Enable support for parsing JSON environment variables (#272)

* Add support for applying JSON string

* only take JSON Object or JSON Array into consideration

* Add tests and make JSON-parsing opt-in

lib/nconf/stores/env.js

@@ -24,6 +24,7 @@ var Env = exports.Env = function (options) {
   this.whitelist = options.whitelist || [];
   this.separator = options.separator || '';
   this.lowerCase = options.lowerCase || false;
+  this.parseJson = options.parseJson || false;
 
   if (({}).toString.call(options.match) === '[object RegExp]'
       && typeof options !== 'string') {
@@ -78,11 +79,31 @@ Env.prototype.loadEnv = function () {
       return !self.whitelist.length || self.whitelist.indexOf(key) !== -1
     }
   }).forEach(function (key) {
+    
+    var val = env[key];
+
+    if (self.parseJson) {
+      try {
+        var ret = JSON.parse(val);
+
+        // apply JSON parsing only if its non-primitive types: JSON Object or Array
+        // avoid breaking backward-compatibility
+        if (typeof ret !== 'number' &&
+            typeof ret !== 'string' &&
+            typeof ret !== 'boolean') {
+          val = ret;
+        }
+
+      } catch (ignore) {
+        //ignore
+      }
+    }
+
     if (self.separator) {
-      self.set(common.key.apply(common, key.split(self.separator)), env[key]);
+      self.set(common.key.apply(common, key.split(self.separator)), val);
     }
     else {
-      self.set(key, env[key]);
+      self.set(key, val);
     }
   });
 

test/complete-test.js

@@ -22,6 +22,8 @@ process.env.FOO = 'bar';
 process.env.BAR = 'zalgo';
 process.env.NODE_ENV = 'debug';
 process.env.FOOBAR = 'should not load';
+process.env.json_array = JSON.stringify(['foo', 'bar', 'baz']);
+process.env.json_obj = JSON.stringify({foo: 'bar', baz: 'foo'});
 
 vows.describe('nconf/multiple-stores').addBatch({
   "When using the nconf with multiple providers": {
@@ -156,4 +158,40 @@ vows.describe('nconf/multiple-stores').addBatch({
       nconf.remove('env');
     }
   }
+}).addBatch({
+  // Threw this in it's own batch to make sure it's run separately from the
+  // sync check
+  "When using env with parseJson:true": {
+    topic: function () {
+      var that = this;
+      helpers.cp(complete, completeTest, function () {
+        nconf.env({ parseJson: true });
+        that.callback();
+      });
+    },
+    "env vars": {
+      "JSON keys properly parsed": function () {
+        Object.keys(process.env).forEach(function (key) {
+          var val = process.env[key];
+          
+          try {
+            var ret = JSON.parse(val);
+            
+            // apply JSON parsing only if its non-primitive types: JSON Object or Array
+            // avoid breaking backward-compatibility
+            if (typeof ret !== 'number' &&
+                typeof ret !== 'string' &&
+                typeof ret !== 'boolean') {
+              val = ret;
+            }
+          } catch (err) {}
+
+          assert.deepEqual(nconf.get(key), val);
+        });
+      }
+    },
+    teardown: function () {
+      nconf.remove('env');
+    }
+  }
 }).export(module);