Added streaming jsonl format

documentation/OUTPUT_FORMATS.md

@@ -82,6 +82,7 @@ hug provides a large catalog of built-in output formats, which can be used to bu
  - `hug.output_format.html`: Outputs Hyper Text Markup Language (HTML).
  - `hug.output_format.json_camelcase`: Outputs in the JSON format, but first converts all keys to camelCase to better conform to Javascript coding standards.
  - `hug.output_format.pretty_json`: Outputs in the JSON format, with extra whitespace to improve human readability.
+ - `hug.output_format.json_streaming_lines`: Takes an interable or yield statements and streams it as newline-seperated json objects.
  - `hug.output_format.image(format)`: Outputs an image (of the specified format).
     - There are convenience calls in the form `hug.output_format.{FORMAT}_image for the following image types: 'png', 'jpg', 'bmp', 'eps', 'gif', 'im', 'jpeg', 'msp', 'pcx', 'ppm', 'spider', 'tiff', 'webp', 'xbm',
                'cur', 'dcx', 'fli', 'flc', 'gbr', 'gd', 'ico', 'icns', 'imt', 'iptc', 'naa', 'mcidas', 'mpo', 'pcd',

hug/output_format.py

@@ -175,6 +175,16 @@ def json(content, request=None, response=None, ensure_ascii=False, **kwargs):
         content, default=_json_converter, ensure_ascii=ensure_ascii, **kwargs
     ).encode("utf8")
 
+@content_type("application/jsonl; charset=utf-8")
+def json_streaming_lines(data, request=None, response=None,**kwargs):
+    """Stream a json response using the jsonl format, where each unique json-object is
+    seperated by a newline
+    """
+    now = str(datetime.utcnow())
+    response.append_header('Content-Disposition',
+                           (f'attachment; filename="{now}.jsonl"'))
+    response.stream = (json(i,indent=None,**kwargs)+b"\n" for i in data)
+    return
 
 def on_valid(valid_content_type, on_invalid=json):
     """Renders as the specified content type only if no errors are found in the provided data object"""