WIP: adding CSV decoder

cmd/utils.go

@@ -68,6 +68,10 @@ func configureDecoder() (yqlib.Decoder, error) {
 		return yqlib.NewPropertiesDecoder(), nil
 	case yqlib.JsonInputFormat:
 		return yqlib.NewJSONDecoder(), nil
+	case yqlib.CSVObjectInputFormat:
+		return yqlib.NewCSVObjectDecoder(','), nil
+	case yqlib.TSVObjectInputFormat:
+		return yqlib.NewCSVObjectDecoder('\t'), nil
 	}
 
 	return yqlib.NewYamlDecoder(), nil

pkg/yqlib/csv_test.go

@@ -0,0 +1,193 @@
+package yqlib
+
+import (
+	"bufio"
+	"fmt"
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+)
+
+const csvSimple = `name,numberOfCats,likesApples,height
+Gary,1,true,168.8
+Samantha's Rabbit,2,false,-188.8
+`
+
+const csvSimpleShort = `Name,Number of Cats
+Gary,1
+Samantha's Rabbit,2
+`
+
+const tsvSimple = `name	numberOfCats	likesApples	height
+Gary	1	true	168.8
+Samantha's Rabbit	2	false	-188.8
+`
+
+const expectedYamlFromCSV = `- name: Gary
+  numberOfCats: 1
+  likesApples: true
+  height: 168.8
+- name: Samantha's Rabbit
+  numberOfCats: 2
+  likesApples: false
+  height: -188.8
+`
+
+const csvTestSimpleYaml = `- [i, like, csv]
+- [because, excel, is, cool]`
+
+const csvTestExpectedSimpleCsv = `i,like,csv
+because,excel,is,cool
+`
+
+const tsvTestExpectedSimpleCsv = `i	like	csv
+because	excel	is	cool
+`
+
+var csvScenarios = []formatScenario{
+	{
+		description:  "Encode CSV simple",
+		input:        csvTestSimpleYaml,
+		expected:     csvTestExpectedSimpleCsv,
+		scenarioType: "encode-csv",
+	},
+	{
+		description:  "Encode TSV simple",
+		input:        csvTestSimpleYaml,
+		expected:     tsvTestExpectedSimpleCsv,
+		scenarioType: "encode-tsv",
+	},
+	{
+		description:    "Encode array of objects to csv",
+		subdescription: "Add the header row manually, then the we convert each object into an array of values - resulting in an array of arrays. Nice thing about this method is you can pick the columns and call the header whatever you like.",
+		input:          expectedYamlFromCSV,
+		expected:       csvSimpleShort,
+		expression:     `[["Name", "Number of Cats"]] +  [.[] | [.name, .numberOfCats ]]`,
+		scenarioType:   "encode-csv",
+	},
+	{
+		description:    "Encode array of objects to csv - generic",
+		subdescription: "This is a little trickier than the previous example - we dynamically work out the $header, and use that to automatically create the value arrays.",
+		input:          expectedYamlFromCSV,
+		expected:       csvSimple,
+		expression:     `(.[0] | keys | .[] ) as $header |  [[$header]] +  [.[] | [ .[$header] ]]`,
+		scenarioType:   "encode-csv",
+	},
+	{
+		description:    "Parse CSV into an array of objects",
+		subdescription: "First row is assumed to define the fields",
+		input:          csvSimple,
+		expected:       expectedYamlFromCSV,
+		scenarioType:   "decode-csv-object",
+	},
+	{
+		description:    "Parse TSV into an array of objects",
+		subdescription: "First row is assumed to define the fields",
+		input:          tsvSimple,
+		expected:       expectedYamlFromCSV,
+		scenarioType:   "decode-tsv-object",
+	},
+}
+
+func testCSVScenario(t *testing.T, s formatScenario) {
+	switch s.scenarioType {
+	case "encode-csv":
