Add CSV support to transform.Unmarshal

Fixes gohugoio#5555

commands/convert.go

@@ -238,7 +238,7 @@ func parseContentFile(r io.Reader) (parsedFile, error) {
 
 	iter.PeekWalk(walkFn)
 
-	metadata, err := metadecoders.UnmarshalToMap(pf.frontMatterSource, pf.frontMatterFormat)
+	metadata, err := metadecoders.Default.UnmarshalToMap(pf.frontMatterSource, pf.frontMatterFormat)
 	if err != nil {
 		return pf, err
 	}

commands/hugo.go

@@ -1045,7 +1045,7 @@ func (c *commandeer) isThemeVsHugoVersionMismatch(fs afero.Fs) (dir string, mism
 
 		b, err := afero.ReadFile(fs, path)
 
-		tomlMeta, err := metadecoders.UnmarshalToMap(b, metadecoders.TOML)
+		tomlMeta, err := metadecoders.Default.UnmarshalToMap(b, metadecoders.TOML)
 
 		if err != nil {
 			continue

commands/import_jekyll.go

@@ -257,7 +257,7 @@ func (i *importCmd) loadJekyllConfig(fs afero.Fs, jekyllRoot string) map[string]
 		return nil
 	}
 
-	c, err := metadecoders.UnmarshalToMap(b, metadecoders.YAML)
+	c, err := metadecoders.Default.UnmarshalToMap(b, metadecoders.YAML)
 
 	if err != nil {
 		return nil

config/configLoader.go

@@ -57,7 +57,7 @@ func FromFileToMap(fs afero.Fs, filename string) (map[string]interface{}, error)
 }
 
 func readConfig(format metadecoders.Format, data []byte) (map[string]interface{}, error) {
-	m, err := metadecoders.UnmarshalToMap(data, format)
+	m, err := metadecoders.Default.UnmarshalToMap(data, format)
 	if err != nil {
 		return nil, err
 	}
@@ -69,7 +69,7 @@ func readConfig(format metadecoders.Format, data []byte) (map[string]interface{}
 }
 
 func loadConfigFromFile(fs afero.Fs, filename string) (map[string]interface{}, error) {
-	m, err := metadecoders.UnmarshalFileToMap(fs, filename)
+	m, err := metadecoders.Default.UnmarshalFileToMap(fs, filename)
 	if err != nil {
 		return nil, err
 	}

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/bep/debounce v1.1.0
 	github.com/bep/gitmap v1.0.0
 	github.com/bep/go-tocss v0.6.0
+	github.com/bep/mapstructure v0.0.0-20180511142126-bb74f1db0675
 	github.com/chaseadamsio/goorgeous v1.1.0
 	github.com/cpuguy83/go-md2man v1.0.8 // indirect
 	github.com/danwakefield/fnmatch v0.0.0-20160403171240-cbb64ac3d964 // indirect

go.sum

@@ -21,6 +21,8 @@ github.com/bep/gitmap v1.0.0 h1:cTTZwq7vpGuhwefKCBDV9UrHnZAPVJTvoWobimrqkUc=
 github.com/bep/gitmap v1.0.0/go.mod h1:g9VRETxFUXNWzMiuxOwcudo6DfZkW9jOsOW0Ft4kYaY=
 github.com/bep/go-tocss v0.6.0 h1:lJf+nIjsQDpifUr+NgHi9QMBnrr9cFvMvEBT+uV9Q9E=
 github.com/bep/go-tocss v0.6.0/go.mod h1:d9d3crzlTl+PUZLFzBUjfFCpp68K+ku10mzTlnqU/+A=
+github.com/bep/mapstructure v0.0.0-20180511142126-bb74f1db0675 h1:FsEl9Z/kzas/wM6yhI0AQ0H+hHOL0b5EERNs3N5KYcU=
+github.com/bep/mapstructure v0.0.0-20180511142126-bb74f1db0675/go.mod h1:i5WrwxccbJYFpJIcQxfKglzwXT0NE71ElOzBJrO0ODE=
 github.com/chaseadamsio/goorgeous v1.1.0 h1:J9UrYDhzucUMHXsCKG+kICvpR5dT1cqZdVFTYvSlUBk=
 github.com/chaseadamsio/goorgeous v1.1.0/go.mod h1:6QaC0vFoKWYDth94dHFNgRT2YkT5FHdQp/Yx15aAAi0=
 github.com/cheekybits/is v0.0.0-20150225183255-68e9c0620927 h1:SKI1/fuSdodxmNNyVBR8d7X/HuLnRpvvFO0AgyQk764=

