AJAX Using a REST API Without Server Side Framework - java

I am building a REST based API (Read only) for accessing services of my application. I plan on writing a web application that will leverage these APIs to provide basic information on the status of the application. I plan to use AJAX (using jQuery) to show the information.
Originally I planned on using Grails, Spring MVC, RoR or one of the web frameworks to handle the back end of my application. The REST APIs I will be providing though are already built on a stanalone REST framework so I would only be leveraging the web framework for the core application and not the business logic. In the future, I might need the server side framework to handle other tasks but for now most of the work is done in the REST APIs.
My question is, should I bother with using a web application framework on the server side? I should be able to make all the API calls I need from AJAX directly from the browser. I cannot think of much I would need to do on the server side. Would it make sense to have the application be standard HTML + AJAX + REST?

Its hard to say without actually knowing more about your current setup. This is what your situation sounds like:
You already have an app ready to go with all of the business logic contained. Sounds like its written in Java?
You already have the services written and exposed through a REST api using some other standalone framework. Meaning that if you wanted to, you could access the data right now with the browser without any extra work.
You have not yet built the web application, but when you do, it will get all of its content from the REST api using XHR and jquery. I say that, because otherwise, I would think that you would already be using some kind of framework to generate the other content.
If I am correct in my assumptions, then I would say that you have no need for an additional framework layer. Grails, RoR, SpringMVC my use ajax, and aid in exposing REST services, but the bulk of what they provide is an easy way to make an application that must generate html on the server, deal with form submissions, and handle sessions in a request/response cycle. It doesn't really sound like you'll be doing any of that, and it will likely make your app more complicated.
If you did at some point need the things that rails etc. provides, I would say that you may not need to use rails to expose the rest apis you have now. You could use rails just for what you need, and continue to use what you have for the REST api.

Well, the AJAX calls need to pull data from a server somewhere. If the goal is to avoid a complicated setup on the server side, CherryPy can keep the server side code VERY small.
I've written a simple exapmle below. The first class would be where you put the logic for your ReST API. The code below the class is all you need to get the server up and running.
Install Python 2.6, save the code below to restExample.py. Then in your command line run the python file by doing "python restExample.py". Point your browser to http://localhost:8080/blog/999 and see some JSON come back.
import cherrypy
import json
# Create the controller
class Blog_Controller(object):
def get(self, entryID):
cherrypy.response.headers['Content-Type'] = 'application/json'
return json.dumps({'title':'Entry Title from DB', 'entry_text': 'Text From DB'})
def update(self, entryID, titleFromPOSTFormInput, textFromPOSTFormInput):
# Update DB with passed in arguments. entryID comes from URL,
# other two entries come from POST
cherrypy.response.headers['Content-Type'] = 'application/json'
return json.dumps({'success':True})
# Setup URL routes
d = cherrypy.dispatch.RoutesDispatcher()
d.connect(name='blog_entry', route='blog/:entryID', action='get',
controller=Blog_Controller(),
conditions={'method': ['GET']})
d.connect(name='blog_entry', route='blog/update/:entryID', action='update',
controller=Blog_Controller(),
conditions={'method': ['POST']})
config = { '/' : { 'request.dispatch': d } }
cherrypy.tree.mount(root=None, config=config)
# Start the webserver
engine = cherrypy.engine
try:
engine.start()
except:
sys.exit(1)
else:
engine.block()

It sounds like this might be a good use case for GWT with Restlet.

Forgive me for tooting my own horn, but if you are doing AJAX REST stuff with jQuery, you should probably check out my JSON-REST plugin:
http://plugins.jquery.com/project/rest
If you are getting XML back, then this won't be as useful, but you may still be able to adapt some of the code to your needs.

Related

How do I test a REST client?

I have a REST client in Java that is ready to connect to a REST server, send a specific request and get a response back. However, the actual REST server is not available during development time (it is hosted by a 3rd party and only available in the isolated local net of the target machine) and we still want to test connectivity and interaction with the server.
Can you point me to a product or technology that in the first place lets me quickly create a fake REST server (or at least mock it) according to the specification of the REST call parameters? I did some research on the web but haven't had a "yes, this is it!" moment yet.
You can use any rest mocking framework to achieve this. As per my experience
Wiremock is the best framework for RES API Mocking.
http://wiremock.org/
You can use mockwebserver library by square. It's pretty simple to use and do exactly what you attempt to do.
Little usage sample:
MockWebServer server = new MockWebServer();
server.enqueue(new MockResponse().setBody("hello world"));
server.start();
For client testing, I would recommend a tool like SOAP UI or Postman. But for mocking the REST service itself, I would actually recommend just creating some dummy endpoints in your Java web application and using that. At each endpoint you could do something hard code a simple response, in JSON, XML, or whatever would make sense with your service. Then, when you finally come to actual development, you will already have a functioning framework for your REST service. You would just need to fill in the missing pieces.
This makes sense because you are going to need to setup REST support in your Java code anyway, and the amount of effort to just add stubs should be minimal. This approach is also attractive from the point of view that it avoids any potential surprises from switching from a mock REST service to the actual one.

