I have the following struct
type Server struct {
*http.Server
chain core.Blockchainer
coreServer *network.Server
}
with its corresponding handler
func (s *Server) methodHandler(w http.ResponseWriter, req *Request, reqParams Params) {
.....
}
How can I unit test my handler?
The handler above
func (s *Server) methodHandler(w http.ResponseWriter, req *Request, reqParams Params) {
.....
}
can be tested by following these steps
handler := http.HandlerFunc(s.methodHandler)
req := httptest.NewRequest(...)
w := httptest.NewRecorder()
handler(w, req)
resp := w.Result()
assert.Equal(t, expected, resp)
Related
I'm developing a service rest in Go using go-kit. I need send a header response. This header response should have the same value of request header.
This is a part of my transport.go:
func MakeHandler(m **http.ServeMux) http.Handler {
const URL = "..."
var serverOptions []kithttp.ServerOption
logger := log.NewLogfmtLogger(os.Stderr)
var svc repositories.SignDocumentRepository
impl := persistence.NewSignerDocumentRepository()
svc = middleware.LoggingMiddlewareSignDocument{Logger: logger, Next: impl}
registerHandler := kithttp.NewServer(
makeSignDocumentEndpoint(svc),
decodeRequest,
encodeResponse,
serverOptions...,
)
r := mux.NewRouter()
r.Handle(URL, handlers.LoggingHandler(os.Stdout, registerHandler))
(*m).Handle(URL, r)
return nil
}
func decodeRequest(_ context.Context, r *http.Request) (interface{}, error) {
return r, nil
}
func encodeResponse(_ context.Context, w http.ResponseWriter, response interface{}) error {
w.Header().Set("headerA", "val1")
w.Header().Set("headerB", "") // This header should be equal that a header request
switch response.(type) {
case model.MsgRsHdr:
w.WriteHeader(http.StatusPartialContent)
default:
w.WriteHeader(http.StatusAccepted)
}
if response != nil {
return json.NewEncoder(w).Encode(response)
}
return nil
}
How do I get a request header in encodeResponse method?
You can use ServerBefore to put *http.Request in the context, and can get it in encodeResponse to read request headers.
type ctxRequestKey struct{}
func putRequestInCtx(ctx context.Context, r *http.Request, _ Request) context.Context {
return context.WithValue(ctx, ctxRequestKey{}, r)
}
func encodeResponse(ctx context.Context, w http.ResponseWriter, response interface{}) error {
r := ctx.Value(ctxRequestKey{}).(*http.Request)
// can use r.Header.Get here to read request here.
}
serverOptions := []kithttp.ServerOptions{
kithttp.ServerBefore(putRequestInCtx),
}
registerHandler := kithttp.NewServer(
makeSignDocumentEndpoint(svc),
decodeRequest,
encodeResponse,
serverOptions...,
)
I have this simple http server. How can i access the request data to a global variable and use it in any part of the application.
package main
import (
"io"
"net/http"
)
var data string // Get URL data globally and use it in other part of the application
func hello(w http.ResponseWriter, r *http.Request) {
data := r.URL.Query().Get("somestring")
}
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", hello)
http.ListenAndServe(":8000", mux)
}
You could use net/context with http.Handler. for example you have "X-Request-ID" in header, you could define middlware like this:
func middleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
ctx := newContextWithRequestID(req.Context(), req)
next.ServeHTTP(rw, req.WithContext(ctx))
})
}
type key int
const requestIDKey key = 0
func newContextWithRequestID(ctx context.Context, req *http.Request) context.Context {
reqID := req.Header.Get("X-Request-ID")
if reqID == "" {
reqID = generateRandomID()
}
return context.WithValue(ctx, requestIDKey, reqID)
}
func requestIDFromContext(ctx context.Context) string {
return ctx.Value(requestIDKey).(string)
}
you could get requestIDKey in any handler with Context object.
func handler(rw http.ResponseWriter, req *http.Request) {
reqID := requestIDFromContext(req.Context())
fmt.Fprintf(rw, "Hello request ID %v\n", reqID)
}
this is just an example. insted of requestIDKey you could have any data which you should put in Context and read from it with a key.
for more detail information visit this blog.
How do you set up Gorilla Mux r.Use to return errors down the middleware chain? https://godoc.org/github.com/gorilla/mux#Router.Use
Main.go
r := mux.NewRouter()
r.Use(LoggingFunc)
r.Use(AuthFunc)
Basic middleware
Starts with logging middleware which can catch and handle errors from further down the chain
type HandlerFunc func(w http.ResponseWriter, r *http.Request) error
func LoggingFunc(next HandlerFunc) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Logging middleware
defer func() {
if err, ok := recover().(error); ok {
w.WriteHeader(http.StatusInternalServerError)
}
}()
err := next(w, r)
if err != nil {
// log error
}
})
}
The next middleware handles authentication and returns an error to the logging middleware.
