We are about to start GPS tracking development using C# and web services to communicate with a third party java'ish receptor on the hardware units.
We have a contract for the handling of the vehicle GPS unit to cloud exchange. We need to integrate the cloud to consumer integration for our current real time tracking view portion of our software.
I've been given the task to create a method of using web services to relay the data in to our application. The data will consist, initially, of few and basic elements; lat, long, vehicleid, etc. Given the nature of GPS 'real-time' viewing this needs to be as fast as possible with small bandwidth consumption.
It has been suggested to me to use a web service that simply passes comma delimited data. I've been unable to find anything along these lines.
I'm open to any suggestions as I'm new to C# since our application is in VB currently. These are the requirements given to me so far:
Fast!
Low bandwidth consumption
Consumable by the following technologies; ASP.NET, IOS, VB, and VB.NET
JSON would be a good choice. It's relatively efficient and it's easy to implement using WCF REST or MVC Web API. Many people aren't old enough to remember the bad old days of comma delimited files, but I would caution you not to use the format, mainly because it is neither standardized nor supported by mainstream components.
CSV seems like a simple format at first glance because it has a very simple specification: just separate everything by commas. But the devil is in the details, for example quoted strings and escapes for commas and quotes. Perhaps the main problem with CSV is a human factors issue: many developers think they already understand the format, so they tend to make decision about escaping and quotes differently. Although there is a standard, it is generally not followed. There is an interesting discussion of lack of standardization problem as well as some other specific issues on Wikipedia.
JSON is a standardized format with very little room for interpretation (there is some wiggle room on date representations). If you keep your JSON property names short, you can achieve an over the wire efficiency that is close to what you would see in a CSV file (if you're presenting to management, it might be a good idea to mock up a JSON vs. CSV payload with actual overhead figures). And you can be reasonably sure that when clients communicate with your service, they will be using well known and well tested JSON parsers. Finally, if IOS is present in your client platform requirements, it's not unreasonable to expect that HTML5 will be added at some point, and JSON is naturally a good choice for HTML5.
I think that ASP .NET Web API is your best bet.
1) Fast!:
Yes, but depends more on your domain logic performance.
2) Low bandwith consumption:
Use JSON has default response type.
3) Consumable by the following technologies; ASP.NET, IOS, VB, and VB.NET:
JSON again. It's easy consumable in all above technologies (there any many libraries for this purpose)
If you choose this option, please, take a look on Apigee Web API Design e-book. It's a very good start point.
It sounds like you want to make it as close to realtime as possible. I would consider a WebSocket-based approach in order to eliminate the latency of scheduled polling. WebSocket is supported by .NET and IOS, but I don't know about classic VB.
Related
I'm getting into socket programming on C#.net for the project I am writing.
The project will be a multi-client system of which the client services monitor system resources and report back to a central server(s).
I was looking into Remoting, WCF etc. to determine which would be best for me. I settled with socket programming because of a number of requirements:
Sockets are faster than the rest with little overhead
I can support more connections per resources on the servers
Sockets can, with albeit modifications, allow me to interact with UNIX based systems also.
I can implement encryption on the link myself in code without having to rely on an SSL cert.
I may be wrong in my thinking here? If I am please do tell. Some suggest WCF as it is "wasy to use" and does everything I want but I believe it is that much slower with overheads.
My main issue is, that while the client machine will not keep a connection open, there could be thousands, or tens of thousands, of client machines and I would have to assume that the machine will be hammered with connections. Considering minimum times between connections, per client, may be as small as 1 min.
Now to my problem at hand: How to send multiple objects over the link and more importantly how to determine what they are on the other side?
I'm assuming this is possible over one connection as I have read a number of articles saying so, albeit they describe the methods differently and so are the examples.
The issue is I can't find any example that actually does this. No example shows how to send multiple objects and then how to determine what they are on the other side.
Can anyone help me here or point me to examples. I'm quite able to figure stuff out once I have a base to work from.
