Sending GET request with Authentication headers using restTemplate

Question

I need to retrieve resources from my server by sending a GET request with some Authorization headers using RestTemplate  After going over the docs I noticed that none of the GET methods accepts headers as a parameter  and the only way to send Headers such as accept and Authorization is by using the exchange method  Since it is a very basic action I am wondering if I am missing something and there another  easier way to do it

User · Accepted Answer

You re not missing anything  RestTemplate exchange     is the appropriate method to use to set request headers   Here s an example  with POST  but just change that to GET and use the entity you want     Here s another example   Note that with a GET  your request entity doesn t have to contain anything  unless your API expects it  but that would go against the HTTP spec   It can be an empty String

User · Answer

All of these answers appear to be incomplete and or kludges   Looking at the RestTemplate interface  it sure looks like it is intended to have a ClientHttpRequestFactory injected into it  and then that requestFactory will be used to create the request  including any customizations of headers  body  and request params     You either need a universal ClientHttpRequestFactory to inject into a single shared RestTemplate or else you need to get a new template instance via new RestTemplate myHttpRequestFactory     Unfortunately  it looks somewhat non-trivial to create such a factory  even when you just want to set a single Authorization header  which is pretty frustrating considering what a common requirement that likely is  but at least it allows easy use if  for example  your Authorization header can be created from data contained in a Spring-Security Authorization object  then you can create a factory that sets the outgoing AuthorizationHeader on every request by doing SecurityContextHolder getContext   getAuthorization   and then populating the header  with null checks as appropriate   Now all outbound rest calls made with that RestTemplate will have the correct Authorization header     Without more emphasis placed on the HttpClientFactory mechanism  providing simple-to-overload base classes for common cases like adding a single header to requests  most of the nice convenience methods of RestTemplate end up being a waste of time  since they can only rarely be used   I d like to see something simple like this made available   Configuration public class MyConfig      Bean   public RestTemplate getRestTemplate         return new RestTemplate new AbstractHeaderRewritingHttpClientFactory              Override         public HttpHeaders modifyHeaders HttpHeaders headers              headers addHeader  Authorization   computeAuthString               return headers                    public String computeAuthString                  do something better than this  but you get the idea           return SecurityContextHolder getContext   getAuthorization   getCredential                              At the moment  the interface of the available ClientHttpRequestFactory s are harder to interact with than that   Even better would be an abstract wrapper for existing factory implementations which makes them look like a simpler object like AbstractHeaderRewritingRequestFactory for the purposes of replacing just that one piece of functionality   Right now  they are very general purpose such that even writing those wrappers is a complex piece of research

User · Answer

You can use postForObject with an HttpEntity  It would look like this   HttpHeaders headers   new HttpHeaders    headers setContentType MediaType APPLICATION JSON   headers set  Authorization    Bearer   accessToken    HttpEntity lt String gt  entity   new HttpEntity lt String gt  requestJson headers   String result   restTemplate postForObject url  entity  String class     In a GET request  you d usually not send a body  it s allowed  but it doesn t serve any purpose   The way to add headers without wiring the RestTemplate differently is to use the exchange or execute methods directly  The get shorthands don t support header modification   The asymmetry is a bit weird on a first glance  perhaps this is going to be fixed in future versions of Spring

User · Answer

Here s a super-simple example with basic authentication  headers  and exception handling     private HttpHeaders createHttpHeaders String user  String password        String notEncoded   user         password      String encodedAuth    Basic     Base64 getEncoder   encodeToString notEncoded getBytes         HttpHeaders headers   new HttpHeaders        headers setContentType MediaType APPLICATION JSON       headers add  Authorization   encodedAuth       return headers     private void doYourThing          String theUrl    http   blah blah com 8080 rest api blah       RestTemplate restTemplate   new RestTemplate        try           HttpHeaders headers   createHttpHeaders  fred   1234            HttpEntity lt String gt  entity   new HttpEntity lt String gt   parameters   headers           ResponseEntity lt String gt  response   restTemplate exchange theUrl  HttpMethod GET  entity  String class           System out println  Result - status     response getStatusCode        has body      response hasBody               catch  Exception eek            System out println     Exception     eek getMessage

User · Answer

A simple solution would be to configure static http headers needed for all calls in the bean configuration of the RestTemplate   Configuration public class RestTemplateConfig         Bean     public RestTemplate getRestTemplate  Value  quot   did-service bearer-token  quot   String bearerToken            RestTemplate restTemplate   new RestTemplate            restTemplate getInterceptors   add  request  body  clientHttpRequestExecution  - gt                HttpHeaders headers   request getHeaders                if   headers containsKey  quot Authorization quot                      String token   bearerToken toLowerCase   startsWith  quot bearer quot     bearerToken    quot Bearer  quot    bearerToken                  request getHeaders   add  quot Authorization quot   token                             return clientHttpRequestExecution execute request  body                       return restTemplate

User · Answer

These days something like the following will suffice  HttpHeaders headers   new HttpHeaders    headers setBearerAuth accessToken   restTemplate exchange RequestEntity get new URI url   headers headers  build    returnType

[java] Sending GET request with Authentication headers using restTemplate

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