feat(constants): add CSV and Parquet media types (#2439)

* feat(constants): add csv and parquet media type

Signed-off-by: Keming <kemingy94@gmail.com>

* update the csv recipe to use the MEDIA_CSV

Signed-off-by: Keming <kemingy94@gmail.com>

Author: kemingy

docs/_newsfragments/2335.newandimproved.rst

@@ -0,0 +1,2 @@
+Add :data:`~falcon.constants.MEDIA_PARQUET` and :data:`~falcon.constants.MEDIA_CSV`
+media file types to the constant file.

docs/user/recipes/output-csv.rst

@@ -23,7 +23,7 @@ and then assign its value to :attr:`resp.text <falcon.Response.text>`:
         .. literalinclude:: ../../../examples/recipes/output_csv_text_asgi.py
             :language: python
 
-Here we set the response ``Content-Type`` to ``"text/csv"`` as
+Here we set the response ``Content-Type`` to :data:`~falcon.constants.MEDIA_CSV` as
 recommended by `RFC 4180 <https://tools.ietf.org/html/rfc4180>`_, and assign
 the downloadable file name ``report.csv`` via the ``Content-Disposition``
 header (see also: :ref:`serve-downloadable-as`).

examples/recipes/output_csv_stream_asgi.py

@@ -1,5 +1,7 @@
 import csv
 
+import falcon
+
 
 class Report:
     class PseudoTextStream:
@@ -28,6 +30,6 @@ async def fibonacci_generator(self, n=1000):
             stream.clear()
 
     async def on_get(self, req, resp):
-        resp.content_type = 'text/csv'
+        resp.content_type = falcon.MEDIA_CSV
         resp.downloadable_as = 'report.csv'
         resp.stream = self.fibonacci_generator()

examples/recipes/output_csv_stream_wsgi.py

@@ -1,5 +1,7 @@
 import csv
 
+import falcon
+
 
 class Report:
     class PseudoTextStream:
@@ -27,6 +29,6 @@ def fibonacci_generator(self, n=1000):
             stream.clear()
 
     def on_get(self, req, resp):
-        resp.content_type = 'text/csv'
+        resp.content_type = falcon.MEDIA_CSV
         resp.downloadable_as = 'report.csv'
         resp.stream = self.fibonacci_generator()

examples/recipes/output_csv_text_asgi.py

@@ -1,6 +1,8 @@
 import csv
 import io
 
+import falcon
+
 
 class Report:
     async def on_get(self, req, resp):
@@ -10,6 +12,6 @@ async def on_get(self, req, resp):
         writer.writerow(('apples', 13))
         writer.writerow(('oranges', 37))
 
-        resp.content_type = 'text/csv'
+        resp.content_type = falcon.MEDIA_CSV
         resp.downloadable_as = 'report.csv'
         resp.text = output.getvalue()

examples/recipes/output_csv_text_wsgi.py

@@ -1,6 +1,8 @@
 import csv
 import io
 
+import falcon
+
 
 class Report:
     def on_get(self, req, resp):
@@ -10,6 +12,6 @@ def on_get(self, req, resp):
         writer.writerow(('apples', 13))
         writer.writerow(('oranges', 37))
 
-        resp.content_type = 'text/csv'
+        resp.content_type = falcon.MEDIA_CSV
         resp.downloadable_as = 'report.csv'
         resp.text = output.getvalue()

falcon/__init__.py

@@ -336,13 +336,15 @@
 from falcon.constants import DEFAULT_MEDIA_TYPE
 from falcon.constants import HTTP_METHODS
 from falcon.constants import MEDIA_BMP
+from falcon.constants import MEDIA_CSV
 from falcon.constants import MEDIA_GIF
 from falcon.constants import MEDIA_HTML
 from falcon.constants import MEDIA_JPEG
 from falcon.constants import MEDIA_JS
 from falcon.constants import MEDIA_JSON
 from falcon.constants import MEDIA_MSGPACK
 from falcon.constants import MEDIA_MULTIPART
+from falcon.constants import MEDIA_PARQUET
 from falcon.constants import MEDIA_PNG
 from falcon.constants import MEDIA_TEXT
 from falcon.constants import MEDIA_URLENCODED

falcon/constants.py

@@ -104,6 +104,8 @@
 # but the use of the 'x-' prefix is discouraged by RFC 6838.
 MEDIA_MSGPACK = 'application/msgpack'
 
+MEDIA_PARQUET = 'application/vnd.apache.parquet'
+
 MEDIA_MULTIPART = 'multipart/form-data'
 
 MEDIA_URLENCODED = 'application/x-www-form-urlencoded'
@@ -137,6 +139,11 @@
 MEDIA_HTML = 'text/html; charset=utf-8'
 MEDIA_TEXT = 'text/plain; charset=utf-8'
 
+# NOTE(kemingy): According to RFC 4180, common usage of CSV is US-ASCII,
+# but other charsets can also be used. We use UTF-8 to make it compatible
+# with most modern systems.
+MEDIA_CSV = 'text/csv; charset=utf-8'
+
 MEDIA_JPEG = 'image/jpeg'
 MEDIA_PNG = 'image/png'
 MEDIA_GIF = 'image/gif'
@@ -167,6 +174,7 @@
     (ext, media_type.split(';', 1)[0])
     for ext, media_type in (
         ('.bmp', MEDIA_BMP),
+        ('.csv', MEDIA_CSV),
         ('.gif', MEDIA_GIF),
         ('.htm', MEDIA_HTML),
         ('.html', MEDIA_HTML),
@@ -175,6 +183,7 @@
         ('.js', MEDIA_JS),
         ('.json', MEDIA_JSON),
         ('.mjs', MEDIA_JS),
+        ('.parquet', MEDIA_PARQUET),
         ('.png', MEDIA_PNG),
         ('.txt', MEDIA_TEXT),
         ('.xml', MEDIA_XML),