Suppose I have 2 web services A and B in SOA project. Both web services are running on a remote servers. Web Service A depends on information available from only a locally installed desktop application on a human actor machine and thats all web service A does i.e. provide this information). There are hundreds of such human actors with the same locally installed application providing its own information that web service A needs. Web service B needs this information from web service A, the result of which (which is the whole benefit of this project) is provided to that human actor who originated this process (by loging into system and clicking some command button). So this human actor is acting like the consumer of Web service B. The question is how can I make this locally installed application act as Web Service A (in the context of SOA project)?
This question could best be answered by some one with extensive experience in Web services and SOA.
This SOA project uses java, like ESB based on Java and there is no Microsoft specific services running although the desktop application is a Windows application. The application provides c/C++ API for an external process to call and retrieve the information needed by Web service A. What I want is the both web services A and B are hosted on remote server and interacting with each other via ESB but the problem is how to make local application information available to Web Service A?
There are two types of solutions
The first: have the original client application add a parameter with the address of web service A, and use this address for calling the service.
The second: pass a more abstract user identifier from the client (actually, there's a good chance you have such a field in the service). and use a translation service to retrieve the physical address corresponding to this id.
To allow such translation, the desktop application that acts as a server needs to "register" with the translation service when starting up.
If you are using an ESB, or other SOA infrastructure (like a service directory, message queuing service) it will include much of the functionality you need to build the translation service.
regarding the actual hosting of the service in the client machine.
the simplest solution is to use a different process from the actual application, and just access the files or DB the application uses.
In this case you can use any infrastructure you like to develop the service.
a more complex scenario is when you need the actual application to supply the service. in this case you will need to have a thread in the application that listens to service requests.
if you are using WCF see Hosting Services about how to host a web service in your application.
EDIT
some additions regarding you clarification.
as I understand, the desktop application exposes a C\C++ API that is available for external processes on the same machine.
You can either write a web service that will use this API. Googling "C++ Web Services Windows" will give yo several relevant pointers on implementing those.
Another good option is to use a messaging infrastructure. most JMS providers provide API's in languages other then Java - including C++.
Your application will be a C++ windows service that listens and sends messages to you JMS provider.
I'm investigating integrating a 3rd party web application with PeopleSoft via web services. I'm not that familiar with PeopleSoft. After some initial investigation, it appears that in order to expose any PeopleSoft functionality as web services, you have to do some considerable configuration in the Integration Broker component of the PeopleTools module. It seems that you can either define internal PeopleSoft services with "service operations" and related "handlers" or you can create a PeopleSoft service for an existing "Component Interface." Then, you have to expose that PeopleSoft service as a web service.
Are there any standard, default, out-of-the-box web services available for a PeopleSoft system, or do you always need to go through the steps of defining them in the Integration Broker?
After looking at a system like Salesforce, which has a standard web services API, it seems like there might be something similar for PeopleSoft, but I'm not finding it. Am I on the right track in thinking that the Integration Broker is the only way to go, or am I just not aware of some standard web services API that exposes basic PeopleSoft functionaity as web services?
Integration Broker (IB) is what you need to expose business logic from peoplesoft and consume it with your 3rd party tool, or to consume a webservice from your tool in peoplesoft.
There are some out of the box messages, but most of them are made to have different PIA (PeopleSoft Internet Architecture) communicate.
Be aware, IB components were almost complemently remixed in peopletools version 8.47. So it's important to give your tool's version when talking about IB.
Never heard about a standalone API for implementing web services, outside of the IB framework. IB will use dedicated class to handle sending and reception of your messages. You mention it as the handler. And if a component interface need to be used it will be done throughout this class.
Integration broker is used to setup the basic configurations that will be used in exposing and using web services. this includes making nodes and its routing available for other system to use.
http://docs.oracle.com/cd/B14099_19/integrate.1012/b14060/int_broker.htm
There are many web services available in peoplesoft. you can alsi expose any componemnt as a web services by executing very simple steps.
http://docs.oracle.com/cd/E15645_01/pt850pbr0/eng/psbooks/tibr/chapter.htm?File=tibr/htm/tibr14.htm
Custom web services can also be build.
What are the differences between a web service and a Windows service?
