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the concept of development is never static better software solutions are being implemented every day with the help of ever emerging technologies apis are essential if you want to build a system with multiple functions and are well documented on that note hey everyone i am vavo khandelwal and i welcome you all to our simply launch youtube channel we will talk about c-sharp rest api but first let me remind you that we have our daily updates on numerous technologies so if you are a tech geek looking for the latest technological advancements then try subscribing to our youtube channel and don't forget to hit the bell icon to never miss an update on simply launch youtube channel so now without any further ado let's get started with the agenda for today's session we will begin a session with the discussion on what is rest api then we will have a brief discussion on http verbs following that we will have a look at some http status code then we will take a deeper look at the res api constraints after that we will create our own rest api project finally we will wind up this session with a few takeaways now let's start with what is c sharp rest api rest is an acronym that stands for representational state transfer rest is architecturally styled for distributed system based on ideas refining and addressing network resources http is used to communicate between restful services where http stands for hyper tax transfer protocol the rest systems communicate with external systems using uri identified web resources where uri stands for uniform resource identifiers after understanding the c sharp rest api let's discuss http works the restful web api relies heavily on http verbs post cat put and delete are the most typical http verbs used for crude that is create read and delete and update activities now let's discuss each of them in detail first we have post if we need to insert data into the database then method the method must be defined as the post method we decorate this method with http post method next we have get retrieving data or information is possible through get work we decorate a method with http get to define a get method then we have put if we need to update or modify the data in the database then the method must be defined as the put method we decorate method with http port to define a put method at last we have delete if we need to delete the data in the database then the method must be defined as the delete method we decorate method with http delete tag to define as the delete method next let's have a look at the sum http status codes there are five types of status quo series first the hundred series this represents the information status codes after that we have 200 series this represents success status codes fine after that we have 300 series that represents the dire redirecting status codes then we have the 400 series which represent the client side error status scores at last we have the 500 series which represent the server side error status code now our main focus will be on success client and server error only so let's have a look at three of them first up 200 series at number 200 we have ok status then at 201 we have created at 202 we have accepted at 204 we have no content next we have 400 series which is client side error status code so at 400 we have bad request letters at 401 we get unauthorized status at 403 we get forbidden at 404 we get not found next we have 500 series which is which represent server side error at 500 we have internal server error at 501 we get not implemented five or three we are getting service unavailable and at five or four we get a gate away timeout next let's discuss the constraints of c sharp rest api constraints of c sharp rest api there are five constraints for this uniform interface stateless client server cache level and layered system let's discuss each of them in detail first up we have uniform interface the uniform interface requirements specify how client and server must interact it simplifies and decouples the design allowing each component to evolve independently next we have stateless a single client can send many requests to the server but each request must be independent each request must contain all of the essential information for the server to interpret and process in this situation the server must not save any client state information such as sessions and only these data should only remain on the client then we have client server the uniform interface separates clients and server because of this separation of concern clients for example are not concerned with data storage which stays internal to each server improving the mobility of client program then servers do not care about the user interface or user status allowing them to be simpler and more scalable after that we have cacheable since multiple clients visit the same server and frequently request the same resources these responses must be cached to save wasteful processing and considerably increase speed at last layered system normally a client cannot know whether it is connected directly to the end server or through an intermediary in terms intermediary server can improve system scalability by facilitating load balancing and providing shared caches layers can also enforce security policies now these were the constraints for c-sharp rest api so now let's try to implement them with the help of a project this will be our end result for this demo now let's go to our visual studio we will use asp.net core web api which hit we'll name it student rest api then we'll click on next make sure to remember which dotnet framework version you are using since we will be installing some packages which will be only available for certain versions since i am using 5.0 so i will be only installing packages which are compatible with the 5.0 framework let's hit the create this will take some time to create a project now let's install some packages so we will right click here and select manage and new get packages we will go to browse and search microsoft entity framework dot tools we will select this we will use since we are using 5.0 so we will only be using the version starting with 5.0 so i selected this and i hit install click ok and accept we'll wait for it to install then we will go and install ntd framework dot co we will also install it as 5.0.0 here click on install click on ok ixr we'll wait for it to install we have tools installed and we also have a microsoft entity framework core also installed we also want to install dot sql server we will use this to interact with the server to make a database we'll click ok and i accept and it's installed we are close that we also want to make one folder so we will go to add and click on folder we'll name it models now now let's start by creating a class file we will go to this we will go to add and click on class we will name this class as students click on add now we will write the members for the student class we will