hex-decode-fix/main.go

package main

import (
	"database/sql"
	"encoding/hex"
	"fmt"
	"log"
	"os"
	"strings"

	_ "rsc.io/sqlite"
)

const prefix = "\\x"

var file string
var table string
var idColumn string
var hexColumn string

func init() {
	if len(os.Args) < 5 {
		log.Fatal("Requires args: file, table, id column, and hex column")
	}
	file = os.Args[1]
	table = os.Args[2]
	idColumn = os.Args[3]
	hexColumn = os.Args[4]
}

func main() {
	db, err := sql.Open("sqlite3", file)
	if err != nil {
		log.Fatal(err)
	}

	err = db.Ping()
	if err != nil {
		log.Fatal(err)
	}

	tx, err := db.Begin()
	if err != nil {
		log.Fatal(err)
	}

	rows, err := tx.Query(fmt.Sprintf("SELECT %s, %s FROM %s", idColumn, hexColumn, table))
	if err != nil {
		log.Fatal(err)
	}
	defer rows.Close()

	var updated int
	var skipped int
	var failed int
	for rows.Next() {
		var id int
		var raw string
		if err = rows.Scan(&id, &raw); err != nil {
			log.Print(err)
			failed++
			continue
		}

		if !strings.HasPrefix(raw, prefix) {
			skipped++
			continue
		}

		decoded, err := hex.DecodeString(strings.TrimPrefix(raw, prefix))
		if err != nil {
			log.Print(err)
			failed++
			continue
		}

		_, err = tx.Exec(fmt.Sprintf("UPDATE %s SET %s = $1 WHERE %s = $2", table, hexColumn, idColumn), decoded, id)
		if err == nil {
			updated++
		} else {
			log.Print(err)
			failed++
		}
	}

	log.Print("Skipped: ", skipped)
	log.Print("Failed: ", failed)
	log.Print("Updated: ", updated)

	err = rows.Err()
	if err != nil {
		log.Fatal(err)
	}

	err = tx.Commit()
	if err != nil {
		log.Fatal(err)
	}
}