Add support for version param (#7)

Author: typpo

README.md

@@ -116,6 +116,9 @@ The background color of the chart. Any valid HTML color works. Defaults to #ffff
 ### device_pixel_ratio: float
 The device pixel ratio of the chart. This will multiply the number of pixels by the value. This is usually used for retina displays. Defaults to 1.0.
 
+### version: str
+The version of Chart.js to use. Acceptable values are documented [here](https://quickchart.io/documentation/#parameters). Usually used to select Chart.js 3+.
+
 ### host
 Override the host of the chart render server. Defaults to quickchart.io.
 

quickchart/__init__.py

@@ -44,6 +44,7 @@ def __init__(self):
         self.background_color = '#ffffff'
         self.device_pixel_ratio = 1.0
         self.format = 'png'
+        self.version = '2.9.4'
         self.key = None
         self.scheme = 'https'
         self.host = 'quickchart.io'
@@ -65,6 +66,7 @@ def get_url(self):
             'bkg': self.background_color,
             'devicePixelRatio': self.device_pixel_ratio,
             'f': self.format,
+            'v': self.version,
         }
         if self.key:
             params['key'] = self.key
@@ -83,6 +85,7 @@ def _post(self, url):
             'backgroundColor': self.background_color,
             'devicePixelRatio': self.device_pixel_ratio,
             'format': self.format,
+            'version': self.version,
         }
         if self.key:
             postdata['key'] = self.key

tests.py

@@ -26,6 +26,23 @@ def test_simple(self):
         self.assertIn('devicePixelRatio=2', url)
         self.assertIn('Hello+world', url)
 
+    def test_version(self):
+        qc = QuickChart()
+        qc.version = '3.4.0'
+        qc.config = {
+            "type": "bar",
+            "data": {
+                "labels": ["Hello world", "Test"],
+                "datasets": [{
+                    "label": "Foo",
+                    "data": [1, 2]
+                }]
+            }
+        }
+
+        url = qc.get_url()
+        self.assertIn('v=3.4.0', url)
+
     def test_no_chart(self):
         qc = QuickChart()
         qc.width = 600