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Looking at LaunchDarkly for feature flagging across our enterprise apps.
Two questions:
1) I'm concerned about being able to effectively flag features across our Java back end and React front ends (2 of them). What are some strategies that people use to define features appropriately so that they are easy to manage across multiple applications/platforms?
2) Have you replaced most/all of your git / Bitbucket / ?? branching workflow with feature flags and purely trunk - based development? If not, have you made significant changes to your existing git / Bitbucket branching strategy?
Disclamer: I work at DevCycle
I'm a few years late, but, I really wanted to make sure anyone finding their way to this question has a little more information.
1) While levlaz provided an answer explaining that you should put your management as far up the stack as possible, I don't necessarily agree that this is the best approach to consider first.
Consider this: A simple setup of a single feature across multiple platforms
Within DevCycle (and others), when you create a Feature, it is available across all platforms and the API.
You simply request the features for a user on any platform, and if the user qualifies, you'll receive it. There is no extra setup necessary to enable it on various platforms.
This means that if a feature is meant to be accessed on either your Java backend or React frontend, you can be guaranteed that the feature will be available at the correct times for the correct user/service regardless of where you call it from.
In short: one single Feature is managed across all platforms in one spot, with one toggle (if desired).
Another Approach: A single feature across multiple platform with different toggles or use cases.
You could very easily simply create multiple flags for each individual platform a feature is meant to be available on, and manage each individually. However, this isn't entirely necessary!
Within a feature setup, you can simply have two separate rules defining different variations being delivered to each platform. For example, you can set up a simple rule which ensures that Java will receive the feature, but React would not.
A unique DevCycle approach: Managing multiple platforms independently.
Here is something DevCycle offers that would may handle your use case in a unique way:
Imagine every single time you create a feature, both a Java and React version of that feature are created.
These platforms would be managed separately within each feature, meaning that there is no potential of any accidental feature data bleeding between platforms in event that a feature doesn't exist on one platform but it does on another.
You can set up each platform as an entirely separate entity, meaning they would use different SDK keys, and all targeting will always be separate.
In the example above for example, the feature would be entirely disabled and not available in any Java SDKs calling out to DevCycle, but it would be available in React.
tl;dr
It's up to you how you want to manage things across platforms. DevCycle makes it easy to do this however you'd like: have all features across all platforms, splitting up your platforms, or just choosing to target differently depending on the feature.
2) Like levlaz said, that is the ideal, but you'll likely never want to achieve fully trunk-based nirvana, as there are a lot of use cases for having various environments and paths for your team to take in various scenarios.
That said, we've seen a lot of folks successfully get REALLY close by using Feature Flags.
I wouldn't suggest removing your build pipelines and CI/CD in favor of feature flags, instead, feature flags enhance those.
For example, with feature flags, you can remove the concept of feature branches and large feature pull requests. Instead, ensure that everything that ever gets put into production is always behind a feature flag. To ensure this happens, you can use workflow tools like github actionsthat do these safety checks for you. With these guards in place, you should now always be able to simply push through to prod without any concerns and run your deploy scripts on each merge. Then you can just target your internal / QA users for testing, and not worry about things hitting prod users!
You may still want to have some sort of disaster recovery environment and local environments, so never truly hitting a pure trunk, but you can get close!
[Disclamer: I work at LaunchDarkly]
For your first question, my general recommendation is to put flags as "high up on the stack" as possible. At the end of the day, you are making a decision somewhere. Where you put that decision point is entirely up to you. Within LaunchDarkly the flags are agnostic to the implementation so a single flag can live on the server, mobile, and client-side without any issues. Keep things simple.
For your second question, in practice, it is very rare to see teams fully make the switch to trunk-based development. This is the goal of 99% of the teams that I work with but depending on if you have a greenfield or a brownfield project the complexity of making the switch can be not worth the effort.
