Root static resource router not supported

[LoSunny]

Description

This is a follow up of the issue: https://github.com/gin-gonic/gin/issues/2537

How to reproduce

package route

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    var app = gin.Default()

    api.RunRoot(app.Group("/api"))
    app.StaticFS("/", gin.Dir("dist", false))
    app.Run(":8080")
}

Expectations

If the URL starts with the `/api`, then it is handled by the other router, else it searches the file in the `StaticFS`

Actual result

An error occur:
[GIN-debug] GET    /*filepath                --> github.com/gin-gonic/gin.(*RouterGroup).createStaticHandler.func1 (4 handlers)
[GIN-debug] HEAD   /*filepath                --> github.com/gin-gonic/gin.(*RouterGroup).createStaticHandler.func1 (4 handlers)
[GIN-debug] GET    /api/ping                 --> SunnyMovie/server/route/routes/api.RunRoot.func1 (4 handlers)
panic: '/api/ping' in new path '/api/ping' conflicts with existing wildcard '/*filepath' in existing prefix '/*filepath'

Environment

• go version: 1.17
• gin version (or commit ref): v1.7.4
• operating system: MacOS 10.15.7

[automano]

your code snip is not runnable with the error "undeclared name: api"

[LoSunny]

Sorry, this should work

package route

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    var app = gin.Default()

    app.Group("/api").GET("/", func(c *gin.Context) {
        c.JSON(200, gin.H{
            "message": "pong",
        })
    })
    app.StaticFS("/", gin.Dir("dist", false))
    app.Run(":8080")
}

[automano]

Basically, you can't use gin like this and the panic error message already describes your problem. This problem occurs mainly because many golang frameworks use httprouter as their routing module. httprouter uses explicit matching for performance optimization, which causes many wildcards to conflict with specific routes.

app.StaticFS("/", gin.Dir("dist", false)) will register the wildcard /*filename as the router path but this is already occupied by /api app.Group("/api")

I recommend you don't use the root path to serve your static files.

you may find some other similar issues like #1301

[LoSunny]

But according to https://github.com/gin-gonic/gin/pull/2663 , this issue should be been solved

[automano]

Did a careful read and noticed this "This only works for param wildcards of the form :name and doesn't change the existing * " Maybe this is why in your situation there is still conflict error.