Apache module that stores entries in the filesystem.
Last time I checked (2007 or so) Atompub was fairly complex to implement. While you can whip together something that emits valid Atom feeds during the lunch break, implementing AtomPub was a fairly big undertaking.
That might have changed due to better libraries and tools but still it might be too complex to be implemented by smaller sides just because it's cool.
And the lack of killer AtomPub client applications puts little or no pressure on server operators to offer an AtomPub interface.
Related
I have an interesting conundrum. I have been challenged with identifying the most suitable process in which to create a "browser front-end" to an existing multi-user application built within the TigerLogic/Pick D3 environment. My research indicates there are many ways to do this; but I am struggling to decide which method is best or where to start. I have "played" with a few technologies but a commitment to one is needed to get started.
These methods include:
Creation of a complex webservice using MVS Toolkit; and engineering a client from WSDL either from scratch or using maven/wsimport. Tests indicate there is a lot more to this process than originally though for a simply WSDL.
Development of a Java based web app that harnesses the MVSPJavaAPI - I am not a JAVA developer so this means learning a new language. Development would most likely take place in Eclipse.
Using TigerLogics FlashCONNECT - resulting in additional expenditure to clients so not preferable - and more or less ruled
out.
There is also the .NET option - but I have ruled this out on the basis of needing portability.
My question is, has anyone else out there done anything like this and could you share your experience? My first task is to build a web-app that will reliably give me the D3 TCL prompt in a browser that I can customise.
I am not sure there is a definitive answer here but would like peoples thoughts and will label the most useful as the answer.
What path you choose depends in some part on your existing skill-set and whether that fits in with your portability needs. It is very difficult to give you a concrete answer to your question becaue of not knowing in which part of the chain you need the portability.
It is however possible to develop a web-browser front-end using .NET which will run on Linux or Windows, so I don't see an issue with portability here. Your web server will have to be windows based but it shouldn't matter whether D3 is running on Linux or Windows at the server-end, or whether the client desktops are running Linux or Windows.
You could try TigerLogics MVSP .NET API but I do not know if it has the power to deliver based on your needs. I believe you may find mv.NET from Bluefinity could fulfill your needs. This is in my opinion the leading product on the MultiValue market for achieving the goals you have in mind. This will mean spending money of course. For this you will get a very powerful set of tools. Also, the cost of investing in a good tool could end up smaller than the cost in terms of time, effort and potential complications of trying to do this piecemeal without spending any extra money. I am sure Flashconnect would also do the job. You would have to weigh up the cost of the different options to find out which one is right for you both technically and financially.
Not knowing whether or not you have .NET in your skill-set, I don't know whether the .NET option would be easier for you. It is however technically possible.
I would suggest using Rocket's D3 (formerly TigerLogic D3) .NET APIs and create a Web API RESTful service that you can consume with JavaScript in any other web technology and if you need to call from a D3 subroutine (in case you would) then use the MVS Toolkit.
Requirements though are D3 9.0 or later.
I've used all of the technologies described, and many more to interface with D3. I agree with #Glenn and will add... I understand you're edging away from .NET. That's fine, you don't need it. But consider that most LAMP implementations separate the DBMS servers from the web servers. That topology introduces short delays between the tiers but decouples them in case you want to use multiple web servers or multiple databases - a common topology even with D3 / MV.
I have a client where we have a Java/Grails front-end over Linux, with all data queries filtered through a single, elegant data provider class that's abstracted from application logic. That uses a web service call which I wrote in Java, calling to a .NET web service. The service is easily generated/modified, as is the client from the WSDL. From there IIS carries inbound queries to D3 via mv.NET, and at this point it doesn't matter if the D3 DBMS is in Linux or Windows. My web service could have as easily been in Linux with Java but it would then lack a pooling mechanism - see below.
If you want all Linux then you can go with the MVSP Java library. TigerLogic (now acquired by Rocket Software) committed to a PHP binding for MVSP some months ago. Rather than wait, one of my clients created a PHP wrapper around mv.NET, though MVSP is as easy. So the resulting application is essentially LAMP, but with the M = Multivalue. I have written code like this too - we can write a wrapper in any language which exposes a useful API and abstracts both connectivity method and OS dependencies. In other words it doesn't matter what languages we want to use or what OS's are involved. That part is rather trivial and subject to change later. It's better to focus on the application than the communications.
