xmp

package

v1.8.5 Latest Latest Go to latest Published: Jul 5, 2026 License: Apache-2.0 Imports: 10 Imported by: 0

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github.com/mutablelogic/go-media

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Documentation ¶

Overview ¶

Package xmp provides XMP (Extensible Metadata Platform) encoding and decoding. XMP stores structured metadata as RDF/XML, organized into namespaced properties that can be simple strings, ordered or unordered arrays, localized alternatives, or nested structures.

Constants ¶

This section is empty.

Variables ¶

This section is empty.

Functions ¶

This section is empty.

Types ¶

type Item ¶

type Item struct {
	// contains filtered or unexported fields
}

Item represents a single XMP metadata property and implements media.Metadata.

func NewAlt ¶

func NewAlt(ns, prefix, name string, langValues ...[2]string) *Item

NewAlt creates an alternatives property. langValues is a sequence of [lang, value] pairs; use "x-default" as the lang for the canonical value.

func NewBag ¶

func NewBag(ns, prefix, name string, values ...string) *Item

NewBag creates an unordered-set property.

func NewItem ¶

func NewItem(ns, prefix, name, value string) *Item

NewItem creates a Simple property.

func NewItemLang ¶

func NewItemLang(ns, prefix, name, lang, value string) *Item

NewItemLang creates a Simple property with an xml:lang qualifier.

func NewSeq ¶

func NewSeq(ns, prefix, name string, values ...string) *Item

NewSeq creates an ordered-sequence property.

func NewStruct ¶

func NewStruct(ns, prefix, name string, fields ...*Item) *Item

NewStruct creates a structured property with named fields.

func (*Item) Any ¶

func (it *Item) Any() any

Any returns the property value as an appropriate Go type (implements media.Metadata):

Simple → string
Bag/Seq → []string
Alt → map[string]string (lang → value)
Struct → []*Item

func (*Item) Bytes ¶

func (it *Item) Bytes() []byte

Bytes returns nil — XMP properties are text-only (implements media.Metadata).

func (*Item) Image ¶

func (it *Item) Image() image.Image

Image returns nil (implements media.Metadata).

func (*Item) ItemKind ¶

func (it *Item) ItemKind() Kind

ItemKind returns the value kind.

func (*Item) Items ¶

func (it *Item) Items() []*Item

Items returns child items: members of Bag/Seq/Alt, or fields of a Struct.

func (*Item) Key ¶

func (it *Item) Key() string

Key returns "prefix:name" (implements media.Metadata).

func (*Item) Lang ¶

func (it *Item) Lang() string

Lang returns the xml:lang qualifier (non-empty for Simple items with a language tag and for Alt child items).

func (*Item) LocalName ¶

func (it *Item) LocalName() string

LocalName returns the local property name.

func (*Item) MarshalJSON ¶

func (it *Item) MarshalJSON() ([]byte, error)

MarshalJSON implements json.Marshaler.

func (*Item) NS ¶

func (it *Item) NS() string

NS returns the namespace URI.

func (*Item) Prefix ¶

func (it *Item) Prefix() string

Prefix returns the preferred namespace prefix.

func (*Item) String ¶

func (it *Item) String() string

String returns "key=value".

func (*Item) Value ¶

func (it *Item) Value() string

Value returns the string value (implements media.Metadata). For Bag/Seq, values are joined with "; ". For Alt, the "x-default" value is returned, falling back to the first entry. For Struct, an empty string is returned.

type Kind ¶

type Kind uint8

Kind describes the shape of an XMP property value.

const (
	Simple Kind = iota // a single string (optionally language-tagged)
	Bag                // unordered set of strings
	Seq                // ordered sequence of strings
	Alt                // localized alternatives keyed by xml:lang
	Struct             // nested record with named fields
)

func (Kind) String ¶

func (k Kind) String() string

type XMP ¶

type XMP struct {
	// contains filtered or unexported fields
}

XMP holds a parsed XMP metadata document.

func New ¶

func New() *XMP

New returns an empty XMP document.

func Parse ¶

func Parse(data []byte) (*XMP, error)

Parse parses an XMP document from a byte slice.

func Read ¶

func Read(r io.Reader) (*XMP, error)

Read parses an XMP document from r.

func (*XMP) Add ¶

func (x *XMP) Add(items ...*Item)

Add appends items to the document.

func (*XMP) Delete ¶

func (x *XMP) Delete(key string) int

Delete removes all items matching key and returns the count removed.

func (*XMP) First ¶

func (x *XMP) First(keys ...string) *Item

First returns the first item with a non-empty value from the first matching key in the ordered list. This implements the priority-fallback pattern used when the same semantic field can appear under multiple namespace prefixes, e.g. x.First("photoshop:DateCreated", "exif:DateTimeOriginal", "xmp:CreateDate").

func (*XMP) Get ¶

func (x *XMP) Get(key string) []*Item

Get returns all items whose key equals key. The key may be "prefix:name" or just the local name.

func (*XMP) Items ¶

func (x *XMP) Items() []*Item

Items returns all top-level metadata properties.

func (*XMP) MarshalJSON ¶

func (x *XMP) MarshalJSON() ([]byte, error)

MarshalJSON implements json.Marshaler.

func (*XMP) String ¶

func (x *XMP) String() string

String returns the document encoded as an XMP/XML string.

func (*XMP) Write ¶

func (x *XMP) Write(w io.Writer) error

Write encodes the XMP document as an XMP/RDF/XML packet to w.

Source Files ¶

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