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https://github.com/gotenberg/gotenberg.git
synced 2026-08-14 19:32:15 +01:00
feat(exiftool): refactor read write metadata
This commit is contained in:
Julien Neuhart
@@ -4,59 +4,25 @@ import (
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"context"
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"errors"
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"fmt"
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"net/http"
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"os"
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"github.com/barasher/go-exiftool"
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"go.uber.org/zap"
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"github.com/gotenberg/gotenberg/v8/pkg/gotenberg"
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"github.com/gotenberg/gotenberg/v8/pkg/modules/api"
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)
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func init() {
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gotenberg.MustRegisterModule(new(ExifTool))
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}
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// MetadataValueTypeError is constructed when metadata value types cannot be processed.
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// The underlying library used in this implementation supports the writing of a limited
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// number of metadata value types.
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//
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// For example, according to https://exiftool.org/TagNames/PDF.html metadata can be a boolean,
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// i.e. "value format... may be string, date, integer, real, boolean or name".
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// Furthermore, a native boolean type is also supported by JSON and Go. However, the
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// underlying library does not currently support writing native Go boolean (bool) types.
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// Therefore, an instance of this struct is created when a boolean metadata entry is supplied.
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//
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// The struct contains a key/value map corresponding to individual invalid metadata entries supplied by a consumer.
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// This allows a helpful error message to be produced for API consumers.
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// See API.WriteMetadata for more information on valid metadata value types.
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type MetadataValueTypeError struct {
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Entries map[string]interface{}
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}
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// Error returns a helpful error message.
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func (e *MetadataValueTypeError) Error() string {
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return fmt.Sprintf("invalid metadata value types supplied - identified by Entries: %s", e.Entries)
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}
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// GetKeys returns an array of keys with corresponding invalid value types,
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func (e *MetadataValueTypeError) GetKeys() []string {
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keys := make([]string, len(e.Entries))
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i := 0
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for key := range e.Entries {
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keys[i] = key
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i++
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}
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return keys
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}
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// ExifTool abstracts the CLI tool ExifTool and implements the [gotenberg.PdfEngine] interface .
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// ExifTool abstracts the CLI tool ExifTool and implements the
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// [gotenberg.PdfEngine] interface.
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type ExifTool struct {
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binPath string
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}
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// Descriptor returns ExifTool's module descriptor.
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// Descriptor returns [ExifTool]'s module descriptor.
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func (engine *ExifTool) Descriptor() gotenberg.ModuleDescriptor {
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return gotenberg.ModuleDescriptor{
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ID: "exiftool",
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@@ -64,9 +30,7 @@ func (engine *ExifTool) Descriptor() gotenberg.ModuleDescriptor {
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}
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}
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// Provision sets the module properties. It returns an error if
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// - the environment variable EXIFTOOL_BIN_PATH is not set
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// - there is an error creating an instance of exiftool.ExifTool
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// Provision sets the module properties.
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func (engine *ExifTool) Provision(ctx *gotenberg.Context) error {
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binPath, ok := os.LookupEnv("EXIFTOOL_BIN_PATH")
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if !ok {
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@@ -90,99 +54,82 @@ func (engine *ExifTool) Validate() error {
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// Merge is not available in this implementation.
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func (engine *ExifTool) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
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return fmt.Errorf("merge PDFs with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
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return fmt.Errorf("merge PDFs with ExifTool: %w", gotenberg.ErrPdfEngineMethodNotSupported)
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}
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// Convert is not available in this implementation.
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func (engine *ExifTool) Convert(ctx context.Context, logger *zap.Logger, formats gotenberg.PdfFormats, inputPath, outputPath string) error {
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return fmt.Errorf("convert PDF to '%+v' with PDFtk: %w", formats, gotenberg.ErrPdfEngineMethodNotSupported)
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return fmt.Errorf("convert PDF to '%+v' with ExifTool: %w", formats, gotenberg.ErrPdfEngineMethodNotSupported)
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}
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// ReadMetadata reads the metadata of the given PDF files.
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func (engine *ExifTool) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string, metadata map[string]interface{}) error {
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logger.Debug(fmt.Sprintf("reading metadata of file: %s", inputPath))
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exifTool, err := exiftool.NewExiftool()
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// ReadMetadata extracts the metadata of a given PDF file.
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func (engine *ExifTool) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
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exifTool, err := exiftool.NewExiftool(exiftool.SetExiftoolBinaryPath(engine.binPath))
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if err != nil {
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fmt.Printf("Error intializing ExifTool: %v\n", err)
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return err
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return nil, fmt.Errorf("new ExifTool: %w", err)
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}
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fileMetadataInfos := exifTool.ExtractMetadata([]string{inputPath}...)