You can also go off the menu, so to speak, and create your own Java/PHP wrapper around the OS-level d3tcl command, which is a script/wrapper around the d3 executable. This allows you to open a connection yourself and pass in commands.
Whatever option you select, you need to consider that opening and closing a DBMS connection is a slow process. You do not want to script a login around every data request. You do want to open a connection and keep that open persistently, while your client code accesses and releases that persistent connection as required. This is why we like mv.NET and FlashCONNECT. With MVSP and other mechanisms you need to create your own persistence model. You'll also need to manage a pool of connection resources - what happens when you get 10 simultaneous queries, or just 1 short one after one long one? You don't want queries to back up, you don't want to reject or timeout connections, and you don't want to fire up a connection for every client. You do want the proper number of DBMS sessions waiting for inbound connections. mv.NET and FlashCONNECT do this for you, the others do not.
Personally I'd shy away from FlashCONNECT. I was there for its initial development and testing and for years of end-user implementations. It's not as widely used as the other options and is more a tool for those who aren't familiar with other options. If you're talking about Java then you're probably not inclined to use FlashCONNECT. That said, if you have developers who are not familiar with anything outside D3 then FlashCONNECT is a decent server-side tool for them while someone else is focusing on the client-side with other technologies. Everyone should use their best skillset.
Finally, (already?) if someone is not familiar with external technologies, and more intimate with D3, then other options exist like DesignBAIS and Viságe, mostly removing the burden of communications and allowing developers to work on the client-side features and back-end rules in BASIC.
I discuss all of these topics plus mobile and telephony on my blog.
HTH
Note: I'm a backend (Java) developer by trade and work in Clojure in my spare time, so forgive me for my ignorance.
I'm trying to get my head around Clojurescript and how it could potentially fit in with projects I'm working on, or plan to work on in the future. As I've grown up with the "classic" web development mindset (e.g. Clojure running the backend, distributing data to the frontend via JSON to be processed in JS or returning a HTML page for the browser to render), I'm having trouble trying to understand how Clojurescript might make things better than this model.
Could anyone explain to me what the general approach to Clojurescript/Clojure development would be, seeing as the "Clojurescript One" project moniker signifies that application development will be unified under one language (as such)
What tasks would normally be done in the Clojurescript portion of the application?
What tasks would normally be done in the Clojure (e.g. backend) portion of the application?
Any help would be appreciated, or if anyone can point me towards some diagrams or explanations or anything - that would be great too!
I think Clojure/ClojureScript applications will be structured very similarly to X backend technology + JavaScript.
One big benefit with architecting applications with Clojure and ClojureScript - a richer data format than JSON (you can represent hash-maps and sets with arbitrary keys) without losing compactness.
JavaScript is a fine, fine language but ClojureScript offers quite a few benefits. It's semantically simpler (functional), ships with a rich standard library, a robust battle tested application library (Google Closure), and all the benefits you get from the tasteful application of syntactic abstraction via macros.
That said, it's still very much alpha software and the tooling still needs a lot of work.
A bit of background about me, I have developed with Clojurescript, JQuery, Vaadin, Servlets, JSP, and many other web technologies.
1) Clojurescript is much harder to learn than any other web technology I have used as you need, Java, Clojure, Closure (with an s ;), Closure Lib, and Closurescript specific knowledge.
2) Clojurescript doesn't make sense for a small app. It only makes sense when you will have ALOT of client side processing
3) Clojurescript's only use as far as I see is as a better javascript (which is why it is better suited to larger apps) as the minifier part of Clojurescript is available for javascript too
4) Only the client end would be written in Javascript, the server would be in Clojure/Java servlets
Maybe Ganelon micro-framework (which incidentally I am author of) will suit your needs - the execution model is similiar to Vaadin's: server-side Clojure code pushes UI updates to the browser through AJAX/JavaScript, but we don't store application state in session by default.
The demo and docs are available at http://ganelon.tomeklipski.com/
For me, clojure and clojurescript offers cleaner code than mixed stack. There is only one language to think of and code is quite easy to read.
At the backend clojure does things that java usually would do. Input validation, saving to database and above all, implementing business logic. Our backend also validates incoming / outgoing data by types using prismatic schemas.
