Add GET /nbconvert to list available formats

IPython/html/nbconvert/handlers.py

@@ -1,8 +1,9 b''
+import json
 import os
 
 from tornado import web
 
-from ..base.handlers import IPythonHandler
+from ..base.handlers import IPythonHandler, json_errors
 from IPython.nbformat.current import to_notebook_json
 from IPython.nbconvert.exporters.export import exporter_map
 from IPython.utils import tz
@@ -69,6 +70,19 b' class NbconvertPostHandler(IPythonHandler):'
         
         self.finish(output)
 
+class NbconvertRootHandler(IPythonHandler):
+    SUPPORTED_METHODS = ('GET',)
+
+    @web.authenticated
+    @json_errors
+    def get(self):
+        res = {}
+        for format, exporter in exporter_map.items():
+            res[format] = info = {}
+            info['output_mimetype'] = exporter.output_mimetype
+
+        self.finish(json.dumps(res))
+
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
@@ -82,4 +96,5 b' default_handlers = ['
     (r"/nbconvert/%s%s" % (_format_regex, _notebook_path_regex),
          NbconvertFileHandler),
     (r"/nbconvert/%s" % _format_regex, NbconvertPostHandler),
+    (r"/nbconvert", NbconvertRootHandler),
 ]
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IPython/html/nbconvert/tests/test_nbconvert_api.py

@@ -32,6 +32,9 b' class NbconvertAPI(object):'
         body = json.dumps(nbmodel)
         return self._req('POST', format, body)
 
+    def list_formats(self):
+        return self._req('GET', '')
+
 class APITest(NotebookTestBase):
     def setUp(self):
         nbdir = self.notebook_dir.name
@@ -92,3 +95,10 b' class APITest(NotebookTestBase):'
         r = self.nbconvert_api.from_post(format='python', nbmodel=nbmodel)
         self.assertIn(u'text/x-python', r.headers['Content-Type'])
         self.assertIn(u'print(2*6)', r.text)
+
+    def test_list_formats(self):
+        formats = self.nbconvert_api.list_formats().json()
+        self.assertIsInstance(formats, dict)
+        self.assertIn('python', formats)
+        self.assertIn('html', formats)
+        self.assertEqual(formats['python']['output_mimetype'], 'text/x-python')
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