better return type for http client functions

added helper features

library/client/http_client/src/http_client_request.e

@@ -59,17 +59,17 @@ feature -- Authentication
 			Result := session.auth_type_id
 		end
 
-	username: detachable READABLE_STRING_8
+	username: detachable READABLE_STRING_32
 		do
 			Result := session.username
 		end
 
-	password: detachable READABLE_STRING_8
+	password: detachable READABLE_STRING_32
 		do
 			Result := session.password
 		end
 
-	credentials: detachable READABLE_STRING_8
+	credentials: detachable READABLE_STRING_32
 		do
 			Result := session.credentials
 		end

library/client/http_client/src/http_client_request_context.e

@@ -8,7 +8,8 @@ class
 	HTTP_CLIENT_REQUEST_CONTEXT
 
 create
-	make
+	make,
+	make_with_credentials_required
 
 feature {NONE} -- Initialization
 
@@ -19,6 +20,12 @@ feature {NONE} -- Initialization
 			create form_data_parameters.make (10)
 		end
 
+	make_with_credentials_required
+		do
+			make
+			set_credentials_required (True)
+		end
+
 feature -- Settings
 
 	credentials_required: BOOLEAN
@@ -40,6 +47,16 @@ feature -- Status report
 
 feature -- Element change
 
+	add_query_parameter (k: READABLE_STRING_8; v: READABLE_STRING_32)
+		do
+			query_parameters.force (v, k)
+		end
+
+	add_form_data_parameter (k: READABLE_STRING_8; v: READABLE_STRING_32)
+		do
+			form_data_parameters.force (v, k)
+		end
+
 	set_credentials_required (b: BOOLEAN)
 		do
 			credentials_required := b

library/client/http_client/src/http_client_session.e

@@ -92,12 +92,17 @@ feature -- Authentication
 			-- See {HTTP_CLIENT_CONSTANTS}.Auth_type_*
 
 	username,
-	password: detachable READABLE_STRING_8
+	password: detachable READABLE_STRING_32
 
-	credentials: detachable READABLE_STRING_8
+	credentials: detachable READABLE_STRING_32
 
 feature -- Change
 
+	set_base_url (u: like base_url)
+		do
+			base_url := u
+		end
+
 	set_timeout (n: like timeout)
 		do
 			timeout := n
@@ -113,6 +118,11 @@ feature -- Change
 			headers.force (v, k)
 		end
 
+	remove_header (k: READABLE_STRING_8)
+		do
+			headers.prune (k)
+		end
+
 	set_credentials (u: like username; p: like password)
 		do
 			username := u