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Spring Cloud Gateway and CORS header

I am trying to proxy-forward a request using org.springframework.cloud.gateway.mvc.ProxyExchange.
The call is working fine.
In my scenario I like to integrate it with the browser calls, but
get a CORS-header issue there.
(1) Source in the controller:
#RequestMapping(value = "/public**", method = RequestMethod.GET)
public ResponseEntity<byte[]> forwardHttpRequestForGet(
HttpServletRequest httpServletRequest,
#RequestParam MultiValueMap<String, String> requestParams,
#RequestHeader HttpHeaders requestHeaders,
ProxyExchange<byte[]> proxy) throws Exception {
ResponseEntity<byte[]> responseEntity = cloudGatewayService.proxyForwardToApplication(httpServletRequest, requestParams,requestHeaders, proxy);
return responseEntity;
}
(2) Source of used CloudGatewayService:
public ResponseEntity<byte[]> proxyForwardToApplication(
HttpServletRequest httpServletRequest,
MultiValueMap<String, String> requestParams,
HttpHeaders requestHeaders, ProxyExchange<byte[]> proxy) throws Exception {
String authorizationHeader = httpServletRequest.getHeader(AUTHORIZATION_HEADER);
String forwardUrl = "newUrl"
return proxy.sensitive("cookie")
.headers(requestHeaders)
.uri(forwardUrl).get();
}
How can I add CORS support for Spring Cloud Gateway ?

There is nothing specific to cloud MVC. Even if it is a proxy, we have to add CORS support to the web application.
As it is a spring boot project, I have added spring security as well here. Added a filter which can populate the headers did the job.
Note : add whatever required headers for your OPTION call (preflight),
Also support GET,POST, DELETE, etc calls accordingly.
The response headers can be added to the http response

Get request header in spring boot

How do I get the header and body of the current request from an application which called my Springboot application? I need to extract this information. Unfortunately this does not work. I tried to get the current request with this code sample (https://stackoverflow.com/a/26323545/5762515):
public static HttpServletRequest getCurrentHttpRequest(){
RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
if (requestAttributes instanceof ServletRequestAttributes) {
HttpServletRequest request = ((ServletRequestAttributes)requestAttributes).getRequest();
return request;
}
throw new IllegalArgumentException("Request must not be null!");
}
And then I tried to get the body
ContentCachingRequestWrapper requestWrapper = (ContentCachingRequestWrapper) currentRequest;
String requestBody = new String(requestWrapper.getContentAsByteArray());
Can someone tell me what im doing wrong?
Thanks in advance

#RestController
public class SampleController {
#PostMapping("/RestEndpoint")
public ResponseEntity<?> sampleEndpoint(#RequestHeader Map<String, String> headers,#RequestBody Map<String,String> body) {
//Do something with header / body
return null;
}
}
If the application's are communicating through a rest endpoint I believe this would be the simplest solution. In spring you can add RequestHeader and RequestBody annotations to method arguments to have them setup to be used.
Of course you can map RequestBody directly to some POJO instead of using a map but just as an example.
Let me know if this is what you were looking for !

#TryHard, You're using spring boot then following way is more preferable for you,
#RestController
public class SampleController {
#RequestMapping("/get-header-data")
public ResponseEntity<?> sampleEndpoint(HttpServletRequest request) {
// request object comes with various in-built methods use as per your requirement.
request.getHeader("<key>");
}
}

you can get header with your code but need apply some changes.
private String getRequest() throws Exception {
RequestAttributes attribs = RequestContextHolder.getRequestAttributes();
if (attribs != null) {
HttpServletRequest request = ((ServletRequestAttributes) attribs).getRequest();
return request ;
}
throw new IllegalArgumentException("Request must not be null!");
}
after you can extract header info from request. For example if you want get Accept-Encoding
String headerEncoding = getRequest().getHeader("Accept-Encoding");
obliviusly you don't use this approce if not necessary.
If you want exract the body NOT use this solution

Java Spring error 404 while trying to get JSON from API. Works in postman

I am trying to get a JSON Object from an API while using an API key in the header.
This works perfectly when I test it in Postman, but when I try it in my Spring application.
I got an error:
There was an unexpected error (type=Not Found, status=404). No message available.
API-Key and the URL are changed out with dummy data
#RequestMapping(value = "/apitest", method = RequestMethod.GET, headers ="APIKey=12345")
public #ResponseBody void testingAPI() throws ParseException {
final RestTemplate restTemplate = new RestTemplate();
final String response = restTemplate.getForObject("url", String.class);
System.out.println(response);
}

If your are testing your API in Postman and it works perfectly, and in your application it's not working, this means that your method mapping isn't correct or it's not correctly called.
But from the comments where you said that the same configuration works if you don't have an API key, this means that your header isn't correctly mapped, in this case I'd recommend using #RequestHeader annotation to handle your API key.
Your method mapping will be like this:
#RequestMapping(value = "/apitest", method = RequestMethod.GET)
public #ResponseBody void testingAPI(#RequestHeader("APIKey") String apiKey) throws ParseException {
final RestTemplate restTemplate = new RestTemplate();
final String response = restTemplate.getForObject("url", String.class);
System.out.println(response);
}
If you want to use 12345 as a default value for your API key param you can write:
#RequestMapping(value = "/apitest", method = RequestMethod.GET)
public #ResponseBody void testingAPI(#RequestHeader(name = "APIKey", defaultValue = "12345") String apiKey) throws ParseException {
You can check How to Read HTTP Headers in Spring REST Controllers tutorial for further reading about the #RequestHeader annotation.

