How to develop a REST Webservice method which accepts multiple URI - java

How to develop a REST Webservice method which accepts multiple URIs for example
If we have a method
#RequestMapping(/add)
public Response add(#RequestParam List elements){
}
The method above serves for URL https://local host:8080/add
I have asked in interview how do we have a single Webservice which serves multiple URIs which I was not able to answer as I thought we should have unique URIs for each method
A follow up to this how do we have a method which returns the format whatever choosen (JSON, XML, PLAIN TEXT) from postman client.

Modify URI:
#RequestMapping(value = "/", produces = {
MediaType.APPLICATION_JSON_VALUE,
MediaType.APPLICATION_XML_VALUE
})
public Response add(#RequestParam List elements){
}

For the first question there is many ways to do that
Spring restTemplate can allow you to call a rest service in another method so all you have to do is to call your rest service when another uri is requested
You can also use proxies (web server proxies) to map same webservice to many URIs
For the second one you need to pass format as parameter and call specific service linked to format when executing
Hope that helps

Related

Postman mock server for requests with dynamic request headers/body

I am using Postman mock server to create a mock endpoint where I need the response of the request to contain the request parameter as well as few other key values.
For example if my endpoint is /test?id=123 then i need the response as
{
"id":"123",
"name":"anyRandomName"
}
Similarly, when I hit /test?id=234 then the response should be
{
"id":"234",
"name":"anyRandomName2"
}
One way to achieve this is by making 2 endpoints with specific query parameters, in this example /test?id=123 and /test?id=234.
But i am looking for a way where i can read the request parameter just like {{$id}} or something like this. Postman do provide keywords like {{$randomAlphaNumeric}} which returns random strings but this will change in every hit.
You can pass the example name in headers while making a call to the mock API with key "x-mock-response-name". this will return the example set with that name.

How to sign JSON message used by Spring Rest controller?

I have a Spring REST application that accepts JSON messages, written like
#RequestMapping(value = "/myhook", method = RequestMethod.POST,
produces = JSON, consumes = JSON)
public #ResponseBody MyResponse doIt
(#Valid #RequestBody(required = true) MyContractRequest request) {
MyResponse response;
...
return response;
}
This works really well with almost no code to support, but now I have a requirement to sign both response and request.
I started from simply computing the shared signature of all message fields at Java level and assigning it to the dedicated signature field. However this requires to have and maintain code for computing the signatures:
public void update(java.security.Signature sign) throws Exception {
sign.update(name);
sign.update(value);
sign.update(etc);
}
Some people around me expressed opinion that the need to write and maintain this signing code may not be the best design, and it may be better to sign the whole message as a single JSON string. I could fetch the request as a string manually, and then process JSON manually, but I really would like to preserve the Spring controller concepts.
Also, I cannot longer have the signature field in the message itself because the value of this field obviously also changes the signature of the JSON string.
Is there any way to compute the signature of the whole JSON message body on the message departure and arrival, and where to place the signature so it could be passed together with the message? One of the idea is to use the custom HTTP header for the signature. Anyway, how to compute it first?
You can use a servlet filter with Spring MVC and modified your content whatever you want in request and response as well
Example :
http://www.mkyong.com/spring-mvc/how-to-register-a-servlet-filter-in-spring-mvc/
or you can use Spring 3 MVC Interceptor
http://viralpatel.net/blogs/spring-mvc-interceptor-example/

Any simple way to test a #RequestBody method?

If I have a #Controller method whose parameter is a #RequestBody param, I usually have to write some jQuery script or something similar to perform an AJAX request with JSON object in order to call that method. If I tried calling that method via a web browser directly, it returns with a Error 415 Unsupported Media Type.
Is there any alternative to just quickly call such method using browser without having to write some jQuery code? Like perhaps a way to write the JSON object in the URL/address bar?
code:
#RequestMapping("testCall")
#ResponseBody
public List<TestObject> getTestCall (#RequestBody TestParams testParams) {
return stuff;
}
public class TestParams {
private Integer testNumber;
//getter/setter for testNumber
}
I thought maybe I could just do:
http://localhost/testCall?testNumber=1
maybe Spring would auto populate a new TestParams instance with that property set to 1 but that didnt work...
maybe I need to do something extra for that?
The whole point of a #RequestBody annotated parameters is for the Spring MVC stack to use the HTTP request body to produce an argument that will be bound to the parameter. As such, you need to provide a request body. Sending a request body is very atypical for a GET request. As such, browsers don't typically support it, at least not when simply entering an address in the address bar and submitting the request.
You'll need to use a different HTTP client, like jQuery. I typically have a small Java project in Eclipse that's setup with an Apache HTTP components client which can send HTTP requests to whatever server. It takes a few seconds/minutes to setup the correct request body and run.
I have spent the last year building a REST API, and by far the best way to exercise that API manually is using the Chrome Extension, Postman. I cannot recommend this tool enough.
https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm?hl=en
To test your simple example you'll need to invoke a POST (I assume that as you have a request body, but your controller method doesn't define a HTTP Verb) using POSTMAN to your Url (like the following example):
POST /contextRoot/testCall
{
"testNumber": 1
}
If you want to test your API automatically (which I recommend), you can use the excellent Spring Mvc Test project. This allows your to call your API via a rest-like DSL and assert that the response is in the shape you want. More details can be found here:
http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/testing.html#spring-mvc-test-framework
you can add request params to the getTestCall method:
#RequestParam(value = "testNumber", required = false, defaultValue = "") String testNumber
There is a chrome app called Advanced REST client. You can pass the data in form of json to your controller using this chrome app. For eg. json data is
id:1,
name:"xyz"
whereas the controller can have #RequestBody Person form.
The Person class would be a POJO having id and name as instance variables. The Spring would automatically map the json data to the form.
I think this is the easiest and simplest way of checking your spring controller.
Check the extension Advanced REST client here
From what I know You can send JSON object to the webbrowser and it will be displayed without further need of AJAX.
useful tutorial:
http://www.mkyong.com/spring-mvc/spring-3-mvc-and-json-example/

