tornado_requests: set Content-Type header correctly for JSON

Dumping the data first to a string caused the Content-Type header to be set
to application/x-www-form-urlencoded. Now if the request function gets a
dict, it is converted to a JSON string and the Content-Type header is set
to application/json.

Signed-off-by: Thore Sommer <mail@thson.de>

keylime/cloud_verifier_common.py

@@ -199,8 +199,7 @@ def prepare_v(agent):
     post_data = {
         'encrypted_key': b64_encrypted_V
     }
-    v_json_message = json.dumps(post_data)
-    return v_json_message
+    return post_data
 
 
 def prepare_get_quote(agent):

keylime/tornado_requests.py

@@ -7,6 +7,8 @@
 
 from tornado import httpclient
 
+from keylime import json
+
 
 async def request(method, url, params=None, data=None, context=None, headers=None):
 
@@ -20,6 +22,14 @@ async def request(method, url, params=None, data=None, context=None, headers=Non
     if context is not None:
         url = url.replace('http://', 'https://', 1)
 
+    # Convert dict to JSON before sending
+    if isinstance(data, dict):
+        data = json.dumps(data)
+        if headers is None:
+            headers = {}
+        if "Content-Type" not in headers:
+            headers["Content-Type"] = "application/json"
+
     try:
         req = httpclient.HTTPRequest(url=url,
                                      method=method,