Add a :sort_keys option to Encoder

ext/yajl/yajl_ext.c

@@ -165,6 +165,9 @@ void yajl_encode_part(void * wrapper, VALUE obj, VALUE io) {
 
             /* TODO: itterate through keys in the hash */
             keys = rb_funcall(obj, intern_keys, 0);
+            if (w->sortKeys) {
+              keys = rb_funcall(keys, intern_sort, 0);
+            }
             for(idx=0; idx<RARRAY_LEN(keys); idx++) {
                 entry = rb_ary_entry(keys, idx);
                 keyStr = rb_funcall(entry, intern_to_s, 0); /* key must be a string */
@@ -590,7 +593,7 @@ static VALUE rb_yajl_encoder_new(int argc, VALUE * argv, VALUE klass) {
     yajl_gen_config cfg;
     VALUE opts, obj, indent;
     unsigned char *indentString = NULL, *actualIndent = NULL;
-    int beautify = 0, htmlSafe = 0;
+    int beautify = 0, htmlSafe = 0, sortKeys = 0;
 
     /* Scan off config vars */
     if (rb_scan_args(argc, argv, "01", &opts) == 1) {
@@ -613,6 +616,9 @@ static VALUE rb_yajl_encoder_new(int argc, VALUE * argv, VALUE klass) {
         if (rb_hash_aref(opts, sym_html_safe) == Qtrue) {
           htmlSafe = 1;
         }
+        if (rb_hash_aref(opts, sym_sort_keys) == Qtrue) {
+          sortKeys = 1;
+        }
     }
     if (!indentString) {
       indentString = defaultIndentString;
@@ -623,6 +629,7 @@ static VALUE rb_yajl_encoder_new(int argc, VALUE * argv, VALUE klass) {
     wrapper->indentString = actualIndent;
     wrapper->encoder = yajl_gen_alloc(&cfg, NULL);
     wrapper->on_progress_callback = Qnil;
+    wrapper->sortKeys = sortKeys;
     if (opts != Qnil && rb_funcall(opts, intern_has_key, 1, sym_terminator) == Qtrue) {
         wrapper->terminator = rb_hash_aref(opts, sym_terminator);
 #ifdef HAVE_RUBY_ENCODING_H
@@ -922,10 +929,12 @@ void Init_yajl() {
     intern_to_sym = rb_intern("to_sym");
     intern_has_key = rb_intern("has_key?");
     intern_as_json = rb_intern("as_json");
+    intern_sort = rb_intern("sort");
 
     sym_allow_comments = ID2SYM(rb_intern("allow_comments"));
     sym_check_utf8 = ID2SYM(rb_intern("check_utf8"));
     sym_pretty = ID2SYM(rb_intern("pretty"));
+    sym_sort_keys = ID2SYM(rb_intern("sort_keys"));
     sym_indent = ID2SYM(rb_intern("indent"));
     sym_html_safe = ID2SYM(rb_intern("html_safe"));
     sym_terminator = ID2SYM(rb_intern("terminator"));

ext/yajl/yajl_ext.h

@@ -55,8 +55,8 @@ static rb_encoding *utf8Encoding;
 
 static VALUE cParseError, cEncodeError, mYajl, cParser, cEncoder;
 static ID intern_io_read, intern_call, intern_keys, intern_to_s,
-            intern_to_json, intern_has_key, intern_to_sym, intern_as_json;
-static ID sym_allow_comments, sym_check_utf8, sym_pretty, sym_indent, sym_terminator, sym_symbolize_keys, sym_symbolize_names, sym_html_safe;
+            intern_to_json, intern_has_key, intern_to_sym, intern_as_json, intern_sort;
+static ID sym_allow_comments, sym_check_utf8, sym_pretty, sym_sort_keys, sym_indent, sym_terminator, sym_symbolize_keys, sym_symbolize_names, sym_html_safe;
 
 #define GetParser(obj, sval) Data_Get_Struct(obj, yajl_parser_wrapper, sval);
 #define GetEncoder(obj, sval) Data_Get_Struct(obj, yajl_encoder_wrapper, sval);
@@ -105,6 +105,7 @@ typedef struct {
     VALUE terminator;
     yajl_gen encoder;
     unsigned char *indentString;
+    int sortKeys;
 } yajl_encoder_wrapper;
 
 static VALUE rb_yajl_parser_new(int argc, VALUE * argv, VALUE self);

lib/yajl.rb

@@ -57,6 +57,8 @@ class Encoder
     #
     # :indent accepts a string and will be used as the indent character(s) during the pretty print process
     #
+    # :sort_keys accepts a boolean and will cause the keys of an object to be output in sorted order
+    #
     # If a block is passed, it will be used as (and work the same as) the +on_progress+ callback
     def self.encode(obj, *args, &block)
       # TODO: this code smells, any ideas?
@@ -73,4 +75,4 @@ def self.encode(obj, *args, &block)
       new(options).encode(obj, io, &block)
     end
   end
-end
+end

spec/encoding/encoding_spec.rb

@@ -312,4 +312,30 @@ def to_s
       Yajl::Encoder.encode(root)
     }.should raise_error(Yajl::EncodeError)
   end
-end
+
+  it "should sort keys when asked to" do
+    a = {}
+    a["z"] = 1
+    a["a"] = 2
+
+    Yajl::Encoder.encode(a, :sort_keys=> true).should eql(%({"a":2,"z":1}))
+  end
+
+  it "should not sort keys when not asked to" do
+    a = {}
+    a["z"] = 1
+    a["a"] = 2
+
+    Yajl::Encoder.encode(a).should eql(%({"z":1,"a":2}))
+  end
+
+  it "should sort keys without error when the keys are various crazy things" do
+    a = {}
+    a[:hello] = 1
+    a[0] = 2
+    a[Yajl] = 3
+
+    Yajl::Encoder.encode(a, :sort_keys=>true).should eql(%({"0":2,"Yajl":3,"hello":1}))
+  end
+
+end