This content originally appeared on DEV Community and was authored by Sushil Subedi
If you’ve ever uploaded an iPhone photo and noticed your captured_at
field missing, you’re not alone.
Modern iPhones save images as HEIC/HEIF instead of traditional JPEGs. These formats store metadata a little differently and that’s where many Ruby EXIF libraries fall short.
In this post, I’ll walk you through a reliable way to read photo capture dates (DateTimeOriginal
, CreateDate
, etc.) from HEIC/HEIF files inside a Rails app even if you’re using Active Storage.
Quick Summary
- Use ExifTool (through the
mini_exiftool
orexiftool
gem), it works with HEIC/HEIF files directly. - You don’t need to decode or convert images (
libheif
orlibvips
) just to read metadata. - Always convert timestamps to UTC and check multiple EXIF date fields for reliability.
- When using Active Storage, call
blob.open
to access a temporary file path for ExifTool.
Why HEIC/HEIF can be tricky
Here’s the issue in plain terms:
- HEIC stores metadata inside QuickTime-style boxes, not the standard EXIF segments used by JPEG.
- Most Ruby EXIF libraries (like
exifr
) only understand JPEG/TIFF files. - ExifTool is a Perl-based tool that can read just about anything, including HEIC/HEIF, RAW, and Live Photo sidecars.
Setup
Install the ExifTool CLI on your machine/container:
- macOS (Homebrew):
brew install exiftool
- Debian/Ubuntu:
sudo apt-get install -y libimage-exiftool-perl
- Alpine:
apk add exiftool
Then add one of these gems to your Gemfile
:
gem 'exiftool' # lightweight wrapper; also shells out to exiftool
And install them:
bundle install
Reading EXIF data from a file
Here’s a simple Ruby method using the exiftool
gem:
require 'exiftool'
def extract_capture_time(path)
data = Exiftool.new(path).to_hash # symbolized keys
raw = data[:date_time_original] ||
data[:create_date] ||
data[:media_create_date] ||
data[:modify_date]
return nil unless raw
case raw
when Time then raw.utc
when DateTime then raw.to_time.utc
else
(Time.parse(raw.to_s) rescue nil)&.utc
end
end
That’s it!
ExifTool takes care of all the format quirks, so this works for HEIC, JPEG, and even Live Photos.
Reading EXIF with Active Storage
When your image lives in Active Storage (e.g., S3 or Disk), just open it temporarily before reading EXIF:
def extract_capture_time_from_blob(blob)
blob.open do |file|
extract_capture_time(file.path) # call one of the helpers above
end
end
This downloads the file into a Tempfile, passes its path to ExifTool, and cleans up afterward, no extra libraries required.
Normalizing captured_at
in your models
When you save your capture time, normalize it to UTC and support multiple sources:
def normalized_captured_at(file_path: nil, client_value: nil)
exif_time = file_path && extract_capture_time(file_path)
client_time = begin
case client_value
when Time then client_value
when DateTime then client_value.to_time
when String then Time.iso8601(client_value) rescue Time.parse(client_value)
end
rescue ArgumentError
nil
end
(exif_time || client_time)&.utc
end
This way, even if the photo doesn’t have EXIF data, you can still fall back to a timestamp sent from the frontend.
Troubleshooting
-
No DateTimeOriginal
Some devices only setCreateDate
orMediaCreateDate
. Always try fallbacks. -
Nil/empty type from browser
, client uploads may sendapplication/octet-stream
. Fix on the frontend by inferring a proper MIME type from the filename before direct upload; EXIF reading itself is unaffected but downstream analyzers may behave better with the right type. -
It worked for JPEG but not HEIC
, ensure you’re using ExifTool, not EXIFR, for HEIC files.
References
If you’d like to make this reusable, you can wrap the logic into a small service class, ImageMetadataExtractor
that returns either a UTC Time or nil.
Once you have this in place, your app can reliably extract captured_at from any image, regardless of format.
This content originally appeared on DEV Community and was authored by Sushil Subedi