Add option to disable forward slash escape

Ref issue #144

README.rst

@@ -59,7 +59,16 @@ Controls how many decimals to encode for double or decimal values. Default is 9:
     '3'
     >>> ujson.dumps(math.pi, double_precision=4)
     '3.1416'
-    
+
+escape_forward_slashes
+----------------------
+Controls whether forward slashes (``/``) are escaped. Default is True::
+
+    >>> ujson.dumps('http://esn.me')
+    '"http:\/\/esn.me"'
+    >>> ujson.dumps('http://esn.me', escape_forward_slashes=False)
+    '"http://esn.me"'
+
 ~~~~~~~~~~~~~~~~
 Decoders options
 ~~~~~~~~~~~~~~~~    

lib/ultrajson.h

@@ -241,6 +241,10 @@ typedef struct __JSONObjectEncoder
   If true, '<', '>', and '&' characters will be encoded as \u003c, \u003e, and \u0026, respectively. If false, no special encoding will be used. */
   int encodeHTMLChars;
 
+  /*
+  If true, '/' will be encoded as \/. If false, no escaping. */
+  int escapeForwardSlashes;
+
   /*
   Private pointer to be used by the caller. Passed as encoder_prv in JSONTypeContext */
   void *prv;

lib/ultrajsonenc.c

@@ -184,7 +184,6 @@ int Buffer_EscapeStringUnvalidated (JSONObjectEncoder *enc, const char *io, cons
       }
       case '\"': (*of++) = '\\'; (*of++) = '\"'; break;
       case '\\': (*of++) = '\\'; (*of++) = '\\'; break;
-      case '/':  (*of++) = '\\'; (*of++) = '/'; break;
       case '\b': (*of++) = '\\'; (*of++) = 'b'; break;
       case '\f': (*of++) = '\\'; (*of++) = 'f'; break;
       case '\n': (*of++) = '\\'; (*of++) = 'n'; break;
@@ -206,6 +205,19 @@ int Buffer_EscapeStringUnvalidated (JSONObjectEncoder *enc, const char *io, cons
           break;
         }
       }
+      case '/':
+      {
+        if (enc->escapeForwardSlashes)
+        {
+          (*of++) = '\\'; (*of++) = '/';
+        }
+        else
+        {
+          // Same as default case below.
+          (*of++) = (*io);
+        }
+        break;
+      }
       case 0x01:
       case 0x02:
       case 0x03:
@@ -423,9 +435,17 @@ int Buffer_EscapeStringValidated (JSOBJ obj, JSONObjectEncoder *enc, const char
       case 22:
       case 24:
       {
-        *(of++) = *( (char *) (g_escapeChars + utflen + 0));
-        *(of++) = *( (char *) (g_escapeChars + utflen + 1));
-        io ++;
+        if (enc->escapeForwardSlashes)
+        {
+          *(of++) = *( (char *) (g_escapeChars + utflen + 0));
+          *(of++) = *( (char *) (g_escapeChars + utflen + 1));
+          io ++;
+        }
+        else
+        {
+          // Same as case 1 above.
+          *(of++) = (*io++);
+        }
         continue;
       }
       // This can never happen, it's here to make L4 VC++ happy

python/objToJSON.c

@@ -818,7 +818,7 @@ char *Object_iterGetName(JSOBJ obj, JSONTypeContext *tc, size_t *outLen)
 
 PyObject* objToJSON(PyObject* self, PyObject *args, PyObject *kwargs)
 {
-  static char *kwlist[] = { "obj", "ensure_ascii", "double_precision", "encode_html_chars", NULL};
+  static char *kwlist[] = { "obj", "ensure_ascii", "double_precision", "encode_html_chars", "escape_forward_slashes", NULL };
 
   char buffer[65536];
   char *ret;
@@ -826,6 +826,7 @@ PyObject* objToJSON(PyObject* self, PyObject *args, PyObject *kwargs)
   PyObject *oinput = NULL;
   PyObject *oensureAscii = NULL;
   PyObject *oencodeHTMLChars = NULL;
+  PyObject *oescapeForwardSlashes = NULL;
 
   JSONObjectEncoder encoder =
   {
@@ -848,13 +849,14 @@ PyObject* objToJSON(PyObject* self, PyObject *args, PyObject *kwargs)
     10,  // default double precision setting
     1, //forceAscii
     0, //encodeHTMLChars
+    1, //escapeForwardSlashes
     NULL, //prv
   };
 
 
   PRINTMARK();
 
-  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|OiO", kwlist, &oinput, &oensureAscii, &encoder.doublePrecision, &oencodeHTMLChars))
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O|OiOO", kwlist, &oinput, &oensureAscii, &encoder.doublePrecision, &oencodeHTMLChars, &oescapeForwardSlashes))
   {
     return NULL;
   }
@@ -869,6 +871,11 @@ PyObject* objToJSON(PyObject* self, PyObject *args, PyObject *kwargs)
     encoder.encodeHTMLChars = 1;
   }
 
+  if (oescapeForwardSlashes != NULL && !PyObject_IsTrue(oescapeForwardSlashes))
+  {
+    encoder.escapeForwardSlashes = 0;
+  }
+
   PRINTMARK();
   ret = JSON_EncodeObject (oinput, &encoder, buffer, sizeof (buffer));
   PRINTMARK();

python/ujson.c

@@ -53,7 +53,7 @@ PyObject* objToJSONFile(PyObject* self, PyObject *args, PyObject *kwargs);
 PyObject* JSONFileToObj(PyObject* self, PyObject *args, PyObject *kwargs);
 
 
-#define ENCODER_HELP_TEXT "Use ensure_ascii=false to output UTF-8. Pass in double_precision to alter the maximum digit precision of doubles. Set encode_html_chars=True to encode < > & as unicode escape sequences."
+#define ENCODER_HELP_TEXT "Use ensure_ascii=false to output UTF-8. Pass in double_precision to alter the maximum digit precision of doubles. Set encode_html_chars=True to encode < > & as unicode escape sequences. Set escape_forward_slashes=False to prevent escaping / characters."
 
 static PyMethodDef ujsonMethods[] = {
   {"encode", (PyCFunction) objToJSON, METH_VARARGS | METH_KEYWORDS, "Converts arbitrary object recursivly into JSON. " ENCODER_HELP_TEXT},

tests/tests.py

@@ -49,6 +49,7 @@ class UltraJSONTests(unittest.TestCase):
         input = "A string \\ / \b \f \n \r \t </script> &"
         not_html_encoded = '"A string \\\\ \\/ \\b \\f \\n \\r \\t <\\/script> &"'
         html_encoded = '"A string \\\\ \\/ \\b \\f \\n \\r \\t \\u003c\\/script\\u003e \\u0026"'
+        not_slashes_escaped = input
 
         def helper(expected_output, **encode_kwargs):
             output = ujson.encode(input, **encode_kwargs)
@@ -68,6 +69,9 @@ class UltraJSONTests(unittest.TestCase):
         helper(html_encoded, ensure_ascii=True, encode_html_chars=True)
         helper(html_encoded, ensure_ascii=False, encode_html_chars=True)
 
+        # Do escape forward slashes if disabled.
+        helper(not_slashes_escaped, escape_forward_slashes=False)
+
     def testWriteEscapedString(self):
         self.assertEqual('"\\u003cimg src=\'\\u0026amp;\'\\/\\u003e"', ujson.dumps("<img src='&amp;'/>", encode_html_chars=True))