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defer func(exifTool *exiftool.Exiftool) {
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err := exifTool.Close()
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if err != nil {
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logger.Error(fmt.Sprintf("close ExifTool: %v", err))
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}
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}(exifTool)
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if fileMetadataInfos[0].Err != nil {
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return fmt.Errorf("error reading metadata to following file: %+v", fileMetadataInfos[0])
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fileMetadata := exifTool.ExtractMetadata(inputPath)
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if fileMetadata[0].Err != nil {
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return nil, fmt.Errorf("read metadata with ExitfTool: %w", fileMetadata[0].Err)
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}
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// load into metadata
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for k, v := range fileMetadataInfos[0].Fields {
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metadata[k] = v
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}
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return exifTool.Close()
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return fileMetadata[0].Fields, nil
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}
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// WriteMetadata write the metadata to the given PDF files.
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func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, inputPath string, newMetadata map[string]interface{}) error {
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logger.Debug(fmt.Sprintf("writing new metadata %s to %s", newMetadata, inputPath))
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exifTool, err := exiftool.NewExiftool()
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// WriteMetadata writes the metadata into a given PDF file.
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func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
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exifTool, err := exiftool.NewExiftool(exiftool.SetExiftoolBinaryPath(engine.binPath))
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if err != nil {
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fmt.Printf("Error intializing ExifTool: %v\n", err)
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return err
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return fmt.Errorf("new ExifTool: %w", err)
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}
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fileMetadataInfos := exifTool.ExtractMetadata([]string{inputPath}...)
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defer func(exifTool *exiftool.Exiftool) {
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err := exifTool.Close()
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if err != nil {
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logger.Error(fmt.Sprintf("close ExifTool: %v", err))
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}
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}(exifTool)
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// there is only file metadata info
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if fileMetadataInfos[0].Err != nil {
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return fmt.Errorf("error reading metadata to following file: %+v", fileMetadataInfos[0])
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fileMetadata := exifTool.ExtractMetadata(inputPath)
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if fileMetadata[0].Err != nil {
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return fmt.Errorf("read metadata with ExitfTool: %w", fileMetadata[0].Err)
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}
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// Metadata values can only be specific value types.
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// An error is returned if metadata with an invalid type is requested.
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metadataValueErrors := MetadataValueTypeError{
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Entries: make(map[string]interface{}),
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}
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// transform metadata
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for key, value := range newMetadata {
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for key, value := range metadata {
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switch val := value.(type) {
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case string:
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fileMetadataInfos[0].SetString(key, val)
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fileMetadata[0].SetString(key, val)
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case int:
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fileMetadataInfos[0].SetInt(key, int64(val))
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fileMetadata[0].SetInt(key, int64(val))
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case int64:
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fileMetadataInfos[0].SetInt(key, val)
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fileMetadata[0].SetInt(key, val)
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case float32:
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fileMetadataInfos[0].SetFloat(key, float64(val))
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fileMetadata[0].SetFloat(key, float64(val))
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case float64:
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fileMetadataInfos[0].SetFloat(key, val)
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fileMetadata[0].SetFloat(key, val)
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case []string:
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fileMetadataInfos[0].SetStrings(key, val)
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// TODO: support more complex cases, e.g. arrays and nested objects (limitations in underlying library)
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fileMetadata[0].SetStrings(key, val)
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// TODO: support more complex cases, e.g., arrays and nested objects
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// (limitations in underlying library).
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default:
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metadataValueErrors.Entries[key] = value
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return fmt.Errorf("write PDF metadata with ExifTool: %w", gotenberg.ErrPdfEngineMetadataValueNotSupported)
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}
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}
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logger.Debug(fmt.Sprintf("writing metadata %s to %s", fileMetadataInfos[0].Fields, fileMetadataInfos[0].File))
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if len(metadataValueErrors.Entries) > 0 {
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return api.WrapError(
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fmt.Errorf("write metadata: %w", err),
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api.NewSentinelHttpError(
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http.StatusBadRequest,
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fmt.Sprintf("Invalid metdata value types supplied by keys '%s'", metadataValueErrors.GetKeys())),
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)
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exifTool.WriteMetadata(fileMetadata)
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if fileMetadata[0].Err != nil {
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return fmt.Errorf("write PDF metadata with ExifTool: %w", fileMetadata[0].Err)
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}
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exifTool.WriteMetadata(fileMetadataInfos)
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if fileMetadataInfos[0].Err != nil {
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return fmt.Errorf("error writing metadata to following file: %+v", fileMetadataInfos[0])
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}
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return exifTool.Close()
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return nil
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}
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// Interface guards.
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