Frontend in short: We get pretty code using ClojureScript and it is fast to write. We are using ClojureScript version of material-ui when writing UI components. We have to write less code when compared to the JavaScript and I find our UI component code to be easier to read than JavaScript counterpart. One of the main reasons is shorter closing tags and less noise by coding language. Development with ClojureScript is quite fast.
Of course ClojureScript is used for simple imput validation like RegExp for phone numbers etc.
One of the disadvantages of clojure which you have probably noticed is long lines after giving proper names to the functions. I havent found silver bullet how to cope with that.
As dnolen said: ClojureScript is still developing. It is way better now than it was 6 months ago, so you'll have to keep checking its maturity now and then.
How should a Windows 8 Metro application connect to a central database?
I've read about local storage, but I haven't read anything about connecting to a central database.
Obviously, this architectural design decision needs to support the disconnected scenario.
WCF web services seem to make sense.
But even if they do make sense, should we really create separate methods for all read/write operations?
Or are OData WCF services the way to go?
It seems like tablet software architecture should be able to borrow a lot from smartphone software architecture (but I am new to both).
Has Microsoft made any recommendations in its app samples?
It appears that others are asking similar questions on the Microsoft Developer Forums.
Here is what I've found:
According to Tim Heuer:
...You cannot directly have a SQL db embedded in your app or use
something like ADO.NET. This is more of an async/services
infrastructure. So if your data was exposed via services, then of
course you could connect that way. There are some other light-weight
methods you could use for local storage as well using things like the
Windows.Storage namespace (which is similar to Isolated Storage in
.NET).
Morten Nielsen agrees:
You can use HttpClient to download pretty much anything from the web.
Why don't you configure your WCF service to return data as JSON, and
use the DataContractJsonSerializer to deserialize the results?
Also, Tim Heuer cautions:
...Please note that while awesome, the SQLWinRT project on codeplex is a
wrapper to communicate with the classic SQLite engine...which uses
APIs that would not pass store validation currently.
Generic Object Storage Helper for WinRT and WinRTFile Based Database seem to have some promise.
But Daniel Stolt raises some good points:
It's awesome that there is good support for building OData clients and
other REST clients - but this only addresses the online scenario. The
"structured" part of Windows.Storage is a very limited model,
essentially limited to name/value pairs, insufficient for all but the
most basic scenarios. Yes there is local file storage, which is great
of course. But forcing every app developer out there to build her own
DBMS on top of local file storage will simply not cut it, especially
with all of System.Data having been removed from the profile. If local
file storage was sufficient for most device apps, then things like
SQLCE would have no purpose today already. And SQLCE clearly has a
purpose, and has played a very important role for occasionally
connected device apps for a very long time. There is also a tremendous
need for synchronization with a server-side database such as SQL
Azure, mostly to be able to roam data between devices. Yes there is
the roaming storage model in WinRT, but it shares the same limitations
of local storage mentioned above, and on top of this is very limited
in capacity (currently 30KB if memory serves). It is simply
insufficient for all but the simplest roaming data needs. Again,
forcing every app developer to design and implement her own
synchronization solution is very bad. You can do much better to enable
developers.
Many people are disappointed that the System.Data namespace is not supported in WinRT.
Richard Bethell said:
I don't even have words for this. This is astonishing. Leave aside for
the moment they want to force you to abstract to middleware for
database connectivity - I don't agree, but I can quasi understand a
rationale for that. I can even see pathways for developing like that.
But no System.Data.... at all? Do you even understand what you've done
to us?
What System.Data can do, outside of just having providers for Sql,
OleDb and other custom providers like Oracle, is provide a rich
abstraction of XML datasets that allow you to very quickly build a
data oriented Service Oriented Architecture.
For instance, I can easily create a web service using SOAP or WCF that
returns DataSets or DataTables, and then consume those objects easily
and directly. Being able to do this allows very rapid construction of
n-tier architectures, even without direct data connections available.
Without System.Data, and the power of DataViews, DataTables, etc. this
gets a lot harder. Sure you can custom create structs, put data in
there, and serve up structs, and use Linq to do whatever sorting,
filtering, etc. you want to do.... but it ends up being twice the
work, and makes code reuse a lot harder. And it means using our
existing service oriented architecture is impossible (without a big
overhaul.)
