This is the architecture I am trying to build where I first check in Redis cache and incase of a cache miss go to downstream. Found Caching web client in vert x 4.2.0 and newer version but does that allow us to communicate with Redis cache or it works with in-memory cache only ? Also any suggestions to achieve this are welcome.
Architecture
currently vert.x web client doesn't have any redis based caching implementation, yet nothing really stops one from quickly building one.
The important bit is the interface io.vertx.ext.web.client.spi.CacheStore. A custom implementation that stores data in redis would sufice to get your architecture complete.
Currently, vert.x web client offers a local in-memory cache or a SharedData based cache, usefull for sharing data across verticles.
If one would follow the shared data implementation as a blueprint, supporting redis would be a nice good first contribution project.
In a "computer system" there are two web servers that manage independent applications, both using JSP technology. There is a necessity to have access from server A to information stored in server B. In case of interconnection with:
Invocation of a data access service with GET/POST of an URL.
Definition and use of Web services.
Direct integration in Java, with Java RMI.
Which would be the best solution? Why? What are the advantages and disadvantages of each of them?
A solution would be to use REST API on the server from where you need to invoke the information. You might want to use an ajax call or just include contact via iframe.
Get call will be simple and quick to develop and maintain however if it is low latency and high throughput application then you might want to go with Java RMI.
We are currently trying to decide how to implement workflow into our enterprise application. We must support very complex workflow scenarios and we must also handle approx 10000 concurrent users. The application domain is healthcare. The client is a WPF application talking to an IIS backend using WCF. The question is: Does anybody have any experience with Windows workflow foundation in such a large enterprise application? From the requirements is seems like WWF fits the bill, but I am worried about performance and scalability. Should I continue to investigate into WWF or is WWF just not suitable for this kind of applications? We also need to let our consultants have the ability to alter workflows and re-hosting the WWF designer certainly sounds tempting. What do you think. Is WWF the way to go?
You can create a workflow that is directly hosted by IIS. You can use the "Receive" activity to setup the WF to handle requests. You can then attach a "Send" activity to reply back to the client with a response, and even have the workflow continue processing in the background that activity. Hope that provides some direction to get you started. You can achieve this with either the .NET Framework 3.5 or 4.x versions, but .NET 4.0 is much easier to setup.
The performance will rely on the hardware.
Anyway, workflow services are perfectly scalables in IIS. You will be able to set up a server farm that will serve all the request.
Regarding the requirement of altering workflows, always is possible to alter the workflow in a way that future requests will create instances of the new altered workflow. Old and already initiated workflows can not take any variation. So,if I have not understood wrongly, WWF does not fit this requirement.
I have heard a lot of people talking recently about middleware, but what is the exact definition of middleware? When I look into middleware, I find a lot of information and some definitions, but while reading these information and definitions, it seems that mostly all 'wares' are in the middle of something. So, are all things middleware?
Or do you have an example of a ware that isn't middleware?
Lets say your company makes 4 different products, your client has another 3 different products from another 3 different companies.
Someday the client thought, why don't we integrate all our systems into one huge system. Ten minutes later their IT department said that will take 2 years.
You (the wise developer) said, why don't we just integrate all the different systems and make them work together? The client manager staring at you... You continued, we will use a Middleware, we will study the Inputs/Outputs of all different systems, the resources they use and then choose an appropriate Middleware framework.
Still explaining to the non tech manager
With Middleware framework in the middle, the first system will produce X stuff, the system Y and Z would consume those outputs and so on.
Middleware is a terribly nebulous term. What is "middleware" in one case won't be in another. In general, you can expect something classed as middleware to have the following characteristics:
Primarily (usually exclusively) software; usually doesn't need any specialized hardware.
If it weren't there, applications that depend on it would have to incorporate it as part of their application and would experience a lot of duplication.
Almost certainly connects two applications and passes data between them.
You'll notice that this is pretty much the same definition as an operating system. So, for instance, a TCP/IP stack or caching could be considered middleware. But your OS could provide the same features, too. Indeed, middleware can be thought of like a special extension to an operating system, specific to a set of applications that depend on it. It just provides a higher-level service.
Some examples of middleware:
distributed cache
message queue
transaction monitor
packet rewriter
automated backup system
Wikipedia has a quite good explanation: http://en.wikipedia.org/wiki/Middleware
It starts with
Middleware is computer software that connects software components or applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact.
What is Middleware gives a few examples.
There are (at least) three different definitions I'm aware of
in business computing, middleware is messaging and integration software between applications and services
in gaming, middleware is pretty well anything that is provided by a third-party
in (some) embedded software systems, middleware provides services that applications use, which are composed out of the functions provided by the hardware abstraction layer - it sits between the application layer and the hardware abstraction layer.
Simply put Middleware is a software component which provides services to integrate disparate systems together.
In an complex enterprise environment, there are a number of challenges when you need to integrate two or more enterprise systems together to talk to each other. Normally these systems do not understand each others language as they are developed on different platforms using different languages (like C++, Java, Cobol, etc.).
So here comes middleware software in picture which provides services like
transformation of messages formats from one app to other,
routing and enriching messages besides taking care of security,
encryption,
validation and
applying different business rules to these messages.