func AuthFunc(next HandlerFunc) HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) error {
if r.GET("JWT") == "" {
return fmt.Errorf("No JWT")
}
return next(w, r)
}
}
I keep getting errors like
cannot use AuthFunc (type func(handlers.HandlerFunc) http.Handler) as type mux.MiddlewareFunc in argument to r.Use
Thanks
According to the mux.Use doc its argument type is MiddlewareFunc which return type is http.Handler not error type. You have to define which return type is http.HandlerFunc
type Middleware func(http.HandlerFunc) http.HandlerFunc
func main() {
r := mux.NewRouter()
// execute middleware from right to left of the chain
chain := Chain(SayHello, AuthFunc(), LoggingFunc())
r.HandleFunc("/", chain)
println("server listening : 8000")
http.ListenAndServe(":8000", r)
}
// Chain applies middlewares to a http.HandlerFunc
func Chain(f http.HandlerFunc, middlewares ...Middleware) http.HandlerFunc {
for _, m := range middlewares {
f = m(f)
}
return f
}
func LoggingFunc() Middleware {
return func(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// Loggin middleware
defer func() {
if _, ok := recover().(error); ok {
w.WriteHeader(http.StatusInternalServerError)
}
}()
// Call next middleware/handler in chain
next(w, r)
}
}
}
func AuthFunc() Middleware {
return func(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if r.Header.Get("JWT") == "" {
fmt.Errorf("No JWT")
return
}
next(w, r)
}
}
}
func SayHello(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "Hello client")
}
It will execute the LogginFunc then AuthFunc and then SayHello method which is your desire method after passing all those middlewares.
I would like to ask if we can create 'middleware' functions for Go http client? Example I want to add a log function, so every sent request will be logged, or add setAuthToken so the token will be added to each request's header.
You can use the Transport parameter in HTTP client to that effect, with a composition pattern, using the fact that:
http.Client.Transport defines the function that will handle all HTTP requests;
http.Client.Transport has interface type http.RoundTripper, and can thus be replaced with your own implementation;
For example:
package main
import (
"fmt"
"net/http"
)
// This type implements the http.RoundTripper interface
type LoggingRoundTripper struct {
Proxied http.RoundTripper
}
func (lrt LoggingRoundTripper) RoundTrip(req *http.Request) (res *http.Response, e error) {
// Do "before sending requests" actions here.
fmt.Printf("Sending request to %v\n", req.URL)
// Send the request, get the response (or the error)
res, e = lrt.Proxied.RoundTrip(req)
// Handle the result.
if (e != nil) {
fmt.Printf("Error: %v", e)
} else {
fmt.Printf("Received %v response\n", res.Status)
}
return
}
func main() {
httpClient := &http.Client{
Transport: LoggingRoundTripper{http.DefaultTransport},
}
httpClient.Get("https://example.com/")
}
Feel free to alter names as you wish, I did not think on them for very long.
I worked on a project that had similar requirement so I built a middleware pipeline library that allows setting multiple middleware to the http client. You can check it out here.
Using the library, you would solve this in the following way
type LoggingMiddleware struct{}
func (s LoggingMiddleware) Intercept(pipeline pipeline.Pipeline, req *http.Request) (*http.Response, error) {
body, _ := httputil.DumpRequest(req, true)
log.Println(fmt.Sprintf("%s", string(body)))
/*
If you want to perform an action based on the response, do the following
resp, err = pipeline.Next
// perform some action
return resp, err
*/
return pipeline.Next(req)
}
transport := pipeline.NewCustomTransport(&LoggingMiddleware{})
client := &http.Client{Transport: transport}
resp, err := client.Get("https://example.com")
if err != nil {
// handle err
}
fmt.Println(resp.Status)
I wrote a small tutorial/library to do just that https://github.com/HereMobilityDevelopers/mediary
Here is some basic usage example:
client := mediary.Init().AddInterceptors(dumpInterceptor).Build()
client.Get("https://golang.org")
func dumpInterceptor(req *http.Request, handler mediary.Handler) (*http.Response, error) {
if bytes, err := httputil.DumpRequestOut(req, true); err == nil {
fmt.Printf("%s", bytes)
//GET / HTTP/1.1
//Host: golang.org
//User-Agent: Go-http-client/1.1
//Accept-Encoding: gzip
}
return handler(req)
}
There is also an explanation here https://github.com/HereMobilityDevelopers/mediary/wiki/Reasoning
Good idea! Here is a simple implementation of HTTP service middleware in Go.
Usually a simple http service framework is to register a bunch of routes, and then call different logics to process them according to the routes.
But in fact, there may be some unified processing involving almost all routes, such as logs, permissions, and so on.
So it is a good idea to engage in intermediate preprocessing at this time.