The withdrawal of System.Data is as big a thing for developers to deal
with as the loss of the Printer object in VB6 to vb.net 1.0 was. What
is harder to understand in this case is why it is necessary -
re-enabling it in the Metro profile can't possibly be a technical
difficulty of the product, can it?
It is valuable enough that I would seriously consider including Mono's
System.Data classes as part of any app I create (which would obviously
have to be open source.)
I think that this is another of those "it depends" questions...
The first and most obvious issue is that it very much depends on the context in which the application is running as to whether, to take the first case "Obviously...support...disconnected" is actually true - if the app is an internal corporate app then quite possibly not in that case no db == not work.
Secondly you could look (hmm, rash... one assumes you could look, this could be a bad assumption) at database synchronisation between a local SQL database and the remote db and so on and so forth.
Taking a step back... yes - you're absolutely right, look at it as being the same as phone or silverlight (although I don't know if there is yet RIA support) - but the thing is at this point its very hard to be prescriptive because given a general purpose platform one can therefore write applications to suit all sorts of purposes.
Not a hugely helpful answer really - but a start.
Having read #Jim G's answer it seems that I should probably withdrawn mine?
Background:
I have a new site in the design phase and am considering using ColdFusion. The Server is currently set-up with ColdFusion and Python (done for me).
It is my choice on what to use and ColdFusion seems intriguing with the tag concept. Having developed sites in PHP and Python the idea of using a new tool seems fun but I want to make sure it is as easy to use as my other two choices with things like URL beautification and scalability.
Are there any common problems with using ColdFusion in regards to scalability and speed of development?
My other choice is to use Python with WebPy or Django.
ColdFusion 9 with a good framework like Sean Cornfeld's FW/1 has plenty of performance and all the functionality of any modern web server development language. It has some great integration features like exchange server support and excel / pdf support out of the box.
Like all tools it may or may not be the right one for you but the gotchas in terms of scalability will usually be with your code, rarely the platform.
Liberally use memcached or the built in ehache in CF9, be smart about your data access strategy, intelligently chunk returned data and you will be fine performance wise.
My approach with CF lately involves using jQuery extensively for client side logic and using CF for the initial page setup and ajax calls to fill tables. That dramatically cuts down on CF specific code and forces nice logic separation. Plus it cuts the dependency on any one platform (aside from the excellent jQuery library).
To specifically answer your question, if you read the [coldfusion] tags here you will see questions are rarely on speed or scalability, it scales fine. A lot of the questions seem to be on places where CF is a fairly thin layer on another tool like Apache Axis (web services) and ExtJs (cfajax) - neither of which you need to use. You will probably need mod-rewrite or IIS rewrite to hide .cfm
Since you have both ColdFusion and Python available to you already, I would carefully consider exactly what it is you're trying to accomplish.
Do you need a gradual learning curve, newbie-friendly language (easy for someone who knows HTML to learn), great documentation, and lots of features that make normally difficult tasks easy? That sounds like a job for ColdFusion.
That said, once you get the basics of ColdFusion down, it's easy to transition into an Object Oriented approach (as others have noted, there are a plethora of MVC frameworks available: FW/1, ColdBox, Fusebox, Model-Glue, Mach-ii, Lightfront, and the list goes on...), and there are also dependency management (DI/IoC) frameworks (my favorite of which is ColdSpring, modeled after Java's Spring framework), and the ability to do Aspect-Oriented Programming, as well. Lastly, there are also several ORM frameworks (Transfer, Reactor, and DataFaucet, if you're using CF8 or earlier, or add Hibernate to the list in CF9+).
ColdFusion also plays nicely with just about everything else out there. It can load and use .Net assemblies, provides native access to Java classes, and makes creating and/or consuming web services (particularly SOAP, but REST is possible) a piece of cake. (I think it even does com/corba, if you feel like using tech from 1991...)
Unfortunately, I've got no experience with Python, so I can't speak to its strengths. Perhaps a Python developer can shed some light there.
As for url rewrting, (again, as others have noted) that's not really done in the language (though you can fudge it); to get a really nice looking URL you really need either mod_rewrite (which can be done without .htaccess, instead the rules would go into your Apache VHosts config file), or with one of the IIS URL Rewriting products.
