Middleware
Overview 🔗
Middleware is a function chained in the HTTP request-response cycle with access
to Echo#Context which it uses to perform a specific action, for example, logging
every request or limiting the number of requests.
Handler is processed in the end after all middleware are finished executing.
Middleware registered using Echo#Use() is executed for paths which are
registered both before and after Echo#Use() has been called. These middlewares are executed along with the group and handler
middlewares after routing has done.
Levels 🔗
Root Level (Before router) 🔗
Echo#Pre() can be used to register a middleware which is executed before router
processes the request. It is helpful to make any changes to the request properties,
for example, adding or removing a trailing slash from the path so it matches the
route.
The following built-in middleware should be registered at this level:
- HTTPSRedirect
- HTTPSWWWRedirect
- WWWRedirect
- NonWWWRedirect
- AddTrailingSlash
- RemoveTrailingSlash
- MethodOverride
- Rewrite
As router has not processed the request, middleware at this level won’t have access to any path related API from
echo.Context.
Root Level (After router) 🔗
Most of the time you will register a middleware at this level using Echo#Use().
This middleware is executed after router processes the request and has full access
to echo.Context API.
The following built-in middleware should be registered at this level:
- BodyLimit
- Logger
- Gzip
- Recover
- BasicAuth
- JWTAuth
- Secure
- CORS
- Static
Group Level 🔗
When creating a new group, you can register middleware just for that group. For example, you can have an admin group which is secured by registering a BasicAuth middleware for it.
Usage
e := echo.New()
admin := e.Group("/admin", middleware.BasicAuth())
You can also add a middleware after creating a group via admin.Use().
Route Level 🔗
When defining a new route, you can optionally register middleware just for it.
Usage
e := echo.New()
e.GET("/", <Handler>, <Middleware...>)
Skipping Middleware 🔗
There are cases when you would like to skip a middleware based on some condition,
for that each middleware has an option to define a function Skipper func(c echo.Context) bool.
Usage
e := echo.New()
e.Use(middleware.LoggerWithConfig(middleware.LoggerConfig{
Skipper: func(c echo.Context) bool {
if strings.HasPrefix(c.Request().Host, "localhost") {
return true
}
return false
},
}))
Example above skips Logger middleware when request host starts with localhost.