Python 標準ライブラリ mimetypes を使って GeoJSON ファイル名 (.geojson) から MIME タイプに変換しようとしたら (None, None) になってしまった😇
>>> import mimetypes >>> mimetypes.guess_type('example.geojson') (None, None)
前提条件
- Python 3.12
mimetypes.types_map を確認する
MIME タイプのマッピングは環境によって異なる場合があって，今回は macOS (Sonoma) と AWS Lambda 関数 (Python 3.12) で mimetypes.types_map の値から JSON 関連のマッピングを確認してみた．やはり .geojson のマッピングはなかった🥲
macOS (Sonoma)
{'.json': 'application/json', '.jsonml': 'application/jsonml+json'}
AWS Lambda 関数 (Python 3.12)
{'.json': 'application/json'}
mimetypes.add_type() で追加する
mimetypes.add_type() でマッピングを追加すれば OK👌
>>> mimetypes.add_type('application/geo+json', '.geojson') >>> mimetypes.guess_type('example.geojson') ('application/geo+json', None)
knownfiles を確認する
MIME タイプのマッピング (knownfiles) は mimetypes.knownfiles で確認できる．
>>> mimetypes.knownfiles ['/etc/mime.types', '/etc/httpd/mime.types', '/etc/httpd/conf/mime.types', '/etc/apache/mime.types', '/etc/apache2/mime.types', '/usr/local/etc/httpd/conf/mime.types', '/usr/local/lib/netscape/mime.types', '/usr/local/etc/httpd/conf/mime.types', '/usr/local/etc/mime.types']
macOS だと /etc/apache2/mime.types に knownfiles があって，JSON 関連のマッピングを確認してみた．
mimetypes.types_map の値と同じで application/json と application/jsonml+json はサポートされていて，application/geo+json はコメントアウトになっていた💡
$ grep -i json /etc/apache2/mime.types # application/alto-costmap+json # application/alto-costmapfilter+json # application/alto-directory+json # application/alto-endpointcost+json # application/alto-endpointcostparams+json # application/alto-endpointprop+json # application/alto-endpointpropparams+json # application/alto-error+json # application/alto-networkmap+json # application/alto-networkmapfilter+json # application/calendar+json # application/coap-group+json # application/csvm+json # application/geo+json # application/jose+json # application/jrd+json application/json json # application/json-patch+json # application/json-seq application/jsonml+json jsonml # application/jwk+json # application/jwk-set+json # application/ld+json # application/merge-patch+json # application/ppsp-tracker+json # application/problem+json # application/rdap+json # application/reputon+json # application/scim+json # application/vcard+json # application/vnd.apache.thrift.json # application/vnd.api+json # application/vnd.bekitzur-stech+json # application/vnd.collection+json # application/vnd.collection.doc+json # application/vnd.collection.next+json # application/vnd.coreos.ignition+json # application/vnd.document+json # application/vnd.drive+json # application/vnd.geo+json # application/vnd.hal+json # application/vnd.heroku+json # application/vnd.hyperdrive+json # application/vnd.ims.lis.v2.result+json # application/vnd.ims.lti.v2.toolconsumerprofile+json # application/vnd.ims.lti.v2.toolproxy+json # application/vnd.ims.lti.v2.toolproxy.id+json # application/vnd.ims.lti.v2.toolsettings+json # application/vnd.ims.lti.v2.toolsettings.simple+json # application/vnd.mason+json # application/vnd.micro+json # application/vnd.miele+json # application/vnd.oftn.l10n+json # application/vnd.oma.lwm2m+json # application/vnd.oracle.resource+json # application/vnd.pagerduty+json # application/vnd.siren+json # application/vnd.vel+json # application/vnd.xacml+json # model/gltf+json
Python 3.13 だと
ちなみに Python 3.13 のドキュメントを読むと mimetypes.guess_type() は soft deprecated（警告は出ずに引き続き使える非推奨）になっていて，今後は mimetypes.guess_file_type() を使うことになりそう📝 覚えておこう〜
Deprecated since version 3.13: Passing a file path instead of URL is soft deprecated. Use guess_file_type() for this.
>>> import mimetypes >>> mimetypes.guess_file_type('example.json') ('application/json', None)
