gorilla/mux requests not matching URL pattern

Question

I'm visiting some old code for a simple webserver I wrote some time ago, and my request patterns are no longer working. I have a function that initializes my routes as follows:

func (a *App) InitializeRoutes() {
    a.Router.HandleFunc("/api/forecast/detailed?city={city}&state={state}&period={period}", a.DetailedForecast).Methods("GET")
    a.Router.HandleFunc("/api/forecast/detailed?city={city}&state={state}", a.DetailedForecast).Methods("GET")
    a.Router.HandleFunc("/api/forecast/detailed?random", a.RandomDetailedForecast).Methods("GET")
    a.Router.HandleFunc("/api/forecast/hourly?city={city}&state={state}&hours={hours}", a.HourlyForecast).Methods("GET")
    a.Router.HandleFunc("/api/forecast/hourly?city={city}&state={state}", a.HourlyForecast).Methods("GET")
    a.Router.NotFoundHandler = http.HandlerFunc(a.Custom404Handler)
}

My custom 404 handler just returns a json of {"error": "Not Found"}

From here, I initialize these routes at the end of my app's initialize function (bottom 3 lines):

func (a *App) Initialize() {
    var err error
    conf.configure()
    sqlDataSource := fmt.Sprintf(
        "postgres://%s:%s@%s:%s/%s?sslmode=disable",
        conf.sqlUsername,
        conf.sqlPassword,
        conf.sqlHost,
        conf.sqlPort,
        conf.sqlDbName)
    a.DB, err = sql.Open("postgres", sqlDataSource)
    if err != nil {
        log.Fatal(err)
    }
    a.Redis = redis.NewClient(&redis.Options{
        Addr:     fmt.Sprintf("%s:%s", conf.redisHost, conf.redisPort),
        Password: conf.redisPassword,
        DB:       conf.redisDb,
    })
    a.Router = mux.NewRouter()
    a.Logger = handlers.CombinedLoggingHandler(os.Stdout, a.Router)
    a.InitializeRoutes()
}

My app runs on the following function:

func (a *App) Run() {
    port := fmt.Sprintf(":%s", os.Getenv("SERVER_PORT"))
    log.Fatal(http.ListenAndServe(port, a.Logger))
}

And my server runs on:

func main() {
    a := App{}
    a.Initialize()
    a.Run()
}

When I try and make a request to what as far as I can tell is a valid URL pattern, I get the following:

>>> import requests
>>> r = requests.get("http://localhost:8000/api/forecast/detailed?city=Chicago&state=IL")
>>> r
<Response [404]>
>>> r.json()
{'error': 'Not Found'}

EDIT

I made the change to move the query out of the URL. My routes now look like this:

a.Router.HandleFunc("/api/forecast/detailed", a.DetailedForecast).Queries("city", "{city:[a-zA-Z+]+}", "state", "{state:[a-zA-Z+]+}", "period", "{period:[a-zA-Z+]+}").Schemes("http").Methods("GET")
a.Router.HandleFunc("/api/forecast/detailed", a.DetailedForecast).Queries("city", "{city:[a-zA-Z+]+}", "state", "{state:[a-zA-Z+]+}").Schemes("http").Methods("GET")
a.Router.HandleFunc("/api/forecast/detailed/random", a.RandomDetailedForecast).Schemes("http").Methods("GET")
a.Router.HandleFunc("/api/forecast/hourly", a.HourlyForecast).Queries("city", "{city:[a-zA-Z+]+}", "state", "{state:[a-zA-Z+]+}", "hours", "{hours:[0-9]+}").Schemes("http").Methods("GET")
a.Router.HandleFunc("/api/forecast/hourly", a.HourlyForecast).Queries("city", "{city:[a-zA-Z+]+}", "state", "{state:[a-zA-Z+]+}").Schemes("http").Methods("GET")

When I make the same request, I am now seeing:

Get : unsupported protocol scheme ""

I've inspected the URL to see what is being sent:

2020/02/20 18:19:41 Scheme is:
2020/02/20 18:19:41 Host is:
2020/02/20 18:19:41 Path is: /api/forecast/detailed
2020/02/20 18:19:41 Query is: city=Chicago&state=IL

The path and the query look correct, but I do not understand why the scheme is invalid. My request is still r = requests.get("http://localhost:8000/api/forecast/detailed?city=Chicago&state=IL")

HandleFunc takes a path only, no query params etc. For query params use Route.Queries. — mkopriva
@mkopriva is that a recent change to gorilla? I don't seem to recall having that issue before. — K Pekosh
I've never used gorilla/mux so I really don't know. If you care enough, you can go to their github page and search through the commits. — mkopriva

Lucas Katayama Lucas Katayama · Accepted Answer · 2020-02-20T17:35:57

From the README... To match queries you need to use

r := mux.NewRouter()
...
r.Queries("key", "value")

To match PathPrefix

r.PathPrefix("/products/")

I think you need to combine those two to achieve what you want.

gorilla/mux requests not matching URL pattern

1 Answers