It feels like the classic case of premature optimization and reinventing the wheel. I might be mistaken because I don't know what are your performance requirements, development resources and time frame. But I suspect that very smart people had the same problems before you. And they came up with the variety of solutions, including HTTP (SOAP, REST) and XMPP (if you want statefull protocol). A lot can be done to improve performance even at the app level (minimizing amount of data send over wire, caching etc). Without complexity overhead introduced by using sockets directly. You probably know all of this but I highly recommend you to evaluate your decision again.
As to usual serialization format suspects like XML and JSON you might also want to look at Protocol Buffers:
protocol buffers is the name of the binary serialization format used
by Google for much of their data communications. It is designed to be:
small in size - efficient data storage (far smaller than xml)
cheap to process - both at the client and server
platform independent - portable between different programming architectures
extensible - to add new data to old messages
You might be trying to reinvent the wheel here. But since you have set your mind about using sockets (been there, done that, learned a lot), read those links on serialization:
How to deal with XML in C#
XML Serialization and Inherited Types
How do I serialize a C# anonymous type to a JSON string?
Parse JSON in C#
What "technology" would you suggest to exchange some kind of messages between a Java server and several clients written in C#, Javascript and Java?
The background story:
In our current project we're trying to build a generic UI backend in Java (running on the server) which is then "bridged" into several UI frontends by means of different UI adaptors (running on the client, the server, or both). While our server technology will always be Java, there will be C# (Silverlight), JavaScript and Java clients. Maybe even more in the future (different Smartphones, Tablets).
The UI backend and UI frontends communicate through a bunch of more or less simple messages (mostly name/value-pairs) each of which encapsulates a specific property/state/data change on the client or server respectively. Within a single request cycle, several such simple messages are aggregated into one big message which is then passed from backend to frontend or vice versa. At the moment sending and receiving messages is done at a single entry point on the client as well as on the server. So there are no server methods exposed as WebService etc. - simply because this would most definitely be to slow in our case.
Our current prototype consists solely of a Java server, a Java Desktop Client (Swing) and a Java Web Client (Vaadin). The message exchanged between backend and frontend is effectively a list of POJOs (each representing a specific "change") serialized/deserialized to/from XML. So far, so good.
Now C# and Javascript come to the table. Since we want to work with some kind of object in each technology, we thought it would be a good idea to specify the messages/changes/pojos in some kind of abstract language and then generate objects for each target language. At some point these objects could then be serialized/deserialized and sent over the wire (probably via http/s). For this purpose we thought of Google's protocol buffers or Thrift. What do you think?
For the moment our synchronous request-response-cycle is enough but we will need asynchronous request-response or server-push respectively pretty soon. That's why we thought of using something like ActiveMQ straight away. What do you think? Too much? If not, how can we accomplish the object generation mentioned above (xsd, jaxb, ? for js)? Are there better ways? I've never used ActiveMQ but according to the website it should be possible with Java, C# (Spring.NET) and somehow with Javascript (STOMP) too. However, this seems pretty complex to me...
Any tips, hints, experiences or comments about this or related topics would be really helpful.
Thank you in advance.
I would recommend using webservices. The WSDL language defines objects and messages of your protocol in abstract form. Most modern languages like Java and C# have tools for converting WSDL to native types and libraries for handling I/O.
For the last two years i have been involved in building a similar system: backend for our project is c#, java and bunch of other languages, frontend is phone clients for ios, android, symbian, all the common webbrowsers and even windows desktop apps.
For all these services we use JSON, since it seems to be most widely supported format across all languages and platforms, it decodes fairly fast on the clients compared to xml based solution (esp. webbrowsers/javascript) and it has a pretty low overhead that compresses extremely well which is great for clients that lack bandwidth.
the ways I can think of
Web service or soap
Socket
Database table
shared file
Any concise example you know of for webservice?
Web services or soap would be fairly easy, however, if the C++ application isn't a web server naturally (or the C# application), it may be easier to just use socket programming directly.
