path: root/media/mediaType.go

// Copyright 2019 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package media

import (
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"strings"

	"github.com/gohugoio/hugo/common/maps"

	"github.com/mitchellh/mapstructure"
)

const (
	defaultDelimiter = "."
)

// Type (also known as MIME type and content type) is a two-part identifier for
// file formats and format contents transmitted on the Internet.
// For Hugo's use case, we use the top-level type name / subtype name + suffix.
// One example would be application/svg+xml
// If suffix is not provided, the sub type will be used.
// See // https://en.wikipedia.org/wiki/Media_type
type Type struct {
	MainType string `json:"mainType"` // i.e. text
	SubType  string `json:"subType"`  // i.e. html

	// This is the optional suffix after the "+" in the MIME type,
	//  e.g. "xml" in "applicatiion/rss+xml".
	mimeSuffix string

	Delimiter string `json:"delimiter"` // e.g. "."

	// TODO(bep) make this a string to make it hashable + method
	Suffixes []string `json:"suffixes"`

	// Set when doing lookup by suffix.
	fileSuffix string
}

// FromStringAndExt is same as FromString, but adds the file extension to the type.
func FromStringAndExt(t, ext string) (Type, error) {
	tp, err := fromString(t)
	if err != nil {
		return tp, err
	}
	tp.Suffixes = []string{strings.TrimPrefix(ext, ".")}
	return tp, nil
}

// FromString creates a new Type given a type string on the form MainType/SubType and
// an optional suffix, e.g. "text/html" or "text/html+html".
func fromString(t string) (Type, error) {
	t = strings.ToLower(t)
	parts := strings.Split(t, "/")
	if len(parts) != 2 {
		return Type{}, fmt.Errorf("cannot parse %q as a media type", t)
	}
	mainType := parts[0]
	subParts := strings.Split(parts[1], "+")

	subType := strings.Split(subParts[0], ";")[0]

	var suffix string

	if len(subParts) > 1 {
		suffix = subParts[1]
	}

	return Type{MainType: mainType, SubType: subType, mimeSuffix: suffix}, nil
}

// Type returns a string representing the main- and sub-type of a media type, e.g. "text/css".
// A suffix identifier will be appended after a "+" if set, e.g. "image/svg+xml".
// Hugo will register a set of default media types.
// These can be overridden by the user in the configuration,
// by defining a media type with the same Type.
func (m Type) Type() string {
	// Examples are
	// image/svg+xml
	// text/css
	if m.mimeSuffix != "" {
		return m.MainType + "/" + m.SubType + "+" + m.mimeSuffix
	}
	return m.MainType + "/" + m.SubType
}

func (m Type) String() string {
	return m.Type()
}

// FullSuffix returns the file suffix with any delimiter prepended.
func (m Type) FullSuffix() string {
	return m.Delimiter + m.Suffix()
}

// Suffix returns the file suffix without any delmiter prepended.
func (m Type) Suffix() string {
	if m.fileSuffix != "" {
		return m.fileSuffix
	}
	if len(m.Suffixes) > 0 {
		return m.Suffixes[0]
	}
	// There are MIME types without file suffixes.
	return ""
}

// Definitions from https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types etc.
// Note that from Hugo 0.44 we only set Suffix if it is part of the MIME type.
var (
	CalendarType   = Type{MainType: "text", SubType: "calendar", Suffixes: []string{"ics"}, Delimiter: defaultDelimiter}
	CSSType        = Type{MainType: "text", SubType: "css", Suffixes: []string{"css"}, Delimiter: defaultDelimiter}
	SCSSType       = Type{MainType: "text", SubType: "x-scss", Suffixes: []string{"scss"}, Delimiter: defaultDelimiter}
	SASSType       = Type{MainType: "text", SubType: "x-sass", Suffixes: []string{"sass"}, Delimiter: defaultDelimiter}
	CSVType        = Type{MainType: "text", SubType: "csv", Suffixes: []string{"csv"}, Delimiter: defaultDelimiter}
	HTMLType       = Type{MainType: "text", SubType: "html", Suffixes: []string{"html"}, Delimiter: defaultDelimiter}
	JavascriptType = Type{MainType: "application", SubType: "javascript", Suffixes: []string{"js"}, Delimiter: defaultDelimiter}
	JSONType       = Type{MainType: "application", SubType: "json", Suffixes: []string{"json"}, Delimiter: defaultDelimiter}
	RSSType        = Type{MainType: "application", SubType: "rss", mimeSuffix: "xml", Suffixes: []string{"xml"}, Delimiter: defaultDelimiter}
	XMLType        = Type{MainType: "application", SubType: "xml", Suffixes: []string{"xml"}, Delimiter: defaultDelimiter}
	SVGType        = Type{MainType: "image", SubType: "svg", mimeSuffix: "xml", Suffixes: []string{"svg"}, Delimiter: defaultDelimiter}
	TextType       = Type{MainType: "text", SubType: "plain", Suffixes: []string{"txt"}, Delimiter: defaultDelimiter}
	TOMLType       = Type{MainType: "application", SubType: "toml", Suffixes: []string{"toml"}, Delimiter: defaultDelimiter}
	YAMLType       = Type{MainType: "application", SubType: "yaml", Suffixes: []string{"yaml", "yml"}, Delimiter: defaultDelimiter}

	// Common image types
	PNGType  = Type{MainType: "image", SubType: "png", Suffixes: []string{"png"}, Delimiter: defaultDelimiter}
	JPEGType = Type{MainType: "image", SubType: "jpeg", Suffixes: []string{"jpg", "jpeg"}, Delimiter: defaultDelimiter}
	GIFType  = Type{MainType: "image", SubType: "gif", Suffixes: []string{"gif"}, Delimiter: defaultDelimiter}
	TIFFType = Type{MainType: "image", SubType: "tiff", Suffixes: []string{"tif", "tiff"}, Delimiter: defaultDelimiter}
	BMPType  = Type{MainType: "image", SubType: "bmp", Suffixes: