routers.go

// Copyright 2022 Coinbase, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Generated by: OpenAPI Generator (https://openapi-generator.tech)

package server

import (
	"encoding/json"
	"net/http"

	"github.com/gorilla/mux"
)

// A Route defines the parameters for an api endpoint
type Route struct {
	Name        string
	Method      string
	Pattern     string
	HandlerFunc http.HandlerFunc
}

// Routes are a collection of defined api endpoints
type Routes []Route

// Router defines the required methods for retrieving api routes
type Router interface {
	Routes() Routes
}

// CorsMiddleware handles CORS and ensures OPTIONS requests are
// handled properly.
//
// This may be used to expose a Rosetta server instance to requests made by web
// apps served over a different domain. Note that his currently allows _all_
// third party domains so callers might want to adapt this middleware for their
// own use-cases.
func CorsMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().
			Set("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept")
		w.Header().Set("Access-Control-Allow-Methods", "GET, POST,OPTIONS")
		if r.Method == "OPTIONS" {
			w.WriteHeader(http.StatusOK)
			return
		}
		next.ServeHTTP(w, r)
	})
}

// NewRouter creates a new router for any number of api routers
func NewRouter(routers ...Router) http.Handler {
	router := mux.NewRouter().StrictSlash(true)
	for _, api := range routers {
		for _, route := range api.Routes() {
			router.
				Methods(route.Method).
				Path(route.Pattern).
				Name(route.Name).
				Handler(route.HandlerFunc)
		}
	}

	return router
}

// EncodeJSONResponse uses the json encoder to write an interface to the http response with an
// optional status code
func EncodeJSONResponse(i interface{}, status int, w http.ResponseWriter) {
	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
	w.WriteHeader(status)

	if err := json.NewEncoder(w).Encode(i); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}