Rework implementation to use exiftool as the facit

README.md

@@ -2,7 +2,29 @@
 [![Go Report Card](https://goreportcard.com/badge/github.com/bep/imagemeta)](https://goreportcard.com/report/github.com/bep/imagemeta)
 [![GoDoc](https://godoc.org/github.com/bep/imagemeta?status.svg)](https://godoc.org/github.com/bep/imagemeta)
 
-# Work in progress
 
-This is not ready, yet, but the goal is to use this as the library to read image metadata in Hugo. The existing Go libraries I have found is not maintained anymore and too complex to build on top of. The goal of this library is to be relatively small and simple, but I may prove myself wrong.
+## When in doubt, Exiftools is right
 
+The output of this library is tested against `exiftool -n -json`. This means, for example, that:
+
+*  We use f-numbers and not APEX for aperture values.
+*  We use seconds and not APEX for shutter speed values.
+*  EXIF field definitions are fetched from this table:  https://exiftool.org/TagNames/EXIF.html
+*  IPTC field definitions are fetched from this table:  https://exiftool.org/TagNames/IPTC.html
+*  The XMP handling is currently very simple, you can supply your own XMP handler (see the `HandleXMP` option) if you need more.
+
+
+## Development
+
+Many of the tests depends on generated golden files. To update these, run:
+
+```bash
+ go generate ./gen
+```
+
+Note that you need a working `exiftool` and updated binary in your `PATH` for this to work. This was tested OK with:
+
+```
+exiftool -ver
+12.76
+```

gen/main.go

@@ -0,0 +1,53 @@
+//go:generate go run main.go
+package main
+
+import (
+	"bytes"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+func main() {
+	outDir := "testdata_exiftool"
+	os.RemoveAll(outDir)
+	if err := os.MkdirAll(outDir, 0o755); err != nil {
+		log.Fatal(err)
+	}
+	base := "../testdata"
+
+	if err := filepath.Walk(base, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() || strings.HasPrefix(info.Name(), ".") {
+			return nil
+		}
+
+		basePath := strings.TrimPrefix(path, base)
+
+		var buf bytes.Buffer
+		cmd := exec.Command("exiftool", path, "-json", "-n", "-g", "-e")
+		cmd.Stdout = &buf
+		cmd.Stderr = os.Stderr
+
+		if err := cmd.Run(); err != nil {
+			return err
+		}
+
+		outFilename := filepath.Join(outDir, basePath+".json")
+		if err := os.MkdirAll(filepath.Dir(outFilename), 0o755); err != nil {
+			return err
+		}
+
+		if err := os.WriteFile(outFilename, buf.Bytes(), 0o644); err != nil {
+			return err
+		}
+
+		return nil
+	}); err != nil {
+		log.Fatal(err)
+	}
+}