Lastly, Our CTO wrote a book this year called "Effective Feature Management"[1]. If you have not heard of this, I would recommend you take a look. I think you'll find some great insights there.
https://launchdarkly.com/effective-feature-management-ebook/
I want to develop a web application using ANSI C. Since, I want have to have the application to be fast enough than others and also it should support the all kind of operations as the normal scripting php, python or any scripting language provides. Even if you have idea for fastest access with database rather than C, please recommend anything better
If anyone have idea please share the tutorials to start.
I'm not aware of any C web application frameworks, and so if you did wish to write your application in C you will need to handle all communication between your application / framework and the web server through a web server interface - the easiest starting point for understanding this is probably to read up on CGI, however once you understand how CGI works you will want to move onto understanding FastCGI instead, as although FastCGI is more complex, CGI is notoriously slow.
However I strongly recommend that you don't bother unless you are attempting this for academic purposes!:
The path you are suggesting involves low level stuff - its interesting, but a lot of work to achieve things that can be done incredibly easily in any half-decent web application framework.
With web applications is that the thing that matters is throughput (number of requests you can handle in a given time period), not speed (the time it takes to process a single request) - it might seem that a web site written in C would be much faster, however in reality the execution speed of C counts for incredibly little vs (for example) Caching and other optimisations.
Other frameworks already exist that are proven and lightning fast!
The end result is that anything that you come up with will almost certainly be more work and slower than using "slow" scripting languages.
Any kind of 'scripting' won't give you the 'raw speed' it seems you might be looking for.
I would generally strongly discourage this whole train of thought, though. There are plenty of web frameworks out there where you produce code that runs very efficiently. Even 'scripted' web frameworks often cache the scripts and reduce much of the initial slowdown involved in parsing and executing.
And frameworks that use compiled bytecode/IL can be quite fast once loaded/JIT'ed.
If you plan to write your own HTTP engine in C, though; I doubt you would be able to get something remotely close to as fast as anything else out there until you were very familiar with what's already out there; how they all work, all the variations in the protocols involved, etc, etc...
I've heard a lot of good things about FastCGI. Maybe you should try that?
You should checkout g-wan by trustleap. It allows you to write servlets in
ansi-c, taking care of all the nitty gritty regarding the http protocol.
http://www.trustleap.com/
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Closed 10 years ago.
We're currently looking at using the Force.com platform as our development platform and the sales guys and the force.com website are full of reasons why it's the best platform in the world. What I'm looking for, though, is some real disadvantages to using such a platform.
Here are 10 to get you started.
Apex is a proprietary language. Other than the force.com Eclipse plugin, there's little to no tooling available such as refactoring, code analysis, etc.
Apex was modeled on Java 5, which is considered to be lagging behind other languages, and without tooling (see #1), can be quite cumbersome.
Deployment is still fairly manual with lots of gotchas and manual steps. This situation is slowly improving over time, but you'll be disappointed if you're used to having automated deployments.
Apex lacks packages/namespaces. All of your classes, interfaces, etc. live in one folder on the server. This makes code much less organized and class/interface names necessarily long to avoid name clashes and to provide context. This is one of my biggest complaints, and I would not freely choose to build on force.com for this reason alone.
The "force.com IDE", aka force.com eclipse plugin, is incredibly slow. Saving any file, whether it be a class file, text file, etc., usually takes at least 5 seconds and sometimes up to 30 seconds depending on how many objects, data types, class files, etc. are in your org. Saving is also a blocking action, requiring not only compilation, but a full sync of your local project with the server. Orders of magnitude slower than Java or .NET.
The online developer community does not seem very healthy. I've noticed lots of forum posts go unanswered or unsolved. I think this may have something to do with the forum software salesforce.com uses, which seems to suck pretty hard.
The data access DSL in Apex leaves a lot to be desired. It's not even remotely competitive with the likes of (N)Hibernate, JPA, etc.
Developing an app on Apex/VisualForce is an exercise in governor limits engineering. Easily half of programmer time is spent trying to optimize to avoid the numerous governor limits and other gotchas like visualforce view state limits. It could be argued that if you write efficient code to begin with you won't have this problem, which is true to an extent. However there are many times that you have valid reasons to make more than x queries in a session, or loop through more than x records, etc.