Create json rest api without writing or integrating any code

I've 2 questions about Java Rest APIs
1'st:
I would like to create a Rest API with Java Servlets for using in the mobile applications(IOS and Android)
and before doing that I would like to clarify the rest api content. However as much as I search through google all I found was automatic API creators from your Java code. But what I want is different first I want to document our Json Rest API so mobile and server developers can start to work independently.
Do you know any tool for that?
2'nd:
What I want to achive in our java server application is simple. Get simple json requests from mobile clients and do some database query and respond back with simple json objects.
For achiving this do I need to use any additional Rest API framework such as spring mvc (or something else) or just using Java Servlets and parse the request in doPost method and respond it there
Which one do you suggest?
Thanks
Restlet Studio (http://restlet.com/technical-resources/restlet-studio) or APISpark (http://restlet.com/products/apispark/) can bring you what you expect.
Restlet Studio allows you to define / design you API with a Web IDE: resources and their methods, representations (exchanged data structures). You can then have access to corresponding Swagger content and generate online client SDKs and even server skeletons for your API (this is internally based on Swagger Codegen)...
To implement your RESTful applications, Restlet can help you. It's a Java REST framework to access and / or implement RESTful applications. Restlet can be used within a servlet container with its servlet extension (see this link https://github.com/restlet/restlet-tutorial/blob/master/modules/org.restlet.tutorial.markdown/02_Server_Side/04_Server_Deployment/02_Servlet_Deployment.md).
Hope it helps you.
Thierry
I aggree with Stephan comment.
With Spring Boot and Spring Data Rest, the only code you will need to write is the mapping between your DB and your DAO Entities.
To document your API before writing it, you can use in fact any regular tools.
REST APIs don't have anything specific compared to others APIs to be documented.
Much of the documentation of APIs I've written were using Ms-Word...
Swagger provide a Json syntax to document a REST API, but it is mainly useful when used with Swagger-Ui, which allow to request the deployed server dynamically. You can use Swagger for your documentation, but as there will be no already existing server, I'm not sure it is worth the cost of learning its syntax. The main benefits is to give you constraints (like predefined fields) to follow.
By the way, I think that writing a REST Api Mapping or just document it takes the same amount of time, so I'm not sure it is really worth making all the documentation in a stand-alone way.

Build an Web UI with AngularJS for a java project?

I would like to add a Web User Interface for an existing Java project I did time ago. I learned basics of AngularJS on codeschool.com courses and now I know how to send an http or REST request to get data for my web UI.
My Java project has a set of methods that elaborate some data from a local database and return integers or integers arrays.
The goal of the interface would be to show a bunch of charts and data directly from that Java project.
What would be the most appropriate way to do this? I heard of implementing REST services on my Java project but it seems overkill for the purpose and i'm totally confused by all the frameworks for this. What would you use?
Thanks everyone for your answers!
I would use SprinvMVC to provide data from server to client side.
Here is my project from which you can start and learn basics :
https://github.com/xwid/thaimaster
Basicly you should create spring controllers mapped to urls, by doing it this way, you will be able to retrive server data using angular js.
http://www.javabeat.net/spring-mvc-angularjs-integration/
If you don't want to use a full REST framework such as Jersey, another possibility would be to use an embeddable HTTP server (there are several) and handle the requests yourself. This would mean that requests to something like /myapp/ would return your AngularJS filled HTML page, and requests to /resources/* would provide with REST functionality.
This would give you a standalone Java program that doesn't need a servlet container, but it would be a somewhat hacky solution. Not production grade, but you'd probably learn something from having to handle the HTTP traffic yourself.
With the Spring Framework's SprigBoot, it's quite easy to implement a REST service and have a runnable java application. You can follow this Building a RESTful Web Service guide from spring.io. They are clear and quickly understandable.
Also if you are not already familiar, through these guides you can have a glimpse of gradle and maven as well.

How to create Single Page Application (SPA) in java with hibernate and MySQL

I'm trying to choose best set of tools to create Single Page Applications. I would like to be able to use Java and Hibernate on server side along with MySQL. But what about ajax layer of SPA?
Maybe I have entirely wrong idea about that and Java and Hibernate make no sense in this case? But than how to implement complex server side operations?
It's rather question of UI part. The page asks a server for pages data. Java + hibernate could be used to implement service (e.g. REST service which returns data in JSON format). You can use SpringMVC to implement the service.
AJAX calls the service and process obtained data.
You can use angularJS for creating Single Page Application. this is the best framework i found for SPA development so far and using in most of projects developing which needs SPA.
for sample application refer to github
and detail about angularJS

Connecting a PHP front-end to a back-end java service

I am currently using various back-end services and I want to use PHP to simply query these services and perform the final page construction. These services could be coded in any number of programming langauges such as Erlang, Java, Python etc. However I am unsure of the best way to actually interface the back-end services with the web app. Requests to these services would be both synchronous and asynchronous. Would I use something like SOAP or JSON-RPC??
Any help greatly appreciated.
You might want to have a look to Thrift:
http://incubator.apache.org/thrift/
I think you are on the right track
using JSON-RPC. I don't like SOAP at
all because it is just way too
complicated in my opinion
I would create an interface(document it properly like for example twitter) which I can easily test using cURL from the command line.
I think Twitter has a pretty good(not perfect) API.
Also ProgrammableWeb.com is a good place to look up API's(see how other people create API's).
This is a general question how to design web services and there is a hype using REST-like web services. This way you simply can call a given URL (which is even user readable). This increase the interoperability of your web service so you can mix the programming languages which use the REST interface. IMHO its easier than using a SOAP like web service as you simply calls GET on an url like http://www.example.com/user/5/ (think of it as the mod_rewrite of web services)
I'd use NuSOAP (to consume java webservices).

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