My experience has mostly been with Windows services, and I have never created a web service.
Do web services behave similarly to Windows services?
Can they have scheduling, run at certain times, etc.?
When you would use a web service in place of a Windows service, and vice versa?
They're about as different as two things can be.
A Windows service is an application that runs without a user being logged into the system, usually to process some data on the machine that needs no user intervention to work with.
A Web service is a website that, when contacted, returns XML (typically) in one of several standard formats for the service consumer to process.
One can't be substituted for the other. They are fundamentally different.
You are asking us to compare apples and oranges. I am posting definitions as well as links to further reading for you so you can see why these two things are exclusive and cannot be compared like you are trying to do.
Web service:
Web services are frequently just Internet application programming interfaces (API) that can be accessed over a network, such as the Internet, and executed on a remote system hosting the requested services
Windows service:
A Windows service is a long-running executable that performs specific functions and which is designed not to require user intervention.
A web service is an HTTP interface to a system. For example: the Twitter API or the Google Maps API are REST web services.
A Windows Service is a background process that runs without user interaction.
The two are not related.
Webservices are simply a way of exposing services for consumption. They are about interaction between components.
A windows service is an executable that runs for a long time on a machine to perform some task.
You wouldn't use one in place of the other - they perform two entirely different functions.
For (a simple) example (to highlight the difference), if you wanted a method to pass control messages to your service, you could expose a webservice as the protocol through which third parties would communicate with your service.
A web service is software system used for machine to machine communication over a network.
Here's the wiki for Web Service.
A windows service, in contract, is a service that runs on an local machine.
Here's the wiki for Windows Service.
They are independent technologies, one would not replace the other.
I don't think there is a very large difference, a web service runs in IIS or Apache, a windows service doesn't. You can call windows service methods by using remoting and you can create windows service with WCF. The methods of a windows service can return xml or json too.
IIS 6 doesn't support all the WCF possibilities so we have build WCF windows services (this is called self hosting).
Both a web service and a windows service are apps that run in the background. You can use WCF to build both kind of services.
web service was mostly used in application integration between systems.
windows service was mostly used in background tasks, scheduled tasks.
A windows service program can call web service methods.
web service program cannot call window service methods.
A Web Service is a dll hosted by a web server and run as a web application and can be spun up upon request.
A windows service is an exe hosted by the operating system and runs continuously waiting on a request.
I've been reading about "web services" here on SO, on Wikipedia, Google, etc., and I don't quite understand what they are. What is the plain English definition/description?
If I make a simple website using PHP that just, say, prints a random integer to the page... is this a "web service"? If not, why not?
A simple definition: A web service is a function that can be accessed by other programs over the web (HTTP).
For example, when you create a website in PHP that outputs HTML, its target is the browser and by extension the human reading the page in the browser. A web service is not targeted at humans but rather at other programs.
So your PHP site that generates a random integer could be a web service if it outputs the integer in a format that may be consumed by another program. It might be in an XML format or another format, as long as other programs can understand the output.
The full definition is obviously more complex but you asked for plain English.
Simplified, non-technical explanation:
A web serivce allows a PROGRAM to talk to a web page, instead of using your browser to open a web page.
Example:
I can go to maps.google.com, and type in my home address, and see a map of where I live in my browser.
But what if you were writing a computer program where you wanted to take an address and show a pretty map, just like Google maps?
Well, you could write a whole new mapping program from scratch, OR you could call a web service that Google maps provides, send it the address, and it will return a graphical map of the location, which you can display in your program.
There is a lot more to it, as some of the other posts go into, but the upshot is that it allows your application to either retrieve information FROM, or submit information TO some resource. Some other examples:
You can use a web service to retrieve information about books at Amazon.com
You can use a similar web service to submit an order to Amazon.com
You could CREATE a web service to allow outside applications to find out about product information within your company
you could create a web service to allow outside applications to submit orders to your company.
Yes that is a simple web service.
Web services are really nothing more than a request/ response mechanism that allows a client to remotely access/ modify data. There are formal standards for web services (SOAP, SOA etc), but your simple page is a service too.
The main downside to printing it to a page is that your service would return HTML. Preferable data formats are JSON and XML, because most client frameworks (and server frameworks) are designed around using JSON and XML.
