Small script that downloads images I publish on Imgur to my own server

imgur-assets-dl.go

package main

import (
	"errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

var (
	defaultDir = "/var/www/assets.c7.se/imgur"
	defaultURL = "https://assets.c7.se/imgur/"
	defaultRaw = false
)

const (
	iImgurCom = `https://i.imgur.com/`
	firefoxUA = `Mozilla/5.0 (X11; Linux i686; rv:135.0) Gecko/20100101 Firefox/135.0`
)

type config struct {
	dir string
	url string
	src string
	img string
	raw bool
}

func (cfg config) path() string {
	return filepath.Join(cfg.dir, cfg.img)
}

func (cfg config) out() string {
	return cfg.url + cfg.img
}

func main() {
	if err := run(os.Args, os.Stdout); err != nil {
		fmt.Fprintf(os.Stderr, "❌ %s\n", err)
		os.Exit(1)
	}
}

func run(args []string, w io.Writer) error {
	cfg, err := parse(args)
	if err != nil {
		return err
	}

	client := &http.Client{
		Timeout: time.Minute,
	}

	if err := download(cfg, client); err != nil {
		return err
	}

	return output(w, cfg)
}

func request(cfg config) (*http.Request, error) {
	req, err := http.NewRequest(http.MethodGet, cfg.src, nil)
	if err != nil {
		return nil, err
	}

	req.Header.Set("User-Agent", firefoxUA)

	return req, nil
}

func download(cfg config, client *http.Client) error {
	name := cfg.path()

	if _, err := os.Stat(name); !errors.Is(err, os.ErrNotExist) {
		return fmt.Errorf("file already exists, served on %s", cfg.out())
	}

	req, err := request(cfg)
	if err != nil {
		return err
	}

	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("bad status: %s", resp.Status)
	}

	dst, err := os.Create(name)
	if err != nil {
		return err
	}
	defer dst.Close()

	_, err = io.Copy(dst, resp.Body)

	return err
}

func output(w io.Writer, cfg config) error {
	if cfg.raw {
		return fprintf(w, "%s\n", cfg.out())
	}

	return fprintf(w, "✅ file downloaded, served on %s\n", cfg.out())
}

func fprintf(w io.Writer, format string, a ...any) error {
	_, err := fmt.Fprintf(w, format, a...)

	return err
}

func parse(args []string) (config, error) {
	var cfg config

	flags := flag.NewFlagSet(args[0], flag.ExitOnError)

	flags.StringVar(&cfg.dir, "dir", defaultDir, "Local directory to download to")
	flags.StringVar(&cfg.url, "url", defaultURL, "URL to construct links from")
	flags.BoolVar(&cfg.raw, "raw", defaultRaw, "If to output just the link URL")

	if err := flags.Parse(args[1:]); err != nil {
		return cfg, err
	}

	cfg.src = strings.Join(flags.Args(), "")

	switch {
	case cfg.src == "":
		return cfg, fmt.Errorf("no URL provided")
	case !strings.HasPrefix(cfg.src, iImgurCom):
		return cfg, fmt.Errorf("provided source %q does not have the required prefix %q", cfg.src, iImgurCom)
	}

	cfg.img = filepath.Base(cfg.src)

	return cfg, nil
}

On my workstation I have a small script that rely on SSHFS to mount my server to a local directory:

#!/bin/bash

umount /var/www/assets.c7.se
sshfs -o allow_other,default_permissions [email protected]:/var/www/assets.c7.se /var/www/assets.c7.se