Read preference

_includes/cloudcode/cloud-code.md

@@ -381,6 +381,7 @@ Parse.Cloud.beforeFind('MyObject', (req) =>  {
 Parse.Cloud.beforeFind('MyObject2', (req) => {
   req.readPreference = 'SECONDARY_PREFERRED';
   req.subqueryReadPreference = 'SECONDARY';
+  req.includeReadPreference = 'PRIMARY';
 });
 
 ```

_includes/js/queries.md

@@ -537,3 +537,15 @@ query.distinct("age")
     // There was an error.
   });
 ```
+
+## Read Preference
+
+When using a MongoDB replica set, you can use the `query.readPreference(readPreference, includeReadPreference, subqueryReadPreference)` function to choose from which replica the objects will be retrieved. The `includeReadPreference` argument chooses from which replica the included pointers will be retrieved and the `subqueryReadPreference` argument chooses in which replica the subqueries will run. The possible values are `PRIMARY` (default), `PRIMARY_PREFERRED`, `SECONDARY`, `SECONDARY_PREFERRED`, or `NEAREST`. If the `includeReadPreference` argument is not passed, the same replica chosen for `readPreference` will be also used for the includes. The same rule applies for the `subqueryReadPreference` argument.
+
+```javascript
+query.readPreference(
+  'SECONDARY',
+  'SECONDARY_PREFERRED',
+  'NEAREST'
+);
+```