Sockets are fairly easy to use from both C# and C++. They give you complete control over the type of date transmitted, at the cost of potentially a little more work in the handling.
The biggest issues to watch for are probably endianness of binary data, and encoding of text data, if you use sockets directly. Otherwise, it's very easy.
Since you are already aware of the Web service and socket approach, I'll mention some other options. If you like simplicity, check out XML-RPC. This is what SOAP was before large standards committees and corporate interests began to control the specification. You can find implementations of XML-RPC for just about every major programming language out there. Hessian is an interesting binary protocol that has many fans and supports just about every major language as well. Protocol Buffers is popular within Google. The official version from Google does not support C#. However, the two highest rep users of SO do provide ports of protobuf for the .Net space.
I will probably be ridiculed for this, but also take a look at CORBA. It's not in vogue these days, but has many substantial technical creds, especially if one end of the communication is C++. IMHO, it's WS-* with OO support and no angle brackets required. For interop, I think it still should have a seat at the table. When engaged in C++ development, I found OmniOrb to be quite effective and efficient. Take a look at this SO Question for some pointers concerning using CORBA in .Net.
Sockets are easiest; and I would always go for that first. If database is an option, that's also trivial, but that would really depend. If it's queued events, that would make sense, but if it's request/response, it's probably not so great.
you can use gsoap to have a C/C++ program use a webservice.
You can also call a cgi program that is written in C++.
I have written a server in C that communicated with a C# client, and the endianess can be a pain to deal with, webservices is so much simpler.
Do you want it to communicate with each other (for instance, through tcp (like many others have pointed)) or do you want to be able to translate objects from C# to C++? If so, check out Apache Thrift (http://incubator.apache.org/thrift/).
My friend and I are having a disagreement over an application development issue. It's a simple production management application.
According to my friend, the front-end stores data in XML, and a Java program will read the XML document, store it (at the back-end), and apply some business logic and again store the results into another XML document. And a C# front-end will display the result ( He wants to use sockets for communicating the status of XML ).
I think this is a bad idea. I suggested that whole application should either be written in C# or in Java.
Note: The application is standalone. It's not used over a network.
Have any of you tried this? Please share your thoughts :)
You're right and your friend gave a bad idea. In addition, from your question, I see there are several troubled issues, I don't know where to begin so I will just list them but not in any particular oder. But the ground rule for you to read on is you must agree that simpler is better as Einstein said "Things should be made as simple as possible but not simpler" (or something like that, I don't remember the exact quote).
The notion of front end and back end do not really apply to a desktop application. Rather, you want to use the MVC pattern for the separation of concerns. Wikipedia might be a good place to start learning or reviewing.
Why use of socket (which is totally unnecessary) if you don't have to. This is the first reason why it's a bad idea as you would not need using sockets if everything is done in language, running in the same process space (Your app is a desktop or standalone app).
Similarly, why XML (again unnecessary). No need because you can just pass Java or C# objects around. With XML, first there is the signal to noise issue as tags are added to the true data. Then there is the time to parse, to construct the XML, additional libraries potentially, etc. Thid would be all that code which are introduced in your friend's approach.
These are the most obvious reasons. There are other reasons from a manager's or company's perspective:
To maintain this application, the manager or company needs to hire 2 different skillsets. This might not be true as most programmers are multilingual anyway. But that's not always the case.
In term of deployment, now you force your users to have both the JRE and the .NET framework installed just to be able to run your application. And either of those is not exactly a small footprint.
Talk about making it complex. Either Java or C#. One really isn't a backend for another. They both 'do the same things' as languages. The only difference is whether you want to leverage the power of .NET, or the power of the immensely huge Java frameworks.
This is a desktop application that "is not used over a network"... I'm failing to see a need for a real "backend" at all.
Write the desktop application in a single language, and store your data in XML.
So your application is standalone and doesn't need to work over a network, but your friend insists on connecting the front and back ends of the app using sockets? Something is wrong with this setup, seems more complicated than it needs to be.
