Serve static files with golang - go

I'm trying to develop a simple web application but I'mhaving problem with serving my static files.
The file structure is:
main
--main.go
-serve
--listenAndServe.go
--templates
---login.html
---assets
----css
----fonts
----js
my code is this:
import (
"log"
"net/http"
"time"
"github.com/gorilla/mux"
)
var (
router = mux.NewRouter()
)
func (c *Conn) ListenAndServe() {
fs := http.FileServer(http.Dir("./templates/assets"))
http.Handle("/assets/", http.StripPrefix("/assets/", fs))
router.HandleFunc("/", c.IndexPageHandler)
router.HandleFunc("/login.html", c.LoginPageHandler)
log.Println("Listening...")
http.Handle("/", router)
muxWithMiddlewares := http.TimeoutHandler(router, time.Minute*30,
"Timeout!")
http.ListenAndServe(":8080", muxWithMiddlewares)
}
But for some reason when I run it from main.go it serves the html but not the assets. I would really apreciate some tips. Thanks!

Try This:
mux.Handle("/static/", http.StripPrefix("/static", fileServer))
Note that static, in your case assets only has a single forward slash within the stripPreFix function.
Hope this helps.

Related

Blank page when using swaggo/http-swagger with julienschmidt/httprouter

I am making an api and used swaggo/swag to build a swagger interface. Previously, I used the net/http package, and everything was working fine.
I switched to julienschmidt/httprouter, but I don't manage to make the swagger interface work again. Here is my code
package main
import (
"fmt"
"log"
"net/http"
"github.com/julienschmidt/httprouter"
httpSwagger "github.com/swaggo/http-swagger"
)
func main() {
router := httprouter.New()
router.ServeFiles("/api/doc/static/*filepath", http.Dir("api/swagger/static"))
router.HandlerFunc(http.MethodGet, "/api/doc/index.html", swaggerHandler)
// router.HandlerFunc(http.MethodGet, "/api/doc", swaggerHandler)
fmt.Println("Server on port 8080")
log.Fatal(http.ListenAndServe(":8080", router))
}
func swaggerHandler(w http.ResponseWriter, r *http.Request) {
swaggerFileUrl := "http://localhost:8080/api/doc/static/swagger.json"
handler := httpSwagger.Handler(httpSwagger.URL(swaggerFileUrl))
handler.ServeHTTP(w, r)
}
I checked if swaggerFileUrl variable is correct, and I am able to access the json file with this url. The interface is a complete blank page titled "Swagger UI". Because the title is replaced, I am assuming, that something happened, but I don't know if the issue comes from httpSwagger or httprouter.
Edit: Issue is caused because javascript files loading the interface are not present. See this github issue
You can do it like this:
routes := httprouter.New()
routes.GET("/doc/:any", swaggerHandler)
func swaggerHandler(res http.ResponseWriter, req *http.Request, p httprouter.Params) {
httpSwagger.WrapHandler(res, req)
}
Do not forget import doc files
import (
_ "example.project/docs"
)

go 1.16 embed - strip directory name

i was previously using statik to embed files into a Go application.
with Go 1.16 i can remove that deps
for example:
//go:embed static
var static embed.FS
fs := http.FileServer(http.FS(static))
http.Handle("/", fs)
this will serve the ./static/ directory from http://.../static/
Is there a way I can serve that directory from / root path, without /static?
Use fs.Sub:
Sub returns an FS corresponding to the subtree rooted at fsys's dir.
package main
import (
"embed"
"io/fs"
"log"
"net/http"
)
//go:embed static
var static embed.FS
func main() {
subFS, _ := fs.Sub(static, "static")
http.Handle("/", http.FileServer(http.FS(subFS)))
log.Fatal(http.ListenAndServe(":4000", nil))
}
fs.Sub is also useful in combination with http.StripPrefix to "rename" a directory. For instance, to "rename" the directory static to public, such that a request for /public/index.html serves static/index.html:
//go:embed static
var static embed.FS
subFS, _ := fs.Sub(static, "static")
http.Handle("/", http.StripPrefix("/public", http.FileServer(http.FS(subFS))))
Alternatively, create a .go file in the static directory and move the embed directive there (//go:embed *). That matches a little more closely what the statik tool does (it creates a whole new package), but is usually unnecessary thanks to fs.Sub.
// main.go
package main
import (
"my.module/static"
"log"
"net/http"
)
func main() {
http.Handle("/", http.FileServer(http.FS(static.FS)))
log.Fatal(http.ListenAndServe(":4000", nil))
}
// static/static.go
package static
import "embed"
//go:embed *
var FS embed.FS

Golang routing in different controllers

I am new to Golang and I am trying to learn how to do efficient routing. For instance I have a controller folder/directory and inside that controller I want to have different Func/methods with their own unique routes but I do not know how to do that. I have downloaded the github.com/gorilla/mux package and my application looks like this
The main section of my application looks like this and it is working perfectly: tim.go
package main
import(
"net/http"
"fmt"
"github.com/gorilla/mux"
)
func HomeHandler(writer http.ResponseWriter, req *http.Request) {
writer.WriteHeader(200)
fmt.Fprintf(writer, "Home!!!\n")
}
func main() {
r := mux.NewRouter()
r.HandleFunc("/home", HomeHandler).Name("bob")
http.Handle("/",r)
http.ListenAndServe(":8000", nil)
}
The issue is how can I get the func/methods inside my Controller file(s) to also display on the browser. My sample.go file does not show in the browser when I go to that URL
package Controllers
import(
"net/http"
"fmt"
"github.com/gorilla/mux"
)
func HomeHandler(writer http.ResponseWriter, req *http.Request) {
writer.WriteHeader(200)
fmt.Fprintf(writer, "New Home")
}
func main() {
r := mux.NewRouter()
r.HandleFunc("/new", HomeHandler).Name("bob")
http.Handle("/",r)
http.ListenAndServe(":8000/new", nil)
}
When I go into my browser and type localhost:8000/new it says file not found. Any suggestions would be great
I suppose you run the tim.go file to start the server.
If so, the problem is you don't have the route you're calling /new, you should have an answer with /home.
To do it, you should move your HomeHandler function to Controllers package and then import this package in your main ad instantiate the routes you need.
Hope this helps.

