web_renderjs_ui: make error page a bit more readable

 - indent the json representation of error
 - if error is an XMLHttpRequest:
   - include the server side error response in an iframe
   - split response headers

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_launcher_js.js

@@ -120,9 +120,9 @@
     var error_list = [original_error],
       i,
       error,
+      error_response,
       error_text = "";
 
-
     // Do not break the application in case of errors.
     // Display it to the user for now,
     // and allow user to go back to the frontpage
@@ -144,6 +144,9 @@
         }
       }
       if (error instanceof XMLHttpRequest) {
+        if (error.getResponseHeader('Content-Type').indexOf('text/') === 0) {
+          error_response = error.response;
+        }
         error = {
           message: error.toString(),
           readyState: error.readyState,
@@ -151,14 +154,16 @@
           statusText: error.statusText,
           response: error.response,
           responseUrl: error.responseUrl,
-          response_headers: error.getAllResponseHeaders()
+          response_headers: (error.getAllResponseHeaders()
+                             ? error.getAllResponseHeaders().split('\r\n')
+                             : null)
         };
       }
       if (error.constructor === Array ||
           error.constructor === String ||
           error.constructor === Object) {
         try {
-          error = JSON.stringify(error);
+          error = JSON.stringify(error, null, '  ');
         } catch (ignore) {
         }
       }
@@ -185,9 +190,20 @@
       // Gadget has not yet been correctly initialized
       throw error;
     }
-
+    if (error_response) {
+      return error_response.text().then(
+        function (request_error_text) {
+          return gadget.changeState({
+            error_text: error_text,
+            request_error_text: request_error_text,
+            url: undefined
+          });
+        }
+      );
+    }
     return gadget.changeState({
       error_text: error_text,
+      request_error_text: undefined,
       url: undefined
     });
 
@@ -664,6 +680,7 @@
             var element = gadget.props.content_element,
               container = document.createElement("section"),
               paragraph,
+              iframe,
               link;
 
             paragraph = document.createElement("p");
@@ -712,6 +729,16 @@
             }
             element.appendChild(container);
 
+            // make an iframe to display error page from XMLHttpRequest
+            // we can only access contentDocument once the iframe is added to
+            // the DOM, so we do this after element is added.
+            if (gadget.state.request_error_text) {
+              iframe = document.createElement('iframe');
+              container.appendChild(iframe);
+              iframe.contentDocument.body.innerHTML =
+                gadget.state.request_error_text;
+            }
+
             // reset gadget state
             gadget.state = JSON.parse(default_state_json_string);
           });

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_launcher_js.xml

@@ -303,7 +303,7 @@
                     </tuple>
                     <state>
                       <tuple>
-                        <float>1469697401.26</float>
+                        <float>1469697402.26</float>
                         <string>UTC</string>
                       </tuple>
                     </state>