A quick fix could be to change the void to a Class. like
#RequestMapping(value = "/apitest", method = RequestMethod.GET, headers ="APIKey=12345")
#ResponseBody
public XXXResponse testingAPI() throws ParseException {
...
return new XXXRepsonse();
}
or:
#RequestMapping(value = "/apitest", method = RequestMethod.GET, headers ="APIKey=12345")
public void testingAPI() throws ParseException {
...
}

Where are you add header in your request? You controller should look like this:
#RestController
public class DemoController {
#GetMapping("/apitest" )
public void doRequest(#RequestHeader(name = "Ocp-Apim-Subscription-Key", defaultValue = "12345") String apiKey) {
RestTemplate restTemplate = new RestTemplate();
MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
headers.add("Ocp-Apim-Subscription-Key", apiKey);
ResponseEntity<String> responseEntity = restTemplate.exchange("https://api.kognif.ai/AIS/v1/aispositioncurrent?vesselimo=8505941&output=json",
HttpMethod.GET, new HttpEntity<String>(headers), String.class);
System.out.println(responseEntity.toString());
}
}
Postman request to your Spring app must be :
And of course, specify valid Ocp-Apim-Subscription-Key

How to receive application/x-www-form-urlencoded Request parameters in Spring rest controller

I'm trying to write a rest endpoint which receives application/x-www-form-urlencoded. But the endpoint does not accept request parameters for #RequestBody or #RequestParam
I Have tried using MultiValueMap to grab the request parameters. But I always get 0 parameters.
Is there a way to get request values to the MultiValueMap or some other POJO class.
AD=&value=sometestvalue - This is the application/x-www-form-urlencoded requestbody. I'm trying to do the request using postman
#RequestMapping(value = "/test/verification/pay/{id}", method = RequestMethod.POST,
consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
#ResponseBody
public Response testVerificationPay(#PathVariable("id") long id, #RequestParam MultiValueMap formData,
HttpServletRequest servletRequest, ServiceContext serviceContext){
log.info("!--REQUEST START--!"+formData.toString());
}

You need to use MultiValueMap<String, String>
#RequestMapping(value = "/test/verification/pay/{id}", method = RequestMethod.POST, consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
#ResponseBody
public Response testVerificationPay(#PathVariable("id") long id, #RequestParam MultiValueMap<String, String> formData) {
System.out.println("!--REQUEST START--!" + formData.toString());
return null;
}

You do not use #RequestParam on a POST request as the data is not in the URL as in a GET request.
You should use #RequestBody (doc) along with registering appropriate HttpMessageConverter. Most likely you should use: FormHttpMessageConverter

Try #ResponseBody. Then, change to a String, not a MultiValueMap, to see if the body comes in to the request.

Optional Request Header in Spring Rest Service

I'm using Spring Restful web service & having request body with request header as shown below:
#RequestMapping(value = "/mykey", method = RequestMethod.POST, consumes="applicaton/json")
public ResponseEntity<String> getData(#RequestBody String body, #RequestHeader("Auth") String authorization) {
try {
....
} catch (Exception e) {
....
}
}
I want to pass one more optional request header called "X-MyHeader". How do I specify this optional request header in Spring rest service?
Also, how do I pass this same value in response header??
Thanks!
UPDATE: I just found that I can set required=false in request header, so one issue is resolved. Now, the only issue remaining is how do I set the header in the response??

Use required=false in your #RequestHeader:
#PostMapping("/mykey")
public ResponseEntity<String> getData(
#RequestBody String body,
#RequestHeader(value = "Auth", required = false) String authorization) {}

This question is answered here:
In Spring MVC, how can I set the mime type header when using #ResponseBody
Here is a code sample from: http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-ann-httpentity
#RequestMapping("/something")
public ResponseEntity<String> handle(HttpEntity<byte[]> requestEntity) throws UnsupportedEncodingException {
String requestHeader = requestEntity.getHeaders().getFirst("MyRequestHeader");
byte[] requestBody = requestEntity.getBody();
// do something with request header and body
HttpHeaders responseHeaders = new HttpHeaders();
responseHeaders.set("MyResponseHeader", "MyValue");
return new ResponseEntity<String>("Hello World", responseHeaders, HttpStatus.CREATED);
}