+		test.AssertResultWithContext(t, s.expected, processFormatScenario(s, NewYamlDecoder(), NewCsvEncoder(',')), s.description)
+	case "encode-tsv":
+		test.AssertResultWithContext(t, s.expected, processFormatScenario(s, NewYamlDecoder(), NewCsvEncoder('\t')), s.description)
+	case "decode-csv-object":
+		test.AssertResultWithContext(t, s.expected, processFormatScenario(s, NewCSVObjectDecoder(','), NewYamlEncoder(2, false, true, true)), s.description)
+	case "decode-tsv-object":
+		test.AssertResultWithContext(t, s.expected, processFormatScenario(s, NewCSVObjectDecoder('\t'), NewYamlEncoder(2, false, true, true)), s.description)
+	default:
+		panic(fmt.Sprintf("unhandled scenario type %q", s.scenarioType))
+	}
+}
+
+func documentCSVDecodeObjectScenario(t *testing.T, w *bufio.Writer, s formatScenario, formatType string) {
+	writeOrPanic(w, fmt.Sprintf("## %v\n", s.description))
+
+	if s.subdescription != "" {
+		writeOrPanic(w, s.subdescription)
+		writeOrPanic(w, "\n\n")
+	}
+
+	writeOrPanic(w, fmt.Sprintf("Given a sample.%v file of:\n", formatType))
+	writeOrPanic(w, fmt.Sprintf("```%v\n%v\n```\n", formatType, s.input))
+
+	writeOrPanic(w, "then\n")
+	writeOrPanic(w, fmt.Sprintf("```bash\nyq -p=%v sample.%v\n```\n", formatType, formatType))
+	writeOrPanic(w, "will output\n")
+
+	separator := ','
+	if formatType == "tsv" {
+		separator = '\t'
+	}
+
+	writeOrPanic(w, fmt.Sprintf("```yaml\n%v```\n\n",
+		processFormatScenario(s, NewCSVObjectDecoder(separator), NewYamlEncoder(s.indent, false, true, true))),
+	)
+}
+
+func documentCSVEncodeScenario(w *bufio.Writer, s formatScenario, formatType string) {
+	writeOrPanic(w, fmt.Sprintf("## %v\n", s.description))
+
+	if s.subdescription != "" {
+		writeOrPanic(w, s.subdescription)
+		writeOrPanic(w, "\n\n")
+	}
+
+	writeOrPanic(w, "Given a sample.yml file of:\n")
+	writeOrPanic(w, fmt.Sprintf("```yaml\n%v\n```\n", s.input))
+
+	writeOrPanic(w, "then\n")
+
+	expression := s.expression
+
+	if expression != "" {
+		writeOrPanic(w, fmt.Sprintf("```bash\nyq -o=%v '%v' sample.yml\n```\n", formatType, expression))
+	} else {
+		writeOrPanic(w, fmt.Sprintf("```bash\nyq -o=%v sample.yml\n```\n", formatType))
+	}
+	writeOrPanic(w, "will output\n")
+
+	separator := ','
+	if formatType == "tsv" {
+		separator = '\t'
+	}
+
+	writeOrPanic(w, fmt.Sprintf("```%v\n%v```\n\n", formatType,
+		processFormatScenario(s, NewYamlDecoder(), NewCsvEncoder(separator))),
+	)
+}
+
+func documentCSVScenario(t *testing.T, w *bufio.Writer, i interface{}) {
+	s := i.(formatScenario)
+	if s.skipDoc {
+		return
+	}
+	switch s.scenarioType {
+	case "encode-csv":
+		documentCSVEncodeScenario(w, s, "csv")
+	case "encode-tsv":
+		documentCSVEncodeScenario(w, s, "tsv")
+	case "decode-csv-object":
+		documentCSVDecodeObjectScenario(t, w, s, "csv")
+	case "decode-tsv-object":
+		documentCSVDecodeObjectScenario(t, w, s, "tsv")
+
+	default:
+		panic(fmt.Sprintf("unhandled scenario type %q", s.scenarioType))
+	}
+}
+
+func TestCSVScenarios(t *testing.T) {
+	for _, tt := range csvScenarios {
+		testCSVScenario(t, tt)
+	}
+	genericScenarios := make([]interface{}, len(csvScenarios))
+	for i, s := range csvScenarios {
+		genericScenarios[i] = s
+	}
+	documentScenarios(t, "usage", "csv-tsv", genericScenarios, documentCSVScenario)
+}

