challiwill / gocsv

The GoCSV package aims to provide easy CSV serialization and deserialization to the golang programming language

Go CSV

The GoCSV package aims to provide easy serialization and deserialization functions to use CSV in Golang

API and techniques inspired from https://godoc.org/gopkg.in/mgo.v2

Installation

go get -u github.com/gocarina/gocsv

Full example

Consider the following CSV file

client_id,client_name,client_age
1,Jose,42
2,Daniel,26
3,Vincent,32

Easy binding in Go!

package main

import (
	"fmt"
	"gocsv"
	"os"
)

type Client struct { // Our example struct, you can use "-" to ignore a field
	Id      string `csv:"id"`
	Name    string `csv:"name"`
	Age     string `csv:"age"`
	NotUsed string `csv:"-"`
}

func main() {
	clientsFile, err := os.OpenFile("clients.csv", os.O_RDWR|os.O_CREATE, os.ModePerm)
	if err != nil {
		panic(err)
	}
	defer clientsFile.Close()

	clients := []*Client{}

	if err := gocsv.UnmarshalFile(clientsFile, &clients); err != nil { // Load clients from file
		panic(err)
	}
	for _, client := range clients {
		fmt.Println("Hello", client.Name)
	}

	if _, err := clientsFile.Seek(0, 0); err != nil { // Go to the start of the file
		panic(err)
	}

	clients = append(clients, &Client{Id: "12", Name: "John", Age: "21"}) // Add clients
	clients = append(clients, &Client{Id: "13", Name: "Fred"})
	clients = append(clients, &Client{Id: "14", Name: "James", Age: "32"})
	clients = append(clients, &Client{Id: "15", Name: "Danny"})
	csvContent, err := gocsv.MarshalString(&clients) // Get all clients as CSV string
	//err = gocsv.MarshalFile(&clients, clientsFile) // Use this to save the CSV back to the file
	if err != nil {
		panic(err)
	}
	fmt.Println(csvContent) // Display all clients as CSV string

}

Customizable Converters

type DateTime struct {
	time.Time
}

// Convert the internal date as CSV string
func (date *DateTime) MarshalCSV() (string, error) {
	return date.Time.Format("20060201"), nil
}

// You could also use the standard Stringer interface 
func (date *DateTime) String() (string) {
	return date.String() // Redundant, just for example
}

// Convert the CSV string as internal date
func (date *DateTime) UnmarshalCSV(csv string) (err error) {
	date.Time, err = time.Parse("20060201", csv)
	if err != nil {
		return err
	}
	return nil
}

type Client struct { // Our example struct with a custom type (DateTime)
	Id       string   `csv:"id"`
	Name     string   `csv:"name"`
	Employed DateTime `csv:"employed"`
}

Customizable CSV Reader / Writer

func main() {
	...
	
	gocsv.SetCSVReader(func(in io.Reader) *csv.Reader {
    	//return csv.NewReader(in)
    	return gocsv.LazyCSVReader(in) // Allows use of quotes in CSV
    })

    ...

    gocsv.UnmarshalFile(file, &clients)

    ...

    gocsv.SetCSVWriter(func(out io.Writer) *csv.Writer {
    	return csv.NewWriter(out)
    })

    ...

    gocsv.MarshalFile(&clients, file)

	...
}