The save->compile->run cycle is extremely slow, esp. when it involves zipping and uploading the entire static resource bundle just to do something like test a minor CSS or javascript change.
In general, the pain of a young, fledgling platform without the benefits of it being open source. You have no way to validate and/or fix bugs in the platform. They say to post it to their IdeaExchange. Yeah, good luck with that.
Disclaimers/Disclosures: There are lots of benefits to a hosted platform such as force.com. Force.com does regularly enhance the platform. There are plenty of things about it I like. I make money building on force.com
I see you've gotten some answers, but I would like to reiterate how much time is wasted getting around the various governor limits on the platform. As much as I like the platform on certain levels, I would very strongly, highly, emphatically recommend against it as a general application development platform. It's great as a super configurable and extensible CRM application if that's what you want. While their marketing is exceptional at pushing the idea of Force.com as a general development platform, it's not even remotely close yet.
The efficiency of having a stable platform and avoiding big performance and stability problems is easily wasted in trying to code around the limits that people refer to. There are so many limits to the platform, it becomes completely maddening. These limits are not high-end limits you'll hit once you have a lot of users, you'll hit them almost right away.
While there are usually techniques to get around them, it's very hard to figure out strategies for avoiding them while you're also trying to develop the business logic of your actual application.
To give you a simple sense of how developer un-friendly the environment is, take the "lack of debugging environment" referred to above. It's worse than that. You can only see up to 20 of the most recent requests to the server in the debug logs. So, as you're developing inside the application you have to create a "New" debug request, select your name, hit "Save", switch back to your app, refresh the page, click back to your debug tab, try to find the request that will house your debug log, hit "find" to search for the text you're looking for. It's like ten clicks to look at a debug output. While it may seem trivial, it's just an example of how little care and consideration has been given to the developer's experience.
Everything about the development platform is a grafted-on afterthought. It's remarkable for what it is, but a total PITA for the most part. If you don't know exactly what you are doing (as in you're certified and have a very intimate understanding of Apex), it will easily take you upwards of 10-20x the amount of time that it would in another environment to do something that seems like it would be ridiculously simple, if you can even succeed at all.
The governor limits are indeed that bad. You have a combination of various limits (database queries, rows returned, "script statements", future calls, callouts, etc.) and you have to know exactly what you are doing to avoid these. For example, if you have a calculated rollup "formula" field on an object and you have a trigger on a child object, it will execute the parent object triggers and count those against your limits. Things like that aren't obvious until you've gone through the painful process of trying and failing.
You'll try one thing to avoid one limit, and hit another in a never ending game of "whack a limit". In the process you'll have to drastically re-architect your entire app and approach, as well as rewrite all of your test code. You must have 75% test code coverage to deploy into production, which is actually very good thing, but combined with all of the other limits, it's very burdensome. You'll actually hit governor limits writing your test code that wouldn't come up in normal user scenarios, but that will prevent you from achieving the coverage.
That is not to mention a whole host of other issues. Packaging isn't what you expect. You can't package up your app and deliver it to users without significant user intervention and configuration on the part of the administrator of the org. The AppExchange is a total joke, and they've even started charging 5K just to get your app listed. Importing with the data loader sucks, especially if you have any triggers. You can't export all of your data in one step that includes your relationships in such a way that it can easily be re-imported into another org in a single step (for example a dev org). You can only refresh a sandbox once a month from production, no exceptions, and you can't include your data in a refresh by default unless you have called your account executive to get that feature unlocked. You can't mass delete data in custom objects. You can't change your package names. Certain things can take numerous days to complete after you have requested them, such as a data backup before you want to deploy an app, with no progress report along the way and not much sense of when exactly the export occurred. Given that there are synchronicity issues of data if there are relationships between the data, there are serious data integrity issues in that there is no such thing as a "transaction" that can export numerous objects in a single step. There are probably some commercial tools to facilitate some of this, but these are not within reach to normal developers who may not have a huge budget.
