enabled auth server specific proxy settings

README.md

@@ -16,6 +16,7 @@ _If you need support for other grant types or authentication methods, please che
 
 ## Getting started ##
 Install with Maven:
+
 ```xml
 <dependency>
     <groupId>com.scalepoint</groupId>
@@ -52,3 +53,16 @@ ClientCredentialsGrantTokenClient tokenClient = new ClientCredentialsGrantTokenC
 
 String accessToken = tokenClient.getToken("scope1", "scope2");
 ```
+
+### Using Proxies ###
+
+The token client respects the proxy settings in the system properties, e.g. `http.proxyHost` or `http.proxyPort`.
+
+However in some cases the OAuth server needs to be accessed through a different proxy than the resource server.
+In these cases the OAuth server's proxy can be set like this:
+
+```java
+String proxyHost = "proxy.example.com"; // ip address works as well
+int    proxyPort = 8080;
+tokenClient.setProxy(proxyHost, proxyPort);
+```

src/main/java/com/scalepoint/oauth_token_client/CustomGrantTokenClient.java

@@ -18,6 +18,16 @@ public CustomGrantTokenClient(String tokenEndpointUri, ClientCredentials clientC
         this.cache = cache;
     }
 
+    /**
+     * Sets the proxy to be used for token requests.
+     *
+     * @param host Host name or IP address of the proxy
+     * @param port TCP port of the proxy
+     */
+    public void setProxy(final String host, final int port) {
+        tokenEndpointHttpClient.setProxy(host, port);
+    }
+
     /**
      * Retrieve access token for the configured "client_id" and specified scopes. Request to the server is only performed if matching valid token is not in the cache
      *

src/main/java/com/scalepoint/oauth_token_client/TokenEndpointHttpClient.java

@@ -5,6 +5,8 @@
 
 import java.io.*;
 import java.net.HttpURLConnection;
+import java.net.InetSocketAddress;
+import java.net.Proxy;
 import java.net.URL;
 import java.net.URLEncoder;
 import java.util.List;
@@ -15,6 +17,8 @@ class TokenEndpointHttpClient {
 
     private final String tokenEndpointUri;
 
+    private Proxy proxy;
+
     public TokenEndpointHttpClient(String tokenEndpointUri) {
         this.tokenEndpointUri = tokenEndpointUri;
     }
@@ -27,6 +31,10 @@ ExpiringToken getToken(List<NameValuePair> params) throws IOException {
         return parseResponse(tokenResponse);
     }
 
+    void setProxy(final String host, final int port) {
+        proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(host, port));
+    }
+
     private String formatRequest(List<NameValuePair> params) throws UnsupportedEncodingException {
         String body = "";
         for (NameValuePair p: params) {
@@ -38,7 +46,13 @@ private String formatRequest(List<NameValuePair> params) throws UnsupportedEncod
 
     private HttpURLConnection makeRequest(String body) throws IOException {
         URL u = new URL(tokenEndpointUri);
-        HttpURLConnection c = (HttpURLConnection)u.openConnection();
+        HttpURLConnection c;
+        if (proxy != null) {
+            c = (HttpURLConnection)u.openConnection(proxy);
+        }
+        else {
+            c = (HttpURLConnection)u.openConnection();
+        }
         c.setRequestMethod("POST");
         c.setInstanceFollowRedirects(false);
         c.setDoInput(true);