Documentation
¶
Overview ¶
Package middleware provides flexibility at the HTTP request/response process. For this purpose, the Adapter pattern is used, which consist in wrapping handlers. An adapter may run code before and/or after the handler it is wrapping.
func MyAdapter(h http.Handler) http.Handler {
nh := func(w http.ResponseWriter, r *http.Request) {
// Code that run before
h.ServeHTTP(w, r) // Breaks the flow if not used
// Code that run after
}
return http.HandlerFunc(nh)
}
When a set of adapters is used, the result is a sequence of wrappers and its execution flow depends in the order that the adapters were given.
Adapt(h, f1, f2, f3)
1. f1 before code
2. f2 before code
3. f3 before code
4. h
5. f3 after code
6. f2 after code
7. f1 after code
Index ¶
- func Adapt(h http.Handler, a ...Adapter) http.Handler
- func AdaptFunc(h func(w http.ResponseWriter, r *http.Request), a ...Adapter) http.Handler
- type Adapter
- func AddHeader(key, value string) Adapter
- func Cache(directives string) Adapter
- func DelHeader(key string) Adapter
- func Gzip(level int) Adapter
- func JSONRequest(body interface{}) Adapter
- func JSONResponse() Adapter
- func Replace(old, New string) Adapter
- func SetHeader(key, value string) Adapter
- func StripPrefix(prefix string) Adapter
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Adapt ¶
Adapt wraps a http.Handler into a list of Adapters. Takes a http.Handler and a list of Adapters, which will be wrapped from right to left (and ran left to right).
Example ¶
package main
import (
"fmt"
"net/http"
"net/http/httptest"
"nt.web.ve/go/ntgo/net/http/middleware"
)
func main() {
h := middleware.Adapt(
http.FileServer(http.Dir(".")),
middleware.Cache("max-age=3600, s-max-age=3600"),
middleware.Gzip(-1),
)
// http.Handle("/", h)
w := httptest.NewRecorder()
r := httptest.NewRequest(http.MethodGet, "/", nil)
r.Header.Set("Accept-Encoding", "gzip")
h.ServeHTTP(w, r)
res := w.Result()
fmt.Printf("Status: %v\n", res.Status)
fmt.Printf("Cache-Control: %+v\n", res.Header.Get("Cache-Control"))
fmt.Printf("Content-Encoding: %v", res.Header.Get("Content-Encoding"))
}
Output: Status: 200 OK Cache-Control: max-age=3600, s-max-age=3600 Content-Encoding: gzip
func AdaptFunc ¶
AdaptFunc works as Adapt but for http.HandlerFunc.
Example ¶
package main
import (
"fmt"
"net/http"
"net/http/httptest"
"nt.web.ve/go/ntgo/net/http/middleware"
)
func main() {
h := middleware.AdaptFunc(
func(w http.ResponseWriter, r *http.Request) {},
middleware.JSONResponse(),
middleware.Cache("max-age=3600, s-max-age=3600"),
)
// http.Handle("/", h)
w := httptest.NewRecorder()
r := httptest.NewRequest(http.MethodGet, "/", nil)
h.ServeHTTP(w, r)
res := w.Result()
fmt.Printf("Status: %v\n", res.Status)
fmt.Printf("Cache-Control: %+v\n", res.Header.Get("Cache-Control"))
fmt.Printf("Content-Type: %v", res.Header.Get("Content-Type"))
}
Output: Status: 200 OK Cache-Control: max-age=3600, s-max-age=3600 Content-Type: application/json; charset=utf-8
Types ¶
type Adapter ¶
Adapter is a wrapper for http.Handler. Takes a http.Handler as argument and creates a new one that may run code before and/or after calling the given.
func AddHeader ¶
AddHeader creates/appends a HTTP header before calling the http.Handler.
func Cache ¶
Cache sets HTTP cache headers for GET requests.
Directives ¶
* public/private: whether the cached response is for any or a specific user.
* max-age=TIME: cache life time in seconds. The maximum value is 1 year.
* s-max-age=TIME: same as max-age, but this one has effect in proxies.
* must-revalidate: force expired cached response revalidation, even in special circumstances (like slow connections, were cached responses are used even after they had expired).
* proxy-revalidate: same as must-revalidate, but this one has effect in proxies.
* no-cache: disables cache.
* no-store: disables cache, even in proxies.
func DelHeader ¶
DelHeader removes a HTTP header before calling the http.Handler.
func Gzip ¶
Gzip compresses the response body. The compression level is given as an integer value according to the compress/flate package.
func JSONRequest ¶
func JSONRequest(body interface{}) Adapter
JSONRequest checks that request has the appropriate HTTP method and the appropriate 'Content-Type' header. Responds with http.StatusMethodNotAllowed if the used method is not one of POST, PUT or PATCH. Responds with http.StatusUnsupportedMediaType if the 'Content-Type' header is not valid. body is used as response body.
func JSONResponse ¶
func JSONResponse() Adapter
JSONResponse prepares the response to be a JSON response.
func Replace ¶
Replace replaces old by new from the request URL.
func SetHeader ¶
SetHeader creates/replaces a HTTP header before calling the http.Handler.
Source Files