start with public and student id we will give it get set as the method functions then we will have public string as first name we will give a get and set similarly we will create public string last name we will give it get set then we have public string email will give it get set then we have public we will also use an enum called gender we will be defining this later on so gender get set so now public and we have a department id as well this will also have get and set functions then we will have one last member as public string photo path we have get and set we will save this now let's create the enum gender so we will right click here we'll go on add and select class we will name it as gender now add we will remove class from here and make it enum then we will go here and type in members as male then we also want females and we can also have others let's save this now if we go to the student class you can see gender is now green which means it is representing an enum as you can see so now let's create an db context file so we will go to models right click here add a class we will name this one as app db context we will add now to save up some time i will add in the prebig code here's some prereq code as you can see we are getting some errors so let's rectify them first first let's consider db contacts we'll press ctrl period to check what we can what's the problem since we didn't include the microsoft entity framework code so it's giving us this error so we will include it and it's it removed db context error we are not getting any other error anymore now so let's save it now let me go over the different so at start we are using we are inheriting this appdb context class from db contacts which is the part of entry framework core what this lets us is use db set which will help us in creating the on model builder to create a table so now let's start with our table for the first member we have a student id we have given it a student id one first name last name email database gender department id and photo path similarly we are also giving using the model builder we are giving to student 2 sam matthews then model 3 christina frost then model 4 racial stone now next we have to create an entity framework layer which we can create using repository but before that we need to include this db context in our startup file so we will go to startup file we will go to services configure services we will type in services dot add db context then we will add f db context then we will have here as options switch to options dot use sql server then you will have configuration dot get connection string then in bracket we will have db connection now we will rectify this error so for fdb context we will include student rest api models and for use sql server we will include microsoft entity framework core we also need to go to our app setting json and add a connection string so we will add connection string db connection then we have server equals to local db then mss ql local db database equals to studentdb trusted connection equals to true let's see this let's go to our student.cs now our entity framework is now complete now we will create a repository an abstraction layer between our application and data access layer which in our instance is app db context but before that let's create a server so we will go to view and open other windows and select package manager console here we will type in add dash migration initial create this will build up our server and build succeeded we can enable it now we will update now we will update a database so we will type in update data and hit enter this will initiate build started and will succeed as you can see we have got a new folder as migration here let's close intellicode and we can close the package now now let's go ahead and create an interface so we will go new item interface we will name it i student repository we will add will make it public we will start with task i innumerable in that we will have students and then we can have search with arguments as string name comma gender within question mark small gender then let's have some more functions as task students okay student and student id then we have task as i in a miracle student get student we also have a task student cat student by email with the argument as trying email then we have task student as ad students next we will add task by the name update student and we will pass an student student at last we have task as delete student we will pass on an argument as student id so that when we will pass and student id in this release student function it will delete that entry let's save it and see if there are any error there or not so now let's make an class called student repository now to save up some time i will add some pre-baked code here is our code for a student repository let's go over let's go over each function first we have add student this function is responsible for creating as entry in the database then we have delete student it is getting an error so let's rectify it first we will click on control period it's asking us to include ntd framework let's add it and it has removed in the first statement it is requesting student id from us when we'll provide the student id it will compare it if it's not null then it will find the student id and remove that result and then it will save the changes then we have get student by id so we will provide the id then it will basically print that student then we have student get student by email where it is email so it will just take the email from us and compare the database with the email and provide us the result for the same then we have get student this will basically list each and every entry in the database then we have search this will ask for us ask us for the name and the gender then it will basically search if those two things are available the entry which have both of these common it will list out all of them here we have search which will ask us for the name and the gender it will basically compare each and every entry for both of them and give us the common common list between them next we have update student this function is responsible for updating entries in a function however this will not be able to change the student id of a person and that's it let's save it we also want to add scope of these in the startup so let's go to startup we will go here we will go services dot add scope i student repository comma student repository let's save it and with that the student repository part is over now we will construct a rest api controller so we will go to controller we right click here we will add a controller we will select an empty we will name this controller as students controller let's add it now to save up some time i will add the pre-baked code now let's start with this code first we will remove some error so we will control period it's asking us to include these models then we have an error here so we will add some http now let's go over each function one by one so