Spring RestTemplate session - spring

I'm trying to use spring rest template to do a post request to login in.
When I receive the response in my first request i store my session id which is received via cookie. I retrieve it in a set-cookie response header which i get via:
//first request
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
LinkedMultiValueMap<String, Object> mvm = new LinkedMultiValueMap<String, Object>();
mvm.add("LoginForm_Login", "login");
mvm.add("LoginForm_Password", "password");
ResponseEntity<String> result = restTemplate.exchange(uriDWLogin, HttpMethod.POST, requestEntity, String.class);
result.getHeaders().get("Set-Cookie").stream().forEach(System.out::println);
then in every subsequent request i set the Cookie request header with the values received in the first request:
//subsequent request
RestTemplate restTemplate = new RestTemplate(); HttpHeaders headers = new HttpHeaders();
headers.set("Cookie",cookies.stream().collect(Collectors.joining(";")));
HttpEntity<String> entity = new HttpEntity<String>(headers);
RestTemplate.exchange("http://url", HttpMethod.POST, entity, String.class);
all goes well for the second request, but I can not keep the session for the others requests

You will need to use some kind of cache to store your access token.
When you'll be accessing downstream service, you take the token from cache. If cache doesn't contain token, you will authenticate and retrieve it and store to cache first.
Caching is always tricky topic, because it has to be thread-safe. I would try to avoid servlet sessions. You are consuming service, not being consumed.
There are various caching options, but as you are already using Spring, spring caching may be good fit. Take a look at this Spring Cache guide to start.

Related

Kerberos client - kerberoRestTemplate not working

Im trying to consume an api which is authenticating with Kerberos. I have referred the below spring documentation related to KerberosRestTemplate.reference link, im passing the correct keytab file and the userPrincipal values as mentioned in the reference doc. But still im receiving 401 from the server.
But when I execute the kinit command in the terminal it receives a ticket from KDC and with that, im able to execute the curl command and get a working response.
KerberosRestTemplate kerberosRestTemplate = new KerberosRestTemplate("svc_dfsd.keytab", "svc_dfsd#sswe.AD");
String url="https://wexample.com:20550/aggr_subscriber_summary_hbase/03434809824";
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.TEXT_XML));
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = kerberosRestTemplate.exchange(url, HttpMethod.GET, entity, String.class);
Can you suggest any other better approach to do this or fix this. All your comments are highly appreciated!!!
Troubleshooting Kerberos might be tricky since the errors are often misleading and Java implementation does a lot if implicit actions (canonicalization of URLs, etc.).
I suggest trying Kerb4J library which allows you to generate the kerberos token explicitly:
SpnegoClient spnegoClient = SpnegoClient.loginWithKeyTab("svc_dfsd#sswe.AD", "svc_dfsd.keytab");
SpnegoContext context = spnegoClient.createContext("https://wexample.com"); // Will result in HTTP/wexample.com SPN
RestTemplate restTemplate = new RestTemplate();
String url="https://wexample.com:20550/aggr_subscriber_summary_hbase/03434809824";
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.TEXT_XML));
headers.add("Authorization", context.createTokenAsAuthroizationHeader());
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = restTemplate .exchange(url, HttpMethod.GET, entity, String.class);
If default SPN resolution works for you, you can also use SpnegoRestTemplate from this Kerb4J:
SpnegoClient spnegoClient = SpnegoClient.loginWithKeyTab("svc_dfsd#sswe.AD", "svc_dfsd.keytab");
SpnegoRestTemplate spnegoRestTemplate = new SpnegoRestTemplate(spnegoClient);
String url="https://wexample.com:20550/aggr_subscriber_summary_hbase/03434809824";
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.TEXT_XML));
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = spnegoRestTemplate.exchange(url, HttpMethod.GET, entity, String.class);
Disclaimer: I'm the author of Kerb4J

