stripe: support creating checkout session with all dicts and lists serialized

```py
kw = {...}
kw['metadata[key]'] = 'value'
connector.createSession(**kw)
```

but it would be more beautiful to be able to write it like this:

```py
kw = {...}
kw['metadata] = {'key': 'value'}
connector.createSession(**kw)
```

This would need change in the way the request data is serialised in
createSession.

bt5/erp5_stripe/DocumentTemplateItem/portal_components/document.erp5.StripeConnector.py

@@ -26,10 +26,7 @@
 #
 ##############################################################################
 
-
-
 from six.moves import urllib
-from copy import deepcopy
 
 import requests
 import six
@@ -60,23 +57,16 @@ class StripeConnector(XMLObject):
     PropertySheet.DublinCore
   )
 
-  def buildLineKey(self, prefix, key_list):
-    for key in key_list:
-      prefix += "[%s]" % key
-    return prefix
-
-  def buildLine(self, data_dict, prefix, key_list, value):
-    if not isinstance(value, dict):
-      data_dict[self.buildLineKey(prefix, key_list)] = value
+  def serializeSessionParameter(self, request_data, key, value):
+    if isinstance(value, list) or isinstance(value, dict):
+      iterator = six.iteritems(value) if isinstance(value, dict) else enumerate(value)
+      for subkey, subvalue in iterator:
+        self.serializeSessionParameter(
+          request_data,
+          "{}[{}]".format(key, subkey),
+          subvalue)
     else:
-      for subkey, subvalue in six.iteritems(value):
-        self.buildLine(data_dict, prefix, key_list + [subkey,], subvalue)
-
-  def buildLineItemList(self, prefix, line_item_list):
-    data_dict = {}
-    for key, value in enumerate(line_item_list):
-      self.buildLine(data_dict, prefix, [key,], value)
-    return data_dict
+      request_data[key] = value
 
   def createSession(self, data, **kw):
     """
@@ -85,12 +75,6 @@ class StripeConnector(XMLObject):
       data is a dict, see https://stripe.com/docs/api/checkout/sessions/create
     """
     end_point = "checkout/sessions"
-    # copy data, not to mutate caller's data
-    request_data = deepcopy(data)
-
-    if "mode" not in request_data:
-      request_data["mode"] = "payment"
-
     header_dict = {
       'Content-Type': 'application/x-www-form-urlencoded',
     }
@@ -98,8 +82,13 @@ class StripeConnector(XMLObject):
     if not url_string.endswith("/"):
       url_string += "/"
     url_string += end_point
-    line_item_list = request_data.pop("line_items")
-    request_data.update(self.buildLineItemList("line_items", line_item_list))
+    request_data = {}
+    for key, value in six.iteritems(data):
+      self.serializeSessionParameter(request_data, key, value)
+
+    if "mode" not in request_data:
+      request_data["mode"] = "payment"
+
     response = requests.post(
       url_string,
       headers=header_dict,

bt5/erp5_stripe/TestTemplateItem/portal_components/test.erp5.testStripe.py

@@ -45,10 +45,7 @@ class TestStripePaymentSession(ERP5TypeTestCase):
 
     self.connector_reference = "abc"
     self.session_url = "https://mock:8080/checkout/sessions"
-    self.data = {
-      "success_url": "http://success",
-      "cancel_url": "http://cancel",
-      "line_items": [{
+    self.default_item_line = {
       "price_data": {
         "currency": "eur",
         "unit_amount": "100",
@@ -57,7 +54,11 @@ class TestStripePaymentSession(ERP5TypeTestCase):
         }
       },
       "quantity": 1
-      }, {
+    }
+    self.data = {
+      "success_url": "http://success",
+      "cancel_url": "http://cancel",
+      "line_items": [self.default_item_line, {
         "price_data": {
           "currency": "eur",
           "unit_amount": "200",
@@ -220,6 +221,157 @@ class TestStripePaymentSession(ERP5TypeTestCase):
       response = connector.createSession(data=self.data.copy())
       self.assertEqual(response["id"], "123")
 