Everything else the other people said here is true. It can take anywhere from five seconds to a minute sometimes to save a file.
I don't mean to be so negative because the platform is very cool in some ways and they're trying to do things in a multi-tenant environment that no one else is doing. It's a very innovative environment and powerful on some levels (I actually like VisualForce a lot), but give it another year or two. They're partnering with VMware, maybe that will lead to giving developers a bit more of a playpen rather than a jail cell to work in.
Here are a few things I can give you after spending a fair bit of time developing on the platform in the last fortnight or so:
There's no RESTful API. They have a soap based API that you can call, but there is no way of making true restful calls
There's no simple way to take their SObjects and convert them to JSON objects.
The visual force pages are ok until you want to customize them and then it's a whole world of pain.
Visual force pages need to be bound to SObjects otherwise there's no way to get the standard input fields like the datepicker or select list to work.
The eclipse plugin is ok if you want to work by yourself, but if you want to work in a large team with the eclipse plugin forget it. It doesn't handle synchronizing to and from the server, it crashes and it isn't really helpful at all.
THERE IS NO DEBUGGER! If you want to debug, it's literally debugged by system.debug statements. This is probably the biggest problem I've found
Their "MVC" model isn't really MVC. It's a lot closer to ASP.NET Webforms. Your views are tightly coupled to not only the models but the controllers as well.
Storing a large number of documents is not feasible. We need to store over 100gb's of documents and we were quoted some ridiculous figure. We've decided to implement our document storage on amazons S3 infrastructure
Even tho the language is java based, it's not java. You can't import any external packages or libraries. Also, the base libraries that are available are severely limited so we've found ourselves implementing a bunch of stuff externally and then exposing those bits as services that are called by force.com
You can call external SOAP or REST based services but the message body is limited to 100kb's so it's very restrictive in what you can call.
In all honesty, whilst there are potential benefits to developing on something like the force.com platform, for me, you couldn't use the force.com platform for true enterprise level apps. At best you could write some basic crud style applications but once you move into anything remotely complicated I'd be avoiding it like the plague.
Wow- there's a lot here that I didn't even know were limitations - after working on the platform for a few years.
But just to add some other things...
The reason you don't have a line-by-line debugger is precisely because it's a multi-tenant platform. At least that's what SFDC says - it seems like in this age of thread-rich programming, that isn't much of an excuse, but that's apparently the reason. If you have to write code, you have "System.debug(String)" as your debugger - I remember having more sophisticated server debugging tools in Java 1.2 about 12 years ago.
Another thing I really hate about the system is version control. The Spring framework is not used for what Spring is usually used for - it's really more off a configuration tool in SFDC rather than version control. SFDC provides ZERO version-control.
You can find yourself stuck for days doing something that should seem so ridiculously easy, like, say, scheduling a SFDC report to export to a CSV file and email to a list of recipients... Well, about the easiest way to do that is create a custom object with a custom field, with a workflow rule and a Visualforce email template... and then for code you need to write a Visualforce component that streams the report data to the Visualforce email template as an attachment and you write anonymous APEX code schedule field-update of the custom object... For SFDC developers, this is almost a daily task... trying to put about five different technologies together to do tasks that seem so simple.... And this can cause management headaches and tensions too - Typically, you'd find this out after getting a suggestion to do something that doesn't work in the user-community (like someone already said), and then trying many things that, after you developed them you'd find they just don't work for some odd-ball reason - like "you can't schedule a VisualForce page", or "you can't call getContent from a schedulable context" or some other arcane reason.
There are so many, many maddening little gotcha's on the SFDC platform, that once you know WHY they're there, it makes sense... but they're still very bad limitations that keep you from doing what you need to do. Here's some of mine;
You can't get record owner information "out of the box" on pretty much any kind of record - you have to write a trigger that links the owner on create of the record to the record you're inserting. Why? Short answer because an owner can be either a "person" or a "queue", and the two are drastically different entities... Makes sense, but it can turn a project literally upside down.