pkg/yqlib/decoder.go

@@ -15,6 +15,8 @@ const (
 	PropertiesInputFormat
 	Base64InputFormat
 	JsonInputFormat
+	CSVObjectInputFormat
+	TSVObjectInputFormat
 )
 
 type Decoder interface {
@@ -32,6 +34,10 @@ func InputFormatFromString(format string) (InputFormat, error) {
 		return PropertiesInputFormat, nil
 	case "json", "ndjson", "j":
 		return JsonInputFormat, nil
+	case "csv":
+		return CSVObjectInputFormat, nil
+	case "tsv":
+		return TSVObjectInputFormat, nil
 	default:
 		return 0, fmt.Errorf("unknown format '%v' please use [yaml|xml|props]", format)
 	}

pkg/yqlib/decoder_csv_object.go

@@ -0,0 +1,77 @@
+package yqlib
+
+import (
+	"encoding/csv"
+	"errors"
+	"io"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+type csvObjectDecoder struct {
+	separator rune
+	reader    csv.Reader
+	finished  bool
+}
+
+func NewCSVObjectDecoder(separator rune) Decoder {
+	return &csvObjectDecoder{separator: separator}
+}
+
+func (dec *csvObjectDecoder) Init(reader io.Reader) {
+	dec.reader = *csv.NewReader(reader)
+	dec.reader.Comma = dec.separator
+	dec.finished = false
+}
+
+func (dec *csvObjectDecoder) convertToYamlNode(content string) *yaml.Node {
+	node, err := parseSnippet(content)
+	if err != nil {
+		return createScalarNode(content, content)
+	}
+	return node
+}
+
+func (dec *csvObjectDecoder) createObject(headerRow []string, contentRow []string) *yaml.Node {
+	objectNode := &yaml.Node{Kind: yaml.MappingNode, Tag: "!!map"}
+
+	for i, header := range headerRow {
+		objectNode.Content = append(
+			objectNode.Content,
+			createScalarNode(header, header),
+			dec.convertToYamlNode(contentRow[i]))
+	}
+	return objectNode
+}
+
+func (dec *csvObjectDecoder) Decode(rootYamlNode *yaml.Node) error {
+	if dec.finished {
+		return io.EOF
+	}
+	headerRow, err := dec.reader.Read()
+	log.Debugf(": headerRow%v", headerRow)
+	if err != nil {
+		return err
+	}
+
+	rootArray := &yaml.Node{Kind: yaml.SequenceNode, Tag: "!!seq"}
+
+	contentRow, err := dec.reader.Read()
+
+	for err == nil && len(contentRow) > 0 {
+		log.Debugf("Adding contentRow: %v", contentRow)
+		rootArray.Content = append(rootArray.Content, dec.createObject(headerRow, contentRow))
+		contentRow, err = dec.reader.Read()
+		log.Debugf("Read next contentRow: %v, %v", contentRow, err)
+	}
+	if !errors.Is(err, io.EOF) {
+		return err
+	}
+
+	log.Debugf("finished, contentRow%v", contentRow)
+	log.Debugf("err: %v", err)
+
+	rootYamlNode.Kind = yaml.DocumentNode
+	rootYamlNode.Content = []*yaml.Node{rootArray}
+	return nil
+}

pkg/yqlib/doc/usage/csv-tsv.md

@@ -0,0 +1,143 @@
+
+{% hint style="warning" %}
+Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
+
+`yq e <exp> <file>`
+{% endhint %}
+
+## Encode CSV simple
+Given a sample.yml file of:
+```yaml
+- [i, like, csv]
+- [because, excel, is, cool]
+```
+then
+```bash
+yq -o=csv sample.yml
+```
+will output
+```csv
+i,like,csv
+because,excel,is,cool
+```
+
+## Encode TSV simple
+Given a sample.yml file of:
+```yaml
+- [i, like, csv]
+- [because, excel, is, cool]
+```
+then
+```bash
+yq -o=tsv sample.yml
+```
+will output
+```tsv
+i	like	csv
+because	excel	is	cool
+```
+
+## Encode array of objects to csv
+Add the header row manually, then the we convert each object into an array of values - resulting in an array of arrays. Nice thing about this method is you can pick the columns and call the header whatever you like.
+
+Given a sample.yml file of:
+```yaml
+- name: Gary
+  numberOfCats: 1
+  likesApples: true
+  height: 168.8
+- name: Samantha's Rabbit
+  numberOfCats: 2
+  likesApples: false
+  height: -188.8
+
+```
+then
+```bash
+yq -o=csv '[["Name", "Number of Cats"]] +  [.[] | [.name, .numberOfCats ]]' sample.yml
+```
+will output
+```csv
+Name,Number of Cats
+Gary,1
+Samantha's Rabbit,2
+```
+
+## Encode array of objects to csv - generic
+This is a little trickier than the previous example - we dynamically work out the $header, and use that to automatically create the value arrays.
+
+Given a sample.yml file of:
+```yaml
+- name: Gary
+  numberOfCats: 1
+  likesApples: true
+  height: 168.8
+- name: Samantha's Rabbit
+  numberOfCats: 2
+  likesApples: false
+  height: -188.8
+
+```
+then
+```bash
+yq -o=csv '(.[0] | keys | .[] ) as $header |  [[$header]] +  [.[] | [ .[$header] ]]' sample.yml
+```
+will output
+```csv
+name,numberOfCats,likesApples,height
+Gary,1,true,168.8
+Samantha's Rabbit,2,false,-188.8
+```
+
+## Parse CSV into an array of objects
+First row is assumed to define the fields
+
+Given a sample.csv file of:
+```csv
+name,numberOfCats,likesApples,height
+Gary,1,true,168.8
+Samantha's Rabbit,2,false,-188.8
+
+```
+then
+```bash
+yq -p=csv sample.csv
+```
+will output
+```yaml
+- name: Gary
+  numberOfCats: 1
+  likesApples: true
+  height: 168.8
+- name: Samantha's Rabbit
+  numberOfCats: 2
+  likesApples: false
+  height: -188.8
+```
+
+## Parse TSV into an array of objects
+First row is assumed to define the fields
+
+Given a sample.tsv file of:
+```tsv
+name	numberOfCats	likesApples	height
+Gary	1	true	168.8
+Samantha's Rabbit	2	false	-188.8
+
+```
+then
+```bash
+yq -p=tsv sample.tsv
+```
+will output
+```yaml
+- name: Gary
+  numberOfCats: 1
+  likesApples: true
+  height: 168.8
+- name: Samantha's Rabbit
+  numberOfCats: 2
+  likesApples: false
+  height: -188.8
+```
+

pkg/yqlib/operators_test.go

@@ -31,7 +31,7 @@ type expressionScenario struct {
 }
 
 func TestMain(m *testing.M) {
-	logging.SetLevel(logging.ERROR, "")
+	logging.SetLevel(logging.DEBUG, "")
 	Now = func() time.Time {
 		return time.Date(2021, time.May, 19, 1, 2, 3, 4, time.UTC)
 	}