On my client side i'm using Bowman library to consume a Spring Data Rest api. I'm trying to access to the "prev", "next", "last" of my _links node in my hal+json response.
How can i do that ?
I can access to the _links node of an object of my client model with the #LinkedResource annotation but how with _links node that contains the "prev", "first", "next" etc...
Unfortunately, there is currently no support for pagination in Bowman library. It's a known issue (See Github issue) that has not been solved yet.
Related
I'm attempting to update the "Springwolf" library (used to document async API definitions) to support rabbit consumer listeners using spring cloud functions for spring cloud stream. In order to accomplish this I need to find from application context
spring cloud functions defined.
map this to a channel name
map that channel name to its binding.. hopefully pulling out exchange, queue and routing key values.
I've been able to successfully track down the defined functions, get the expected payload type of the function, and map that to a channel name using defined values in application.properties.
Depending on our application properties are set up I can get the other info from there but this is not always possible. Is there a way I can pull this data from defined spring beans.
I've found bean "bindingService" has a private field "consumerBindings" which has a field "destination" which has a field "bindings" and those bindings have all of the details that I need... but given they're private and buried I don't think this would be a good way to go.
I've also found spring.cloud.stream-org.springframework.cloud.stream.config.BindingServiceProperties has a "getBindings" method on it, but those values appear to be incomplete. for instance with a rabbit consumer defined as below the "group name" is generated randomly but its name is not available from the Bindings provided in BindingServiceProperties
spring.cloud.stream.bindings.anotherConsumerMethod-in-0.destination=someDestination2
spring.cloud.stream.bindings.anotherConsumerMethod-in-0.consumer.bindingRoutingKey=testgroup.testDestination.queue2
Any help/guidance would be awesome... also if the answer is "you can't do this" I completely understand.
I have a sling servlet that invokes a 3rd party api and fetches a json response. I have mapped the json response to a pojo class using Jackson. I now have to display this dynamically fetched and mapped response in sightly. How do i do that? I am stuck after the response mapping
With the new version of Sling Models, you can directly expose a model as a Servlet by specifying a resource type and the selector to use in your model annotations. When the Model is loaded into Apache Sling, it automatically registers a Servlet corresponding to the model, allowing you to with nearly zero additional code, create a Servlet to access a JSON representation of the model. That’s super cool!
The above life makes your Life Easier!!
You can have all your objects in Sling Model. Since the sling model acts as a servlet You can make the AJAX call and get a real-time response.
Please refer to this document.
https://blogs.perficient.com/2018/07/26/no-servlets-required-exporting-data-with-sling-models/
The correct path is:
HTL/Sightly -> Sling Model -> OSGi Service -> External API
So you have to extract the code that fetches the data into an OSGi service.
But please secure your code that calls the external API. As example if the External API is not responding or is extremely slow, it could consume all available threads of AEM. Then AEM could be completely unusable. To secure it, you could use as Example a Semaphore.
Assuming the JSON returned is arbitrary, the best thing to do is simply display it as a string. To do that, instead of mapping the JSON response to a POJO I would recommend adapting a Sling model to the response.
Then, you can set that Sling model to be the model in your sightly code, using data-sly-use.model, and in the Sling model constructor you can set the response value to an attribute of the sling model.
Then all you'd need to do is put that attribute in a ${} in the sightly html.
If the format/structure of the JSON isn't completely unknown, you could use the POJO in the sightly. Create some conditionals to test what attributes the POJO has, so you can put them into the sightly code.
I need to calculate some kind of digest of the request body using the WebClient of Webflux and this digest must be set into a HTTP header. Using the good old Spring MVC ClientHttpRequestInterceptor is easy because the request body is provided as an array of bytes.
The ExchangeFilterFunction does not provide access to the request body.
The body is sent as JSon and Spring uses Jackson in order to serialize Java objects, so an option could be serialize my Object into Json and calculate the digest on it, but this strategy has two drawbacks:
my code would repeat what Spring will do when the request is actually sent
there's no guarantee that the acutal bytes sent by Spring as a request are equal to what I've passed to the digest function
I suppose that I should use some low level API of Netty, but I can't find any example.
I implemented the solution proposed by #rewolf and it worked, but I encountered an issue because of the multi-threading nature of WebFlux.
In fact, it's possible that the client request is saved into the thread-local map by one thread, but a different thread tries to get it, so a null value is returned.
For example, it happens if the request to be signed is created inside a Rest controller method which has a Mono as a request body parameter:
#PostMapping
public String execute(#RequestBody Mono<MyBody> body){
Mono<OtherBody> otherBody = body.map(this::transformBodyIntoOtherBody);
...
webClient.post()
.body(otherBody)
.exchange();
...
}
According to Reactor specs, the Reactor Context should be used instead of Thread Local.
