ASP.NET webservices use HTTP protocol to send/receive messages.
But the messaging protocol is SOAP
and SOAP makes use of XML.
This is right?
It is right to some extent, but it is not the whole truth!
I don't think that ASP.NET imposes many constraints on what formats you use to send/receive messages when you implement web services. After all, you're still on top of the .NET framework which offers a really wide variety of options.
That being said, HTTP is the application layer protocol used for message transmission with web services. But other protocol might also be used.
SOAP is XML-based, and is a commonly used as format of exchange of structured information. But you can also have REST services (see http://spf13.com/post/soap-vs-rest) that do not use SOAP. You can even exchange plain text or XML or some private format - it depends on your case.
It really depends on your purpose and the client applications you expect will consume the service. Is this an in-house service where you should follow some obscure internal protocols/formats of communication, or is it a service that has to be accessible from the web and must offer as much compatibility as possible? If it is the latter, go in a standardized manner with SOAP or REST.
Related
I have to connect an old but critical software to RabbitMQ. The software doesn't support AMQP, but it can do HTTP Requests.
Does RabbitMQ support plain HTTP? Or should I use a "proxy" or "app" that actively transforms the HTTP Requests to AMQP 1.0 and pushes it to the RabbitMQ server?
https://www.rabbitmq.com/management.html
The management plugin supports a simple HTTP API to send and receive messages. This is primarily intended for diagnostic purposes but can be used for low volume messaging without reliable delivery.
As mentioned, it's designed for very low loads, but it may be usable. If you need higher loads, then by all means cast around for a library that does the job and create a proxy. Most languages will have something. I've personally created a lightweight API using Lumen and https://github.com/bschmitt/laravel-amqp to tie a few disparate services together in the past, and it seems to work very well.
It is possible not but really recommended depending on load. You have three options really, two of which are web socket based and one that seems like what you're looking for. I'd suggest starting with the rabbitmq docs.
Hi went through Enterprise Integration Patterns by Gregor Hohpe and Bobby Woolf.
http://www.eaipatterns.com/toc.html
I also went through Camel and Mule's compliance with these integration patterns -
http://www.mulesoft.org/documentation/display/current/Understanding+Enterprise+Integration+Patterns+Using+Mule
http://camel.apache.org/enterprise-integration-patterns.html
I see that both Mule and Camel allow applications to be deployed and accessed via webservices like SOAP or REST, SOAP being more RPC style. They allow massive integration support using opensource utilities like CXF and Jersey. In fact Mule also supports RMI endpoints - which will give remote method invokation capability as well which is a well-accepted form of Integration.
I understands ESBs are built around a Message Bus with additional support for other protocols however ESBs only comply to EIP and EIP is not just ESBs.
Question is why SOAP/REST or their transport protocol not considered as "Integration Styles" and which is Enterprise Integration so "Message Oriented"?
I am a novice compared to the great minds which designed these patterns but trying to understand the lopsided message-y nature of Integration patterns. I admit it isn't quite the QnA format of stack overflow but will request Mods to keep it alive for a while so that people can share their opinions.
As for SOAP, it would put it under the Integration Style "Remote Procedure Invocation", since it's pretty much what SOAP implements in reality (I won't consider the SOAP over JMS hybrids here with a potential to mix RPC with Messaging..).
REST is, interface wise, very different from SOAP in that it's resource driven instead of service driven. I would non the less group it under the "RPC" style since it's just another format of syncrhonous RPC calls.
I would, however, not put too much effort in theory of what EIP integration style a specific message pattern implements.
Look at a specific scenario at hands instead and use the EIP to model your specific integration.
I've seen integrations of file transfers that in realtiy implemented RPC patterns or SOAP services that in reality implemented messaging (although I don't really recommend do this).
A concrete example: consider the usage of a dedicated file upload service, which happends to be built using SOAP technolgy, which uploads a CSV file to a file area on a server, from where it's picked up by some other system. I would call this file based integration on a high level.
Another example is that Messaging systems sometimes are implemented using a shared database. Still the integration style using them is messaging, not "Shared Database".
Think about how your integration should work on a high level, then apply the various protocols to do the grunt work.
What's the difference between an RPC System, like Twitter's Finagle, and an Enterprise Service Bus, like Mule? What kind of problems are each of them good at solving?
I will try to answer this as a soft explanation, rather than a technical breakdown of features:
One may say that Finagle is a asynchronous messaging library that allows services to connect to one another freely (not tightly tied to architectural system integration standards) while supporting multiple protocols.
From the Finagle website:
Finagle is a network stack for the JVM that you can use to build asynchronous Remote Procedure Call (RPC) clients and servers in Java, Scala, or any JVM-hosted language. Finagle provides a rich set of protocol-independent tools.
An enterprise service bus (ESB), on the other hand, is a asynchronous messaging architecture which typically adheres to industry standards and protocols. An ESB promotes a system where message flow is controlled and routed between systems, and where servers can register their service and clients can register what messages they are interested in. The services offered by servers can be registered and versioned.
You will typically find Finagle being used somewhere between a website and backend services. But, you will typically find an ESB inside a large corporate, where it's responsible to integrating systems like finance, support, sales, etc.
Both solutions offer asynchronous messaging and buffering to various extends, but are not designed to solve the same problem. For ESB, you would probably think 'strict, enterprise', but for Finagle you would probably think 'flexible, web'.
