Hello And Welcome to this Session on Web Services today we are going to learn what a web service is what is the Basic concept behind web services and why do we use it so let us begin and let us see what a web service is so we can say Web Services is a service available over the web now this is very straightforward expansion of the word web service but what does it actually means so Let Us see let us say that we go to a hotel or restaurant so let us say this is you and you have gone to a hotel for having your dinner ok so this is you and let us say this is the kitchen from where the food will be served so this is the kitchen ok now what we are going to have is we are going to communicate our order to the kitchen and the kitchen is going to serve our order ok now there is an a person who is involved in communication process the person takes your order from your table goes to the kitchen Places the order and then takes your food from the kitchen once it is prepared and you get your food through the same person and who is that person so that person is a waiter right so let us say this is our waiter who is doing all this communication between you and the kitchen so this is our waiter so his responsibility is he has to take your order go to the kitchen then make sure the kitchen prepare’s the order and serve you back now here our waiter is performing the role of a web service API or we can also say web service he is communicating between two applications and making sure that the communication is proper and successful ok now you might have a question that what is the criticality of the presence of this particular person in this communication process even if this person or waiter is not present you can still go and place your order to the kitchen and then take it from there and have your food ok now think about a scenario you speak English and The Chef who is present inside the kitchen speaks German and you do not understand each other in that case here is a person who makes sure you two applications can communicate with each other and whatever response you have to get from the server or whatever request a server has to get from a client is in an format where two entities can understand each other and communicate so here you are a client and kitchen is a server and you are communicating with each other so therefore the presence of this waiter or Web Services becomes very important let us see a practical example let me go to a website like makemytrip.com and let us try to book a flight so I am booking a flight let us say from India New Delhi to Mumbai ok and let me just click search flights so see this website is doing searching for all the flights between New Delhi to Mumbai on some particular date and within a few seconds it has given me all the options so all the airlines air India Jet Airways go air vistara and all other airlines all the information about the flights have been listed out within few seconds so what has actually happened here let us try to understand this what has happened here so let us say this is the website MakeMyTrip ok and this is Air India this is Go air this is Indigo then we have Jet Airways and others like vistara and so on so what MakeMyTrip website has turn in our example it has communicated between these websites right whether it is go air whether it is Indigo it has send some request received back a response then displayed the details of all the flight of all this website ok so this is what has just happened in our practical example now what do you think how is it possible for a website like makemytrip to quire the databases of all these websites all these applications real-time and provide us information of all the flights within a few seconds well one of the way is this particular website MakeMyTrip or this particular application has access to the data bases of all these website of these all these Airlines but that might not be the case here because no Airlines website or Airlines will allow a third party to go inside their database for some obvious reasons and for some security reasons it will not allow so that might not be the case okay there can be a second possibility that these Airlines are dumping all the data or all the information about the flight to make my trip every hour or every half an hour ok that can be practically possible but think about the situation the status of the flight can get changed every second ok in that case we need real time data what if somebody tries to book a flight but that flight got cancelled five minutes ago but make my trip will show that is available and then there will be a lot of chaos right so that can not be the case either now what happens here is all these Airlines have exposed their Web Services through an API and this website makemytrip.com uses those Web Services to communicate between the airlines ok so it it has a common format in which it sends out a request and receive back the response in the same format and that response is shown on their website here ok so this is how they are communicating and this is how their making use of Web Services ok so now you can appreciate the use of web services let me also put this down here so Web Services is a service available over the web it enables communication between application over the web and it provides a standard protocol or format for communication and the standard standard protocol format we will look into details in our coming sessions ok and we have already seen the basic concept behind the services we will go into more details into the architecture but we know what exactly a web service has to do right ok so so why we use it because it provides a platform independent communication so you can have an application written in C plus plus over Windows 10 platform and then there can be another application written in Java over a Linux platform these two applications can talk to each other using Web Services ok so that is why using web services we can enable communication between two different applications and that is why we use Web Services so in the coming Session we will go into more details about web services and we will also look at what are the different types of web services Thanks for watching.