Spring Boot RestTemplate WebClient - Response Body JSON Empty

I am using Rest Template and have used Web Client as well. I get the key in response but the body is empty always. Using Postman I can see the Response which is a JSON.
My code snippet is below -
HttpHeaders headers = new HttpHeaders();
headers.setBasicAuth("john", "doe");
HttpEntity<String> request = new HttpEntity<String>(headers);
ResponseEntity<String> response = restTemplate.exchange(
"https://www.getMeData.com",
HttpMethod.GET, request, String.class);
System.out.println(response.getBody());
Response is as below -
{"result":[]}
Has anyone faced the same issue?
In Postman the Response Headers I can see is -
KEY VALUE
Content-Encoding gzip
Content-Type application/json;charset=UTF-8
Transfer-Encoding chunked
I just changed the Restemplate exchange method parameter from String url to new URI("url") and it worked.
ResponseEntity<String> response = restTemplate.exchange(new URI("https://www.getMeData.com"),
HttpMethod.GET, request, String.class);
Try to add headers as below:
HttpHeaders headers = new HttpHeaders();
headers.setBasicAuth("john", "doe");
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> request = new HttpEntity<String>(headers);
For gZip - use
Gzip is disabled by default, check whether it's enabled on your application. If not enable Gzip with properties
server.compression.enabled=true
server.compression.mime-types=text/html,text/xml,text/plain,text/css,text/javascript,application/javascript,application/json
server.compression.min-response-size=1024
And add below encoding to test
headers.add(HttpHeaders.CONTENT_ENCODING, "gzip");
headers.add(HttpHeaders.ACCEPT_ENCODING, "gzip");
You can also try with creating a new Http message convertor and add the same to RestTemplate instance before invoking remote api call..
Spring implementation simply does not support it.
From the HTTP 1.1 2014 Spec:
A payload within a GET request message has no defined semantics;
sending a payload body on a GET request might cause some existing
implementations to reject the request.
Having that stated this is how you should refactor your code to make it work:
ResponseEntity<String> response = restTemplate.exchange(
"https://www.getMeData.com",
HttpMethod.POST, // <- this is it
request, String.class);
If you have no control over controller method layout - switch to python + requests library to have this done.

Unable to Retrieve cookies when request is called using Spring RestTemplate

I have two web applications. There is a HttpSession at second application and first application knows the sessionid of it.
I am making a request from First application to second application using RestTemplate by adding its session id to headers.
When the request is received at the second application, I am trying to read all its cookies from request. But, I only see the JSESSIONID cookie and don't get all the cookies that I set previously.
Suppose, I access the same url on the browser manually, I see all those cookies retrieved.
Request made in First application:
String sessionId = "6iuvgwy5ceqzwlxh646qo0ms";//SessionId of second application
String url = "http://example.com/data/retrieve";
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.add("Cookie", "JSESSIONID=" + sessionId);
HttpEntity<String> requestEntity = new HttpEntity<String>(null, requestHeaders);
ResponseEntity<String> responseEntity = restTemplate.exchange(url,
HttpMethod.GET, requestEntity, String.class);
If this can't be done using Spring RestTemplate, please suggest me if there is any other way of doing it.
There is no session cookie. Cookie is just a header.
You lind of reset the header to have only JSESSIONID.
To fix it change the logic a bit
You somehow get the session id (I guess from some request). Get not only the session but all the rest cookie as well and add them to the requestHeaders when you call the restTemplate.

Spring RestTemplate receives "401 Unauthorized"

I am using the following to retrieve JSON via RestTemplate in Spring 4:
protected DocInfoResponse retrieveData(String urlWithAuth) {
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.add("Authorization", "Basic " + auth.getSig());
HttpEntity<String> request = new HttpEntity<String>(headers);
ResponseEntity<DocInfoResponse> response = restTemplate.exchange(urlWithAuth, HttpMethod.GET, request, DocInfoResponse.class);
return response.getBody();
}
I used the same code (with different response class) to successfully get a JSON doc from the same site (with different parameters to get a different doc).
When I execute the above code I receive the following stack trace (in part):
Caused by: org.springframework.web.client.HttpClientErrorException: 401 Unauthorized
at
org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:91) ~[spring-web-4.3.7.RELEASE.jar:4.3.7.RELEASE]
Can anyone point me to why this might be receiving the exception?
I found that my issue originally posted above was due to double encryption happening on the auth params. I resolved it by using UriComponentsBuilder and explicitly calling encode() on the the exchange().
SyncResponse retrieveData(UriComponentsBuilder builder) {
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.set("Accept", MediaType.APPLICATION_JSON_VALUE);
HttpEntity<String> request = new HttpEntity<String>(headers);
ResponseEntity<SyncResponse> response = restTemplate.exchange(builder.build().encode().toUri(), HttpMethod.GET, request, SyncResponse.class);
return response.getBody();
}
My UriComponentsBuilder was built using:
UriComponentsBuilder buildUrl(String urlString) {
UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(urlString);
return auth.appendAuth(builder);
}
(The auth.appendAuth() adds additional .queryParams() needed by the target service in urlString.)
The call to execute this was retrieveData(buildUrl(urlString));.
After investigating on my own problem, I realized that FireFox RESTClient was successful because I was connected to the target URL. The Basic Auth I thought I was using, was not so basic after all.
Eventually, I read the doc of the app i was trying to connect to and realized they propose a connection token mechanism. Now it works.
After reading your code, I say it looks quite OK, although I'm not sure what is your object auth on which you call getSig.
First things first: try to access your service from any client, like a web browser, a PostMan or RESTClient. Make sure you successfully retrieve your infos WITHOUT being connected to your app!!!
Depending on the result, I say you should, either try to encrypt manually your Authorization token (you'll easilly find posts on this site to show you how to) or try another connection mechanism.
The process of creating the Authorization header is relatively straightforward for Basic Authentication, so it can pretty much be done manually with a few lines of code:
HttpHeaders createHeaders(String username, String password){
return new HttpHeaders() {{
String auth = username + ":" + password;
byte[] encodedAuth = Base64.encodeBase64(
auth.getBytes(Charset.forName("US-ASCII")) );
String authHeader = "Basic " + new String( encodedAuth );
set( "Authorization", authHeader );
}};
}
Then, sending a request becomes just as simple:
RestTemplate restTemplate = new RestTemplate();
restTemplate.exchange
(uri, HttpMethod.POST, new HttpEntity<T>(createHeaders(username, password)), clazz);
https://www.baeldung.com/how-to-use-resttemplate-with-basic-authentication-in-spring#manual_auth