The "fudging" I alluded to would be a url like: http://example.com/index.cfm/section/action/?search=foo -- the ".cfm" is in the URL so that the request gets handed from the web server (Apache/IIS) to the Application Server (ColdFusion). To get rid of the ".cfm" in the URL, you really do have to use a URL rewriting tool; there's no way around it.
From two years working with CF, for me the biggest gotchas are:
If you're mainly coding using tags (rather than CFScript) and formatting for readability, be prepared for your output to be filled with whitespace. Unlike other scripting languages, the whitespace between statements are actually sent to the client - so if you're looping over something 100 times and outputting the result, all the linebreaks and tabs in the loop source code will appear 100 times. There are ways around this but it's been a while - I'm sure someone on SO has asked the question before, so a quick search will give you your solution.
Related to the whitespace problem, if you're writing a script to be used with AJAX or Flash and you're trying to send xml; even a single space before the DTD can break some of the more fussy parsing engines (jQuery used to fall over like this - I don't know if it still does and flash was a nightmare). When I first did this I spent hours trying to figure out why what looked like well formed XML was causing my script to die.
The later versions aren't so bad, but I was also working on legacy systems where even quite basic functionality was lacking. Quite often you'll find you need to go hunting for a COM or Java library to do the job for you. Again, though, this is in the earlier versions.
CFAJAX was a heavy, cumbersome beast last time I checked - so don't bother, roll your own.
Other than that, I found CF to be a fun language to work with - it has its idiosyncracies like everything else, but by and large it was mostly headache free and fast to work with.
Hope this helps :)
Cheers
Iain
EDIT: Oh, and for reasons best known to Adobe, if you're running the trial version you'll get a lovely fat HTML comment before all of your output - regardless of whether or not you're actually outputting HTML. And yes, because the comment appears before your DTD, be prepared for some browsers (not looking at any one in particular!) to render it like crap. Again - perhaps they've rethought this in the new version...
EDIT#2: You also mentioned URL Rewriting - where I used to work we did this all the time - no problems. If you're running on Apache, use mod_rewrite, if you're running on IIS buy ISAPI Rewrite 3.
do yourself the favor and check out the CFWheels project. it has the url rewriting support and routes that you're looking for. also as a full stack mvc framework, it comes with it's own orm.
It's been a few years, so my information may be a little out of date, but in my experience:
Pros:
Coldfusion is easy to learn, and quick to get something up and running end-to-end.
Cons:
As with many server-side scripting languages, there is no real separation between persistence logic, business logic, and presentation. All of these are typically interwoven throughout a typical Coldfusion source file. This can mean a lot more work if you want to make changes to the database schema of a mature application, for example.
There are some disciplines that can be followed to make things a little more maintainable; "Fusebox" was one. There may be others.
We are considering to develop a Flash front-end to a web application written using Django. The Flash front-end will send a simple "id" to the server and in response receive a couple of objects. The application will be open only to authenticated users.
To the extend of my current knowledge (which is basic for Flash) we can either use AMF or take an XML or JSON approach. AMF seems to have an upperhand as there are examples out on the internet showing it can cooperate easily with Django's authentication mechanism (most examples feature pyAMF). On the other hand, implementing a XML/JSON based solution may be easier and hassle free.
Guidance will be much appreciated.
We've used pyAMF + Django on many projects here, and it's a breeze to setup and get running. If you need speed, AMF3 is probably your best bet. It's the smallest/fastest way to transfer data, and serialization is taken care of for you.
On the flip side, setting up json with Django isn't much work either, and it would give you the ability to hook other, non-AMF systems into it without any extra work. You just sacrifice a little speed for that benefit.
If you think you'll ever need other systems working with the backend, or if you think you might switch to an HTML-only, or offer some kind of non-Flash version of your app, I'd go JSON, otherwise, I'd use AMF.
first of all, you should design your app in such a way this doesn't matter. the transport layer should be completely encapsulated, leaving the encoding format transparent to the rest of the app.
personally I prefer JSON to AMF because it's human readable (which makes debugging easier) and there are implementations for every platform/language (so you can reuse the server part with JavaScript for example). And I prefer JSON to XML because it's more compact and semantically less unambiguous as well as closer to common object models. Also it can transport numerical and boolean data in a typesafe manner.
JSON will probaby have the least complications and there's a great google code project that has JSON encoders and decoders here: http://code.google.com/p/as3corelib/