It sounds to me like your friend wants to use Java because he understands Java's XML handling framework better. Personally, I think interop between Java and .NET is overkill. You'll save yourself a lot of man hours and frustration by writing the app in a single language of your choice.
What your friend is suggesting is to keep things modular. It doesn't really matter what language you use, but if throw it together in one big project you might make it non modular.
For that type of app I would use one only one language.
It may be possible to leverage the power of C# desktop app on the front-end and Use Java Ejb+Web Service (Jax-ws) on the backend. C# apps can read SOAP wsdl to create the stubs and the interfaces to access Java backend implemented by Jax-ws.
I have two programs. One is in C# and another one in Java.
Those programs will, most probably, always run on the same machine.
What would be the best way to let them talk to each other?
So, to clarify the problem:
This is a personal project (so professional/costly libraries are a no go).
The message volume is low, there will be about 1 to 2 messages per second.
The messages are small, a few primitive types should do the trick.
I would like to keep the complexity low.
The java application is deployed as a single jar as a plugin for another application. So the less external libraries I have to merge, the better.
I have total control over the C# application.
As said earlier, both application have to run on the same computer.
Right now, my solution would be to use sockets with some sort of csv-like format.
I am author of jni4net, open source interprocess bridge between JVM and CLR. It's build on top of JNI and PInvoke. No C/C++ code needed. I hope it will help you.
Kyle has the right approach in asking about the interaction. There is no "correct" answer without knowing what the usage patterns are likely to be.
Any architectural decision -- especially at this level -- is a trade-off.
You must ask yourself:
What kind of messages need to be passed between the systems?
What types of data need to be shared?
Is there an important requirement to support complex model objects or will primitives + arrays do?
what is the volume of the data?
How frequently will the interactions occur?
What is the acceptable communication latency?
Until you have an understanding of the answers, or potential answers, to those questions, it will be difficult to choose an implementation architecture. Once we know which factors are important, it will be far easier to choose the more suitable implementation candidates that reflect the requirements of the running system.
I've heard good things about IKVM, the JVM that's made with .NET.
Ice from ZeroC is a really high performance "enterprisey" interop layer that supports Java and .net amongst others. I think of it as an updated Corba - it even has its own object oriented interface definition language called Slice (like Corba's IDL, but actually quite readable).
The feature set is extensive, with far more on offer than web services, but clearly it isn't an open standard, so not a decision to make lightly. The generated code it spits out is somewhat ugly too...
I realize you're talking about programs on the same machine, but I've always liked the idea of passing messages in XML over HTTP.
Your server could be a web server that's ready to accept an XML payload. Your client can send HTTP messages with XML in the body, and receive an HTTP response with XML in it.
One reason I like this is that HTTP is such a widely used protocol that it's easy to accept or create HTTP POST or GET requests in any language (in the event that you decide to change either the client or server language in the future). HTTP and XML have been around for a while, so I think they're here to stay.
Another reason I like it is that your server could be used by other clients, too, as long as they know HTTP and XML.
I used JNBridge (http://www.jnbridge.com/jnbpro.htm) on a relatively simple project where we had a .NET client app using a relatively significant jar file full of business object logic that we didn't want to port. It worked quite nicely, but I wouldn't say we fully exercised the capabilities of JNBridge.
I am a big fan of Thrift an interoperability stack from Facebook. You said they code will probably run on the same machine so it could be overkill but you can still use it.
If they are separate programs and running as independent applications,you may use sockets. I know it's bit complex to define communication protocol but it'll be quite straight-forward.
However if you have just two separate programs but want to run them as single application, then I guess IKVM is a better approach as suggested by marxidad.
It appears a very similar question has been asked before here on stack overflow (I was searching Google for java windows shared memory):
Efficient data transfer from Java to C++ on windows
From the answer I would suggest you to investigate:
"Your fastest solution will be memory
mapping a shared segment of memory,
and them implementing a ring-buffer or
other message passing mechanism. In
C++ this is straight forward, and in
Java you have the FileChannel.map
method which makes it possible."