get-items handle

package main

import (
    "encoding/csv"
    "encoding/json"
    "fmt"
    "log"
    "net/http"
    "os"
    "slices"
)

const fileDb = "ueba.csv"

type dbLike struct {
    headers []string
    records [][]string
    idIdx   int
}

func newDb() (*dbLike, error) {
    file, err := os.Open(fileDb)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    reader := csv.NewReader(file)
    records, err := reader.ReadAll()
    if err != nil {
        return nil, err
    }

    idIdx := slices.Index(records[0], "id")
    if idIdx == -1 {
        return nil, fmt.Errorf("id field foesn't contain within current csv")
    }
    return &dbLike{records[0], records[1:len(records)], idIdx}, nil
}

func (db *dbLike) getRecordsContainsId(ids []string) ([]map[string]string, error) {
    var result []map[string]string
    for _, row := range db.records {
        if !slices.Contains(ids, row[db.idIdx]) {
            continue
        }

        record := make(map[string]string)
        for i, v := range row {
            record[db.headers[i]] = v
        }
        result = append(result, record)
    }
    return result, nil
}

func main() {
    db, err := newDb()
    if err != nil {
        log.Fatal("Error while reading db-like file: ", err)
    }

    http.HandleFunc("/get-items", func(w http.ResponseWriter, r *http.Request) {
        ids, ok := r.URL.Query()["id"]
        if !ok || len(ids) == 0 {
            http.Error(w, "Id parameter should be in query", http.StatusBadRequest)
            return
        }

        items, err := db.getRecordsContainsId(ids)
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        response, err := json.Marshal(items)
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        w.Header().Set("Content-Type", "application/json")
        w.Write(response)
    })
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal("Server starting have been failed: ", err)
    }
}