hugolib/config.go

@@ -285,7 +285,7 @@ func (l configLoader) loadConfigFromConfigDir(v *viper.Viper) ([]string, error)
 
 			name := helpers.Filename(filepath.Base(path))
 
-			item, err := metadecoders.UnmarshalFileToMap(sourceFs, path)
+			item, err := metadecoders.Default.UnmarshalFileToMap(sourceFs, path)
 			if err != nil {
 				return l.wrapFileError(err, path)
 			}

hugolib/page_content.go

@@ -91,7 +91,7 @@ Loop:
 			result.Write(it.Val)
 		case it.IsFrontMatter():
 			f := metadecoders.FormatFromFrontMatterType(it.Type)
-			m, err := metadecoders.UnmarshalToMap(it.Val, f)
+			m, err := metadecoders.Default.UnmarshalToMap(it.Val, f)
 			if err != nil {
 				if fe, ok := err.(herrors.FileError); ok {
 					return herrors.ToFileErrorWithOffset(fe, iter.LineNumber()-1)

hugolib/resource_chain_test.go

@@ -342,11 +342,19 @@ Publish 2: {{ $cssPublish2.Permalink }}
 		{"unmarshal", func() bool { return true }, func(b *sitesBuilder) {
 			b.WithTemplates("home.html", `
 {{ $toml := "slogan = \"Hugo Rocks!\"" | resources.FromString "slogan.toml" | transform.Unmarshal }}
+{{ $csv1 := "\"Hugo Rocks\",\"Hugo is Fast!\"" | resources.FromString "slogans.csv" | transform.Unmarshal }}
+{{ $csv2 := "a;b;c" | resources.FromString "abc.csv" | transform.Unmarshal (dict "csvComma" ";") }}
+
 Slogan: {{ $toml.slogan }}
+CSV1: {{ $csv1 }} {{ len (index $csv1 0)  }}
+CSV2: {{ $csv2 }}
 
 `)
 		}, func(b *sitesBuilder) {
-			b.AssertFileContent("public/index.html", `Slogan: Hugo Rocks!`)
+			b.AssertFileContent("public/index.html",
+				`Slogan: Hugo Rocks!`,
+				`[[Hugo Rocks Hugo is Fast!]] 2`,
+			)
 		}},
 
 		{"template", func() bool { return true }, func(b *sitesBuilder) {}, func(b *sitesBuilder) {

hugolib/site.go

@@ -1014,7 +1014,7 @@ func (s *Site) readData(f source.ReadableFile) (interface{}, error) {
 	content := helpers.ReaderToBytes(file)
 
 	format := metadecoders.FormatFromString(f.Extension())
-	return metadecoders.Unmarshal(content, format)
+	return metadecoders.Default.Unmarshal(content, format)
 }
 
 func (s *Site) readDataFromSourceFS() error {

parser/metadecoders/decoder.go

@@ -14,6 +14,8 @@
 package metadecoders
 
 import (
+	"bytes"
+	"encoding/csv"
 	"encoding/json"
 	"fmt"
 
@@ -27,22 +29,37 @@ import (
 	yaml "gopkg.in/yaml.v2"
 )
 
+// Decoder provides some configuration options for the decoders.
+type Decoder struct {
+	// Comma is the field delimiter used in the CSV decoder. It defaults to ','.
+	Comma rune
+
+	// Comment, if not 0, is the comment character ued in the CSV decoder. Lines beginning with the
+	// Comment character without preceding whitespace are ignored.
+	Comment rune
+}
+
+// Default is a Decoder in its default configuration.
+var Default = Decoder{
+	Comma: ',',
+}
+
 // UnmarshalToMap will unmarshall data in format f into a new map. This is
 // what's needed for Hugo's front matter decoding.
-func UnmarshalToMap(data []byte, f Format) (map[string]interface{}, error) {
+func (d Decoder) UnmarshalToMap(data []byte, f Format) (map[string]interface{}, error) {
 	m := make(map[string]interface{})
 	if data == nil {
 		return m, nil
 	}
 
