fix(core): implement canonical dereferencing of external json schema …

…fragments

Fixes playlyfe#3

src/themis.js

@@ -88,10 +88,19 @@ var Utils = {
   rollback: function () { return; },
 
   dereferencePath: function (path, schema_id, schemas) {
-    if (path[0] === "#") {
+    var hash_index, index, ref, parts;
+    hash_index = path.indexOf('#');
+    if (hash_index === 0) {
       if (path === "#") { return schemas[schema_id]; }
-      var index, ref = schemas[schema_id];
-      var parts = path.slice(2).split("/").map(function (part) { return Utils.decodeJSONPointer(part); });
+      ref = schemas[schema_id];
+      parts = path.slice(2).split("/").map(function (part) { return Utils.decodeJSONPointer(part); });
+      for (index = 0; index < parts.length; index++) {
+        ref = ref[parts[index]];
+      }
+      return ref;
+    } else if (hash_index > 0) {
+      ref = schemas[path.slice(0, hash_index)];
+      parts = path.slice(hash_index + 2).split("/").map(function (part) { return Utils.decodeJSONPointer(part); });
       for (index = 0; index < parts.length; index++) {
         ref = ref[parts[index]];
       }
@@ -1996,6 +2005,7 @@ var buildSchemas = function (schema_data, options) {
     buffer[index] = [schemas[index], schema_id];
   }
 
+
   // Build refs
   index = buffer.length;
   while (buffer.length > 0) {

test/pattern.js

@@ -0,0 +1,39 @@
+Themis = require('../src/themis');
+
+describe('Issue #3: Crashing when pattern is incorrect in ref(erenced) schema', function() {
+
+  it('should be able to dereference fragments of external schemas', function() {
+    var schemas = [
+      {
+        "id": "types",
+        "$schema": "http://json-schema.org/draft-04/schema#",
+        "definitions": {
+          "uuid": {
+            "type": "string",
+            "pattern": "^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}$"
+          }
+        }
+      },
+      {
+        "id": "kitchensink",
+        "$schema": "http://json-schema.org/draft-04/schema#",
+        "type": "object",
+        "properties": {
+          "id": { "$ref": "types#/definitions/uuid" }
+        }
+      }
+    ];
+
+    var validator = Themis.validator(schemas);
+
+    var invalid_item = {
+      "id": "incorrect value"
+    };
+    var valid_item = {
+      "id": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
+    }
+    validator(invalid_item, 'kitchensink').valid.should.be.false;
+    validator(valid_item, 'kitchensink').valid.should.be.true;
+  });
+
+});