Custom file upload MIME type (#927)

* Support curl-like syntax for custom MIME type for files

In order to specify a custom MIME type for file uploads, a syntax
similar to that used by cURL is used so that

http -F test_file@/path/to/file.bin;type=application/zip https://...

forwards the user-provided file type if provided, otherwise falling
back to the usual guesswork out of the file extension.

CHANGELOG.rst

@@ -13,6 +13,7 @@ This project adheres to `Semantic Versioning <https://semver.org/>`_.
 * Added ``--ciphers`` to allow configuring OpenSSL ciphers (`#870`_).
 * Added support for ``$XDG_CONFIG_HOME`` (`#920`_).
 * Fixed built-in plugins-related circular imports (`#925`_).
+* Fixed custom content types for each multipart uploaded file (`#668`_).
 
 
 `2.1.0`_ (2020-04-18)
@@ -441,3 +442,4 @@ This project adheres to `Semantic Versioning <https://semver.org/>`_.
 .. _#895: https://github.com/jakubroztocil/httpie/issues/895
 .. _#920: https://github.com/jakubroztocil/httpie/issues/920
 .. _#925: https://github.com/jakubroztocil/httpie/issues/925
+.. _#668: https://github.com/jakubroztocil/httpie/issues/668

README.rst

@@ -683,6 +683,13 @@ submitted:
 Note that ``@`` is used to simulate a file upload form field, whereas
 ``=@`` just embeds the file content as a regular text field value.
 
+When uploading files, their content type is inferred from the file name. You can manually
+override the inferred content type:
+
+.. code-block:: bash
+
+   $ http -f POST httpbin.org/post name='John Smith' cv@'~/files/data.bin;type=application/pdf'
+
 
 HTTP headers
 ============

httpie/cli/constants.py

@@ -24,6 +24,7 @@ SEPARATOR_PROXY = ':'
 SEPARATOR_DATA_STRING = '='
 SEPARATOR_DATA_RAW_JSON = ':='
 SEPARATOR_FILE_UPLOAD = '@'
+SEPARATOR_FILE_UPLOAD_TYPE = ';type='  # in already parsed file upload path only
 SEPARATOR_DATA_EMBED_FILE_CONTENTS = '=@'
 SEPARATOR_DATA_EMBED_RAW_JSON_FILE = ':=@'
 SEPARATOR_QUERY_PARAM = '=='

httpie/cli/definition.py

@@ -113,6 +113,7 @@ positional.add_argument(
     '@' Form file fields (only with --form, -f):
 
         cs@~/Documents/CV.pdf
+        cv@'~/Documents/CV.pdf;type=application/pdf'
 
     '=@' A data field like '=', but takes a file path and embeds its content:
 

httpie/cli/requestitems.py

@@ -6,7 +6,8 @@ from httpie.cli.argtypes import KeyValueArg
 from httpie.cli.constants import (
     SEPARATOR_DATA_EMBED_FILE_CONTENTS, SEPARATOR_DATA_EMBED_RAW_JSON_FILE,
     SEPARATOR_DATA_RAW_JSON, SEPARATOR_DATA_STRING, SEPARATOR_FILE_UPLOAD,
-    SEPARATOR_HEADER, SEPARATOR_HEADER_EMPTY, SEPARATOR_QUERY_PARAM,
+    SEPARATOR_FILE_UPLOAD_TYPE, SEPARATOR_HEADER, SEPARATOR_HEADER_EMPTY,
+    SEPARATOR_QUERY_PARAM,
 )
 from httpie.cli.dicts import (
     RequestDataDict, RequestFilesDict, RequestHeadersDict, RequestJSONDataDict,
@@ -95,7 +96,10 @@ def process_query_param_arg(arg: KeyValueArg) -> str:
 
 
 def process_file_upload_arg(arg: KeyValueArg) -> Tuple[str, IO, str]:
-    filename = arg.value
+    parts = arg.value.split(SEPARATOR_FILE_UPLOAD_TYPE)
+    filename = parts[0]
+    mime_type = parts[1] if len(parts) > 1 else None
+
     try:
         with open(os.path.expanduser(filename), 'rb') as f:
             contents = f.read()
@@ -104,7 +108,7 @@ def process_file_upload_arg(arg: KeyValueArg) -> Tuple[str, IO, str]:
     return (
         os.path.basename(filename),
         BytesIO(contents),
-        get_content_type(filename),
+        mime_type or get_content_type(filename),
     )
 
 

tests/test_uploads.py

@@ -17,27 +17,37 @@ class TestMultipartFormDataFileUpload:
 
     def test_upload_ok(self, httpbin):
         r = http('--form', '--verbose', 'POST', httpbin.url + '/post',
-                 'test-file@%s' % FILE_PATH_ARG, 'foo=bar')
+                 f'test-file@{FILE_PATH_ARG}', 'foo=bar')
         assert HTTP_OK in r
         assert 'Content-Disposition: form-data; name="foo"' in r
         assert 'Content-Disposition: form-data; name="test-file";' \
-               ' filename="%s"' % os.path.basename(FILE_PATH) in r
+               f' filename="{os.path.basename(FILE_PATH)}"' in r
         assert FILE_CONTENT in r
         assert '"foo": "bar"' in r
         assert 'Content-Type: text/plain' in r
 
     def test_upload_multiple_fields_with_the_same_name(self, httpbin):
         r = http('--form', '--verbose', 'POST', httpbin.url + '/post',
-                 'test-file@%s' % FILE_PATH_ARG,
-                 'test-file@%s' % FILE_PATH_ARG)
+                 f'test-file@{FILE_PATH_ARG}',
+                 f'test-file@{FILE_PATH_ARG}')
         assert HTTP_OK in r
         assert r.count('Content-Disposition: form-data; name="test-file";'
-                       ' filename="%s"' % os.path.basename(FILE_PATH)) == 2
+                       f' filename="{os.path.basename(FILE_PATH)}"') == 2
         # Should be 4, but is 3 because httpbin
         # doesn't seem to support filed field lists
         assert r.count(FILE_CONTENT) in [3, 4]
         assert r.count('Content-Type: text/plain') == 2
 
+    def test_upload_custom_content_type(self, httpbin):
+        r = http('--form', '--verbose', 'POST', httpbin.url + '/post',
+                 f'test-file@{FILE_PATH_ARG};type=image/vnd.microsoft.icon')
+        assert HTTP_OK in r
+        # Content type is stripped from the filename
+        assert 'Content-Disposition: form-data; name="test-file";' \
+               f' filename="{os.path.basename(FILE_PATH)}"' in r
+        assert FILE_CONTENT in r
+        assert 'Content-Type: image/vnd.microsoft.icon' in r
+
 
 class TestRequestBodyFromFilePath:
     """