Jersey web service proxy

I am trying to implement a web service that proxies another service that I want to hide from external users of the API. Basically I want to play the middle man to have ability to add functionality to the hidden api which is solr.
I have to following code:
#POST
#Path("/update/{collection}")
public Response update(#PathParam("collection") String collection,
#Context Request request) {
//extract URL params
//update URL to target internal web service
//put body from incoming request to outgoing request
//send request and relay response back to original requestor
}
I know that I need to rewrite the URL to point to the internally available service adding the parameters coming from either the URL or the body.
This is where I am confused how can I access the original request body and pass it to the internal web service without having to unmarshall the content? Request object does not seem to give me the methods to performs those actions.
I am looking for Objects I should be using with potential methods that would help me. I would also like to get some documentation if someone knows any I have not really found anything targeting similar or portable behaviour.
Per section 4.2.4 of the JSR-311 spec, all JAX-RS implementations must provide access to the request body as byte[], String, or InputStream.
You can use UriInfo to get information on the query parameters. It would look something like this:
#POST
#Path("/update/{collection}")
public Response update(#PathParam("collection") String collection, #Context UriInfo info, InputStream inputStream)
{
String fullPath = info.getAbsolutePath().toASCIIString();
System.out.println("full request path: " + fullPath);
// query params are also available from a map. query params can be repeated,
// so the Map values are actually Lists. getFirst is a convenience method
// to get the value of the first occurrence of a given query param
String foo = info.getQueryParameters().getFirst("bar");
// do the rewrite...
String newURL = SomeOtherClass.rewrite(fullPath);
// the InputStream will have the body of the request. use your favorite
// HTTP client to make the request to Solr.
String solrResponse = SomeHttpLibrary.post(newURL, inputStream);
// send the response back to the client
return Response.ok(solrResponse).build();
One other thought. It looks like you're simply rewriting the requests and passing through to Solr. There are a few others ways that you could do this.
If you happen to have a web server in front of your Java app server or Servlet container, you could potentially accomplish your task without writing any Java code. Unless the rewrite conditions were extremely complex, my personal preference would be to try doing this with Apache mod_proxy and mod_rewrite.
There are also libraries for Java available that will rewrite URLs after they hit the app server but before they reach your code. For instance, https://code.google.com/p/urlrewritefilter/. With something like that, you'd only need to write a very simple method that invoked Solr because the URL would be rewritten before it hits your REST resource. For the record, I haven't actually tried using that particular library with Jersey.
1/ for the question of the gateway taht will hide the database or index, I would rather use and endpoint that is configured with #Path({regex}) (instead of rebuilding a regexp analyser in your endpoint) .
Use this regex directly in the #path, this is a good practice.
Please take a look at another post that is close to this : #Path and regular expression (Jersey/REST)
for exemple you can have regexp like this one :
#Path("/user/{name : [a-zA-Z][a-zA-Z_0-9]}")
2/ Second point in order to process all the request from one endpoint, you will need to have a dynamic parameter. I would use a MultivaluedMap that gives you the possibility to add params to the request without modifying your endpoint :
#POST
#Path("/search")
#Consumes(MediaType.APPLICATION_FORM_URLENCODED)
#Produces({"application/json"})
public Response search( MultivaluedMap<String, String> params ) {
// perform search operations
return search( params);
}
3/ My 3rd advice is Reuse : make economy and economy make fewer bugs.
it's such a pitty to rewrite a rest api in order to perform solr search. You can hide the params and the endpoint, but could be great to keep the solr uri Rest formatting of the params in order to reuse all the search logic of solr directly in your api. This will make you perform a great economy in code even if you hide your solr instance behind you REST GATEWAY SERVER.
in this case you can imagine :
1. receive a query in search gateway endpoint
2. Transform the query to add your params, controls...
3. execute the REST query on solr (behind your gateway).

#queryparam value assignment in clientside

I have to invoke a restful Web-Service from client side java class.
I need to pass HashMap, Strings and it must return me a list of beans.
I am using jersey restful web service
My REST service is like this:
#put
public List<MilestoneDetailsBean> getMPPReader(
#QueryParam("username") String username,
#QueryParam("projid") String projid,
#QueryParam("mppfile") File file,
#QueryParam("dbtemplate") Map<String,Integer> dbtemplate)
could some one help me with how could I:
assign values to these query parameters in my client side java code
what type of produces and consumes parameter I should put for my Web-Service
1) depends on how you create the query. QueryParams are those parts of an URL behind the ?: ?key=value&key2=value2
So what you could do is to just append the keys and values to the request URL. Remember to encode the values.
Like: http://mydomain/service?username=hage&projid=hello+world&mppfile=myfile.txt
Map is not usable for this. See here
2) Dont't know. Produces definitely depends on how you want to return the data (as xml, json, etc) and Consumes depends on what data you want to send to the server
Generally, for the client there exists a Jersey client API. Didn't use it yet, but you might look at it.

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