app.uti - Uniform Type Identifier API

macOS Uniform Type Identifier (UTI) querying and conversion.

Permission level: L0 (safe, always available)

Methods

app.uti.fromExtension(ext)

Converts a file extension to a UTI.

Parameters:

• ext (string) - File extension (e.g., “pdf”)

Returns: string, error - UTI string

local uti = app.uti.fromExtension("pdf")    -- "com.adobe.pdf"
local uti = app.uti.fromExtension("png")    -- "public.png"
local uti = app.uti.fromExtension("swift")  -- "public.swift-source"

app.uti.fromMimeType(mime)

Converts a MIME type to a UTI.

Parameters:

• mime (string) - MIME type

Returns: string, error

local uti = app.uti.fromMimeType("application/pdf")  -- "com.adobe.pdf"
local uti = app.uti.fromMimeType("image/png")        -- "public.png"

app.uti.toExtension(uti)

Converts a UTI to its preferred file extension.

Parameters:

• uti (string) - UTI string

Returns: string, error

local ext = app.uti.toExtension("com.adobe.pdf")  -- "pdf"
local ext = app.uti.toExtension("public.png")     -- "png"

app.uti.toMimeType(uti)

Converts a UTI to a MIME type.

Parameters:

• uti (string) - UTI string

Returns: string, error

local mime = app.uti.toMimeType("com.adobe.pdf")  -- "application/pdf"

app.uti.conforms(uti, parent)

Checks whether a UTI conforms to a parent type.

Parameters:

• uti (string) - UTI string
• parent (string) - Parent UTI string

Returns: boolean

app.uti.conforms("public.png", "public.image")     -- true
app.uti.conforms("com.adobe.pdf", "public.data")   -- true
app.uti.conforms("public.png", "public.movie")     -- false

app.uti.forFile(path)

Gets the UTI for a file.

Parameters:

• path (string) - File path

Returns: string, error

local uti = app.uti.forFile("/path/to/image.png")  -- "public.png"

app.uti.description(uti)

Gets the localized description of a UTI.

Parameters:

• uti (string) - UTI string

Returns: string|nil

local desc = app.uti.description("com.adobe.pdf")  -- "PDF Document"
local desc = app.uti.description("public.png")     -- "PNG Image"

Examples

Classify Files by Type

function MyPlugin:handleClassify(context)
    local categories = {}
    for _, file in ipairs(context.selectedFiles) do
        local uti = app.uti.forFile(file)
        if uti then
            local category = "other"
            if app.uti.conforms(uti, "public.image") then
                category = "images"
            elseif app.uti.conforms(uti, "public.movie") then
                category = "videos"
            elseif app.uti.conforms(uti, "public.audio") then
                category = "audio"
            elseif app.uti.conforms(uti, "public.text") then
                category = "text"
            end

            categories[category] = (categories[category] or 0) + 1
        end
    end

    local info = ""
    for cat, count in pairs(categories) do
        info = info .. cat .. ": " .. count .. "\n"
    end
    app.dialog.alert("File Classification", info)
end