underbbs/server/api.go

package server

import (
	"encoding/json"
	"errors"
	"fmt"
	"forge.lightcrystal.systems/lightcrystal/underbbs/adapter"
	"forge.lightcrystal.systems/lightcrystal/underbbs/models"
	"hacklab.nilfm.cc/quartzgun/renderer"
	"hacklab.nilfm.cc/quartzgun/router"
	"hacklab.nilfm.cc/quartzgun/util"
	"html/template"
	"log"
	"net/http"
	"strings"
)

func getSubscriberKey(req *http.Request) (string, error) {
	authHeader := req.Header.Get("Authorization")
	if strings.HasPrefix(authHeader, "Bearer ") {
		return strings.Split(authHeader, "Bearer ")[1], nil
	}
	return "", errors.New("No subscriber key")
}

func getSubscriberByKey(key string, subscribers map[*Subscriber][]adapter.Adapter) *Subscriber {
	for s, _ := range subscribers {
		if s.key == key {
			return s
		}
	}
	return nil
}

func setAdaptersForSubscriber(key string, adapters []adapter.Adapter, subscribers map[*Subscriber][]adapter.Adapter) error {
	var ptr *Subscriber = nil
	log.Print("looking for subscriber in map...")
	for s, _ := range subscribers {
		if s.key == key {
			ptr = s
		}
	}
	if ptr != nil {
		log.Print("setting adaters for the found subscriber: " + ptr.key)
		subscribers[ptr] = adapters
		return nil
	}
	return errors.New("subscriber not present in map")
}

func apiConfigureAdapters(next http.Handler, subscribers map[*Subscriber][]adapter.Adapter) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		// get subscriber key
		skey, err := getSubscriberKey(req)
		if err != nil {
			w.WriteHeader(500)
			return
		}
		subscriber := getSubscriberByKey(skey, subscribers)
		if subscriber == nil {
			w.WriteHeader(404)
			return
		}
		// decode adapter config from request body
		settings := make([]models.Settings, 0)
		err = json.NewDecoder(req.Body).Decode(&settings)
		if err != nil {
			w.WriteHeader(400)
			next.ServeHTTP(w, req)
			return
		}
		// iterate through settings and create adapters
		adapters := make([]adapter.Adapter, 0)
		for _, s := range settings {
			var a adapter.Adapter
			switch s.Protocol {
			case "nostr":
				a = &adapter.NostrAdapter{}
			case "mastodon":
				a = &adapter.MastoAdapter{}
			case "misskey":
				a = &adapter.MisskeyAdapter{}
			default:
				break

			}
			err := a.Init(s, &subscriber.data)
			if err != nil {
				util.AddContextValue(req, "data", err.Error())
				w.WriteHeader(500)
				next.ServeHTTP(w, req)
				return
			}

			log.Print("adapter initialized - subscribing with default filter")

			errs := a.Subscribe(a.DefaultSubscriptionFilter())
			if errs != nil {
				errMsg := ""
				for _, e := range errs {
					log.Print("processing an error")
					errMsg += fmt.Sprintf("- %s\n", e.Error())
				}
				util.AddContextValue(req, "data", errMsg)
				w.WriteHeader(500)
				next.ServeHTTP(w, req)
				return
			}

			log.Print("adapter ready for use; adding to array")

			adapters = append(adapters, a)
			log.Print("adapter added to array")
		}

		// TODO: cancel subscriptions on any existing adapters
		// store the adapters in the subscriber map
		err = setAdaptersForSubscriber(skey, adapters, subscribers)
		if err != nil {
			util.AddContextValue(req, "data", err.Error())
			w.WriteHeader(500)
			next.ServeHTTP(w, req)
		}

		w.WriteHeader(201)
		next.ServeHTTP(w, req)
	})
}

func apiGetAdapters(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(201)
		next.ServeHTTP(w, req)
	})
}

func apiAdapterSubscribe(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(201)
		next.ServeHTTP(w, req)
	})
}

func ProtectWithSubscriberKey(next http.Handler, subscribers map[*Subscriber][]adapter.Adapter) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		authHeader := req.Header.Get("Authorization")
		if strings.HasPrefix(authHeader, "Bearer ") {
			subscriberKey := strings.Split(authHeader, "Bearer ")[1]
			if getSubscriberByKey(subscriberKey, subscribers) != nil {
				next.ServeHTTP(w, req)
				return
			}
		}
		w.WriteHeader(http.StatusUnauthorized)
	})
}

func apiAdapterFetch(next http.Handler, subscribers map[*Subscriber][]adapter.Adapter) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		authHeader := req.Header.Get("Authorization")
		if strings.HasPrefix(authHeader, "Bearer ") {
			subscriberKey := strings.Split(authHeader, "Bearer ")[1]
			s := getSubscriberByKey(subscriberKey, subscribers)
			if s != nil {
				apiParams := req.Context().Value("params").(map[string]string)
				queryParams := req.URL.Query()
				for _, a := range subscribers[s] {
					if a.Name() == apiParams["adapter_id"] {
						err := a.Fetch(queryParams["entity_type"][0], queryParams["entity_id"])
						if err != nil {
							log.Print(err.Error())
							w.WriteHeader(http.StatusInternalServerError)
						} else {
							w.WriteHeader(http.StatusAccepted)
						}
						next.ServeHTTP(w, req)
						return
					}
				}
			}
		}
		w.WriteHeader(http.StatusUnauthorized)
	})
}

func (self *BBSServer) apiMux() http.Handler {
	errTemplate, err := template.New("err").Parse("{{ $params := (.Context).Value \"params\" }}<html><body><h1>ERROR {{ $params.ErrorCode }}</h1><p class='error'>{{ $params.ErrorMessage }}</p></body></html>")
	if err != nil {
		panic("error template was malformed")
	}
	rtr := &router.Router{
		Fallback: *errTemplate,
	}

	// adapters (POST & GET)
	rtr.Post("/adapters", ProtectWithSubscriberKey(
		apiConfigureAdapters(renderer.JSON("data"), self.subscribers),
		self.subscribers,
	))
	rtr.Get("/adapters", ProtectWithSubscriberKey(
		apiGetAdapters(renderer.JSON("data")),
		self.subscribers,
	))

	// adapters/:name/subscribe
	rtr.Post(`/adapters/(?P<id>\S+)/subscribe`, ProtectWithSubscriberKey(
		apiAdapterSubscribe(renderer.JSON("data")),
		self.subscribers,
	))

	rtr.Get(`/adapters/(?P<adapter_id>\S+)/fetch`, ProtectWithSubscriberKey(
		apiAdapterFetch(renderer.JSON("data"), self.subscribers),
		self.subscribers,
	))

	return http.HandlerFunc(rtr.ServeHTTP)
}