英文:
Go: Variable from PostgreSQL in template not output value (Echo framework)
问题
许多代码取自Martini示例，但这里使用的是Echo框架。
我可以让它在Martini中工作，但在Echo中不行。
server.go:
package main
import (
"database/sql"
"github.com/labstack/echo"
_ "github.com/lib/pq"
"html/template"
"io"
"log"
"net/http"
)
type Book struct {
Title, Author, Description string
}
type (
Template struct {
templates *template.Template
}
)
func (t *Template) Render(w io.Writer, name string, data interface{}) error {
return t.templates.ExecuteTemplate(w, name, data)
}
func main() {
e := echo.New()
db, err := sql.Open("postgres", "user=postgres password=apassword dbname=lesson4 sslmode=disable")
if err != nil {
log.Fatal(err)
}
t := &Template{
templates: template.Must(template.ParseFiles("public/views/testhere.html")),
}
e.Renderer(t)
e.Get("/post/:idnumber", func(c *echo.Context) {
rows, err := db.Query("SELECT title, author, description FROM books WHERE id=$1", c.Param("idnumber"))
if err != nil {
log.Fatal(err)
}
books := []Book{}
for rows.Next() {
b := Book{}
err := rows.Scan(&b.Title, &b.Author, &b.Description)
if err != nil {
log.Fatal(err)
}
books = append(books, b)
}
c.Render(http.StatusOK, "onlytestingtpl", books)
})
e.Run(":4444")
}
public/views/testhere.html:
{{define "onlytestingtpl"}}Book title is {{.Title}}. Written by {{.Author}}. The book is about {{.Description}}.{{end}}
我无法找出问题所在，因为没有错误消息，也没有关于该框架的SQL文档。运行时，它输出：
Book title is
（变量没有输出值）
英文:
Many codes taken from Martini example, but this using Echo framework.
I can make it works in Martini but not in Echo.
server.go:
package main
import (
"database/sql"
"github.com/labstack/echo"
_ "github.com/lib/pq"
"html/template"
"io"
"log"
"net/http"
)
type Book struct {
Title, Author, Description string
}
type (
Template struct {
templates *template.Template
}
)
func (t *Template) Render(w io.Writer, name string, data interface{}) error {
return t.templates.ExecuteTemplate(w, name, data)
}
func main() {
e := echo.New()
db, err := sql.Open("postgres", "user=postgres password=apassword dbname=lesson4 sslmode=disable")
if err != nil {
log.Fatal(err)
}
t := &Template{
templates: template.Must(template.ParseFiles("public/views/testhere.html")),
}
e.Renderer(t)
e.Get("/post/:idnumber", func(c *echo.Context) {
rows, err := db.Query("SELECT title, author, description FROM books WHERE id=$1", c.Param("idnumber"))
if err != nil {
log.Fatal(err)
}
books := []Book{}
for rows.Next() {
b := Book{}
err := rows.Scan(&b.Title, &b.Author, &b.Description)
if err != nil {
log.Fatal(err)
}
books = append(books, b)
}
c.Render(http.StatusOK, "onlytestingtpl", books)
})
e.Run(":4444")
}
public/views/testhere.html:
{{define "onlytestingtpl"}}Book title is {{.Title}}. Written by {{.Author}}. The book is about {{.Description}}.{{end}}
I cannot figure out since no error message, and no SQL documentation of this framework. When running, it gives:
Book title is
(The variable not output value)
答案1
得分: 1
如我在评论中提到的，你不应该执行一个接受一个包含结构体切片的结构体的模板。要么在你的模板中使用{{range}}，要么执行以下操作：
c.Render(http.StatusOK, "onlytestingtpl", books[0])
英文:
As I mentioned in a comment, you shouldn't execute a template that takes a struct with a slice of structs. Either use {{range}} in your template, or do
c.Render(http.StatusOK, "onlytestingtpl", books[0])
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