_includes/php/queries.md

@@ -455,3 +455,15 @@ $monster = Monster::spawn(200);
 echo monster->strength();  // Displays 200.
 echo monster->hasSuperHumanStrength();  // Displays true.
 ```
+
+## Read Preference
+
+When using a MongoDB replica set, you can use the `$query->readPreference(readPreference, includeReadPreference, subqueryReadPreference)` function to choose from which replica the objects will be retrieved. The `includeReadPreference` argument chooses from which replica the included pointers will be retrieved and the `subqueryReadPreference` argument chooses in which replica the subqueries will run. The possible values are `PRIMARY` (default), `PRIMARY_PREFERRED`, `SECONDARY`, `SECONDARY_PREFERRED`, or `NEAREST`. If the `includeReadPreference` argument is not passed, the same replica chosen for `readPreference` will be also used for the includes. The same rule applies for the `subqueryReadPreference` argument.
+
+```javascript
+$query->readPreference(
+  "SECONDARY",
+  "SECONDARY_PREFERRED",
+  "NEAREST"
+);
+```

_includes/rest/objects.md

@@ -165,6 +165,33 @@ print result
 </code></pre>
 </div>
 
+When using a MongoDB replica set, you can use the `readPreference` option to choose from which replica the object will be retrieved. You can also use the `includeReadPreference` option to choose from which replica the included pointers will be retrieved. The possible values for both options are `PRIMARY` (default), `PRIMARY_PREFERRED`, `SECONDARY`, `SECONDARY_PREFERRED`, or `NEAREST`. If the `includeReadPreference` option is not set, the same replica chosen for `readPreference` will be also used for the includes.
+
+<div class="language-toggle">
+<pre><code class="bash">
+curl -X GET \
+  -H "X-Parse-Application-Id: <span class="custom-parse-server-appid">${APPLICATION_ID}</span>" \
+  -H "X-Parse-REST-API-Key: <span class="custom-parse-server-restapikey">${REST_API_KEY}</span>" \
+  -G \
+  --data-urlencode 'include=game' \
+  --data-urlencode 'readPreference=SECONDARY' \
+  --data-urlencode 'includeReadPreference=SECONDARY_PREFERRED' \
+  <span class="custom-parse-server-protocol">https</span>://<span class="custom-parse-server-url">YOUR.PARSE-SERVER.HERE</span><span class="custom-parse-server-mount">/parse/</span>classes/GameScore/Ed1nuqPvcm
+</code></pre>
+<pre><code class="python">
+import json,httplib,urllib
+connection = httplib.HTTPSConnection('<span class="custom-parse-server-url">YOUR.PARSE-SERVER.HERE</span>', 443)
+params = urllib.urlencode({"include":"game","readPreference":"SECONDARY","includeReadPreference":"SECONDARY_PREFERRED"})
+connection.connect()
+connection.request('GET', '<span class="custom-parse-server-mount">/parse/</span>classes/GameScore/Ed1nuqPvcm?%s' % params, '', {
+       "X-Parse-Application-Id": "<span class="custom-parse-server-appid">${APPLICATION_ID}</span>",
+       "X-Parse-REST-API-Key": "<span class="custom-parse-server-restapikey">${REST_API_KEY}</span>"
+     })
+result = json.loads(connection.getresponse().read())
+print result
+</code></pre>
+</div>
+
 ## Updating Objects
 
 To change the data on an object that already exists, send a PUT request to the object URL. Any keys you don't specify will remain unchanged, so you can update just a subset of the object's data. For example, if we wanted to change the score field of our object:

_includes/rest/queries.md

@@ -1157,3 +1157,51 @@ print result
 </div>
 
 You can also constraint by `limit`, `skip`, `sort`.
+
+## Read Preference
+
+When using a MongoDB replica set, you can use the `readPreference` option to choose from which replica the objects will be retrieved. You can also use the `includeReadPreference` option to choose from which replica the included pointers will be retrieved and the `subqueryReadPreference` option to choose in which replica the subqueries will run. The possible values these options are `PRIMARY` (default), `PRIMARY_PREFERRED`, `SECONDARY`, `SECONDARY_PREFERRED`, or `NEAREST`. If the `includeReadPreference` option is not set, the same replica chosen for `readPreference` will be also used for the includes. The same rule applies for the `subqueryReadPreference` option.
+
+<div class="language-toggle">
+<pre><code class="bash">
+curl -X GET \
+  -H "X-Parse-Application-Id: <span class="custom-parse-server-appid">${APPLICATION_ID}</span>" \
+  -H "X-Parse-REST-API-Key: <span class="custom-parse-server-restapikey">${REST_API_KEY}</span>" \
+  -G \
+  --data-urlencode 'where={"post":{"$inQuery":{"where":{"image":{"$exists":true}},"className":"Post"}}}' \
+  --data-urlencode 'include=post' \
+  --data-urlencode 'readPreference=SECONDARY' \
+  --data-urlencode 'includeReadPreference=SECONDARY_PREFERRED' \
+  --data-urlencode 'subqueryReadPreference=NEAREST' \
+  <span class="custom-parse-server-protocol">https</span>://<span class="custom-parse-server-url">YOUR.PARSE-SERVER.HERE</span><span class="custom-parse-server-mount">/parse/</span>classes/Comment
+</code></pre>
+<pre><code class="python">
+import json,httplib,urllib
+connection = httplib.HTTPSConnection('<span class="custom-parse-server-url">YOUR.PARSE-SERVER.HERE</span>', 443)
+params = urllib.urlencode({
+  "where":json.dumps({
+    "post": {
+      "$inQuery": {
+        "where": {
+          "image": {
+            "$exists": True
+          }
+        },
+        "className": "Post"
+      }
+    }
+  }),
+  "include":"post",
+  "readPreference":"SECONDARY",
+  "includeReadPreference":"SECONDARY_PREFERRED",
+  "subqueryReadPreference":"NEAREST"
+})
+connection.connect()
+connection.request('GET', '<span class="custom-parse-server-mount">/parse/</span>classes/Comment?%s' % params, '', {
+       "X-Parse-Application-Id": "<span class="custom-parse-server-appid">${APPLICATION_ID}</span>",
+       "X-Parse-REST-API-Key": "<span class="custom-parse-server-restapikey">${REST_API_KEY}</span>"
+     })
+result = json.loads(connection.getresponse().read())
+print result
+</code></pre>
+</div>