So if you modified your service to return:
<RANDOM>some random number</RANDOM>
rather than:
<HEAD>...</HEAD>
<BODY>some random number</BODY>
then it would be more useful to most clients
In over simplified terms a web service is something that provides data as a service over the http protocol. Granted that isn't alway the case....but it is close.
Standard Web Services use The SOAP protocol which defines the communication and structure of messages, and XML is the data format.
Web services are designed to allow applications built using different technologies to communicate with each other without issues.
Examples of web services are things like Weather.com providing weather information for that you can use on your site, or UPS providing a method to request shipping quotes or tracking of packages.
Edit
Changed wording in reference to SOAP, as it is not always SOAP as I mentioned, but wanted to make it more clear. The key is providing data as a service, not a UI element.
A web service differs from a web site in that a web service provides information consumable by software rather than humans. As a result, we are usually talking about exposed JSON, XML, or SOAP services.
Web services are a key component in "mashups". Mashups are when information from many websites is automatically aggregated into a new and useful service. For example, there are sites that aggregate Google Maps with information about police reports to give you a graphical representation of crime in your area. Another type of mashup would be to take real stock data provided by another site and combine it with a fake trading application to create a stock-market "game".
Web services are also used to provide news (see RSS), latest items added to a site, information on new products, podcasts, and other great features that make the modern web turn.
Hope this helps!
The best plain English explanation comes from using an analogy:
Web pages allow people to communicate and collaborate with each other.
Web services allow programs to communicate and collaborate with each other.
Your PHP example is a web service by that definition, because the output could be consumed by another program. But in reality, HTML screen-scraping is not a reliable or maintainable way of producing web services.
For most sites you have HTML pages that you visit when you use your browser. These are human-readable pages (once rendered in your browser) where a lot of data might be crammed together, because it makes sense for humans.
Now imagine that someone else want to use some of that data. They could download your page and start filtering out all the "noise" to get the data they wanted, but most websites are not built in a way where data is 100% certain to be placed in the same spot for all elements, so in addition to being cumbersome it also becomes unreliable.
Enter web services.
A web service is something that a website chooses to offer to those who wish to read, update and/or delete data from your website. You might call it a "backdoor" to your data. Instead of presenting the data as part of a webpage it is provided in a pre-determined way where some of the more popular are XML and JSON. There are several ways to communicate with a webservice, some use SOAP, others have REST'ful web services, etc.
What is common for all web services is that they are the machine-readable equivelant to the webpages the site otherwise offers. This means that others who wish to use the data can send a request to get certain data back that is easy to parse and use. Some sites may require you to provide a username/password in the request, for sensitive data, while other sites allow anyone to extract whatever data they might need.
A web service is a collection of open protocols and standards used for exchanging data between applications or systems. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a manner similar to inter-process communication on a single computer. This interoperability (e.g., between Java and Python, or Windows and Linux applications) is due to the use of open standards (XML, SOAP, HTTP).
All the standard Web Services works using following components:
SOAP (Simple Object Access Protocol)
UDDI (Universal Description, Discovery and Integration)
WSDL (Web Services Description Language)
It works somewhat like this:
The client program bundles the account registration information into a SOAP message.
This SOAP message is sent to the Web Service as the body of an HTTP POST request.
The Web Service unpacks the SOAP request and converts it into a command that the application can understand.
The application processes the information as required and responds with a new unique account number for that customer.
Next, the Web Service packages up the response into another SOAP message, which it sends back to the client program in response to its HTTP request.
The client program unpacks the SOAP message to obtain the results of the account registration process.
Simple way to explain web service is ::
A web service is a method of communication between two electronic devices over the World Wide Web.
It can be called a process that a programmer uses to communicate with the server
To invoke this process programmer can use SOAP etc
Web services are built on top of open standards such as TCP/IP, HTTP
The advantage of a webservice is, say you develop one piece of code in .net and you wish to use JAVA to consume this code. You can
interact directly with the abstracted layer and are unaware of what
technology was used to develop the code.
Webservice is a technology by which two or more remote web applications interact with each other over network/internet. It can be implemented using Java, .net, PHP etc.