Put the http.Handler in martini

How do I integrate just like http.FileServer with martini?
` package main
import (
"github.com/go-martini/martini"
"net/http"
)
func main() {
m := martini.Classic()
//http.Handle("/", http.FileServer(http.Dir("."))) //It doesn't work!
m.Run()
}`
I believe the FileServer isn't used directly in Martini: see issues/20:
Unfortunately The fileserver middleware throws a 404 if there is no match, which means we will need to roll our own
Hence PR 26 and commit a945713 in static.go that you can see in static_test.go
m := New()
r := NewRouter()
m.Use(Static(currentRoot))
m.Action(r.Handle)

Profiling Go web application built with Gorilla's mux with net/http/pprof

I have a relatively big web application written in Go that uses Gorilla's mux for routing. I recently realised that my web application is quite slow and I would like to profile the web application.
After reading about it, it seems that net/http/pprof is what I need. But I can't make it run with mux; even in the case of the most trivial web application.
Does anyone knows how to make that work?
Here is an example of a trivial code that does not work (i.e. nothing is served at /debug).
package main
import (
"fmt"
"github.com/gorilla/mux"
"math"
"net/http"
)
import _ "net/http/pprof"
func SayHello(w http.ResponseWriter, r *http.Request) {
for i := 0; i < 1000000; i++ {
math.Pow(36, 89)
}
fmt.Fprint(w, "Hello!")
}
func main() {
r := mux.NewRouter()
r.HandleFunc("/hello", SayHello)
http.ListenAndServe(":6060", r)
}
My preferred method for this is to just let net/http/pprof register itself to http.DefaultServeMux, and then pass all requests starting with /debug/pprof/ along:
package main
import (
"net/http"
_ "net/http/pprof"
"github.com/gorilla/mux"
)
func main() {
router := mux.NewRouter()
router.PathPrefix("/debug/pprof/").Handler(http.DefaultServeMux)
if err := http.ListenAndServe(":6060", router); err != nil {
panic(err)
}
}
I find that this approach is a lot more stable than one that depends on the implementation of a hidden initialization method, and also guarantees that you didn't miss anything.
user983716 - Thanks for your question and solution!
I was not able to use the links from the web index (http://[my-server]/debug/pprof), until I added a few lines to your solution, like so:
...
func AttachProfiler(router *mux.Router) {
router.HandleFunc("/debug/pprof/", pprof.Index)
router.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
router.HandleFunc("/debug/pprof/profile", pprof.Profile)
router.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
// Manually add support for paths linked to by index page at /debug/pprof/
router.Handle("/debug/pprof/goroutine", pprof.Handler("goroutine"))
router.Handle("/debug/pprof/heap", pprof.Handler("heap"))
router.Handle("/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
router.Handle("/debug/pprof/block", pprof.Handler("block"))
}
...
If anyone has the same problem, I hope this helps!
Sorry for that question. The answer is in the init() function of pprof. One just need to add 4 functions from pprof to the mux router. Here is the fixed code from above.
package main
import (
"fmt"
"github.com/gorilla/mux"
"math"
"net/http"
)
import "net/http/pprof"
func AttachProfiler(router *mux.Router) {
router.HandleFunc("/debug/pprof/", pprof.Index)
router.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
router.HandleFunc("/debug/pprof/profile", pprof.Profile)
router.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
}
func SayHello(w http.ResponseWriter, r *http.Request) {
for i := 0; i < 1000000; i++ {
math.Pow(36, 89)
}
fmt.Fprint(w, "Hello!")
}
func main() {
r := mux.NewRouter()
AttachProfiler(r)
r.HandleFunc("/hello", SayHello)
http.ListenAndServe(":6060", r)
}
Previous examples not really work on my side.
To use pprof in an existing golang project with gorrila/mux, try to add :
...previous code
func main() {
r := mux.NewRouter()
r.HandleFunc("/hello", SayHello)
go func() {
log.Fatal(http.ListenAndServe(":6061", http.DefaultServeMux))
}()
http.ListenAndServe(":6060", r)
}
then go to http://localhost:6061/debug/pprof/
I did something else, I added another native http server on a different port and it just works out of the box
package main
import (
"fmt"
"log"
"net/http"
_ "net/http/pprof"
)
func main() {
go func() {
log.Println(http.ListenAndServe(":6060", nil))
}()
log.Fatalln(http.ListenAndServe(":8080", route.Handlers()))
}
Now the pprof endpoint is at :
http://localhost:6060/debug/pprof/ and the applcation is running on port :8080
Just so:
r := mux.NewRouter()
r.PathPrefix("/debug").Handler(http.DefaultServeMux)
Im using https://github.com/julienschmidt/httprouter but i just got this answer from google search.
That's what i did
router := httprouter.New()
router.Handler("GET", "/debug/pprof/profile", http.DefaultServeMux)
router.Handler("GET", "/debug/pprof/heap", http.DefaultServeMux)
I only need this two routes.
This answer is combine of #damien and #user983716 answers.
The following should work:
import (
"net/http"
_ "net/http/pprof"
)
myrouter.PathPrefix("/debug/pprof/").Handler(http.DefaultServeMux)

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