echo: Bug: wrong context ParamNames

Go vesion: latest Echo version: latest

Code:

package main

import (
	"fmt"
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"github.com/labstack/gommon/log"
	"net/http"
)

func main() {
	e := echo.New()
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	e.Logger.SetLevel(log.INFO)

	e.GET("/test", func(c echo.Context) error {
		return c.String(http.StatusOK, "GET /test")
	}).Name = "get-test"
	e.GET("/test/:test", func(c echo.Context) error {
		fmt.Printf("%#v\n", c.ParamValues())
		fmt.Printf("%#v\n", c.ParamNames()) // return []string{"test"}
		return c.String(http.StatusOK, "GET /test/:test=" + c.Param("test"))
	}).Name = "get-list-test"
	e.PUT("/test/:id", func(c echo.Context) error {
		fmt.Printf("%#v\n", c.ParamValues())
		fmt.Printf("%#v\n", c.ParamNames()) // return []string{"test"}
		return c.String(http.StatusOK, "PUT /test/:id=" + c.Param("id"))
	}).Name = "put-test"

	e.Logger.Fatal(e.Start(":3000"))
}

And requests:

$ curl  -X GET   http://localhost:3000/test/test
GET /test/:test=test

$ curl  -X PUT   http://localhost:3000/test/test
PUT /test/:id=

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 16 (1 by maintainers)

Most upvoted comments

Any idea when this will be fixed? I feel this is a huge one, basically it makes it impossible to have the same routes for different methods and I end up having to create a different route for every method…

supa-freak on Aug 29, 2019

So how the progress about this fix? It seems this PR request still unfinished and closed https://github.com/labstack/echo/pull/1430

slaveofcode on Jun 21, 2020

As I understand the problem summary is something like this:

Param names and param values are arrays
Param names are bound to route, not to route+method
Param values are getting by finding their position in ctx.pnames position.
The problem can be solved by converting echo.Node.pnames to map or structure like echo.methodHandler and filling ctx.pnames by route+method. So, it’ll be not like ctx.pnames = node.pnames, but something like ctx.pnames = node.GetPnames(methodName)

I’ll try to provide draft PR in a few days

jerrdasur on Oct 24, 2019

It will be addressed in v5, currently this is hard limitation and you need to work around it i.e. do not name params differently for same path.

Naming param differently for same path seems to be situation where you are thinking/using that param conceptionally differently in another method for same path - which seems really odd to me personally. I can not think situation where different names make sense. If it is conceptionally different thing - why do you use same path? Is it not confusing for API users? For example GET /users/:id POST /users/:name feels really really strange thing to do.

aldas on Jul 22, 2021

This is still a problem for us…

skast96 on Feb 24, 2021

It seems like the first added path decides what the paramter-name is. If you add another handler to the same path, the parameter-names are re-used from the first handler.

from context.go: (about line 130)

cn.addHandler(method, h)
cn.ppath = ppath
cn.pnames = pnames

To me it seems that the parameter names are bound to the node across all http-mehtods. And this might just be correct behaviour. Do you really want different parameter-names for different http-methods?

To support different parameter-names for different http-methods, the node struct could have a map of method-params.

nilsmagnus on Mar 21, 2019