gen/testdata_exiftool/IPTC-PhotometadataRef-Std2021.1.jpg.json

@@ -0,0 +1,232 @@
+[{
+  "SourceFile": "../testdata/IPTC-PhotometadataRef-Std2021.1.jpg",
+  "ExifTool": {
+    "ExifToolVersion": 12.76
+  },
+  "File": {
+    "FileName": "IPTC-PhotometadataRef-Std2021.1.jpg",
+    "Directory": "../testdata",
+    "FileSize": 134078,
+    "FileModifyDate": "2023:08:14 17:57:27+02:00",
+    "FileAccessDate": "2024:07:09 18:54:23+02:00",
+    "FileInodeChangeDate": "2024:07:08 15:16:12+02:00",
+    "FilePermissions": 100644,
+    "FileType": "JPEG",
+    "FileTypeExtension": "JPG",
+    "MIMEType": "image/jpeg",
+    "ExifByteOrder": "MM",
+    "CurrentIPTCDigest": "ed3d9bf1276b54654a9169c8c1e2c081",
+    "Comment": "IPTC Photo Metadata Standard 2021.1 reference image file - release 2b, as of 2022-07-12",
+    "ImageWidth": 2000,
+    "ImageHeight": 1000,
+    "EncodingProcess": 2,
+    "BitsPerSample": 8,
+    "ColorComponents": 3,
+    "YCbCrSubSampling": "2 2"
+  },
+  "EXIF": {
+    "ImageDescription": "The description aka caption (ref2021.1)",
+    "XResolution": 72,
+    "YResolution": 72,
+    "ResolutionUnit": 2,
+    "Artist": "Creator1 (ref2021.1)",
+    "YCbCrPositioning": 1,
+    "Copyright": "Copyright (Notice) 2021.1 IPTC - www.iptc.org  (ref2021.1)",
+    "ExifVersion": "0232",
+    "DateTimeOriginal": "2021:10:20 21:01:01",
+    "OffsetTimeOriginal": "+00:00",
+    "ComponentsConfiguration": "1 2 3 0",
+    "FlashpixVersion": "0100",
+    "ColorSpace": 65535
+  },
+  "IPTC": {
+    "ObjectAttributeReference": "000:Actuality",
+    "ObjectName": "The Title (ref2021.1)",
+    "SubjectReference": ["IPTC:10020211","IPTC:20020211","IPTC:30020211"],
+    "Keywords": ["Keyword1ref2021.1","Keyword2ref2021.1","Keyword3ref2021.1"],
+    "SpecialInstructions": "An Instruction (ref2021.1)",
+    "DateCreated": "2021:10:20",
+    "TimeCreated": "21:01:01+00:00",
+    "By-line": "Creator1 (ref2021.1)",
+    "By-lineTitle": "Creator's Job Title  (ref2021.1)",
+    "City": "City (Core) (ref2021.1)",
+    "Sub-location": "Sublocation (Core) (ref2021.1)",
+    "Province-State": "Province/State(Core)(ref2021.1)",
+    "Country-PrimaryLocationCode": "R21",
+    "Country-PrimaryLocationName": "Country (Core) (ref2021.1)",
+    "OriginalTransmissionReference": "Job Id (ref2021.1)",
+    "Headline": "The Headline (ref2021.1)",
+    "Credit": "Credit Line (ref2021.1)",
+    "Source": "Source (ref2021.1)",
+    "CopyrightNotice": "Copyright (Notice) 2021.1 IPTC - www.iptc.org  (ref2021.1)",
+    "Caption-Abstract": "The description aka caption (ref2021.1)",
+    "Writer-Editor": "Description Writer (ref2021.1)",
+    "ApplicationRecordVersion": 4
+  },
+  "XMP": {
+    "XMPToolkit": "Image::ExifTool 12.41",
+    "AltTextAccessibility": "This is the Alt Text description to support accessibility in 2021.1",
+    "AltTextAccessibility-en": "This is the Alt Text description to support accessibility in 2021.1",
+    "CountryCode": "R21",
+    "CreatorCity": "Creator's CI: City (ref2021.1)",
+    "CreatorCountry": "Creator's CI: Country (ref2021.1)",
+    "CreatorAddress": "Creator's CI: Address, line 1 (ref2021.1)",
