I want to consume data in XML format from an SAP System.
To do that, I implemented an OData Service in the SAP System and activated it.
I tested it in my SAP Web IDE and it works.
But now I am developing another project in NetBeans consisting of HTML and JavaScript, and I want to consume the OData Service in that Project.
To reach that goal, I did a lot of research on the internet and read about a few options, but I'm still confused.
Is XMLHttpRequest the thing to achieve it, or is it Apache Olingo, etc.?
Can anybody please give me a clue which technology to use for it?
Apache Olingo is a framework used to expose an OData service in Java. You already have your OData service, you don't need to touch that.
Both the SAP Web IDE project and your HTML/JavaScript project in Netbeans are clients of your OData service, that is to say, they both query your OData service for data.
Both the SAP Web IDE project and your HTML/JavaScript project in Netbeans are frontend projects. They both use HTML/CSS/JS to display the page nicely and perform CRUD operations on the data.
XMLHttpRequest is an API which can be used in plain JavaScript to send requests. You're probably using it in your SAP Web IDE project to query your OData service. As such, you can use it also in your Netbeans project to query your OData service.
So query your OData service in your Netbeans project the same way you do in your Web IDE project.
Related
I am currently in the process of creating a portfolio website for myself but due to hosting restrictions, I cannot make use of Node.js.
I know Angular can run on any web server, but is it possible to make use of Express.js to create web api's with relying on Node.js to run these web api's using Express.js?
If not, is there an alternative solution to create web api's that I can call using Angular and later for my mobile version of my website?
Please note that my shared hosting runs using cPanel.
As per definition Express.js, or simply Express, is a web application framework for Node.js so you can't do that. Alternatives would be to use a different backend language.
That also depends if your server supports them, for example, you can go with .NET CORE
You cannot use Express without NodeJS by definition so you have to deploy your backend somewhere else in you want to use it.
I suggest giving a look Firebase: you could write your backend using http cloud functions in express without paying anything until a reasonable amount of traffic (after that, is pretty cheap). You could also get rid of cPanel and deploy your frontend there via Firebase hosting.
Maybe you can try to build at first a web application with express. Of course you can create a web app without express if you need it. With express and Node.js I created a MySQL REST API. With HTML and Ajax you can fetch the Data from the API. So you can create two applications. One application where you need to run Node.js because it`s much easier to create a REST API with express. The second one is fully without Node.js.
Maybe there are better solutions, but inside each Web Application you can than but you can then access this API in any web application using jQuery. It doesn't matter if it is written with PHP, ASP.Net Core, Java EE / EE4J. You can also access this API in Ruby, Angular, React, Vue etc. using an AJAX request.
In some scenarios you can't start Node.js as a server because an application is already running on apache2 or nginx. There this would be a workaround to use something like this. For example, one could also integrate applications with HTML+JS in a CMS system that accesses other database tables and thus extend such a system without an iframe.
So can be helpful for few scenarios. Now just doesn't get around the actual goal of doing without Node.js completely or even express. But why are there REST APIs? So that you can query the data and incorporate it somewhere else. Otherwise you would have to build a REST API with another technology. Especially in the example of accessing MySQL with JavaScript, this would not be quickly feasible.
If you are looking for a similar solution to separate the web app and the REST API, but you don't need Node.js, then you should really build a REST API with .Net Core or with another technology, depending on what is possible and installed on your server. It could be Java or PHP behind it or Ruby.
The API that provides the REST access does not have to be written in JavaScript. You only need to be able to access it with JavaScript. So you can use many different approaches to access JSON data. I hope that in the short time with my bad English I have explained the basic idea, how to proceed stylistically and where advantages exist in REST interfaces.
With this, it should be self-explanatory that you don't have to use NodeJS and Express, but with JavaScript it's a pleasant solution. Only you have to ask yourself if a JavaScript application has to provide this interface at all or if in the end only a JavaScript application has to access this interface. Very big difference.
For backend rest api you can use golang with gorilla framework. Golang simple keyword and easy to learn.best important point is performance. If your server support golang you can use golang for backend..
