[FIX] HTTP: prevent access errors when accessing propagated request context

Author: ChristianGruen

basex-api/src/main/java/org/basex/http/HTTPConnection.java

@@ -262,7 +262,8 @@ public void forward(final String location) throws IOException, ServletException
 
   @Override
   public String clientAddress() {
-    return getRemoteAddr() + ':' + request.getRemotePort();
+    final String addr = getRemoteAddr();
+    return addr != null ? addr + ':' + request.getRemotePort() : null;
   }
 
   @Override

basex-api/src/main/java/org/basex/query/func/ApiFunc.java

@@ -6,6 +6,7 @@
 
 import org.basex.http.*;
 import org.basex.query.*;
+import org.basex.query.value.item.*;
 
 /**
  * Request function.
@@ -35,4 +36,13 @@ public final RequestContext requestContext(final QueryContext qc) throws QueryEx
   public final HttpServletRequest request(final QueryContext qc) throws QueryException {
     return requestContext(qc).request;
   }
+
+  /**
+   * Returns a non-null string.
+   * @param string string (can be {@code null})
+   * @return string
+   */
+  public final Str toStr(final String string) {
+    return Str.get(string != null ? string : "");
+  }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestAddress.java

@@ -13,7 +13,7 @@
  */
 public final class RequestAddress extends ApiFunc {
   @Override
-  public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getLocalAddr());
+  public Str item(final QueryContext qc, final InputInfo ii) throws QueryException {
+    return toStr(request(qc).getLocalAddr());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestContextPath.java

@@ -13,7 +13,7 @@
  */
 public final class RequestContextPath extends ApiFunc {
   @Override
-  public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getContextPath());
+  public Str item(final QueryContext qc, final InputInfo ii) throws QueryException {
+    return toStr(request(qc).getContextPath());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestHostname.java

@@ -14,6 +14,6 @@
 public final class RequestHostname extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getServerName());
+    return toStr(request(qc).getServerName());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestMethod.java

@@ -14,6 +14,6 @@
 public final class RequestMethod extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getMethod());
+    return toStr(request(qc).getMethod());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestPath.java

@@ -14,6 +14,6 @@
 public final class RequestPath extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getRequestURI());
+    return toStr(request(qc).getRequestURI());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestRemoteAddress.java

@@ -14,6 +14,6 @@
 public final class RequestRemoteAddress extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getRemoteAddr());
+    return toStr(request(qc).getRemoteAddr());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestRemoteHostname.java

@@ -14,6 +14,6 @@
 public final class RequestRemoteHostname extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getRemoteHost());
+    return toStr(request(qc).getRemoteHost());
   }
 }

basex-api/src/main/java/org/basex/query/func/request/RequestScheme.java

@@ -14,6 +14,6 @@
 public final class RequestScheme extends ApiFunc {
   @Override
   public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
-    return Str.get(request(qc).getScheme());
+    return toStr(request(qc).getScheme());
   }
 }