+    "CreatorPostalCode": "Creator's CI: Postcode (ref2021.1)",
+    "CreatorRegion": "Creator's CI: State/Province (ref2021.1)",
+    "CreatorWorkEmail": "Creator's CI: Email@1, Email@2 (ref2021.1)",
+    "CreatorWorkTelephone": "Creator's CI: Phone # 1, Phone # 2 (ref2021.1)",
+    "CreatorWorkURL": "http://www.Creators.CI/WebAddress/ref2021.1",
+    "ExtDescrAccessibility": "This is the Extended Description to support accessibility in 2021.1",
+    "ExtDescrAccessibility-en": "This is the Extended Description to support accessibility in 2021.1",
+    "IntellectualGenre": "Actuality",
+    "Location": "Sublocation (Core) (ref2021.1)",
+    "Scene": ["010100","010400"],
+    "SubjectCode": [10020211,20020211,30020211],
+    "AboutCvTermCvId": "http://example.com/cv/about/ref2021.1",
+    "AboutCvTermId": "http://example.com/cv/about/ref2021.1/code987",
+    "AboutCvTermName": "CV-Term Name 1 (ref2021.1)",
+    "AboutCvTermRefinedAbout": "http://example.com/cv/refinements2/ref2021.1/codeX145",
+    "AdditionalModelInformation": "Additional Model Info (ref2021.1)",
+    "ArtworkCircaDateCreated": "AO Circa Date: between 1550 and 1600 (ref2021.1)",
+    "ArtworkContentDescription": "AO Content Description 1 (ref2021.1)",
+    "ArtworkContributionDescription": "AO Contribution Description 1 (ref2021.1)",
+    "ArtworkCopyrightNotice": "AO Copyright Notice 1 (ref2021.1)",
+    "ArtworkCreator": ["AO Creator Name 1a (ref2021.1)","AO Creator Name 1b (ref2021.1)"],
+    "ArtworkCreatorID": ["AO Creator Id 1a (ref2021.1)","AO Creator Id 1b (ref2021.1)"],
+    "ArtworkCopyrightOwnerID": "AO Current Copyright Owner ID 1 (ref2021.1)",
+    "ArtworkCopyrightOwnerName": "AO Current Copyright Owner Name 1 (ref2021.1)",
+    "ArtworkLicensorID": "AO Current Licensor ID 1 (ref2021.1)",
+    "ArtworkLicensorName": "AO Current Licensor Name 1 (ref2021.1)",
+    "ArtworkDateCreated": "1921:10:20 21:01:00+00:00",
+    "ArtworkPhysicalDescription": "AO Physical Description 1 (ref2021.1)",
+    "ArtworkSource": "AO Source 1 (ref2021.1)",
+    "ArtworkSourceInventoryNo": "AO Source Inventory No 1 (ref2021.1)",
+    "ArtworkSourceInvURL": "AO Source Inventory URL (ref2021.1)",
+    "ArtworkStylePeriod": ["AO Style Baroque (ref2021.1)","AO Style Italian Baroque (ref2021.1)"],
+    "ArtworkTitle": "AO Title 1 (ref2021.1)",
+    "DigitalImageGUID": "http://example.com/imageGUIDs/TestGUID12345/ref2021.1",
+    "DigitalSourceType": "http://cv.iptc.org/newscodes/digitalsourcetype/softwareImage",
+    "EmbeddedEncodedRightsExpr": "The Encoded Rights Expression (ref2021.1)",
+    "EmbeddedEncodedRightsExprType": "IANA Media Type of ERE (ref2021.1)",
+    "EmbeddedEncodedRightsExprLangID": "http://example.org/RELids/id4711/ref2021.1",
+    "Event": "Event Name (ref2021.1)",
+    "EventID": ["https://example.com/events/id2021.1a","https://example.com/events/id2021.1b"],
+    "GenreCvId": "http://example.com/cv/genre/ref2021.1",
+    "GenreCvTermId": "http://example.com/cv/genre/ref2021.1/code1369",
+    "GenreCvTermName": "Genre CV-Term Name 1 (ref2021.1)",
+    "GenreCvTermRefinedAbout": "http://example.com/cv/genrerefinements2/ref2021.1/codeY864",