Maddening security model. Example: "Manage Public Reports" permission is vastly different from "Create and Customize Reports" and that basically goes for everything on the platform... especially folders of any kind.
As mentioned, support is basically non-existent. If you are an extremely self-sufficient individual, or have a lot of SFDC resources, or have a lot of time and/or a very forgiving manager, or are in charge of a SFDC system that's working fine, you're in pretty good shape. If you are not in any of these positions, you can find yourself in deep trouble.
SFDC is a very seductive business proposition... no equipment footprint, pretty good security, fixed price, no infrastructure, AND you get web-based CRM with batchable, and schedualble processing... But as the other posters said, it is really quite a ramp-up in development learning, and if you go with consulting, I think the lowest price I've seen was $200/hour.
Salesforce tends integrate with other things years after some technologies become common-place - JSON and jquery come to mind... and if you have other common infrastructures that you want to do an integration with, like JIRA, expect to pay a lot extra, and they can be quite buggy.
And as one of the other posters mentioned, you are constantly fighting governor limits that can just drive you nuts... an attachment can NOT be > 5MB. Period. And sometimes < 3MB (if base64 encoded). Ten HTTP callouts in a class. Period. There are dozens of published governor limits, and many that are not which you will undoubtedly find and just want to run out of your office screaming.
I really, REALLY like the platform, but trust me - it can be one really cruel mistress.
But in fairness to SFDC, I'd say this: the biggest problem I find with the platform is not the platform itself, but the gargantuan expectations that almost anyone who sees the platform, but hasn't developed on it has.... and those people tend to be in positions of great authority in business organizations; marketing, sales, management, etc. Huge disconnects occur and heads roll, or are threatened to roll daily - all because there's this great platform out there with weird gotchas and thousands of people struggling daily to get their heads around why things should just work when they just don't and won't.
EDIT:
Just to add to lomaxx's comments about the MVC; In SFDC terminology, this is closely related to what's known as the "viewstate" -- aand it can be really buggy, in that what is on the VF page is not what is in the controller-class for the page. So, you have to go throught weird gyrations to synch whats on the page with what the controller is going to write to SF when you click your "save" button (or make your HTTP callout or whatever).... man, it's annoying.
I think other people have covered the disadvantages in more depth but to me, it doesn't seem to use the MVC paradigm or support much in the way of code reuse at all. To do anything beyond simple applications is an exercise in frustration compared to developing an application using something like ASP.Net MVC.
Furthermore, the tools, the data layer and the frustration of trying to refactor code or rename fields during the development process doesn't help.
I think as a CMS it's pretty cool but as a platform for non CMS applications, it's doesn't make sense to me.
The security model is also very very restrictive... but this isn't the worst part. You can't currently assert whether a user has the ability to perform a particular action.
You can check to see what their role is, but you can't check if that role has permissions to perform the current action.
Even worse is the response from tech support to "try the action and if there's an exception, catch it"
Considering Force.com is a "cloud" platform, its ability to act as a client to an external WSDL-defined service is pretty underwhelming. See http://force201.wordpress.com/2010/05/20/when-generate-from-wsdl-fails-hand-coding-web-service-calls/ for what you might end up having to do.
To all above, I am curious how the release of VMforce, allowing Java programmer to write code for Force.com, changes the disadvantages above?
http://www.zdnet.com/blog/saas/vmforcecom-redefines-the-paas-landscape/1071
I guess they are trying to address these issues. At dreamforce they mentioned they we're trying to drop the Governor limits to only 4. I'm not sure what the details are. They have a REST API for early access, and they bought heroku which is a ruby development in the cloud. They split out the database, with database.com so you can do all your web development on and your db calls using database.com.
I guess they are trying to make it as agnostic as possible. But right about now these are all announcements and early access so like their Safe Harbor statements don't purchase on what they say, only on what they currently have.
Our company has a point of sale system with many extras, such as ordering and receiving functionality, sales and order history etc. Our main issue is that the system was not designed properly from the ground up, so it takes too long to make fixes and handle requests from our customers. Also, the current technology we are using (Progress database, Progress 4GL for the language) incurs quite a bit of licensing expenses on our customers due to mutli-user license fees for database connections etc.
