95 lines
2.6 KiB
Markdown
95 lines
2.6 KiB
Markdown
# Alice
|
|
|
|
[](http://godoc.org/github.com/justinas/alice)
|
|
[](https://travis-ci.org/justinas/alice)
|
|
[](http://gocover.io/github.com/justinas/alice)
|
|
|
|
Alice provides a convenient way to chain
|
|
your HTTP middleware functions and the app handler.
|
|
|
|
In short, it transforms
|
|
|
|
Middleware1(Middleware2(Middleware3(App)))
|
|
|
|
to
|
|
|
|
alice.New(Middleware1, Middleware2, Middleware3).Then(App)
|
|
|
|
### Why?
|
|
|
|
None of the other middleware chaining solutions
|
|
behaves exactly like Alice.
|
|
Alice is as minimal as it gets:
|
|
in essence, it's just a for loop that does the wrapping for you.
|
|
|
|
Check out [this blog post](http://justinas.org/alice-painless-middleware-chaining-for-go/)
|
|
for explanation how Alice is different from other chaining solutions.
|
|
|
|
### Usage
|
|
|
|
Your middleware constructors should have the form of
|
|
|
|
func (http.Handler) http.Handler
|
|
|
|
Some middleware provide this out of the box.
|
|
For ones that don't, it's trivial to write one yourself.
|
|
|
|
```go
|
|
func myStripPrefix(h http.Handler) http.Handler {
|
|
return http.StripPrefix("/old", h)
|
|
}
|
|
```
|
|
|
|
This complete example shows the full power of Alice.
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"net/http"
|
|
"time"
|
|
|
|
"github.com/throttled/throttled"
|
|
"github.com/justinas/alice"
|
|
"github.com/justinas/nosurf"
|
|
)
|
|
|
|
func timeoutHandler(h http.Handler) http.Handler {
|
|
return http.TimeoutHandler(h, 1*time.Second, "timed out")
|
|
}
|
|
|
|
func myApp(w http.ResponseWriter, r *http.Request) {
|
|
w.Write([]byte("Hello world!"))
|
|
}
|
|
|
|
func main() {
|
|
th := throttled.Interval(throttled.PerSec(10), 1, &throttled.VaryBy{Path: true}, 50)
|
|
myHandler := http.HandlerFunc(myApp)
|
|
|
|
chain := alice.New(th.Throttle, timeoutHandler, nosurf.NewPure).Then(myHandler)
|
|
http.ListenAndServe(":8000", chain)
|
|
}
|
|
```
|
|
|
|
Here, the request will pass [throttled](https://github.com/PuerkitoBio/throttled) first,
|
|
then an http.TimeoutHandler we've set up,
|
|
then [nosurf](https://github.com/justinas/nosurf)
|
|
and will finally reach our handler.
|
|
|
|
Note that Alice makes **no guarantees** for
|
|
how one or another piece of middleware will behave.
|
|
It executes all middleware sequentially so that if a
|
|
piece of middleware were to stop the chain,
|
|
the request will not reach the inner handlers.
|
|
This is intentional behavior.
|
|
|
|
Alice works with Go 1.0 and higher,
|
|
but running tests requires at least Go 1.1.
|
|
|
|
### Contributing
|
|
|
|
0. Find an issue that bugs you / open a new one.
|
|
1. Discuss.
|
|
2. Branch off, commit, test.
|
|
3. Make a pull request / attach the commits to the issue.
|