first we have search http so for the search it is asking us for a name and agenda as argument if you look closely we are using try and catch functions so that we will be handling the exception easily so that if any error occur the whole database don't go corrupt so in the trial we are getting result for each entry which have the name and the gender given in the argument if result if any then we will give an okay status and print out the result otherwise it will print out not found now in case of any x exception like internal server error it will print out the error retrieving data from the database as you can see the status 500 internal server error is simply http status code 500 then we have another http get function it is get students this will basically return okay and get and print out all the students or else if it encounters a 500 internal server error then it will print out error retrieving data from the database then we have an http gate which will basically ask us for an id and only show us the entry representing that id now if the result is null then it will return us not found now in case an exception it will print out error retrieving data from the database next we have an http post request this is a create student request so it will be responsible for creating new entries so let's say if student is null basically the end we didn't provide any entry in the during the time of creation so it will just give us a bad request now in case if we are providing a valid entry but we have the email already stored in our database so it will say student email already in use and it will give a bad request again now in case everything it goes by smoothly then it will create the student and it will automatically provide an id to that student now there could be an exception so then it will give us 500 internal server error which will return as error creating new student record now as you can see we are already giving the bad request so when will this occur so basically if none of the criteria for the above matches and it still gives us an error then it will automatically redirect it to an error creating new student record next week we have http report this will be responsible for updating student data so first it will ask us for an id it will compare this id if student id is does not match with the data we are trying to update then it will give us a bad request if it gives us the right request but the id does not exist then it will gives us student with this id does not count if everything goes right then it will just update the method in case if still some error occurs then it will print out error updating student record and it will give us 500 internal server error status then we have delete for this it will always request an id so that it doesn't go and delete whole database now if an id doesn't is not present then it will say id not found otherwise it will delete that id and if we print out student with this id is related now in case some error occur otherwise then it will gives us a 500 internal server error and gives us error deleting record now let's go ahead and save it and run this as you can see we are using a swagger interpreter so let's use this function first let's try it out and execute and as you can see it is printing out every entry from student id 1 akash let me zoom in send id 1 akash guptas akash simplyrun.com and all that then we have sam matthews and have we have christina first then we have rachel stone now let's say we want to add a new entry let's copy this as a sample let's try it out we don't need student id here because the system will give it its own for the first name let's add my entry so let's add that uh then we have for the last name kendall then for the email let's get a webhub at the right simplylearn.com then for the date let's add 1998 let's leave everything else as it is for the gender it should be 0 0 for the mean then we have department id as 2 and for the photo path we can give it as images slash web hub dot png now let's execute and it has basically worked so to check that we will again go and use our getting we have executed and as you can see it has a fifth entry student id five baba kundal so we have tried our post we have tried our get let's use our search one as well so to try it out we need to give it a name so let's search the latest entry we created so that for the gender we have zero and for the path we can give it let's give it email id so that at the right simply learn so let's execute and as you can see it is giving us this entry so we have used get cat we have used post now we have this get method with the id let's try this one as well let's search for the third one and it is giving us the christina that's the fifth one which we just made and it is giving us the web hub so after that let's try to update an entry let's try it out let's do fifth one which is what's mine we can remove the student id for the first name let's change it to let's make it simpler simply then for the last name we can have learn as email we can have simply learn at the rate simplylearn.net we can let the data part be same let's give it two cents for others department id for photo path images slash simply dot png let's execute this if a success it says student id mismatch like maybe we have to give the student id copy here let's give it and execute and it works right so to check it we can simply go to get api with id and execute and as you can see it has changed the first name is simply last name learn and email date of birth and everything now let's go ahead and delete an entry to delete an entry we need to just give it an id let's try it with the three let's execute student id with three is deleted so to check that we can go here and execute now if you look closely we have with akash then sam then we have student id 4 ratio we have lost the christina for frost id let's also try for the fifth one which we made so 5 execute to index id5 is deleted let's execute this and it has lost the r as well let's try to execute the five again and it says not found let's go back to our slides now let's look at some of the takeaways from this session first we have rest api with serve as the interface and communication between the client and the server which takes place over http then we have the rest api which also serves as the gateway or a single point of access into the system we also learn that when a client requests a restful api it sends a representation of the resource state of the requester to the endpoint and this was all for today's session hope you guys found it informative and helpful if you liked this session then like share and subscribe if you have any question then you can drop them in the comment section below thanks for watching and stay tuned for more from simply learn [Music] hi there if you like this video subscribe to the simply learn youtube channel and 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Id: BqDvnDQoMVo

Length: 49min 59sec (2999 seconds)

Published: Sat May 21 2022