Add option to ActiveStorage::Blob to set extract_content_type_from_io

This adds a boolean argument called identify to ActiveStorage::Blob
methods #create_after_upload, #build_after_upload and #upload. It
allows a user to bypass the automatic content_type inference from
the io.

1 files changed, 12 insertions, 0 deletions

diff --git a/guides/source/active_storage_overview.md b/guides/source/active_storage_overview.md
index 09af899074..292928488b 100644
--- a/guides/source/active_storage_overview.md
+++ b/guides/source/active_storage_overview.md
@@ -319,6 +319,18 @@ type you provide if it can’t do that.
 @message.image.attach(io: File.open('/path/to/file'), filename: 'file.pdf', content_type: 'application/pdf')
 ```
 
+You can bypass the content type inference from the data by passing in
+`identify: false` along with the `content_type`.
+
+```ruby
+@message.image.attach(
+  io: File.open('/path/to/file'),
+  filename: 'file.pdf',
+  content_type: 'application/pdf'
+  identify: false
+)
+```
+
 If you don’t provide a content type and Active Storage can’t determine the
 file’s content type automatically, it defaults to application/octet-stream.