What kind of application would be fair choice for comparing performance of message based asynchronous publish/subscribe system with PubsubHubbub (which is synchonous)?
I developed an atom based application for the pubsubhubbub but that application is not suitable to be developed using the other option. I am worried that the two systems are not on the same ground to make an objective comparison of the speed of Pubsubbhubub based application with message(AMQP) based application?
Any insight on how to mitigate this?
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I have recently moved to telecom and working on automation framework to automate the VoIP phone.
In current framework, for a simple call/conference scenario, additional helper phones are being used. The current framework configure these additional physical helper phones which takes considerable time and consumption of resources.
I am trying to replace these physical helper phones with the programmable soft phones, so that the test execution will be little bit fast.
Please let us know if this can be possible.
I am not looking for GUI-based soft SIP client because automating the UI actions will be another challenge and prone to error.
This framework is being developed in Perl
Your help will be highly appreciated!!
Take a look at SIPp. http://sipp.sourceforge.net/
I think it will do what you want, it even has some handling of RTP data.
If perl is not a strict requirement, the KitCAT framework is extremely (Java) developer-friendly. Test cases are written in JUnit, for ease of integration with other tools. It provides logs at varying levels (including SIP messages), and supports multiple user agents, which can all be coordinated within a test case. (The latter is not well supported in other SIP testing tools, such as sipp). It also provides coordination with other protocols (e.g., RTP, HTTP).
There is a (somewhat dated) screencast that shows installation and basic usage of the tool.
I am currently doing my research on building a chat system with more than 10k users connected online. I came across technologies and ways to do it such as jabber(XMPP), websockets, long polling, push. As far as I now, long polling might not work given the number of users. I know there is a lot of ways to accomplish this. I also know that facebook and Google chat systems are developed on XMPP.
I would truly appreciate if anyone could point me to the right direction. I believe all these methods and technologies out there are good depending on the scale of the project. I definitely need performance and scalability.
I've used Socket.io together with NodeJS for such a chat application. It scaled to over 10K concurrent users on moderate servers and there was a lot of room to grow.
This does depend on your limitations, tho.
What kind of hardware are you planning on using?
Which operating system would power your servers?
Which client platforms are you targeting?
Do you have an existing infrastructure you need to fit this into?
Do you have a previously selected programming language?
The existing skill sets your team members have and your team's ability to adopt new platforms and languages if necessary.
Take all of the above into consideration when making your decision.
Personally, I've found XMPP to be quite adequate, but a bit bloated for my purposes. YMMV.
You are comparing a fruit basket and three different variety of oranges.
XMPP is the only protocol that you have mentioned that actually is designed to support a chat system (of which many exist). The others are simply asynchronous messaging protocols/techniques. XMPP already supports http based chat via BOSH. Without a doubt, it will also support WebSockets when the specification is finalized. There is actually a draft of this already written, but at this point it appears to be a draft using a draft, so there will probably be few, if any, implementations.
Using XMPP would allow you to build on a proven technology for implementing a chat system and would allow you to choose what transport you want to use "under the hood". You haven't actually said whether you need a http based transport or not, but with XMPP you can use the stock tcp socket based transport or a http based one (BOSH) with the knowledge that it will also support WebSockets in the future.
The other benefit is of course that this is a widely used standard that will allow reuse of existing clients, servers and libraries in pretty much all popular (and not so popular) languages and platforms.
Scalability is not too much of a concern with the numbers you are quoting, as most (maybe all) existing xmpp servers will handle that many users.
I am wondering if it would be possible to develop an enterprise-level web application without the use of a standard MVC structure and application server by carrying the business/flow logic and session data to the client-size Javascript and make it talk to REST data services directly...maybe we could make use of an authorization/authentication layer and a second validation layer sitting on top of the data services. All these services operate on standard HTTP methods, support configurable logging&monitoring, and content or query parameters are all contained in the HTTP request/response body. Static HTML and Javascript are served to the browser and the rest is carried out by Javascript functions talking to the HTTP-based authorization/authentication, validation and then data services. Do you think this kind of an architecture could satisfy enterprise-level web application requirements?
It's possible but unlikely; what are the drivers that suggest this architecture to you? Is it just to be different or are there some specific aspects that this best addresses?
by carrying the business/flow logic
and session data to the client-side
Javascript and make it talk to REST
data services directly
In theory you'd still be able to have an appropriately layered solution (Business Logic (BL) script vs UI focused script) but practically speaking it'd be messy, and you'd lose the ability to physically separate it into different tiers. This could "bite" you at any number of places in the life of the system.
"Enterprise" grade systems are seldom small, I hate to think how much logic you'd be having to send over the wire to support a given action/process.
Putting all the BL into a scripting language ties you to that platform, and platforms change over time. The bad thing about scripts is that whilst they are stable to a degree I'd suggest they are more exposed to change than server-based platforms like Java or .Net. In an enterprise scenario, the servers will have very tight change control and upgrade paths mapped out for them - whereas browsers are much more open to regular change.