HTTP get with headers using RestTemplate

How can I send a GET request using the Spring RestTemplate?
Other questions have used POST, but I need to use GET.
When I run this, the program continues to work, but it seems that the network is clogged because this is in an AsyncTask, and when I try to run another asynctask after I click on the button for this one, they won't work.
I tried doing
String url = "https://api.blah.com/2.0/search/cubes?w=jdfkl&whitespace=1";
MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
map.add("Bearer", accessToken);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED); //copied this from somewhere else, not sure what its for
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);
HttpMessageConverter<String> stringConverter = new StringHttpMessageConverter();
FormHttpMessageConverter formConverter = new FormHttpMessageConverter();
List<HttpMessageConverter<?>> msgConverters = new ArrayList<HttpMessageConverter<?>>();
msgConverters.add(formConverter);
msgConverters.add(new MappingJacksonHttpMessageConverter());
msgConverters.add(stringConverter);
template.setMessageConverters(msgConverters);
//SetSearchResponseData is my custom class to store the incoming JSON
ResponseEntity<SetSearchResponseData> result = template.exchange(url, HttpMethod.GET, request, SetSearchResponseData.class);
//If I was using post, i could have done SetSearchResponseDataresponse = restTemplate.postForObject(url, request, SetSearchResponseData.class);
The RestTemplate getForObject() method does not support setting headers. The solution is to use the exchange() method.
So instead of restTemplate.getForObject(url, String.class, param) (which has no headers), use
HttpHeaders headers = new HttpHeaders();
headers.set("Header", "value");
headers.set("Other-Header", "othervalue");
...
HttpEntity<Void> requestEntity = new HttpEntity<>(headers);
ResponseEntity<String> response = restTemplate.exchange(
url, HttpMethod.GET, requestEntity, String.class, param);
Finally, use response.getBody() to get your result.
This question is similar to this question.
Take a look at the JavaDoc for RestTemplate.
There is the corresponding getForObject methods that are the HTTP GET equivalents of postForObject, but they doesn't appear to fulfil your requirements of "GET with headers", as there is no way to specify headers on any of the calls.
Looking at the JavaDoc, no method that is HTTP GET specific allows you to also provide header information. There are alternatives though, one of which you have found and are using. The exchange methods allow you to provide an HttpEntity object representing the details of the request (including headers). The execute methods allow you to specify a RequestCallback from which you can add the headers upon its invocation.
The getForObject() method of RestTemplate does not support setting headers. you can use this
syntax:
restTemplate.exchange(url endpoint,
HttpMethod.GET,entity, params)
public List<Employee> getListofEmployee()
{
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
HttpEntity<String> entity = new HttpEntity<String>(headers);
ResponseEntity<List<Employee>> response = restTemplate.exchange("http://hello-server/rest/employees",
HttpMethod.GET,entity, new ParameterizedTypeReference<List<Employee>>() {});
return response.getBody(); //this returns List of Employee
}

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