Fix: file opening path and directory browsing path of filesystem

[fufuok]

Please provide enough information so that others can review your pull request:

Fixes: #1546

github.com/fufuok/fiber/middleware/filesystem# go test -v
=== RUN   Test_FileSystem
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#01
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#02
=== RUN   Test_FileSystem/Should_be_returns_status_404
=== RUN   Test_FileSystem/Should_be_returns_status_404#01
=== RUN   Test_FileSystem/Should_be_returns_status_200
=== RUN   Test_FileSystem/Should_be_returns_status_403
=== RUN   Test_FileSystem/Should_list_the_directory_contents
=== RUN   Test_FileSystem/Should_list_the_directory_contents#01
=== RUN   Test_FileSystem/Should_be_returns_status_200#01
=== RUN   Test_FileSystem/Should_be_return_status_200
=== RUN   Test_FileSystem/PathPrefix_should_be_applied
--- PASS: Test_FileSystem (0.01s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#02 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_404 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_404#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_403 (0.00s)
    --- PASS: Test_FileSystem/Should_list_the_directory_contents (0.00s)
    --- PASS: Test_FileSystem/Should_list_the_directory_contents#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_return_status_200 (0.00s)
    --- PASS: Test_FileSystem/PathPrefix_should_be_applied (0.00s)
=== RUN   Test_FileSystem_Next
--- PASS: Test_FileSystem_Next (0.00s)
=== RUN   Test_FileSystem_NonGetAndHead
--- PASS: Test_FileSystem_NonGetAndHead (0.00s)
=== RUN   Test_FileSystem_Head
--- PASS: Test_FileSystem_Head (0.00s)
=== RUN   Test_FileSystem_NoRoot
--- PASS: Test_FileSystem_NoRoot (0.00s)
=== RUN   Test_FileSystem_UsingParam
--- PASS: Test_FileSystem_UsingParam (0.00s)
=== RUN   Test_FileSystem_UsingParam_NonFile
--- PASS: Test_FileSystem_UsingParam_NonFile (0.00s)
PASS
ok      github.com/gofiber/fiber/v2/middleware/filesystem       0.065s

[ReneWerner87]

@fufuok can you use https://github.com/gofiber/fiber/blob/master/utils/strings.go#L56 instead of strings.TrimSuffix

[fufuok]

@ReneWerner87
https://github.com/gofiber/fiber/blob/master/middleware/filesystem/filesystem.go#L152

Sure.
I see that strings.TrimSuffix is used in the existing code, in order to maintain consistency with it.
Change all to utils.TrimRight?

[ReneWerner87]

Jo right

[ReneWerner87]

Just use slash as a byte char with single quotes for the second parameter

[fufuok]

github.com/fufuok/fiber/middleware/filesystem# go test -v
=== RUN   Test_FileSystem
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#01
=== RUN   Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#02
=== RUN   Test_FileSystem/Should_be_returns_status_404
=== RUN   Test_FileSystem/Should_be_returns_status_404#01
=== RUN   Test_FileSystem/Should_be_returns_status_200
=== RUN   Test_FileSystem/Should_be_returns_status_403
=== RUN   Test_FileSystem/Should_list_the_directory_contents
=== RUN   Test_FileSystem/Should_list_the_directory_contents#01
=== RUN   Test_FileSystem/Should_be_returns_status_200#01
=== RUN   Test_FileSystem/Should_be_return_status_200
=== RUN   Test_FileSystem/PathPrefix_should_be_applied
--- PASS: Test_FileSystem (0.01s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200_with_suitable_content-type#02 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_404 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_404#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_403 (0.00s)
    --- PASS: Test_FileSystem/Should_list_the_directory_contents (0.00s)
    --- PASS: Test_FileSystem/Should_list_the_directory_contents#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_returns_status_200#01 (0.00s)
    --- PASS: Test_FileSystem/Should_be_return_status_200 (0.00s)
    --- PASS: Test_FileSystem/PathPrefix_should_be_applied (0.00s)
=== RUN   Test_FileSystem_Next
--- PASS: Test_FileSystem_Next (0.00s)
=== RUN   Test_FileSystem_NonGetAndHead
--- PASS: Test_FileSystem_NonGetAndHead (0.00s)
=== RUN   Test_FileSystem_Head
--- PASS: Test_FileSystem_Head (0.00s)
=== RUN   Test_FileSystem_NoRoot
--- PASS: Test_FileSystem_NoRoot (0.00s)
=== RUN   Test_FileSystem_UsingParam
--- PASS: Test_FileSystem_UsingParam (0.00s)
=== RUN   Test_FileSystem_UsingParam_NonFile
--- PASS: Test_FileSystem_UsingParam_NonFile (0.00s)
PASS
ok      github.com/gofiber/fiber/v2/middleware/filesystem       0.059s

Done.
Pass the test again. Please review it.

[welcome]

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