After a lot of discussion it is looking like we will probably start over from scratch (while maintaining the current product at least for the time being). We are looking for a couple of things:
Create the system with a nice GUI front end (it is currently CHUI and the application was not built in a way that allows us to redesign the front end... no layering or separation of business logic and gui...shudder).
Create the system with the ability to modularize different functionality so the product doesn't have to include all features. This would keep the cost down for our current customers that want basic functionality and a lower price tag. The bells and whistles would be available for those that would want them.
Use proper design patterns to make the product easy to add or change any part at any time (i.e. change the database or change the front end without needing to rewrite the application or most of it). This is a problem today because the Progress 4GL code is directly compiled against the database. Small changes in the database requires lots of code recompiling.
Our new system will be Linux based, with a possibility of a client application providing functionality from one or more windows boxes.
So what I'm looking for is any suggestions on which database and/or framework or programming language(s) someone might recommend for this sort of product. Anyone that has experience in this field might be able to point us in the right direction or even have some ideas of what to avoid. We have considered .NET and SQL Express (we don't need an enterprise level DB), but that would limit us to windows (as far as I know anyway). I have heard of Mono for writing .NET code in a Linux environment, but I don't know much about it yet. We've also considered a Java and MySql based implementation.
To summarize we are looking to do the following:
Keep licensing costs down on the technology we will use to develop the product (Oracle, yikes! MySQL, nice.)
Deliver a solution that is easily maintainable and supportable.
A solution that has a component capable of running on "old" hardware through a CHUI front end. (some of our customers have 40+ terminals which would be a ton of cash in order to convert over to a PC).
Suggestions would be appreciated.
Thanks
[UPDATE]
I should note that we are currently performing a total cost analysis. This question is intended to give us a couple of "educated" options to look into to include in or analysis. Anyone who could share experiences/suggestions about client/server setups would be appreciated (not just those who have experience with point of sale systems... that would just be a bonus).
[UPDATE]
For anyone who is interested, we ended up going with Microsoft Dynamics NAV, LS Retail (a plugin for the point of sale and various other things) and then did some (and are currently working on) customization work on top of that. This setup gave us the added benefit of having a fully integrated g/l system, which our current system lacked.
Java for language (or Scala if you want to be "bleeding edge", depending on how you plan to support it and what your developers are like it might be better, but also worse)
H2 for database
Swing for GUI
Reason: Free, portable and pretty standard.
Update: Missed the part where the system should be a client-server setup. My assumption was that the database and client should run on the same machine.
I suggest you first research your constraints a bit more - you made a passing reference to a client using a particular type of terminal - this may limit your options, unless the client agrees to upgrade.
You need to do a lot more legwork on this. It's great to get opinions from web forums, but we can't possibly know your environment as well as you do.
My broad strokes advice would be to aim for technology that is widely used. This way, expertise on the platform is cheaper than "niche" technologies, and it will be easier to get help if you hit a brick wall. Of course, following this advice may not be possible if you have non-negotiable technology already in place at customers.
My second suggestion would be to complete a full project plan, with detailed specs and proper cost estimates, before going with the "rewrite from scratch" option. Right now, you're saying that it would be cheaper to rewrite the system than maintain it, and you don't really know how much it would cost to re-write.
I suggest you use browser for the UI.
Organize your application as a web application.
There are tons of options for the back-end. You can use Java + MySQL. Java backend will save you from windows/linux debate as it will run on both platforms. You won't have any licensing cost for both Java and MySQL. (Edit: Definitely there are a lot of others languages that have run-times for both linux & windows including PHP, Ruby, Python etc)
If you go this route, you may also want to consider Google Web Toolkit (GWT) for creating the browser based front-end in a modular fashion.
One word of caution though. Browsers can be pesky when it comes to memory management. In our experience, this was the most significant challenge in doing browser based POS You may want to checkout Adobe Flex that runs in browser but might be more civil in its memory management.
