Get Config settings as Options to benefit from the defaults

thanks to Bombe!

For #691

src/freenet/clients/http/FProxyToadlet.java

@@ -44,6 +44,7 @@
 import freenet.clients.http.updateableelements.ProgressInfoElement;
 import freenet.clients.http.utils.UriFilterProxyHeaderParser;
 import freenet.config.Config;
+import freenet.config.Option;
 import freenet.config.SubConfig;
 import freenet.crypt.SHA256;
 import freenet.keys.FreenetURI;
@@ -991,8 +992,8 @@ private String getSchemeHostAndPort(ToadletContext ctx) {
 		// retrieve config from froxy
 		SubConfig fProxyConfig = core.node.config.get("fproxy");
 
-		String fProxyPort = String.valueOf(fProxyConfig.getInt("port"));
-		String fProxyBindTo = fProxyConfig.getString("bindTo");
+		Option<?> fProxyPort = fProxyConfig.getOption("port");
+		Option<?> fProxyBindTo = fProxyConfig.getOption("bindTo");
 
 		// get uri host and headers
 		MultiValueTable<String, String> headers = ctx.getHeaders();

src/freenet/clients/http/utils/UriFilterProxyHeaderParser.java

@@ -6,18 +6,19 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+import freenet.config.Option;
 import freenet.support.MultiValueTable;
 
 public class UriFilterProxyHeaderParser {
-    private final String fProxyPortConfig;
-    private final String fProxyBindToConfig;
+    private final Option<?> fProxyPortConfig;
+    private final Option<?> fProxyBindToConfig;
     private final String uriScheme;
     private final String uriHost;
     private final MultiValueTable<String, String> headers;
 
     public UriFilterProxyHeaderParser(
-        String fProxyPort,
-        String fProxyBindTo,
+        Option<?> fProxyPort,
+        Option<?> fProxyBindTo,
         String uriScheme,
         String uriHost,
         MultiValueTable<String, String> headers
@@ -33,17 +34,15 @@ public UriFilterProxyHeaderParser(
     public String getSchemeHostAndPort() {
         Set<String> safeProtocols = new HashSet<>(Arrays.asList("http", "https"));
 
-        List<String> bindToHosts = Arrays.asList(fProxyBindToConfig.split(",")).stream()
+        List<String> bindToHosts = Arrays.stream(fProxyBindToConfig.getValueString().split(","))
             .map(host -> host.contains(":") ? "[" + host + "]" : host)
             .collect(Collectors.toList());
         String firstBindToHost = bindToHosts.get(0);
         // set default values
         if (firstBindToHost.isEmpty()) {
             firstBindToHost = "127.0.0.1";
         }
-        String port = fProxyPortConfig.isEmpty()
-            ? "8888"
-            : fProxyPortConfig;
+        String port = fProxyPortConfig.getValueString();
         // allow all bindToHosts
         Set<String> safeHosts = new HashSet<>(bindToHosts);
         // also allow bindTo hosts with the fProxyPortConfig added