How do I create a callback API in springboot framework? - api

The scenario goes something like this. I've a 3rd party system that accepts 'callback' endpoint and upon a specific event (at the 3rd party system), a new API request to my callback endpoint will be posted.
Couple of years back, I've created rest API with springboot - which exposes an endpoint that's callable and other 3rd party systems will call the API as and when needed.
Are they both same?

To answer my question, yes, both are same. I've a bit better understanding of APIs and any publicly accessible endpoint can be used as callback endpoint.

Related

Difference between Webhook and API in Middleware ESB

In few blogs I have read, it is said that a Webhook is a reverse API, where it is the sender who initiates the HTTP call while a receiver receiving the data.
It's also said that a Webhook is Event driven and not Request driven. What does that mean? Is a Webhook just a fancy name for a POST API call?
Moreover, I have known that in technologies like Mulesoft, there can be APIs which work as either a REST http exposed endpoint or an Internal Scheduler trigger. How does that relate with the API vs Webhook definition?
Please answer with respect to Middleware integration patterns rather than being programming language specific.

How add condition routing using Ocelot?

I have a Web API which has two endpoints:
/tenant1/xxx
/tenant2/xxx
The Web API serves multiple tenants and it is hosted as a single instance. Now I have to public this Web API to the outside for using, from the third party, they don't need to know which tenant they should call, instead, they call /api/dosomething (another web API), and inside that API, I will look at the parameter and decide which tenant I should reroute. I use Ocelot as API Gateway but searching on the document I can not find the condition routing. Can anyone help me with this?
Ocelot supports DelegatingHandler which play as middleware for out-going request

How do I implement basic API gateway

I am working on one school project, And my task is to make a simple api gateway, which can placed between any of the 3rd party api and the end users, tha gateway can be used for defining usage limits of the api or to do some security analysis, I am totally new to this, I know the basic concept of API gateway, but don't know how do I implement it using JAVA.
Can anyone please give me some starting point where to start implementation of API gateway?
And what are the frameworks I should use and for what purpose?
Thanks,
Nixit Patel
In a nutshell, API gateway exposes public APIs, applies policies (authentication - typically via OAuth, throttling, adherence to the the defined API, caching, etc.) and then (if allowed) optionally applies transformation rules and forwards the call to the backend. Then, when the backend responds, gateway (after optionally applying transformation rules again) forwards the response to the original caller. Plus, there would typically be an API management solution around it providing subscriber portal, user management, analytics, etc.
So basically any web service framework would work as a quick DYI solution.
You can also use plugin model of an open-source load-balancer such as NGINX.
Or take an open-source API Gateway to learn from it - e.g. WSO2 API Manager (the easiest way to see it in action is the hosted version: WSO2 API Cloud)

RESTful API - Custom Application - C#, Java, php?

This is really basic.I want to implement a RESTful web API.
Now I know you can write custom applications and scripts to integrate with the API.
What I need to know:
In what languages can you write this API? C#, Java, php?
When building/programming a program that implements this API, is this the client and the software that issued the API the server? (eg. Dropbox would be the server and the custom app that integrates with the Dropbox API is the Client?
Thank you.
A REST API can be built in any programming language that allows you to handle HTTP requests (or can be attached to a Web server as a handler for requests). The two methods I've been using:
Stand-alone Windows service implementing a REST service using WCF
WEB server Apache + PHP
You are correct about the terminology. A program consuming a service is called the client, a program providing a service is called the server (while actually in the PHP approach, Apache would be the server as it is taking the request and having the script handle it).
Additional nitpicking: JQuery is not a language, but a framework to help you use some JavaScript features more easily.
On your comment Recap:
Close :-) The Client transfers JSON/XML/whatever to a server using HTTP requests. The Client can be written in any language that can perform HTTP requests.
On the server side, there needs to be some application that handles the HTTP requests (service), also written in any language, as long as it "speaks" HTTP.
The API is the definition of which operations are possible, for example, adding user accounts, getting the current time, etc. (this is what you define - what do you want your service to do?).
The JSON/XML/whatever that you transfer is the workload, the parameters for the API call. For example, if you want to add a new user to your system, the workload could be the new user name, the real name, the eMail address and some other details about the user. If the API call returns the current server time, you might not need any parameters at all, but you get back JSON/XML/whatever from the service.
The actual call being made is determined by the URL you call. For example, the URL for adding a user could be http://localhost/myrestservice/adduser and you'd perform a POST request against that URL with the required workload. For the time example, the URL could be http://localhost/myrestservice/getservertime and you'd perform a GET request against that URL.
I suggest that you read about how REST services actually work before you start, as I see some question marks on your face ;-)
Short:
API = available operations (=> URLs)
Parameters to API calls = JSON/XML/Plain Text/whatever
Client = calls the service through HTTP
Service = handles the calls, replies to client in response to HTTP requests
If you are a php programmer and familiar with Codeigniter framework then go here : Working with RESTful Services in CodeIgniter.
visit also : Rest Tutorial
First of all, you should begin with learning what is a RESTful API.
http://en.wikipedia.org/wiki/Representational_state_transfer
http://www.restapitutorial.com/
http://rest.elkstein.org/
In what languages can you write this API? C#, Java, php, jQuery?
You can write an API in any language. What can help is the framework you'd be using. JQuery is not a language, but a framework for integrating Javascript application in every web browser, so it won't help.
I'd advice you to use a microframework to write your first RESTful API, because they usually are easy to use and help focus on the important (bottle/flask in python, express in javascript, silex in php, spark in java or nina in C#)
When building/programming a program that implements this API, is this the client and the software that issued the API the server? (eg. Dropbox would be the server and the custom app that integrates with the Dropbox API is the Client?
You're right, the server is providing you the service, hence the API. The client is user to that API, and implementing it into something useful.
As most of the people stated already, you can do this in just about any language.
Might I suggest that you look into NodeJS? If so, check out Restify: http://mcavage.github.io/node-restify/
There's a nice community behind NodeJS and I think it's quite open to newcomers. Just try not to pick up bad habits from JavaScript pitfalls. If you're new to programming, I'd suggest reading some intro book.
good luck!

calling rest api from another web application

I have a web application (typical mvc webapp) that needs to call a REST API bundled in a different webapp (war file).
The first web app serves as a front to the separate REST API webapp for customers to register and view their stats, purchase plans etc. But part of the design of this webapp is that it must have example invocations to the other REST API webapp.
There are many rest clients out there, but what would be a reasonable approach to address the above?
I was thinking of using the Spring REST Template to call the REST API but from my mvc controller class in the first webapp. Is this a reasonable approach?
Once you deploy a webapp using your deployment tool of choice, you can simply call the REST URL. That's one of the great things about REST - it doesn't care about what sort of tool is calling it because it deals in a neutral medium (usually HTTP). Twitter's REST API (here) doesn't care what's calling it - in fact the beauty of it is that anyone can make an app that calls it.
So say you deployed a webapp locally to port 8080, you can just make a REST call to http://localhost:8080/firstapp/rest/foo.
If you're deployed to the World Wide Web, then just call the appropriate domain.
Yes, RestTemplate is a very convenient way for server to server REST calls. Though there are some tricks if you are going to serialize generics.