What is CHUI? Character-UI, as in VT terminals? Or even 3270 style?
It sounds like you need a 3-tier system - the database backend, a middle-layer that runs the bulk of the back-end business processes, and a front-end layer for the CHUI / GUI / data-gateway.
All three layers can reside on one machine; or you can distribute the tiers out to various servers. The front-end layer would control the actual terminals, whether they are VT-terminals, or a web-browser, or a custom-written 'client' application.
Make sure you have considered the hardware needs here -- are you going to have barcode scanners, cash drawers, POS debit/credit terminals, et cetra? If you are using a standard browser, it might be hard to reliably integrate those items. (At the very least, you're likely going to have to write special applets to handle them.)
Finally, consider the possibility of a thin-client technology on Windows. It greatly simplifies system management, since you only have to upgrade the software centrally. Thin-client PC's are cheap -- sub $200.
Golden Code Development (see www.goldencode.com) has a technology that does automated conversion of Progress 4GL (the schema and code... the entire application) to a Java application with a relational database backend (e.g. PostgreSQL). They currently support a very complete CHUI environment and they do refactor the code. For example, the conversion separates the UI, the data model and the business logic into separate Java classes. The entire result is a drop-in replacement that is compatible with the original (users don't need retraining, processes don't need to be modified, the data is migrated too). This is possible because they provide an application server and a set of runtime classes that provide that compatibility. The result of the automated conversion is not something that needs further editing before you can compile and run it. True terminal support is included so hardware terminals still work (it requires a small JNI library to access NCURSES from Java). All the rest of the code in the runtime is pure Java. No Progress Software Corp technology is used in the resulting system and it runs on Linux.
At least one converted system is already in production, running a 24 by 7 mission critical environment. It is a converted ERP system that their mid-sized pilot customer uses to run their entire business.
I am going to write a database application for the camp I work for. I am thinking about writing it in C# with a Windows GUI interface but using a browser as the application is seeming more and more appelaing for various reasons. What I am wondering is why someone would not choose to write an application as a web application. Ex. The back button can cause you some trouble. Are there other things that ayone can think of?
There are plenty of cons:
Speed and responsiveness tend to be significantly worse
Complicated UI widgets (such as tree controls) are harder to do
Rendering graphics of any kind is pretty tricky, 3D graphics is even harder
You have to mess around with logins
A centralised server means clients always need network access
Security restrictions may cause you trouble
Browser incompatibilities can cause a lot of extra work
UI conventions are less well-defined on the web - users may find it harder to use
Client-side storage is limited
The question is.. do enough of those apply to your project to make web the wrong choice?
One thing that was not mentioned here is the level of complexity and knowledge required to generate a good web application. The problem being unless you are doing something very simple, there is no "Single" knowledge or technology that goes into these applications.
For example if you were to write an application for some client server platform.. you may develop in Java or C++. For a complex web application you may have to have expertise in Java, Java Script, HTML, Flash, CSS, Ajax, SQL, J2EE.. etc. Also the components of a web based application are also more numerous, Web Application Server, HTTP Server, Database, Browser.. are tipical components but there could be more.. a client server app is tipical just what it says.. a client application and a Server application. My experience and personal preference is not web based .. web based is great for many things. But even though I am an IT Architect for a leading company that is completely emersed in Web Apps as the solution for everything... The cons are many still.. I do thing the technology will evolve and the cons will go away over time though.
Essentially the real limitations are only through of the platform, being the browser. If you have to account for all browsers in current use that can be a pain due to varying degrees of standards in each of them.
If have control of the which browser to use, that is everyone is on computers that you control on site, and say you install firefox on all of them, you could then leverage the latest Javascript and CSS standards to their fullest in your content delivery.
[edit] You could also look into options like the adobe integrated runtime or "AIR" as an option allowing you to code the front-end with traditional browser based options like xhtml/css/javascript, flash/flex and have the backend hooked up to your database online, only also providing functionality of a traditional desktop app at the same time.
