adding request param to every request using spring resttemplate - spring-boot

Question

I am trying to add common request parameters to every request using RestTemplate.
For example if my url is http://something.com/countries/US then I want to add common request param ?id=12345. This common request parameter needs to be added on all request. I don't want to add this on each call and want something common.
this post has answer that was marked correct, but I am not sure how you can add request parameters on org.springframework.http.HttpRequest
Any other way I can achieve this ?

Answer 1

To add request parameters to the HttpRequest , you can first use UriComponentsBuilder to build an new URI based on the existing URI but adding the query parameters that you want to add.
Then use HttpRequestWrapper to wrap the existing request but only override its URI with the updated URI.
Code wise it looks like:
public class AddQueryParamterInterceptor implements ClientHttpRequestInterceptor {
#Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution)
throws IOException {
URI uri = UriComponentsBuilder.fromHttpRequest(request)
.queryParam("id", 12345)
.build().toUri();
HttpRequest modifiedRequest = new HttpRequestWrapper(request) {
#Override
public URI getURI() {
return uri;
}
};
return execution.execute(modifiedRequest, body);
}
}
And set this interceptor to the RestTemplate:
List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();
interceptors.add(new AddQueryParamterInterceptor());
restTemplate.setInterceptors(interceptors);

Answer 2

Two things are required to add common request parameters to every request using RestTemplate.
Create a prototype bean RestTemplate
#Configuration
public class RestTemplateConfig {
#Bean
#Scope(
value = ConfigurableBeanFactory.SCOPE_PROTOTYPE,
proxyMode = ScopedProxyMode.TARGET_CLASS)
public RestTemplate restTemplate() {
RestTemplate localRestTemplate = new RestTemplate();
List<ClientHttpRequestInterceptor> interceptors = localRestTemplate.getInterceptors();
if (CollectionUtils.isEmpty(interceptors)) {
interceptors = new ArrayList<>();
}
interceptors.add(new AddQueryParamterInterceptor());
localRestTemplate.setInterceptors(interceptors);
return localRestTemplate;
}
}
Use the Interceptor code as suggested by #ken-chan to add the request parameters. A new instance of Resttemaple will be created and for each and every request.

Answer 3

You can achieve this by adding interceptor to rest template