data is to be passed to _request as 'params' always, pick POST or GET…

… and convert from 'params' to 'data' as required in the _request function

esridump/dumper.py

@@ -65,12 +65,16 @@ def __init__(self, url, parent_logger=None,
             self._logger = logging.getLogger('esridump')
 
     def _request(self, method, url, **kwargs):
-
+        if method == 'POST' and self._use_only_get:
+            method = 'GET'
+
+        if method == 'POST':
+            if 'params' in kwargs:
+                kwargs['data'] = kwargs['params']
+                del kwargs['params']
+
         if self._proxy:
             url = self._proxy + url
-            params = kwargs.pop('params', None)
-            if params:
-                url += '?' + urlencode(params)
         return self._requester(method, url, self._logger, self._http_timeout, **kwargs)
 
     def _build_url(self, url=None):
@@ -143,9 +147,8 @@ def can_handle_pagination(self, query_fields):
         })
         headers = self._build_headers()
         query_url = self._build_url('/query')
-        verb = 'GET' if self._use_only_get else 'POST'
         response = self._request(
-            verb, query_url, headers=headers, data=check_args)
+            'POST', query_url, headers=headers, params=check_args)
 
         try:
             data = response.json()
@@ -369,8 +372,7 @@ def _is_oid_field_returned(self, oid, oid_field_name, query_fields):
         })
         headers = self._build_headers()
         url = self._build_url('/query')
-        verb = 'GET' if self._use_only_get else 'POST'
-        response = self._request(verb, url, data=query_args, headers=headers)
+        response = self._request('POST', url, params=query_args, headers=headers)
         data = self._handle_esri_errors(response, f"unable to retrieve feature with {oid}")
         if data is None or data.get('features') is None or len(data.get('features')) != 1:
             raise EsriDownloadError('Unable to query for oid field')
@@ -517,9 +519,6 @@ def run_query(self, query_url, headers, query_args, verb='POST'):
         download_exception = None
         data = None
 
-        request_arg_key = 'data' if verb == 'POST' else 'params'
-        request_args = { request_arg_key: query_args }
-
         #  try to do a request "num_of_retry" to increase the probability of fetching data successfully
         for retry in range(self._num_of_retry):
             try:
@@ -528,7 +527,7 @@ def run_query(self, query_url, headers, query_args, verb='POST'):
                     time.sleep(self._pause_seconds)
                     self._logger.info(
                         "pause for %s seconds", self._pause_seconds)
-                response = self._request(verb, query_url, headers=headers, **request_args)
+                response = self._request(verb, query_url, headers=headers, data=query_args)
                 data = self._handle_esri_errors(
                     response, "Could not retrieve this chunk of objects")
                 # reset the exception state.