-	err := unmarshal(data, f, &m)
+	err := d.unmarshal(data, f, &m)
 
 	return m, err
 }
 
 // UnmarshalFileToMap is the same as UnmarshalToMap, but reads the data from
 // the given filename.
-func UnmarshalFileToMap(fs afero.Fs, filename string) (map[string]interface{}, error) {
+func (d Decoder) UnmarshalFileToMap(fs afero.Fs, filename string) (map[string]interface{}, error) {
 	format := FormatFromString(filename)
 	if format == "" {
 		return nil, errors.Errorf("%q is not a valid configuration format", filename)
@@ -52,23 +69,30 @@ func UnmarshalFileToMap(fs afero.Fs, filename string) (map[string]interface{}, e
 	if err != nil {
 		return nil, err
 	}
-	return UnmarshalToMap(data, format)
+	return d.UnmarshalToMap(data, format)
 }
 
 // Unmarshal will unmarshall data in format f into an interface{}.
 // This is what's needed for Hugo's /data handling.
-func Unmarshal(data []byte, f Format) (interface{}, error) {
+func (d Decoder) Unmarshal(data []byte, f Format) (interface{}, error) {
 	if data == nil {
-		return make(map[string]interface{}), nil
+		switch f {
+		case CSV:
+			// TODO(bep) csv check
+			return make([]interface{}, 0), nil
+		default:
+			return make(map[string]interface{}), nil
+		}
+
 	}
 	var v interface{}
-	err := unmarshal(data, f, &v)
+	err := d.unmarshal(data, f, &v)
 
 	return v, err
 }
 
 // unmarshal unmarshals data in format f into v.
-func unmarshal(data []byte, f Format, v interface{}) error {
+func (d Decoder) unmarshal(data []byte, f Format, v interface{}) error {
 
 	var err error
 
@@ -116,6 +140,9 @@ func unmarshal(data []byte, f Format, v interface{}) error {
 				*v.(*interface{}) = mm
 			}
 		}
+	case CSV:
+		return d.unmarshalCSV(data, v)
+
 	default:
 		return errors.Errorf("unmarshal of format %q is not supported", f)
 	}
@@ -128,6 +155,28 @@ func unmarshal(data []byte, f Format, v interface{}) error {
 
 }
 
+func (d Decoder) unmarshalCSV(data []byte, v interface{}) error {
+	r := csv.NewReader(bytes.NewReader(data))
+	r.Comma = d.Comma
+	r.Comment = d.Comment
+
+	records, err := r.ReadAll()
+	if err != nil {
+		return err
+	}
+
+	switch v.(type) {
+	case *interface{}:
+		*v.(*interface{}) = records
+	default:
+		return errors.Errorf("CSV cannot be unmarshaled into %T", v)
+
+	}
+
+	return nil
+
+}
+
 func toFileError(f Format, err error) error {
 	return herrors.ToFileError(string(f), err)
 }

parser/metadecoders/decoder_test.go

@@ -26,6 +26,8 @@ func TestUnmarshalToMap(t *testing.T) {
 
 	expect := map[string]interface{}{"a": "b"}
 
+	d := Default
+
 	for i, test := range []struct {
 		data   string
 		format Format
@@ -40,9 +42,10 @@ func TestUnmarshalToMap(t *testing.T) {
 		{`#+a: b`, ORG, expect},
 		// errors
 		{`a = b`, TOML, false},
+		{`a,b,c`, CSV, false}, // Use Unmarshal for CSV
 	} {
 		msg := fmt.Sprintf("%d: %s", i, test.format)
-		m, err := UnmarshalToMap([]byte(test.data), test.format)
+		m, err := d.UnmarshalToMap([]byte(test.data), test.format)
 		if b, ok := test.expect.(bool); ok && !b {
 			assert.Error(err, msg)
 		} else {
@@ -57,6 +60,8 @@ func TestUnmarshalToInterface(t *testing.T) {
 