The biggest difference and drawback I see with web applications is state management. Since the web is, by nature, stateless every thing you want to maintain has to be sent back and forth from the server with every request and response. How to efficiently store and retrieve it in a matter with respect to page size and performance is hard to do at times. Also the fact that there is no real standard (at least not that everyone adheres to) for browsers makes consistency really..........fun.
You need to have a network access to the server that you are going to have the web application on (if there are going to be multiple users for the application - which is typically the case).
Actually, there are more pros than cons - if you can give some details about your application, we could help a little more...
It completely depends on the requirements of your project. For the most part, there isn't much web applications cannot do these days. Admittedly, certain applications do belong on the desktop as browsers (while currently advancing, and rapidly), still are not quite there yet. From the advent of applications such as Google Docs, Gmail
There isn't much you -cannot- do on the web. If you're creating a World of Warcraft competitor however, the web is most certainly not the optimal solution. Again, unfortunately we'd need more insight on the application you're building for the camp. The best part about the web is that anyone with a browser can use your application.
Web applications delegate processing to a remote machine. Depending on the amount of processing, this can be a con. Consider a photo editor that's a web app.
Web applications also can't deal with a whole lot of data going back and forth to and from a client. You can watch video online.. when it's compressed. It will be awhile before we see any web-based video editing software.
Browser compatibility is also a hassle. You can't control the look-and-feel of the application 100%.
Vaibhav has a good point. What's your application?
A major one is down time for migrations... users will not expect the application to be down, ever, but realistically it will have to be down for major upgrades. When doing this with a desktop application, the user (or end-user systems admin) is in control of when upgrades happen; with an online app, they're not.
For applications which have large data, performance can be a major problem as you're storing a large number of users' data centrally, which means the IO performance will not be as good as it would be if you gave them all a laptop.
In general scalability gives problems for a server-based app. Desktop applications scale really well.
You can do an awful lot with a web-based app, but it is a lot easier to do certain things with a thick client:
Performance: You get simple access to the full power of the client's CPU.
Responsiveness: Interactivity is fast and easy.
Graphics: You can easily use graphics libraries such as DirectX and OpenGL to create fast impressive graphics.
Work with local files
Peer-to-peer
Deciding whether a web application is a good approach depends on what you are trying to achieve. However here are some more general cons of web applications:
Real integration with desktop apps (e.g. Outlook) is impossible
Drag and drop between your app and the desktop / other running apps
With a web application, there are more privacy concerns, when you are storing user data on your servers. You have to make sure that you don't loose/disclose it and your users have to be comfortable with the idea of storing that data on your servers.
Apart from that, there are many security problems, like Man-in-the-middle attacks, XSS or SQL injections.
You also need to make sure that you have enough computing power and bandwidth at hand.
"Ex. The back button can cause you some trouble."
You'll have to be specific on this. A lot of people make fundamental mistakes in their web applications and introduce bugs in how they handle transactions. If you do not use "Redirect after Post" (also known as Post-Redirect-Get, PRG design), then you've created a bug which appears as a problem with the back button.
A blanket statement that the back button in trouble is unlikely to be true. A specific example would clarify your specific question on this.
The back button really is not that much of an issue if you design your application correctly. You can use AJAX to manipulate parts of the current page, without adding items into the browser history (since the page itself wont change).
The biggest issue with designing web applications has to do with state, and the challenges that need to be programmed around. With a desktop application, state is easy to handle, you can leave a database connection opened, lock the record and wait for the user to make the changes and commit. With a web application, you could lock the record...but then what if the user closes the browser? These things must be overcome in the design of your application.
When designing a web application, make sure that each trip to the server "stands alone" and provides a complete answer. Always re-initialize your variables before performing any work and never assume anything. One of the challenges I ran into once was pulling "pages" of grid data back to the user. In a real busy system, with record additions/modifications happening in real time, the user navigation from page to page would vary greatly, sometimes even resulting in viewing the same set of a few records as new additions were added in-front of the query.