+  def test_api_create_session_with_metadata(self):
+    connector = self._create_connector()
+
+    def _request_callback(request):
+      self.assertEqual(
+        'application/x-www-form-urlencoded', request.headers['Content-Type'],
+        request.headers)
+      body = parse_qs(request.body)
+      self.assertEqual(
+        body, {
+          "success_url": ["http://success"],
+          "cancel_url": ["http://cancel"],
+          "line_items[0][price_data][currency]": ["eur"],
+          "line_items[0][price_data][unit_amount]": ["100"],
+          "line_items[0][price_data][product_data][name]": ["First Line"],
+          "line_items[0][quantity]": ["1"],
+          "metadata[key]": ["value"],
+          "mode": ["payment"],
+        })
+      return (
+        200, {
+          'content-type': 'application/json'
+        },
+        json.dumps(
+          {
+            "id": "123",
+            "status": "open",
+            "object": "checkout.session"
+          }))
+
+    with responses.RequestsMock() as rsps:
+      rsps.add_callback(
+        responses.POST,
+        self.session_url,
+        _request_callback,
+      )
+      response = connector.createSession(
+        data={
+          "success_url": "http://success",
+          "cancel_url": "http://cancel",
+          "line_items": [
+            self.default_item_line
+          ],
+          "metadata": {
+            "key": "value",
+          },
+          "mode": "payment"
+        })
+      self.assertEqual(response["id"], "123")
+
+  def test_api_create_session_with_any_hash(self):
+    """ Test if dicts and lists are serialized properly
+    """
+    connector = self._create_connector()
+
+    def _request_callback(request):
+      self.assertEqual(
+        'application/x-www-form-urlencoded', request.headers['Content-Type'],
+        request.headers)
+      body = parse_qs(request.body)
+      self.assertEqual(
+        body, {
+          "automatic_tax[enabled]": ['true'],
+          "automatic_tax[status]": ['complete'],
+          "success_url": ["http://success"],
+          "cancel_url": ["http://cancel"],
+          'custom_text[shipping_text][message]': ['Rue XV'],
+          'custom_text[submit][message]': ['Rue XV'],
+          'customer_details[address]': ['Rue XV'],
+          'customer_details[email]': ['text@text.com'],
+          'customer_details[name]': ['My name'],
+          'customer_details[phone]': ['2199909'],
+          'customer_details[tax_exempt]': ['tax'],
+          'customer_details[tax_ids][0][type]': ['eu_vat'],
+          'customer_details[tax_ids][0][value]': ['33'],
+          'customer_details[tax_ids][1][type]': ['br_cnpj'],
+          'customer_details[tax_ids][1][value]': ['33'],
+          "line_items[0][price_data][currency]": ["eur"],
+          "line_items[0][price_data][unit_amount]": ["100"],
+          "line_items[0][price_data][product_data][name]": ["First Line"],
+          "line_items[0][quantity]": ["1"],
+          "metadata[key]": ["value"],
+          "metadata[key1]": ["value1"],
+          "metadata[key2]": ["value2"],
+          "mode": ["payment"],
+          "payment_method_options[acss_debit][current]": ['usd']
+        })
+      return (
+        200, {
+          'content-type': 'application/json'
+        },
+        json.dumps(
+          {
+            "id": "123",
+            "status": "open",
+            "object": "checkout.session"
+          }))
+
+    with responses.RequestsMock() as rsps:
+      rsps.add_callback(
+        responses.POST,
+        self.session_url,
+        _request_callback,
+      )
+      response = connector.createSession(
+        data={
+          "success_url": "http://success",
+          "cancel_url": "http://cancel",
+          "line_items": [
+            self.default_item_line
+          ],
+          "metadata": {
+            "key": "value",
+            "key1": "value1",
+            "key2": "value2",
+          },
+          "automatic_tax": {
+            "enabled": "true",
+            "status": "complete"
+          },
+          "custom_text": {
+            "shipping_text": {
+            "message": "Rue XV",
+            },
+            "submit": {
+              "message": "Rue XV",
+            }
+          },
+          "customer_details": {
+            "address": "Rue XV",
+            "email": "text@text.com",
+            "name": "My name",
+            "phone": "2199909",
+            "tax_exempt": "tax",
+            "tax_ids": [{
+              "type": "eu_vat",
+              "value": "33"
+            }, {
+              "type": "br_cnpj",
+              "value": "33"
+            }]
+          },
+          "payment_method_options": {
+            "acss_debit": {
+              "current": "usd"
+            }
+          },
+          "mode": "payment"
+        })
+      self.assertEqual(response["id"], "123")
+
   def test_create_stripe_payment_session_open(self):
     connector = self._create_connector()