+    "ImageRegionName": ["Listener 1","Listener 2","Speaker 1"],
+    "ImageRegionOrganisationInImageName": ["Organisation name no 1 in region persltr2 (ref2021.1)","Organisation name no 1 in region persltr2 (ref2021.1)","Organisation name no 1 in region persltr3 (ref2021.1)"],
+    "ImageRegionPersonInImage": ["Person name no 1 in region persltr2 (ref2021.1)","Person name no 1 in region persltr3 (ref2021.1)","Person name no 1 in region persltr1 (ref2021.1)"],
+    "ImageRegionBoundaryH": 0.385,
+    "ImageRegionBoundaryShape": ["rectangle","circle","polygon"],
+    "ImageRegionBoundaryUnit": ["relative","relative","relative"],
+    "ImageRegionBoundaryW": 0.127,
+    "ImageRegionBoundaryX": [0.31,0.59],
+    "ImageRegionBoundaryY": [0.18,0.426],
+    "ImageRegionCtypeName": ["Region Boundary Content Type Name (ref2021.1)","Region Boundary Content Type Name (ref2021.1)","Region Boundary Content Type Name (ref2021.1)"],
+    "ImageRegionCtypeIdentifier": ["https://example.org/rctype/type2021.1a","https://example.org/rctype/type2021.1b","https://example.org/rctype/type2021.1a","https://example.org/rctype/type2021.1b","https://example.org/rctype/type2021.1a","https://example.org/rctype/type2021.1b"],
+    "ImageRegionID": ["persltr2","persltr3","persltr1"],
+    "ImageRegionRoleName": ["Region Boundary Content Role Name (ref2021.1)","Region Boundary Content Role Name (ref2021.1)","Region Boundary Content Role Name (ref2021.1)"],
+    "ImageRegionRoleIdentifier": ["https://example.org/rrole/role2021.1a","https://example.org/rrole/role2021.1b","https://example.org/rrole/role2021.1a","https://example.org/rrole/role2021.1b","https://example.org/rrole/role2021.1a","https://example.org/rrole/role2021.1b"],
+    "ImageRegionBoundaryRx": 0.068,
+    "ImageRegionBoundaryVerticesX": [0.05,0.148,0.375],
+    "ImageRegionBoundaryVerticesY": [0.713,0.041,0.863],
+    "LinkedEncodedRightsExpr": "http://example.org/linkedrightsexpression/id986/ref2021.1",
+    "LinkedEncodedRightsExprType": "IANA Media Type of ERE (ref2021.1)",
+    "LinkedEncodedRightsExprLangID": "http://example.org/RELids/id4712/ref2021.1",
+    "LocationCreatedCity": "City (Location created1) (ref2021.1)",
+    "LocationCreatedCountryCode": "R17",
+    "LocationCreatedCountryName": "CountryName (Location created1) (ref2021.1)",
+    "LocationCreatedLocationId": "Location Id (Location created1) (ref2021.1)",
+    "LocationCreatedLocationName": "Location Name (Location created1) (ref2021.1)",
+    "LocationCreatedProvinceState": "Province/State (Location created1) (ref2021.1)",
+    "LocationCreatedSublocation": "Sublocation (Location created1) (ref2021.1)",
+    "LocationCreatedWorldRegion": "Worldregion (Location created1) (ref2021.1)",
+    "LocationCreatedGPSAltitude": 480,
+    "LocationCreatedGPSLatitude": 48.275,
+    "LocationCreatedGPSLongitude": 16.338,
+    "LocationShownCity": ["City (Location shown1) (ref2021.1)","City (Location shown2) (ref2021.1)"],
+    "LocationShownCountryCode": ["R17","R17"],
+    "LocationShownCountryName": ["CountryName (Location shown1) (ref2021.1)","CountryName (Location shown2) (ref2021.1)"],
