How to have jersey inject a param based on the http header? - jersey

Question

I have an interface and would like to open it as a REST API.
Interface:
string createToken(String username, String scopes);
REST web API:
#GET
#Path("/createToken")
#Override
public string createToken(#InjectParam String username, String scopes) {
...
}
As a simple Java API,, the interface itself makes sense - creating an access token by a specific (unique) user.
But, as an REST web API, I need a previous step to retrieve the username, based on some user data that is passed in the http header, like an SSO key.
How do I inject a value into the username - extracted from the HTTP header? Thanks.

Answer 1

Created a Provider to inject the value into a custom annotation. See small working example here. See source inline below as well.
The example extracts the username from an sso token. It's a dummy extraction.
* I didn't use #InjectParam.
Invocation example:
curl -X POST -H "ssoToken: 1234" http://localhost:8080/JerseyCustomParamInjection-1.0-SNAPSHOT/oauth2/createAccessToken
Custom annotation:
#Target({ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
public #interface LoggedUser {
}
Provider to do the injection:
#Provider
public class LoggedUserProvider implements
Injectable<String>,
InjectableProvider<LoggedUser, Parameter> {
#Context
private HttpServletRequest request;
public LoggedUserProvider() {
}
#Override
public Injectable<String> getInjectable(ComponentContext cc, LoggedUser a, com.sun.jersey.api.model.Parameter c) {
return this;
}
#Override
public ComponentScope getScope() {
return ComponentScope.PerRequest;
}
#Override
public String getValue() {
String sso = request.getHeader("ssoToken");
if (sso == null) {
throw new WebApplicationException(Response.Status.UNAUTHORIZED);
}
// Retreive username from soo
String username = " <extracted username from sso="+sso+">";
return username;
}
}
Resource that defines the wants to inject the value:
#Path("/oauth2")
public class Resource {
#POST
#Path("/createAccessToken")
public String createAccessToken(
#LoggedUser String username
) {
return username + " <created access token using the logged in injected username>";
}
}
Servlet configuration (web.xml):
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>Restful Web Application</display-name>
<servlet>
<servlet-name>jersey-serlvet</servlet-name>
<servlet-class>
com.sun.jersey.spi.container.servlet.ServletContainer
</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>info.fastpace.jerseycustomparaminjection</param-value>
</init-param>
<init-param>
<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
<param-value>true</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>jersey-serlvet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
</web-app>

Answer 2

You should use HeaderParam. See this
#GET
#Path("/createToken")
#Override
public string createToken(#HeaderParam("username") String username, String scopes) {
...
}
If you have to extract username and have to inject it, you will have to implement a provider:
#Provider
public class UsernameProvider
extends AbstractHttpContextInjectable<Locale>
implements InjectableProvider<Context, Type> {
#Override
public Injectable<E> getInjectable(ComponentContext compCntxt, Context cntxt, Type typ) {
if (typ.equals(String.class)) {
return this;
}
return null;
}
#Override
public ComponentScope getScope() {
return ComponentScope.PerRequest;
}
#Override
public String getValue(HttpContext httpCntxt) {
final Request rqst = httpCntxt.getRequest();
String username = null;
//Extract 'username' from Headers
return username;
}
}
Detailed explanation here