Features of Web service:-
Using web services two or more systems exchange data over network. Data are exchanged either using XML or JSON.
Any web service has two parts Server end where the service is deployed and the client part where the service is accessed by its clients. Any web service can have multiple clients. When a travel portal is selling tickets of an airliner. Portal is client and the Airline is the server as it is selling its service.
Web services can be synchronous or it can be asynchronous also.A web application can interact with many web services but these web services are loosely coupled with their client web applications. That means any change in the parent application has little or no effect on the web services or vice versa.
Web services can carry attachment document also like PDF, Word etc. with its XML payload. Java provides separate API for this type of web services.
A web service always hides the internal complexity of the service to its clients. For an example, an airliner which is selling tickets via a third party portal is only gathering end user info via a web service and in return it is providing ticket. The portal which is selling ticket doesn't have to bother about the internal complexity of the airlines ticket reservation systems.
A web service can be of fire and forget type or it can return something. Suppose, a web application just want to send some info to a third party application. The sender doesn't need any acknowledgement from the receiver. In this type of scenario we need a fire and forget type of web service.
A web service, as used by software developers, generally refers to an operation that is performed on a remote server and invoked using the XML/SOAP specification. As with all definitions, there are nuances to it, but that's the most common use of the term.
An operating system provides a GUI (and CLI) that you can interact with. It also provides an API that you can interact with programmatically.
Similarly, a website provides HTML pages that you can interact with and may also provide an API that offers the same information and operations programmatically. Or those services may only be available via an API with no associated user interface.
Well,
As #Vincent Ramdhanie has said that a web service is not meant to be seen / consumed by end user but another program. So technically logic in your program will be:
In case of acting as a normal program
user on website -> HTML/JS/JQuery etc -> give me a random number ->ur program
Now
ur program -> generate random number -> generate HTML and encapsulate o/p -> go back to user
but in case of web service the flow changes a little:
user -> my application -> XML/JSON/some other format -> give me a random number ->ur program
Now
ur program -> generate random number -> generate XML/JSON/some other format -> my application -> generate HTML and encapsulate o/p -> go back to user
Hope this helps :)
A simple definition would be an HTTP request that acts like a normal method call; i.e., it accepts parameters and returns a structured result, usually XML, that can be deserialized into an object(s).
Web services are almost like normal a web page. The difference is that they are formatted to make it very easy for a program to pull data from the page, to the point of probably not using any HTML. They generally also are more reliable as to the consistency of the format, may use a different formal process to define the content such soap or raw xml, and there is often also a descriptor document that formally defines the structure for the data.
A way of sending a message to invoke an operation on another computer. The difference between web services and previous methods is what gets sent over the wire is standardized at a higher level.
Old way: describe endians, encoding, port numbers, etc.
Web Service: URL, XML
Web Service is like a medium of commuication between two unrelated programs. The programs use a specified protocol(Usually Simple Object Access Protocol (SOAP)) as medium to understand what REQUEST/RESPONCE they are to process/execute on there respective end.
A web service defines a contract of actions that a server will perform for you. The format and protocol doesn't really matter, but you should have some set definition of how the communication happens.
In your example, it depends, if that is being used in another application that reads that number, yes it is service, otherwise, it's just a webpage with a number.
In simple words Web service could be any simple program ex: add two numbers which should be published over the UDDI and can be consumed by another program.WSDL will have the endpoint to locate the webservice and also the binding and port details.
'Web Service' is composed of two words,'Web' and 'Service'.
What is 'Web'? 'Web' means 'World Wide Web'.
'Service' for what? Not for Human,if so,it's 'Web Page',such as text,images,video etc.
It's for Programs to communicate through the Internet using the same technology the 'Web' used,such as TCP,HTTP etc.
'Service' also means it provides some functions,like the 'Service Layer' in CRUD.
There are mainly two types:
1. SOAP(Simple Object Access Protocol)
2. RESTful(Representational state transfer)
Without prejudice to other definitions I would say that a web service is software system that allows for inter-operable machine-to-machine / application-to-application interaction over a network. This generic definitions would also help consider REST architectures to be a web service as they provide similar functionality albeit being an architectural style unlike the SOAP which is a fully defined protocol.