Editing a zip file in memory

Question

I am trying to edit a zip file in memory in Go and return the zipped file through a HTTP response

The goal is to add a few files to a path in the zip file example

I add a log.txt file in my path/to/file route in the zipped folder

All this should be done without saving the file or editing the original file.

Answer 1

I have implemented a simple version of real-time stream compression, which can correctly compress a single file. If you want it to run efficiently, you need a lot of optimization.

This is only for reference. If you need more information, you should set more useful HTTP header information before compression so that the client can correctly process the response data.

package main

import (
    "archive/zip"
    "io"
    "net/http"
    "os"

    "github.com/gin-gonic/gin"
)

func main() {
    engine := gin.Default()
    engine.GET("/log.zip", func(c *gin.Context) {
        f, err := os.Open("./log.txt")
        if err != nil {
            c.String(http.StatusInternalServerError, err.Error())
            return
        }

        defer f.Close()
        info, err := f.Stat()
        if err != nil {
            c.String(http.StatusInternalServerError, err.Error())
            return
        }

        z := zip.NewWriter(c.Writer)
        head, err := zip.FileInfoHeader(info)
        if err != nil {
            c.String(http.StatusInternalServerError, err.Error())
            return
        }

        defer z.Close()

        w, err := z.CreateHeader(head)
        if err != nil {
            c.String(http.StatusInternalServerError, err.Error())
            return
        }

        _, err = io.Copy(w, f)
        if err != nil {
            c.String(http.StatusInternalServerError, err.Error())
            return
        }
    })

    engine.Run("127.0.0.1:8080")
}