+    "LocationShownLocationId": ["Location Id 1a(Location shown1) (ref2021.1)","Location Id 1b(Location shown1) (ref2021.1)","Location Id 2a(Location shown2) (ref2021.1)","Location Id 2b(Location shown2) (ref2021.1)"],
+    "LocationShownLocationName": ["Location Name (Location shown1) (ref2021.1)","Location Name (Location shown2) (ref2021.1)"],
+    "LocationShownProvinceState": ["Province/State (Location shown1) (ref2021.1)","Province/State (Location shown2) (ref2021.1)"],
+    "LocationShownSublocation": ["Sublocation (Location shown1) (ref2021.1)","Sublocation (Location shown2) (ref2021.1)"],
+    "LocationShownWorldRegion": ["Worldregion (Location shown1) (ref2021.1)","Worldregion (Location shown2) (ref2021.1)"],
+    "LocationShownGPSAltitude": [140,120],
+    "LocationShownGPSLatitude": [48.147,47.952],
+    "LocationShownGPSLongitude": [17.098,16.83],
+    "MaxAvailHeight": 20,
+    "MaxAvailWidth": 21,
+    "ModelAge": [25,27,30],
+    "OrganisationInImageCode": ["Organisation Code 1 (ref2021.1)","Organisation Code 2 (ref2021.1)","Organisation Code 3 (ref2021.1)"],
+    "OrganisationInImageName": ["Organisation Name 1 (ref2021.1)","Organisation Name 2 (ref2021.1)","Organisation Name 3 (ref2021.1)"],
+    "PersonInImage": ["Person Shown 1 (ref2021.1)","Person Shown 2 (ref2021.1)"],
+    "PersonInImageCvTermCvId": "http://example.com/cv/test99/ref2021.1",
+    "PersonInImageCvTermId": "http://example.com/cv/test99/code987/ref2021.1",
+    "PersonInImageCvTermName": "Person Characteristic Name 1 (ref2021.1)",
+    "PersonInImageCvTermRefinedAbout": "http://example.com/cv/refinements987/codeY765/ref2021.1",
+    "PersonInImageDescription": "Person Description 1 (ref2021.1)",
+    "PersonInImageId": ["http://wikidata.org/item/Q123456789/ref2021.1","http://freebase.com/m/987654321/ref2021.1"],
+    "PersonInImageName": "Person Name 1 (ref2021.1)",
+    "ProductInImageDescription": "Product Description 1 (ref2021.1)",
+    "ProductInImageGTIN": 123456782021.1,
+    "ProductInImageName": "Product Name 1 (ref2021.1)",
+    "RegistryEntryRole": ["Registry Entry Role ID 1 (ref2021.1)","Registry Entry Role ID 2 (ref2021.1)"],
+    "RegistryItemID": ["Registry Image ID 1 (ref2021.1)","Registry Image ID 2 (ref2021.1)"],
+    "RegistryOrganisationID": ["Registry Organisation ID 1 (ref2021.1)","Registry Organisation ID 2 (ref2021.1)"],
+    "Creator": "Creator1 (ref2021.1)",
+    "Description": "The description aka caption (ref2021.1)",
+    "Rights": "Copyright (Notice) 2021.1 IPTC - www.iptc.org  (ref2021.1)",
+    "Subject": ["Keyword1ref2021.1","Keyword2ref2021.1","Keyword3ref2021.1"],
+    "Title": "The Title (ref2021.1)",
+    "AuthorsPosition": "Creator's Job Title  (ref2021.1)",
+    "CaptionWriter": "Description Writer (ref2021.1)",
+    "City": "City (Core) (ref2021.1)",
+    "Country": "Country (Core) (ref2021.1)",
+    "Credit": "Credit Line (ref2021.1)",
+    "DateCreated": "2021:10:20 21:01:01+00:00",
+    "Headline": "The Headline (ref2021.1)",
+    "Instructions": "An Instruction (ref2021.1)",
+    "Source": "Source (ref2021.1)",
+    "State": "Province/State(Core)(ref2021.1)",
