How to make queryparams mandatory in Java Jersey REST services? - jersey

Question

I have a REST API that accepts 3 query params. When the query is called without any one of the query parameters, the API executes and returns the result. How do we make the queryparams mandatory? How can I add validation to check if all the parameters are present? Also, please let me know the best approach.

Answer 1

On a very simple level you could just inject the HttpServletRequest and check yourself:
#GET
public Response example(#Context HttpServletRequest request,
#QueryParam("name") String name) {
if (null == request.getParameter("name")) {
ResponseBuilder builder = Response.status(404);
return builder.build();
}
// Do something with name
}
Or you can implement something more elaborate using AOP. Here's a blog post about further options.

Answer 2

jersey doesn't give a mandatory parameter checking functionality out of the box. however you can do something like implementing your own annotation to achieve it.
Below is the annotation code:
#Target(value = ElementType.METHOD)
#Retention(value = RetentionPolicy.RUNTIME)
public #interface Required {
String[] value();
}
You also need a filter, below is the code:
public class RequiredParamResourceFilterFactory implements ResourceFilterFactory {
#Context
private transient HttpServletRequest servletRequest;
private class RequiredParamFilter implements ResourceFilter, ContainerRequestFilter {
private final String[] requiredParams;
protected List<String> parametersValueMissing;
private RequiredParamFilter(String[] requiredParams) {
this.requiredParams = requiredParams;
}
#Override
public ContainerRequest filter(ContainerRequest containerRequest) {
boolean missingMandatoryParameter = false;
List<String> missingParameters = new ArrayList<String>();
List<String> requiredParametersValueMissing = new ArrayList<String>();
List<String> URLParameters = getURLParameters(containerRequest.getQueryParameters());
List<String> methodRequiredParameters = Arrays.asList(requiredParams);
if (methodRequiredParameters != null) {
for (String methodRequiredParam : methodRequiredParameters) {
if (URLParameters == null) {
missingMandatoryParameter = true; //we will check this flag before returning result set to caller
missingParameters.add(methodRequiredParam);
} else if (!URLParameters.contains(methodRequiredParam)) {
missingMandatoryParameter = true; //we will check this flag before returning result set to caller
missingParameters.add(methodRequiredParam);
//Add to required parameters value missing List, only if the parameter is mandatory and value is not provided
// in the URL
} else if (parametersValueMissing.contains(methodRequiredParam)) {
requiredParametersValueMissing.add(methodRequiredParam);
}
}
if (missingMandatoryParameter && requiredParametersValueMissing.size() > 0) {
throw new YourCustomException("Missing Parameters = " + StringHelper.ArrayToString(missingParameters) +
"\nParameter value missing for " + StringHelper.ArrayToString(requiredParametersValueMissing));
} else if (missingMandatoryParameter) {
throw new YourCustomException("Missing Parameters = " + StringHelper.ArrayToString(missingParameters), MisbarErrorCode.VALIDATION_WRONG_INPUT_ERROR, "Customers");
} else if (requiredParametersValueMissing != null &&
requiredParametersValueMissing.size() > 0) {
throw new YourCustomException("Parameter value missing for " + StringHelper.ArrayToString(requiredParametersValueMissing));
}
}
return containerRequest;
}
#Override
public ContainerRequestFilter getRequestFilter() {
return this;
}
#Override
public ContainerResponseFilter getResponseFilter() {
return null;
}
/**
* To fetch the parameters sent to webservice call, these will be used to find if required parameter
* are present or not
*
* #param queryParams the queryparams sent
* #return all the parameters sent in URL
*/
private List<String> getURLParameters(MultivaluedMap<String,String> queryParams) {
parametersValueMissing = new ArrayList<String>();
List<String> arr = new ArrayList<String>();
for(String key:queryParams.keySet())
{
arr.add(key);
if(queryParams.get(key)==null)
parametersValueMissing.add(key);
}
if(!arr.isEmpty())
return arr;
return null;
}
}
#Override
public List<ResourceFilter> create(AbstractMethod am) {
Required required = am.getAnnotation(Required.class);
if(required!=null)
{
return Collections.<ResourceFilter>singletonList(new RequiredParamFilter(required.value()));
}
return null;
}
}
Below sample shows how to use this annotation, so in below webservice; file_id and count are mandatory parameters:
#GET
#Produces(MediaType.APPLICATION_JSON+";charset=utf-8")
#Cacheable(isCacheable = true)
#Path("posts/clusters")
#Required({"file_id","count"})
#Timed
public Response getClusters(
#QueryParam("file_id") Integer fileId,
#QueryParam("count") Integer count,
#DefaultValue("-1")#QueryParam("start_time") Long startTime){
;
}
If mandatory parameters are not provided in webservice call, you receive an error like below, mentioning the parameter names that are missing:
{
message: "Missing Parameters = file_id, count",
errorCode: "600"
}
Hope this solves your problem.