 	expect := map[string]interface{}{"a": "b"}
 
+	d := Default
+
 	for i, test := range []struct {
 		data   string
 		format Format
@@ -67,12 +72,13 @@ func TestUnmarshalToInterface(t *testing.T) {
 		{`#+a: b`, ORG, expect},
 		{`a = "b"`, TOML, expect},
 		{`a: "b"`, YAML, expect},
+		{`a,b,c`, CSV, [][]string{[]string{"a", "b", "c"}}},
 		{"a: Easy!\nb:\n  c: 2\n  d: [3, 4]", YAML, map[string]interface{}{"a": "Easy!", "b": map[string]interface{}{"c": 2, "d": []interface{}{3, 4}}}},
 		// errors
 		{`a = "`, TOML, false},
 	} {
 		msg := fmt.Sprintf("%d: %s", i, test.format)
-		m, err := Unmarshal([]byte(test.data), test.format)
+		m, err := d.Unmarshal([]byte(test.data), test.format)
 		if b, ok := test.expect.(bool); ok && !b {
 			assert.Error(err, msg)
 		} else {

parser/metadecoders/format.go

@@ -31,6 +31,7 @@ const (
 	JSON Format = "json"
 	TOML Format = "toml"
 	YAML Format = "yaml"
+	CSV  Format = "csv"
 )
 
 // FormatFromString turns formatStr, typically a file extension without any ".",
@@ -51,6 +52,8 @@ func FormatFromString(formatStr string) Format {
 		return TOML
 	case "org":
 		return ORG
+	case "csv":
+		return CSV
 	}
 
 	return ""
@@ -88,11 +91,16 @@ func FormatFromFrontMatterType(typ pageparser.ItemType) Format {
 // FormatFromContentString tries to detect the format (JSON, YAML or TOML)
 // in the given string.
 // It return an empty string if no format could be detected.
-func FormatFromContentString(data string) Format {
+func (d Decoder) FormatFromContentString(data string) Format {
+	csvIdx := strings.IndexRune(data, d.Comma)
 	jsonIdx := strings.Index(data, "{")
 	yamlIdx := strings.Index(data, ":")
 	tomlIdx := strings.Index(data, "=")
 
+	if isLowerIndexThan(csvIdx, jsonIdx, yamlIdx, tomlIdx) {
+		return CSV
+	}
+
 	if isLowerIndexThan(jsonIdx, yamlIdx, tomlIdx) {
 		return JSON
 	}

parser/metadecoders/format_test.go

@@ -88,12 +88,13 @@ func TestFormatFromContentString(t *testing.T) {
 		{`foo: "bar"`, YAML},
 		{`foo:"bar"`, YAML},
 		{`{ "foo": "bar"`, JSON},
+		{`a,b,c"`, CSV},
 		{`asdfasdf`, Format("")},
 		{``, Format("")},
 	} {
 		errMsg := fmt.Sprintf("[%d] %s", i, test.data)
 
-		result := FormatFromContentString(test.data)
+		result := Default.FormatFromContentString(test.data)
 
 		assert.Equal(test.expect, result, errMsg)
 	}

tpl/transform/remarshal.go

@@ -35,12 +35,12 @@ func (ns *Namespace) Remarshal(format string, data interface{}) (string, error)
 		return "", err
 	}
 
-	fromFormat := metadecoders.FormatFromContentString(from)
+	fromFormat := metadecoders.Default.FormatFromContentString(from)
 	if fromFormat == "" {
 		return "", errors.New("failed to detect format from content")
 	}
 
-	meta, err := metadecoders.UnmarshalToMap([]byte(from), fromFormat)
+	meta, err := metadecoders.Default.UnmarshalToMap([]byte(from), fromFormat)
 
 	var result bytes.Buffer
 	if err := parser.InterfaceToConfig(meta, mark, &result); err != nil {