There's the issue of compatibility - unless you're tied to a specific browser (to the version level) guaranteeing consistent behavior is going to be harder, and will likely require more development effort. Let's say you deliver the solution successfully; what do you do when the business wants to take advantage of mobile computing - say iPads? Your only option is going to be a browser - you won't be able to take advantage of any of the native advantages of the platform. "The web and browsers" might seem like they'll be around forever - but then I'm guessing that what MainFrame folks said at the time. A server-centered solution is going to give you more life for less expense.
Staffing will be an issue - you'll need very strong JavaScript and server-side developers.
Security: having your core BL out on the client where it's much more exposed sounds very dangerous.
EDIT:
Web Apps can be sow for many reasons - not many of which are reason enough to put all your BL in JavaScript on the client. Building apps for performance is a whole field of endeavor on its own - I suggest you get more familiar with Architecting and implementing for performance before you write off n-tier web apps altogether :)
Regarding keeping your layers separated: there are different ways of doing this but it boils down to abstraction - and more correctly to keeping good design principles in mind; if you haven't heard of SOLID that would be a good place to start. In terms of implementation start reading up on Dependency Inversion (FYI - self-promotion, the articles mine and is .Net focused, but you should have no problem tracking down Java-based ones too).
I've recently decided to take on a pretty big software engineering project that will involve developing a client-server based application. My plan is to develop as many clients as possible: including native iPhone, Android and Blackberry Apps as well as a web-based app.
For my server I'm planning on using a VPS (possibly from slicehost.com) running a flavor of Linux with a MySQL database. My first question is what should be my strategy for clients to interface with the server. My ideas are:
HTTP-POST or GET based communication with a PHP script.
This is something I'm very familiar with - passing information to a PHP script from a form, working with it and returning output. I'm assuming I'd want to return output to clients as some sort of XML or JSON based string. I'm also assuming I'd want to create a well defined API for clients that want to interface with my server.
Socket based communication with either a PHP script, Java program, or C++ program
This I'm less familiar with. I've worked with basic tutorials on creating a script or simple application that creates a socket, listens for a connection and returns data. I'm assuming there is far less communication data-overhead with this method than an HTTP based method. My dream is for there to be A LOT of concurrent clients in use, all working with the server/database. I'm not sure if a simple HTTP/PHP script based communication design can scale effectively to meet the needs of many clients. Also, I may eventually want the capability of a Server-Push to clients triggered by various server events. I'm also unsure of what programming language is best suited for this. If efficiency is a big concern I'd imagine a PHP script might not be efficient enough?
Is there a commonly accepted way of doing this? For me this is an attempt to bridge a gap between some of my current skills. I have a lot of experience with PHP and interfacing with a MySQl database to serve dynamic web pages. I also have a lot of experience developing native iPhone applications (however none that have had any significant server-based communication). Also I've worked with Java/C++, and I've developed applications in both languages that have interfaced with MySQL.
I don't anticipate my clients sending/receiving a tremendous amount of data to/from a server. Something on par with a set of strings per a given client-side event.
Another question: Using a VPS - good idea? I obviously don't want to pay for a full-dedicated server (slicehost offers a VPS starting at ~ $20/month), and I'm assuming a VPS will be capable of meeting the requirements of a few initial clients. As more and more users begin to interface with my server, I'm assuming it will be possible to migrate to larger and larger 'slices' and possibly eventually moving to a full-dedicated server if necessary.
Thanks for the advice! :)
I'd say go with the simplicity of HTTP, at least until your needs outgrow its capabilities. (The more stateful your application needs to be, the less HTTP fits).
For low cost and scalability, you probably can't go wrong with a cloud like Rackspace's or Amazon's. But I'm just getting started with those, my servers have been VPSs from tektonic until now.
Besides the benefits of this model over the shared-memory model, I'm just trying to understand where to apply it for higher levels use-cases.
As to Scala, Actors model fits most of the multi-threaded cases one can think about:
Swing GUI application
Web Applications (see Lift framework)
Application Server in multicore environment:
Batch processing of requests/data
Background tracking tasks
Notifications & Scheduled tasks
Actors model makes design much clearer and greatly simplifies interprocess communication.
OTP Framework : Provides really good framework for network based applications.
Helps in making fault tolerant applications . (process restart using Supervisor's in OTP).
Both Synchronous and Asynchronous modes of communication can be done using gen_server.
Event based callbacks can be used using gen_event.
State machine can be programmed easily using gen_fsm (In case you need to follow some states in your application).
A process crash does not bring the whole application down. Only that particular process crashes.
Functional programming language.
A lot easier to program at binary level.
Garbage collection.
Native compilation option.
Fair amount of good useful modules are available.
Able to make good solid concurrent applications easily.
And lots more.... I really enjoyed working on some applications in erlang , making those in c/c++ would have been very difficult.