A typical example of middleware is an ESB products like IBM message broker (WMB/IIB), WESB, Datapower XI50, Oracle Fusion, Mule and many others.
Therefore, middleware sits mostly in between the service consuming apps and services provider apps and help these apps to talk to each other.
Middleware is about how our application responds to incoming requests. Middlewares look into the incoming request, and make decisions based on this request. We can build entire applications only using middlewares. For e.g. ASP.NET is a web framework comprising of following chief HTTP middleware components.
Exception/error handling
Static file server
Authentication
MVC
As shown in the above diagram, there are various middleware components in ASP.NET which receive the incoming request, and redirect it to a C# class (in this case a controller class).
Middleware is a general term for software that serves to "glue together" separate, often complex and already existing, programs. Some software components that are frequently connected with middleware include enterprise applications and Web services.
There is a common definition in web application development which is (and I'm making this wording up but it seems to fit): A component which is designed to modify an HTTP request and/or response but does not (usually) serve the response in its entirety, designed to be chained together to form a pipeline of behavioral changes during request processing.
Examples of tasks that are commonly implemented by middleware:
Gzip response compression
HTTP authentication
Request logging
The key point here is that none of these is fully responsible for responding to the client. Instead each changes the behavior in some way as part of the pipeline, leaving the actual response to come from something later in the sequence (pipeline).
Usually, the middlewares are run before some sort of "router", which examines the request (often the path) and calls the appropriate code to generate the response.
Personally, I hate the term "middleware" for its genericity but it is in common use.
Here is an additional explanation specifically applicable to Ruby on Rails.
Middleware stands between web applications and web services that natively can't communicate and often are written in different languages/frameworks.
One such example is OWIN middleware for .NET environment, before owin people were forced to host web apps in a microsoft hosting software called IIS. After owin was developed, it has added capacity to host both in IIS and self host, in IIS was just added support for Owin which acted as an interface. Also it become possible to host .NET web apps on Linux via Mono, which again added support for Owin.
It also added capacity to create Single Page Applications, Owin handling Http request/response context, so on top of owin you can add authentication/authorization logic via OAuth2 for example, you can configure middleware to register a class which contains logic of user authentification (for ex. OAuth2 implementation) or class which contains logic of how to manage http request/response messages, that way you can make one application communicate with other applications/services via different data format (like json, xml, etc if you are targeting web).
Some examples of middleware: CORBA, Remote Method Invocation (RMI),...
The examples mentioned above are all pieces of software allowing you to take care of communication between different processes (either running on the same machine or distributed over e.g. the internet).
From my own experience with webwork, a middleware was stuff between users (the web browser) and the backend database. It was the software that took stuff that users put in (example: orders for iPads, did some magical business logic, i.e. check if there are enough iPads available to fill the order) and updated the backend database to reflect those changes.
It is just a piece of software or a tool on which your application executes and rapplication capabilities with respect to high availability,scalability,integrating with other softwares or systems without you bothering about your application level code changes .
For example : The operating system on which your application runs requires an I.P change , you do not have to worry about it in your code , it is the middleware stack on which you can simple update the configuration.
Example 2 : You experience problems with your runtime memory allocation and feel that the your application usage has increased , you do not have to much about it unless you have a bug or bottleneck in your code , it is easily achievable by tuning middleware software configuration on which your application runs.
Example 3 : You have multiple disparate software and you need them to talk to each other or send data in a common format which is understandable by all the systems then this is where middleware systems comes handy.
Hope the information provided helps.
it is a software layer between the operating system
and applications on each side of a distributed computing system in a network. In fact it connects heterogeneous network and software systems.
If I am not wrong, in software application framework, based on the context, you can consider middleware for the following roles that can be combined in order to perform certain activities in between the user request and the application response.
Adapter
Sanitizer
Validator
I always thought of it as the oldest software I have had to install. The total app used a web server, a database server, and an application server. The web server being the middleware between the data and the app.
What is the best way to use Windows Workflow Foundation in ASP.NET 3.5 Web Application.
In my case there are several workflows(sequential) which includes numerous steps, user has the privilege to save and exit at any of these steps; the state must be persisted, possibly in SQL Server.
Exposing workflows as web service is good idea? I have very little idea about workflows and only tried out wf console applications.
Please guide me in right direction, also I would like to know is there any specific and established architecture to use wf in ASP.NET Web Apps. We have layered architecture for our web apps (BLL, DAL, Services etc) and I would like to know where we can incorporate workflows in current architecture.
Many thanks in advance.
Update: thank you Rubens Farias for helping me out in first place.
We are still unsure which approach will be the best.
Please provide any example frameworks or sample webapplication which use workflow
So far...
1. Is it good idea to use Page Flow Application Block
2. There are lots of changes in WF4, should I wait for that?
3. Or use WF as Rubes Farias suggested
Please guide me friends, am desperate :(
You definitely must read this document: Foundations: Workflow Services
You can to add an out-of-box persistence service, so your workflows get persisted into a SQL Server database, and to expose them as WCF services (RESTfull approaches is also available).