ExpressJS is NodeJS framework so it's impossible to create an API without NodeJS.
Angular is front-end framework so you can host it on web hosting server.
If you need to create back-end APIs, you can use other clouding host servers that support NodeJS.
It's fairly simple to build this with just the net/http package. Set up a router that handles various commands and deal with the response accordingly.
I've implemented the shell of a microservices-based REST API application. I have simply followed the guides on Pivotal Springs' own documentation using Eureka and Ribbon for load balancing. Everything works. I have a discovery server with a handful of independent services which can register with the discovery server.
Now, my problem is that I might prefer not to write my client-side app in Java - maybe Angular or node.js, etc. However, the load balancing and connecting to the discovery server is all done in Java in the examples I've followed.
Is it possible to use JavaScript to do the same things that the Eureka client does with the Spring Boot microservices so that I don't need to be constrained in my choices of browser client technology? Does anybody have any advice for how this should be approached? I had difficulty finding any articles that cover this, to be honest.
Yes. Definitely you can choose technology of your choice for developing front end application. From your front end application, you make calls to API endpoint that you expose via your spring boot application.
You might want to expose your services via single API gateway that will help you route requests to designated micro services using your discovery server.
Actually you should not be doing load balancing/service discover etc. in the front-end. So the question about whether it is possible in JavaScript or with which libraries is irrelevant.
Typically you'll have an API gateway or a (load balancing) proxy which works with your service registry and routes requests accordingly. In the current project we use Consul for service registry and Nginx + consul-template as proxy. We plan to migrate to some API gateway.
With this setup your front-end will connect to just one central endpoint which would do load balancing/routing to individual service instances behind the scenes. Thus your front-end will not need to implement anything like Eureka/Ribbon etc.
I'm studing dojo to create web applications.
The HTTP server will be a Windows machine with IIS.
On the same machine will run my own Qt5 application to provide all backend logic for the web pages. I'm going to use dojo for them.
I wonder what is the best way to exchange data (JSON) between the client (dojo) and my application (Qt5).
In the docs I've learned how to use the AJAX methods to make HTTP requests (https://dojotoolkit.org/documentation/tutorials/1.10/ajax/index.html). But they rely on the HTTP server, instead I need to communicate with my Qt5 application.
What do you recommend?
Of course I'm trying to avoid (web)sockets!
The Dojo main modules for loading data in your application are based on AJAX, examples require, dojo.xhrGet, the content is actually in JSON format. Dojo has also support for restful service with module as dojo/store/JsonRest.
Dojo also offer you some support for socket using dojox
It really depends of the scope of your Qt5 application if you need bidirectional communication web sockets could be a reasonable solution.
I'm trying to create a mobile application using AngularJS and Ionic Framework. However, I'm lost when trying to find a solution for backend database support. Is there a plugin or third-party API available to use to accomplish this?
Client side web applications do not connect directly to SQL database servers.
You need to pick a server side programming language and write a web service interface to your database.
Then access that interface using XMLHttpRequest (which Angular wraps with $http).
I want to use WCF to expose my data layer.
I want to use this WCF in WPF project and Web application.
So i can call this service using javascript or jquery.
But one thing I could not understand that using WPF and wcf is not problem and is very flexible.
Means I am able to create DataContracts and Service Contracts and then later will decide on endpoints etc.
But so far my understanding is that to use using javascript I have to convert wcf into wcf rest services, by adding attributes to the Service Contracts.
Does not this breaks the whole principle of SOA using WCF, where I create WCF and using configuration will be able to use with any application silverlight, wpf, asp.net, php etc
and how I will be able to reuse my wcf data constarcts and service contracts code.
Thanks,
Daljit Singh
Please take a look at WCF Data Services. This toolset allows you to quickly and flexibly have both JSON and XML formatted access to your data layer using the REST protocol. The fact that you choose REST does not mean it is not SOA. And REST is supported very nicely also in WPF. REST just fixes your protocol to http.
For a discussion on REST versus SOAP, please read http://blog.tonysneed.com/2010/04/13/wcf-data-services-versus-wcf-soap-services/.