为什么我的fileServer处理程序不起作用？

Question

I've a simple folder :

Test/
    main.go
    Images/
          image1.png
          image2.png
          index.html

In main main.go I just put :

package main

import (
       "net/http"
)

func main(){
     fs := http.FileServer(http.Dir("./Images"))
     http.Handle("/Images/*", fs)
     http.ListenAndServe(":3003", nil)
}

But when I curl on http://localhost:3003/Images/ or even I add to path file's name, it doesn't work. I don't understand because it's the same as the reply given on this subject

Can you tell me so that this does not work ?

Answer 1

You need to remove * and add extra sub-folder Images :
This works fine:

Test/
    main.go
    Images/
          Images/
                image1.png
                image2.png
                index.html

Code:

package main

import (
    "net/http"
)

func main() {
    fs := http.FileServer(http.Dir("./Images"))
    http.Handle("/Images/", fs)
    http.ListenAndServe(":3003", nil)
}

Then go run main.go

And:

http://localhost:3003/Images/

---

Or simply use:

package main

import (
    "net/http"
)

func main() {
    fs := http.FileServer(http.Dir("./Images"))
    http.Handle("/", fs)
    http.ListenAndServe(":3003", nil)
}

with: http://localhost:3003/

Answer 2

The reason the request failed to return what you expected is because they did not match the pattern defined in the http.Handle(pattern string, handler Handler) call. The ServeMux documentation provides a description of how to compose patterns. Any request is prefixed matched from most specific to least specific. It appears as though you have assumed a glob pattern can be used. Your handler would have been invoked with requests to /Images/*<file system path> . You need to define a directory path like so, Images/ .

On a side note, it is worth considering how your program gets the directory path to serve files from. Hard coding a relative means your program will only function within a specific location within the filesystem which incredibly brittle. You could use a command line argument to allow users to specify a path or use a configuration file parsed at runtime. These considerations make your program easy to modularize and test.

Answer 3

Dot in ./Images refer cwd current working directory, not you project root. For your server to work you must run it from Test/ directory, or address Images with absolute rooted path.