Golang web server not serving static files

Question

I'm fairly certain that I've overlooked something obvious, but I'm not sure what. I'm building a simple web application that serves up templated pages of books. The template works fine, and the path for the image seems to be populating correctly, but I keep getting a 404 error for the image itself.

Here is the template:

<h1>{{.Title}}</h1>
<h2>{{.Author.Name}}</h2>
<image src="../images/{{.ImageURI}}" />

and here is the application itself:

package main
import (
    "html/template"
    "log"
    "net/http"
    "time"

    "github.com/gorilla/mux"
    "github.com/user/marketplace/typelibrary"
)

var books []typelibrary.Book

func ItemHandler(w http.ResponseWriter, r *http.Request) {
    params := mux.Vars(r)
    var selected typelibrary.Book       
    //Retrieve item data
    for _, item := range books {
        if item.ID == params["id"] {
            selected = item
            break
        }
    }
    t, _ := template.ParseFiles("./templates/book.html")
    t.Execute(w, selected)
}

func main() {
    router := mux.NewRouter()
    books = append(books, typelibrary.Book{ID: "1", Title: "The Fellowship of the Ring", ImageURI: "LotR-FotR.jpg", Author: &typelibrary.Author{Name: "JRR Tolkien"}})
    books = append(books, typelibrary.Book{ID: "2", Title: "The Two Towers", ImageURI: "LotR-tTT.jpg", Author: &typelibrary.Author{Name: "JRR Tolkien"}})
    books = append(books, typelibrary.Book{ID: "3", Title: "The Return of the King", ImageURI: "LotR-RotK.jpg", Author: &typelibrary.Author{Name: "JRR Tolkien"}})
    books = append(books, typelibrary.Book{ID: "4", Title: "Monster Hunter International", ImageURI: "MHI1.jpg", Author: &typelibrary.Author{Name: "Larry Correia"}})

    router.Handle("/", http.FileServer(http.Dir(".")))
    router.Handle("/images/", http.FileServer(http.Dir("../images/")))
    router.HandleFunc("/item/{id}", ItemHandler).Methods("GET")

    srv := &http.Server{
        Handler:      router,
        Addr:         ":8080",
        WriteTimeout: 10 * time.Second,
        ReadTimeout:  10 * time.Second,
    }
    log.Fatal(srv.ListenAndServe())
}

The images are stored in the images subdirectory, directly below the directory where the executable is. When I attempt to view the broken image in the page, the path shows up as localhost:8080/images/[imagename] but gives a 404 error. What configuration or routing options am I missing here?

Answer 1

You are creating your route incorrectly to serve your images. The Router.Handle() method matches URLs with the Path() matcher, which matches the entire path, while you actually want to match any path that starts with "/image/". Instead, create the route with the PathPrefix() matcher:

var imgServer = http.FileServer(http.Dir("./images/"))
router.PathPrefix("/images/").Handler(http.StripPrefix("/images/", imgServer))

See https://godoc.org/github.com/gorilla/mux#Router.Handle for more information.