Hope this helps
Update:
Not quite related, but if you are exploring this space, I would look at Kafka these days.
RPC and ESB are two architectural patterns. While RPC is usually a request-reply and synchronous in nature, an ESB works on the concept of messaging (simplified explanation) and of asynchronous in nature. ESB is the foundation for any SOA implementation. ESB enables loose coupling thus promoting true agility. A simplified example from implementation perspective is as follows:
A web service is a typical RPC. The consumer is tightly bound to the producer and any change in the contract on the producer side, will require changes on the consumer side.
In ESB, the service consumer doesn't invoke the service producer directly. It just puts the message in the bus and based on the rules (mediator), appropriate service producer will handle it. If the service consumer and service producer talk in different formats, ESB provides the facility to do the transformation (like formatting the zipcode as xxxxx-xxxx, splitting the name into first name and last name, etc.).
This is just simplified explanation. For more information, please check the following links:
Why do developers need an Enterprise Service Bus?
Enterprise Service Bus
Both solve completely different problems:
An ESB is an intermediation middleware that provides message transformation and routing, protocol adaptation and other value-add operations (like orchestration, guaranteed delivery, idempotent filtering...). It sits in-between your service consumers and providers and transparently (ie without any change in consumer or provider) provides its different features.
An RPC system provides client and server technologies for performing RPC operations.
Hey,
first of all this is a conceptional question and I do not know if StackOverflow is the appropriate place - so my apologies if I am wrong.
Nowadays the web is not only used for passing raw informations. Many and especially complex web applications are in use. These web application seem to be so complex that it seems irrational to use the HTTP protocol, which is based on so simple data exchange, plus it is stateless.
Would it not be more convincing to use remote invocations for this web applications? The big advantage to my mind is a unified GUI by using HTML. But there are applications, which have no need for a graphical interfaces and then it comes to a point where the HTTP protocol is really cumbersome.
Short answer: HTTP is allowed through firewalls where other protocols would be blocked.
A short partial answer is: first, for historical reasons - HTTP was used since the dawn of the web as protocol for requesting documents, and has since been used for some different purposes. One reason to keep using it is that it is generally served on port 80 which you can be sure won't be blocked by firewalls between your client and the server. The statelessness of the protocol may not always be what you want, but it has at least the advantage of protecting the server side from very trivial overloading problems.
OS independence
firewall passing
the web server is already a well understood and mostly "solved" problem in terms of load balancing, server fall over, etc.
don't have to reinvent the wheel
Other protocols are being used more and more now, including remote invocations and (the one I am particularly familiar with) WCF (which allows binary TCP/IP data transfer).
This allows data to travel faster for applications which require more bandwidth. For example an n-tier application may use WCF binary transfer between application and presentation tiers. Also public web services allow multiple protocols, including binary.
For data transfer protocols, firewalls should be configured (ie. expose a port specifically for your application), not worked around, I would not recommend using a protocol because firewalls do not block it.
The protocol used really depends on who will consume it and what control you have over the consumption - eg external third parties may need a plain-text version with a commonly agrreed data interface. On the other hand, two tiers in a single web application may be able to utilise binary data transfer for performance and security.
I am working on an asp.net application (.net 4 framework) design and was wanting to know what are the pros and cons and best practices for using webservices vs WCF techology? This application will eventually be used by outside clients to consume data.
When would you use WebServices and when would you use WCF?
Is one more scalable than the other?
I would use WCF because it can do everything webservices (asmx) does; while giving you the flexibility to extend much further.
You can setup a simple WCF Service just as easily as an ASMX service through Visual Studio. So if you're "Fresh" on both technologies, I'd spend time learning WCF.
Depending on your specific use-case, you might might also look into WCF Data Services (.NET4) and Entity Framework. It basically gives you a nice API that you can use to consume your database over http/https. The beauty of WCF Data Services, is that you end up writing very little code to get at your data, and you can focus on consuming it.
WCF Getting Started -- http://msdn.microsoft.com/en-us/library/ms734712.aspx
WCF Data Services -- http://msdn.microsoft.com/en-us/data/ee720180.aspx
Webservice?
Webservice use SOAP (Simple Object Access protocol) and it is used to
connect the web application using different type of technologies, and
possible to connect the application that have hosted in different type
of servers.
Disadvantage of Webservice
Webservice use only HTTP Protocol. It provides only singlex
communication, not half duplex and full duplex communication. They
work in an stateless fasion over HTTP and are hosted inside a web
server like IIS
Advantages of WCF Service
WCF Service support HTTP, TCP, IPC, and even Message Queues for
communication. We can consume Web Services using server side scripts
(ASP.NET), JavaScript Object Notations (JSON), and even REST
(Representational State Transfer). It can be configured to have
singlex, request-response, or even full duplex communication. These
can be hosted in many ways inside IIS, inside a Windows service, or
even self hosted.
Half duplex
Half-duplex data transmission means that data can be transmitted in
both directions on a signal carrier, but not at the same time.
half-duplex transmission implies a bidirectional line (one that can
carry data in both directions).
They work in an stateless fashion over HTTP and are hosted inside a web server like IIS
Full duplex
Full-duplex data transmission means that data can be transmitted in
both directions on a signal carrier at the same time. Full-duplex
transmission necessarily implies a bidirectional line (one that can
move data in both directions).