Fix support RFC 7807 format (T1156273) (#590)

Author: OlegKipchatov

js-test/test.js

@@ -176,7 +176,7 @@
             QUnit.test("other mime", testCase("unknown/unknown", "any", "Bad Request"));
 
             QUnit.test("RFC 7807 - title", testCase(
-                "application/json",
+                "application/problem+json",
                 JSON.stringify({
                     type: "https://tools.ietf.org/html/rfc7231#section-6.6.1",
                     title: SAMPLE_MESSAGE,
@@ -186,13 +186,20 @@
             ));
 
             QUnit.test("RFC 7807 - detail fallback", testCase(
-                "application/json",
+                "application/problem+json",
                 JSON.stringify({
                     detail: SAMPLE_MESSAGE
                 }),
                 SAMPLE_MESSAGE
-            ))
+            ));
 
+            QUnit.test("RFC 7807 - error format", testCase(
+                "application/problem+json",
+                JSON.stringify({
+                    some_property: SAMPLE_MESSAGE
+                }),
+                '{\"some_property\":\"' + SAMPLE_MESSAGE + '\"}'
+            ));
         });
 
         QUnit.test("Issue #146", function(assert) {

js/dx.aspnet.data.js

@@ -379,9 +379,23 @@
         if(mime.indexOf("application/json") === 0) {
             var jsonObj = safeParseJSON(responseText);
 
-            if(isNonEmptyString(jsonObj))
+            if(typeof jsonObj === "string")
                 return jsonObj;
 
+            if(typeof jsonObj === "object") {
+                for(var key in jsonObj) {
+                    if(typeof jsonObj[key] === "string")
+                        return jsonObj[key];
+                }
+            }
+
+            return responseText;
+        }
+
+        if(mime.indexOf("application/problem+json") === 0) {
+            var jsonObj = safeParseJSON(responseText);
+
+            var candidate;
             if(typeof jsonObj === "object") {
                 candidate = jsonObj.title;
                 if(isNonEmptyString(candidate))
@@ -390,12 +404,6 @@
                 candidate = jsonObj.detail;
                 if(isNonEmptyString(candidate))
                     return candidate;
-
-                for(var key in jsonObj) {
-                    candidate = jsonObj[key];
-                    if(isNonEmptyString(candidate))
-                        return candidate;
-                }
             }
 
             return responseText;