Smart text serialization (#12149)

* Smart text serialization

* Update test_pipeline.py

Author: lmazuel

sdk/core/azure-core/CHANGELOG.md

@@ -7,6 +7,7 @@
 
 - `AzureKeyCredentialPolicy` will now accept (and ignore) passed in kwargs  #11963
 - Better error messages if passed endpoint is incorrect  #12106
+- Do not JSON encore a string if content type is "text"  #12137
 
 ## 1.6.0 (2020-06-03)
 

sdk/core/azure-core/azure/core/pipeline/transport/_base.py

@@ -319,6 +319,19 @@ def set_streamed_data_body(self, data):
         self.data = data
         self.files = None
 
+    def set_text_body(self, data):
+        """Set a text as body of the request.
+
+        :param data: A text to send as body.
+        :type data: str
+        """
+        if data is None:
+            self.data = None
+        else:
+            self.data = data
+            self.headers["Content-Length"] = str(len(self.data))
+        self.files = None
+
     def set_xml_body(self, data):
         """Set an XML element tree as the body of the request.
 
@@ -685,6 +698,11 @@ def _request(
         # type: (...) -> HttpRequest
         """Create HttpRequest object.
 
+        If content is not None, guesses will be used to set the right body:
+        - If content is an XML tree, will serialize as XML
+        - If content-type starts by "text/", set the content as text
+        - Else, try JSON serialization
+
         :param str method: HTTP method (GET, HEAD, etc.)
         :param str url: URL for the request.
         :param dict params: URL query parameters.
@@ -703,8 +721,15 @@ def _request(
             request.headers.update(headers)
 
         if content is not None:
+            content_type = request.headers.get("Content-Type")
             if isinstance(content, ET.Element):
                 request.set_xml_body(content)
+            # https://github.com/Azure/azure-sdk-for-python/issues/12137
+            # A string is valid JSON, make the difference between text
+            # and a plain JSON string.
+            # Content-Type is a good indicator of intent from user
+            elif content_type and content_type.startswith("text/"):
+                request.set_text_body(content)
             else:
                 try:
                     request.set_json_body(content)

sdk/core/azure-core/tests/test_pipeline.py

@@ -264,6 +264,25 @@ def test_request_url_with_params(self):
 
         self.assertIn(request.url, ["a/b/c?g=h&t=y", "a/b/c?t=y&g=h"])
 
+    def test_request_text(self):
+        client = PipelineClientBase('http://example.org')
+        request = client.get(
+            "/",
+            content="foo"
+        )
+
+        # In absence of information, everything is JSON (double quote added)
+        assert request.data == json.dumps("foo")
+
+        request = client.post(
+            "/",
+            headers={'content-type': 'text/whatever'},
+            content="foo"
+        )
+
+        # We want a direct string
+        assert request.data == "foo"
+
 
 if __name__ == "__main__":
     unittest.main()