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"
"os"
"github.com/gocarina/gocsv"
)
type Client struct { // Our example struct, you can use "-" to ignore a field
Id string `csv:"client_id"`
Name string `csv:"client_name"`
Age string `csv:"client_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)
return err
}
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) gocsv.CSVReader {
r := csv.NewReader(in)
r.Comma = ', '
return r // Allows use pipe as delimiter
})
...
gocsv.SetCSVReader(func(in io.Reader) gocsv.CSVReader {
r := csv.NewReader(in)
r.LazyQuotes = true
r.Comma = '.'
return r // Allows use dot as delimiter and use quotes in CSV
})
...
gocsv.SetCSVReader(func(in io.Reader) gocsv.CSVReader {
//return csv.NewReader(in)
return gocsv.LazyCSVReader(in) // Allows use of quotes in CSV
})
...
gocsv.UnmarshalFile(file, &clients)
...
gocsv.SetCSVWriter(func(out io.Writer) *SafeCSVWriter {
writer := csv.NewWriter(out)
writer.Comma = ', '
return gocsv.NewSafeCSVWriter(writer)
})
...
gocsv.MarshalFile(&clients, file)
...
}