I forked #rewolf project and implemented a solution based on Reactor Context: https://github.com/taxone/blog-hmac-auth-webclient
This is not currently easy to do with WebClient. But there are ways to do so by intercepting the body post-serialization. This can be done by registering a custom encoder that intercepts the data after encoding, and the passes it to a custom HttpConnector to inject it as a header.
This blog post explains one way to achieve it: https://andrew-flower.com/blog/Custom-HMAC-Auth-with-Spring-WebClient
Edit: Currently this blog post doesn't take into account concurrent requests. See the accepted answer by Claodio for the modified approach.
Spring Data REST has 2 properties (spring.data.rest.return-body-on-create, spring.data.rest.return-body-on-update) that are apparently true by default.
These properties make Spring return the submitted entity after create/update using POST/PUT/PATCH.
What I want is that the returned entity uses a projection to return its data so I tried submitting to this URL: http://localhost:8080/MYAPP/api/persons?projection=personProjection for new entities using POST and to this URL: http://localhost:8080/MYAPP/api/persons/1?projection=personProjection for old entities using PUT and PATCH.
All trials failed and I got the following exception: "Target bean of type com.sun.proxy.$Proxy231 is not of type of the persistent entity (com.test.entities.Person)!: com.sun.proxy.$Proxy231"
According to this question: After upgrade from Spring Boot 1.5 to 2.1 we get Target bean of type com.sun.proxy.$Proxy is not of type of the persistent entity
It seems that what I was trying to do was possible in older version of Spring Data REST.
So is this a bug ?
Or is there a workaround for this behavior without having to get the entity again in another back-end call or creating a custom controller for submissions ?
I am using Spring Boot v2.2.6.RELEASE
Thanks
I've built my first grails application. My URL mappings are what the default application provides:
static mappings = {
"/$controller/$action?/$id?"{
constraints {
// apply constraints here
}
}
"/"(view:"/index")
"500"(view:'/error')
}
Senario
I have a controller called ColorController with actions save and list. It simply does something like this:
def save () {
def colorInstance = new Color(params)
colorInstance.save(flush: true)
}
def list () {
[colorList: Color.list, colorTotal: Color.count()]
}
I would like to build a simple API for these actions.
The save action should accept parameters as JSON and provide a successful message if the records save.
The list action should provide the list as JSON
Questions
Should I make a separate URL mapping for api? (e.g. http://<domain>/<app>/rest/controller/action)
Should I be making a separate controller for my API's
I am using spring security plugin for authentication. But at some point I might want to authenticate the restful api as well. What are some solutions for that?
If I use the same controller, how can I modify these simple actions to do what I need.
Before even looking below for my opinion/answers I would suggest to visit this SO Question for the basic understanding of RESTful WS in Grails.
Opinions:
"The save action should accept parameters as JSON and provide a successful message if the records save" - Save is mapped to POST RESTful. Instead of binding a JSON body to params it is bound to the request. In order to access the JSON object you just need to use request.JSON in the action method.
request.JSON instanceof JSONObject
"The list action should provide the list as JSON" - list() action is mapped to a GET Request and you can render the map as JSON in the list() as below
//Controller list()
import grails.converter.JSON
def list () {
[colorList: Color.list, colorTotal: Color.count()] as JSON
}
Answers to Questions:-
Should I make a separate URL mapping for api?
Abiding by the basics of REST, the client should only access the resource (Color in this case) and should not bother about the underlying controller or action. The server side logic should be abstracted from the client. URL Mapping is what the client would use to as form of request. I would have something like this in my url mapping for Color Resource.
/color/$id?(resource: "color")
or
/color/$id?(controller: 'color'){
action = [GET: "list", POST: "save"]
}
Should I be making a separate controller for my API's? - Depends on the way the App is designed. You also can have the above controller as the API. For example, currently I am working on a grails app which used AngularJS in the front End which connects to the Grails APP RESTFully. In order to achieve I had a RestClientController which works as an API to Angular. The rationale behind having a REST api in the same app is that in future we can expose the underlying service to external clients other than the Angular client present in the app itself.
I am using spring security plugin for authentication. But at some point I might want to authenticate the restful api as well. What are some solutions for that? - You can use Spring Security here as well. In my case I am using the plugin and I secure the controller by using the plugin's annotated component #Secured. I have custom OAuth enabled as well for authorization which interacts to the company wide LDAP and AD Groups.
If I use the same controller, how can I modify these simple actions to do what I need. - I think you would have got the answer to this question by now (after going through the SO question I mentioned above). Here is my opinion, controller actions can route to appropriate service classes which does the business implementations based on the request parameters.
For example,
//Action
def show(){
if(params.id){
colorService.getColor()
} else {
colorService.searchColor()
}
}
In the above example, the url mapping would be /color/123 or /color. In the former case, it will get the color and in the later it will search the colors