+    "TransmissionReference": "Job Id (ref2021.1)",
+    "CopyrightOwnerID": ["Copyright Owner Id 1 (ref2021.1)","Copyright Owner Id 2 (ref2021.1)"],
+    "CopyrightOwnerName": ["Copyright Owner Name 1 (ref2021.1)","Copyright Owner Name 2 (ref2021.1)"],
+    "ImageCreatorID": "Image Creator Id 1 (ref2021.1)",
+    "ImageCreatorName": "Image Creator Name 1 (ref2021.1)",
+    "ImageCreatorImageID": "Image Creator Image ID (ref2021.1)",
+    "ImageSupplierID": "Image Supplier Id (ref2021.1)",
+    "ImageSupplierName": "Image Supplier Name (ref2021.1)",
+    "ImageSupplierImageID": "Image Supplier Image ID (ref2021.1)",
+    "LicensorCity": ["Licensor City 1 (ref2021.1)","Licensor City 2 (ref2021.1)"],
+    "LicensorCountry": ["Licensor Country 1 (ref2021.1)","Licensor Country 2 (ref2021.1)"],
+    "LicensorEmail": ["Licensor Email 1 (ref2021.1)","Licensor Email 2 (ref2021.1)"],
+    "LicensorExtendedAddress": ["Licensor Ext Addr 1 (ref2021.1)","Licensor Ext Addr 2 (ref2021.1)"],
+    "LicensorID": ["Licensor ID 1 (ref2021.1)","Licensor ID 2 (ref2021.1)"],
+    "LicensorName": ["Licensor Name 1 (ref2021.1)","Licensor Name 2 (ref2021.1)"],
+    "LicensorPostalCode": ["Licensor Postcode 1 (ref2021.1)","Licensor Postcode 2 (ref2021.1)"],
+    "LicensorRegion": ["Licensor Region 1 (ref2021.1)","Licensor Region 2 (ref2021.1)"],
+    "LicensorStreetAddress": ["Licensor Street Addr 1 (ref2021.1)","Licensor Street Addr 2 (ref2021.1)"],
+    "LicensorTelephone1": ["Licensor Phone1 1 (ref2021.1)","Licensor Phone1 2 (ref2021.1)"],
+    "LicensorTelephone2": ["Licensor Phone2 1 (ref2021.1)","Licensor Phone2 2 (ref2021.1)"],
+    "LicensorTelephoneType1": ["work","work"],
+    "LicensorTelephoneType2": ["cell","cell"],
+    "LicensorURL": ["https://example.com/LicensorURL_1_ref2021.1","https://example.com/LicensorURL_2_ref2021.1"],
+    "MinorModelAgeDisclosure": "AG-A25",
+    "ModelReleaseID": ["Model Release ID 1 (ref2021.1)","Model Release ID 2 (ref2021.1)"],
+    "ModelReleaseStatus": "MR-NAP",
+    "PropertyReleaseID": ["Property Release ID 1 (ref2021.1)","Property Release ID 2 (ref2021.1)"],
+    "PropertyReleaseStatus": "PR-NAP",
+    "Rating": 1.0,
+    "UsageTerms": "Rights Usage Terms (ref2021.1)",
+    "WebStatement": "https://example.com/WebStatementOfRights/2021.1"
+  },
+  "APP14": {
+    "DCTEncodeVersion": 100,
+    "APP14Flags0": 32768,
+    "APP14Flags1": 0,
+    "ColorTransform": 1
+  }
+}]

gen/testdata_exiftool/corrupt/huge_tag_exif.jpg.json

@@ -0,0 +1,25 @@
+[{
+  "SourceFile": "../testdata/corrupt/huge_tag_exif.jpg",
+  "ExifTool": {
+    "ExifToolVersion": 12.76,
+    "Warning": "JPEG format error"
+  },
+  "File": {
+    "FileName": "huge_tag_exif.jpg",
+    "Directory": "../testdata/corrupt",
+    "FileSize": 65536,
+    "FileModifyDate": "2023:08:14 17:57:27+02:00",
+    "FileAccessDate": "2024:07:09 18:54:23+02:00",
+    "FileInodeChangeDate": "2023:08:14 17:57:27+02:00",
+    "FilePermissions": 100644,
+    "FileType": "JPEG",
+    "FileTypeExtension": "JPG",
+    "MIMEType": "image/jpeg"
+  },
+  "JFIF": {
+    "JFIFVersion": "1 1",
+    "ResolutionUnit": 1,
+    "XResolution": 72,
+    "YResolution": 72
+  }
+}]