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@alexedwards
Last active May 22, 2024 13:58
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.
├── books
│   ├── handlers.go
│   └── models.go
├── config
│   └── db.go
└── main.go
package config
import (
"database/sql"
_ "github.com/lib/pq"
)
type Env struct {
DB *sql.DB
}
func NewDB(dataSourceName string) (*sql.DB, error) {
db, err := sql.Open("postgres", dataSourceName)
if err != nil {
return nil, err
}
err = db.Ping()
if err != nil {
db.Close()
return nil, err
}
return db, nil
}
package books
import (
"bookstore/config"
"fmt"
"net/http"
)
func BooksIndex(env *config.Env) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.Method != "GET" {
http.Error(w, http.StatusText(405), 405)
return
}
bks, err := AllBooks(env.DB)
if err != nil {
http.Error(w, http.StatusText(500), 500)
return
}
for _, bk := range bks {
fmt.Fprintf(w, "%s, %s, %s, £%.2f\n", bk.Isbn, bk.Title, bk.Author, bk.Price)
}
})
}
package main
import (
"bookstore/books"
"bookstore/config"
"log"
"net/http"
)
func main() {
db, err := config.NewDB("postgres://user:pass@localhost/bookstore")
if err != nil {
log.Panic(err)
}
defer db.Close()
env := &config.Env{DB: db}
http.Handle("/books", books.BooksIndex(env))
http.ListenAndServe(":3000", nil)
}
package books
import (
"database/sql"
)
type Book struct {
Isbn string
Title string
Author string
Price float32
}
func AllBooks(db *sql.DB) ([]*Book, error) {
rows, err := db.Query("SELECT * FROM books")
if err != nil {
return nil, err
}
defer rows.Close()
bks := make([]*Book, 0)
for rows.Next() {
bk := new(Book)
err := rows.Scan(&bk.Isbn, &bk.Title, &bk.Author, &bk.Price)
if err != nil {
return nil, err
}
bks = append(bks, bk)
}
if err = rows.Err(); err != nil {
return nil, err
}
return bks, nil
}
@alexedwards
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Author

@avoidik You're right, thanks for spotting that. I've updated the Gist (and the books too) 👍

@ThatIknow
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ThatIknow commented May 14, 2024

@avoidik

Nice catch. Although, If the function were more bulky than it was then this style would be beneficial. But as it is, wouldn't it be cleaner to just do

......
......
if err != nil {
db.Close()
return nil, err
}

....

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