Merge pull request #1 from tuan78/feat/create-functions-and-tools

feat: create functions and tools

.gitignore

@@ -0,0 +1,24 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+.idea
+.vscode
+.DS_Store
+
+# Project's unused files
+bin/
+*.csv
+*.json

Makefile

@@ -0,0 +1,8 @@
+.PHONY: all test
+all: build
+
+build:
+	go build -o bin/jsonconv github.com/tuan78/jsonconv/tool
+
+test:
+	go test ./... -cover

README.md

@@ -1,2 +1,2 @@
 # jsonconv
-Golang library and cmd for JSON converter (flatten JSON, JSON to CSV, JSON from CSV, JSON from Excel, and more).
+Golang library and cmd for flattening JSON and converting JSON to CSV.

csv_writer.go

@@ -0,0 +1,42 @@
+package jsonconv
+
+import (
+	"encoding/csv"
+	"io"
+)
+
+// A CsvWriter writes records using CSV encoding.
+type CsvWriter struct {
+	Delimiter *rune // Field delimiter. If nil, it uses default value from csv.NewWriter
+	UseCRLF   bool  // True to use \r\n as the line terminator
+	writer    io.Writer
+}
+
+// NewCsvWriter returns a new CsvWriter that writes to w.
+func NewCsvWriter(w io.Writer) *CsvWriter {
+	return &CsvWriter{
+		writer: w,
+	}
+}
+
+// NewDelimiter returns a pointer to v.
+func NewDelimiter(v rune) *rune {
+	return &v
+}
+
+// Write writes all CSV data to w.
+func (w *CsvWriter) Write(data CsvData) error {
+	writer := csv.NewWriter(w.writer)
+	if w.Delimiter != nil {
+		writer.Comma = *w.Delimiter
+	}
+	writer.UseCRLF = w.UseCRLF
+
+	defer writer.Flush()
+	for _, v := range data {
+		if err := writer.Write(v); err != nil {
+			return err
+		}
+	}
+	return nil
+}

csv_writer_test.go

@@ -0,0 +1,75 @@
+package jsonconv
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestCsvWriter_InvalidDelimiter(t *testing.T) {
+	// Prepare
+	data := CsvData{
+		{
+			"id", "user", "score", "is active",
+		},
+	}
+	buf := &bytes.Buffer{}
+	wr := NewCsvWriter(buf)
+	wr.Delimiter = NewDelimiter('\n')
+
+	// Process
+	err := wr.Write(data)
+
+	// Check
+	if err == nil {
+		t.Fatalf("Should throw an error for invalid delimiter")
+	}
+}
+
+func TestCsvWriter(t *testing.T) {
+	// Prepare
+	data := CsvData{
+		{
+			"id", "user", "score", "is active",
+		},
+		{
+			"ce06f5b1-5721-42c0-91e1-9f72a09c250a", "Tuấn", "1.5", "true",
+		},
+		{
+			"b042ab5c-ca73-4460-b739-96410ea9d3a6", "Jon Doe", "-100", "false",
+		},
+		{
+			"4e01b638-44e5-4079-8043-baabbff21cc8", "高橋", "100000000000000000000000", "true",
+		},
+		{
+			"6f0d6265-545c-4366-a78b-4f80c337aa69", "김슬기", "1234567890", "true",
+		},
+		{
+			"3fbae214-006d-4ac5-9eea-76c5d611f54a", "Comma,", "0", "false",
+		},
+	}
+	buf := &bytes.Buffer{}
+	wr := NewCsvWriter(buf)
+	wr.Delimiter = NewDelimiter('|')
+
+	// Process
+	err := wr.Write(data)
+	if err != nil {
+		t.Fatalf("failed to write csv, err: %v", err)
+	}
+
+	// Check
+	s := buf.String()
+	expect := `id|user|score|is active
+ce06f5b1-5721-42c0-91e1-9f72a09c250a|Tuấn|1.5|true
+b042ab5c-ca73-4460-b739-96410ea9d3a6|Jon Doe|-100|false
+4e01b638-44e5-4079-8043-baabbff21cc8|高橋|100000000000000000000000|true
+6f0d6265-545c-4366-a78b-4f80c337aa69|김슬기|1234567890|true
+3fbae214-006d-4ac5-9eea-76c5d611f54a|Comma,|0|false
+`
+	if s == "" {
+		t.Fatalf("failed to write csv to byte buffer")
+	}
+	if s != expect {
+		t.Fatalf("csv output is not correct")
+	}
+}

go.mod

@@ -0,0 +1,10 @@
+module github.com/tuan78/jsonconv
+
+go 1.18
+
+require (
+	github.com/spf13/cobra v1.5.0
+	github.com/spf13/pflag v1.0.5
+)
+
+require github.com/inconshreveable/mousetrap v1.0.0 // indirect

go.sum

@@ -0,0 +1,10 @@
+github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
+github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/spf13/cobra v1.5.0 h1:X+jTBEBqF0bHN+9cSMgmfuvv2VHJ9ezmFNf9Y/XstYU=
+github.com/spf13/cobra v1.5.0/go.mod h1:dWXEIy2H428czQCjInthrTRUg7yKbok+2Qi/yBIJoUM=
+github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
+github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

json_converter.go

@@ -0,0 +1,79 @@
+package jsonconv
+
+import (
+	"fmt"
+	"sort"
+)
+
+// A ToCsvOption converts a JSON Array to CSV data.
+type ToCsvOption struct {
+	FlattenOption *FlattenOption // Set it to apply JSON flattening
+	BaseHeaders   CsvRow         // Base CSV headers used to add before dynamic headers
+}
+
+// ToCsv converts a JsonArray to CsvData with given op.
+func ToCsv(arr JsonArray, op *ToCsvOption) CsvData {
+	if len(arr) == 0 {
+		return CsvData{}
+	}
+
+	// Flatten JSON.
+	if op != nil && op.FlattenOption != nil {
+		for _, obj := range arr {
+			FlattenJsonObject(obj, op.FlattenOption)
+		}
+	}
+
+	// Create CSV rows.
+	var csvData CsvData
+	var hs []string
+	if op != nil && len(op.BaseHeaders) > 0 {
+		hs = CreateCsvHeader(arr, op.BaseHeaders)
+	} else {
+		hs = CreateCsvHeader(arr, nil)
+	}
+	csvData = append(csvData, hs)
+	for _, obj := range arr {
+		row := make(CsvRow, 0)
+		for _, h := range hs {
+			if val, exist := obj[h]; exist {
+				row = append(row, fmt.Sprintf("%v", val))
+				continue
+			}
+			row = append(row, "")
+		}
+		csvData = append(csvData, row)
+	}
+
+	return csvData
+}
+
+// CreateCsvHeader creates CsvRow from arr and baseHs.
+// A baseHs is base header that we want to put at the beginning of dynamic header,
+// we can set baseHs to nil if we just want to have dynamic header only.
+func CreateCsvHeader(arr JsonArray, baseHs CsvRow) CsvRow {
+	hs := make(sort.StringSlice, 0)
+	hss := make(map[string]struct{})
+
+	// Get CSV header from json.
+	for _, obj := range arr {
+		for k := range obj {
+			hss[k] = struct{}{}
+		}
+	}
+
+	// Exclude base headers from detected headers, then sort filtered list.
+	for _, h := range baseHs {
+		delete(hss, h)
+	}
+	for h := range hss {
+		hs = append(hs, h)
+	}
+	hs.Sort()
+
+	// Insert BaseHeaders to the beginning of headers.
+	if len(baseHs) > 0 {
+		hs = append(baseHs, hs...)
+	}
+	return hs
+}