encode as CSV then ZIP in golang

Question

How do I CSV encode and then zip?

Is there a way to chain a writer to another? Must I create a new buffer in between writers?

var buf bytes.Buffer

zipWriter := zip.NewWriter(&buf)
csvwriter := csv.NewWriter(zipWriter) // <--- zip writer doesn't implement `io.writer`

csvwriter.Write([]string{"a", "b\"fwr", "c"})
csvwriter.Write([]string{"a", "e", "ww"})
csvwriter.Flush()

println(buf.String())

Marble

zip is an archive format, so have to add a file before you can write content. Use Create or CreateHeader. – Gudrunguelderrose

Answer 1

zip produces a structured zip file with a directory structure, which means you need to create and add each file independently.

An example playground demonstrates how to add your CSV file. It also demonstrates opening the compressed zip file and enumerating the files.

---

If you want to gzip the file as a single compressed stream, like:

$ gzip somefile.csv

to produce somefile.csv.gz

Then you can do the following as demostrated by this playground

package main

import (
    "bytes"
    "compress/gzip"
    "encoding/csv"
    "fmt"
    "io/ioutil"
)

func main() {
    var buf bytes.Buffer

    zipWriter := gzip.NewWriter(&buf)
    csvwriter := csv.NewWriter(zipWriter)

    csvwriter.Write([]string{"a", "b\"fwr", "c"})
    csvwriter.Write([]string{"a", "e", "ww"})
    csvwriter.Flush()
    zipWriter.Flush()
    zipWriter.Close()

    fmt.Println(buf.Bytes())
    zipReader, _ := gzip.NewReader(bytes.NewReader(buf.Bytes()))
    d, err := ioutil.ReadAll(zipReader)
    if err != nil {
        fmt.Println("err", err)
    }
    fmt.Println(string(d))
}

Quickly

First example playground was what I needed. thanks! – Marble