REQUEST now supports POST (#588)

* REQUEST now supports POST
* Add extra flag for enabling REQUEST, also update README and comments

Co-authored-by: John Cant <a.jonncant@gmail.com>
Co-authored-by: Alex Hall <alex.mojaki@gmail.com>

sandbox/grist/test_requests.py

@@ -4,6 +4,7 @@ import unittest
 import test_engine
 import testutil
 from functions import CaseInsensitiveDict, Response, HTTPError
+from functions.info import _replicate_requests_body_args
 
 
 class TestCaseInsensitiveDict(unittest.TestCase):
@@ -73,6 +74,45 @@ class TestResponse(unittest.TestCase):
     self.assertEqual(r.text, text)
 
 
+class TestRequestsPostInterface(unittest.TestCase):
+    def test_no_post_args(self):
+        body, headers = _replicate_requests_body_args()
+
+        assert body is None
+        assert headers == {}
+
+    def test_data_as_dict(self):
+        body, headers = _replicate_requests_body_args(data={"foo": "bar"})
+
+        assert body == "foo=bar"
+        assert headers == {"Content-Type": "application/x-www-form-urlencoded"}
+
+    def test_data_as_string(self):
+        body, headers = _replicate_requests_body_args(data="some_content")
+
+        assert body == "some_content"
+        assert headers == {}
+
+    def test_json_as_dict(self):
+        body, headers = _replicate_requests_body_args(json={"foo": "bar"})
+
+        assert body == '{"foo": "bar"}'
+        assert headers == {"Content-Type": "application/json"}
+
+    def test_json_as_string(self):
+        body, headers = _replicate_requests_body_args(json="invalid_but_ignored")
+
+        assert body == "invalid_but_ignored"
+        assert headers == {"Content-Type": "application/json"}
+
+    def test_data_and_json_together(self):
+        with self.assertRaises(ValueError):
+            body, headers = _replicate_requests_body_args(
+                json={"foo": "bar"},
+                data={"quux": "jazz"}
+            )
+
+
 class TestRequestFunction(test_engine.EngineTestCase):
   sample = testutil.parse_test_sample({
     "SCHEMA": [
@@ -98,12 +138,14 @@ r = REQUEST('my_url', headers={'foo': 'bar'}, params={'b': 1, 'a': 2})
 r.__dict__
 """
     out_actions = self.modify_column("Table1", "Request", formula=formula)
-    key = '9d305be9664924aaaf7ebb0bab2e4155d1fa1b9dcde53e417f1a9f9a2c7e09b9'
+    key = 'd7f8cedf177ab538bf7dadf66e77a525486a29a41ce4520b2c89a33e39095fed'
     deps = {'Table1': {'Request': [1, 2]}}
     args = {
       'url': 'my_url',
       'headers': {'foo': 'bar'},
       'params': {'a': 2, 'b': 1},
+      'method': 'GET',
+      'body': None,
       'deps': deps,
     }
     self.assertEqual(out_actions.requests, {key: args})