会话

Session 中间件便于进行基于 gorilla/sessions 的 HTTP 会话管理。默认实现提供基于 Cookie 和文件系统的会话 store；你也可以针对不同后端使用 社区维护的 store。

依赖

go get github.com/gorilla/sessions

import (
  "github.com/gorilla/sessions"
)

实现

一个用于创建会话中间件的函数，以及一个从上下文获取会话的工具函数：

func NewSessionMiddleware(store sessions.Store) echo.MiddlewareFunc {
  return func(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c *echo.Context) error {
      c.Set("_session_store", store)
      return next(c)
    }
  }
}

func GetSession(c *echo.Context, name string) (*sessions.Session, error) {
  store, err := echo.ContextGet[sessions.Store](c, "_session_store")
  if err != nil {
    return nil, err
  }
  return store.Get(c.Request(), name)
}

中间件可以像这样初始化：

sessionStore := sessions.NewCookieStore([]byte("secret"))
e.Use(NewSessionMiddleware(sessionStore))

用法示例

此示例暴露两个端点：/create-session 创建新会话，/read-session 在请求包含会话 ID 时 从会话读取值。

package main

import (
  "fmt"
  "net/http"

  "github.com/gorilla/sessions"
  "github.com/labstack/echo/v5"
)

func NewSessionMiddleware(store sessions.Store) echo.MiddlewareFunc {
  return func(next echo.HandlerFunc) echo.HandlerFunc {
    return func(c *echo.Context) error {
      c.Set("_session_store", store)
      return next(c)
    }
  }
}

func GetSession(c *echo.Context, name string) (*sessions.Session, error) {
  store, err := echo.ContextGet[sessions.Store](c, "_session_store")
  if err != nil {
    return nil, fmt.Errorf("failed to get session store: %w", err)
  }
  return store.Get(c.Request(), name)
}

func main() {
  e := echo.New()

  sessionStore := sessions.NewCookieStore([]byte("secret"))
  e.Use(NewSessionMiddleware(sessionStore))

  e.GET("/create-session", func(c *echo.Context) error {
    sess, err := GetSession(c, "session")
    if err != nil {
      return err
    }
    sess.Options = &sessions.Options{
      Path:     "/",
      MaxAge:   86400 * 7,
      HttpOnly: true,
    }
    sess.Values["foo"] = "bar"
    if err := sess.Save(c.Request(), c.Response()); err != nil {
      return err
    }
    return c.NoContent(http.StatusOK)
  })

  e.GET("/read-session", func(c *echo.Context) error {
    sess, err := GetSession(c, "session")
    if err != nil {
      return err
    }
    return c.String(http.StatusOK, fmt.Sprintf("foo=%v\n", sess.Values["foo"]))
  })

  if err := e.Start(":8080"); err != nil {
    e.Logger.Error("failed to start server", "error", err)
  }
}

在不提供会话的情况下请求 /read-session，输出的 foo 值为 nil：

$ curl -v http://localhost:8080/read-session
* processing: http://localhost:8080/read-session
*   Trying [::1]:8080...
* Connected to localhost (::1) port 8080
> GET /read-session HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/8.2.1
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=UTF-8
< Date: Thu, 25 Apr 2024 09:15:14 GMT
< Content-Length: 10
<
foo=<nil>

请求 /create-session 会创建新会话：

$ curl -v -c cookies.txt http://localhost:8080/create-session
* processing: http://localhost:8080/create-session
*   Trying [::1]:8080...
* Connected to localhost (::1) port 8080
> GET /create-session HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/8.2.1
> Accept: */*
>
< HTTP/1.1 200 OK
* Added cookie session="..." for domain localhost, path /, expire 1714641420
< Set-Cookie: session=...; Path=/; Expires=Thu, 02 May 2024 09:17:00 GMT; Max-Age=604800; HttpOnly
< Date: Thu, 25 Apr 2024 09:17:00 GMT
< Content-Length: 0
<
* Connection #0 to host localhost left intact

使用上一个响应中的会话 Cookie 请求 /read-session，会输出会话中的 foo 值：

$ curl -v -b cookies.txt http://localhost:8080/read-session
* processing: http://localhost:8080/read-session
*   Trying [::1]:8080...
* Connected to localhost (::1) port 8080
> GET /read-session HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/8.2.1
> Accept: */*
> Cookie: session=...
>
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=UTF-8
< Date: Thu, 25 Apr 2024 09:18:56 GMT
< Content-Length: 8
<
foo=bar
* Connection #0 to host localhost left intact