Define a middleware unit:
package main
import (
"net/http"
)
// AdaptorHandle middleware func type
type AdaptorHandle func(w http.ResponseWriter, r *http.Request) (next bool, err error)
// MiddleWareAdaptor router middlewares mapped by url
type MiddleWareAdaptor struct {
URLs map[string][]AdaptorHandle
}
// MakeMiddleWareAdaptor make a middleware adaptor
func MakeMiddleWareAdaptor() *MiddleWareAdaptor {
mwa := &MiddleWareAdaptor{
URLs: make(map[string][]AdaptorHandle),
}
return mwa
}
// Regist regist a adaptor
func (mw *MiddleWareAdaptor) Regist(url string, Adaptor ...AdaptorHandle) {
for _, adp := range Adaptor {
mw.URLs[url] = append(mw.URLs[url], adp)
// mw.URLs[url] = adp
}
}
// Exec exec middleware adaptor funcs...
func (mw *MiddleWareAdaptor) Exec(url string, w http.ResponseWriter, r *http.Request) (bool, error) {
if adps, ok := mw.URLs[url]; ok {
for _, adp := range adps {
if next, err := adp(w, r); !next || (err != nil) {
return next, err
}
}
}
return true, nil
}
Then wrap the route processing function with a middleware entry:
func middlewareHandler(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// before call handler
start := time.Now()
do, _ := mwa.Exec(r.URL.Path, w, r) // exec middleware
// call next handler
if do {
log.Println("middleware done. next...")
next.ServeHTTP(w, r)
} else {
log.Println("middleware done.break...")
}
// after call handle
log.Printf("Comleted %s in %v", r.URL.Path, time.Since(start))
})
}
mux.Handle("/", middlewareHandler(&uPlusRouterHandler{}))
type uPlusRouterHandler struct {
}
func (rh *uPlusRouterHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
...
}
Finally, register the middleware you need:
mwa = MakeMiddleWareAdaptor() // init middleware
mwa.Regist("/", testMWAfunc, testMWAfunc2) // regist middleware
...
func testMWAfunc(w http.ResponseWriter, r *http.Request) (bool, error) {
log.Println("I am Alice Middleware...")
log.Printf("Started %s %s", r.Method, r.URL.Path)
return true, nil
}
func testMWAfunc2(w http.ResponseWriter, r *http.Request) (bool, error) {
log.Println("I am Ben Middleware...")
return false, nil // return false,break follow-up actions.
}
This can be achieved using closure functions. It's probably more clear with an example:
package main
import (
"fmt"
"net/http"
)
func main() {
http.HandleFunc("/hello", logged(hello))
http.ListenAndServe(":3000", nil)
}
func logged(f func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
fmt.Println("logging something")
f(w, r)
fmt.Println("finished handling request")
}
}
func hello(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "<h1>Hello!</h1>")
}
credit goes to: http://www.calhoun.io/5-useful-ways-to-use-closures-in-go/
I'd like to use httprouter with muxchain while keeping route parameters like /:user/.
Take the following example:
func log(res http.ResponseWriter, req *http.Request) {
fmt.Println("some logger")
}
func index(res http.ResponseWriter, req *http.Request) {
fmt.Fprintf(res, "Hi there, I love %s!", req.URL.Path[1:])
}
func main() {
logHandler := http.HandlerFunc(log)
indexHandler := http.HandlerFunc(index)
chain := muxchain.ChainHandlers(logHandler, indexHandler)
router := httprouter.New()
router.Handler("GET", "/:user", chain)
http.ListenAndServe(":8080", router)
}
When I visit http://localhost:8080/john I obviously don't have access to ps httprouter.Params
That's because httprouter needs to see type httprouter.Handle but the function is called with type http.Handler.
Is there any way to use both packages together? The HttpRouter GitHub repo says
The only disadvantage is, that no parameter values can be retrieved when a http.Handler or http.HandlerFunc is used, since there is no efficient way to pass the values with the existing function parameters.
If you strongly want to use that packages, you can try to do something like that:
package main
import (
"fmt"
"github.com/gorilla/context"
"github.com/julienschmidt/httprouter"
"github.com/stephens2424/muxchain"
"net/http"
)
func log(res http.ResponseWriter, req *http.Request) {
fmt.Printf("some logger")
}
func index(res http.ResponseWriter, req *http.Request) {
p := context.Get(req, "params").(httprouter.Params)
fmt.Fprintf(res, "Hi there, I love %s!", p.ByName("user"))
}
func MyContextHandler(h http.Handler) httprouter.Handle {
return func(res http.ResponseWriter, req *http.Request, p httprouter.Params) {
context.Set(req, "params", p)
h.ServeHTTP(res, req)
}
}
func main() {
logHandler := http.HandlerFunc(log)
indexHandler := http.HandlerFunc(index)
chain := muxchain.ChainHandlers(logHandler, indexHandler)
router := httprouter.New()
router.GET("/:user", MyContextHandler(chain))
http.ListenAndServe(":8080", router)
}
You would have to patch muxchain to accept httprouter.Handle, but it's rather simple to create your own chain handler, for example:
func chain(funcs ...interface{}) httprouter.Handle {
return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
for _, h := range funcs {
switch h := h.(type) {
case httprouter.Handle:
h(w, r, p)
case http.Handler:
h.ServeHTTP(w, r)
case func(http.ResponseWriter, *http.Request):
h(w, r)
default:
panic("wth")
}
}
}
}
playground