jsonpub/http.go

package main

import (
	"encoding/json"
	"fmt"
	"github.com/gorilla/mux"
	"log"
	"math"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strings"
	"time"
	"willnorris.com/go/webmention"
)

func Serve() {

	hookHandler := func(w http.ResponseWriter, r *http.Request) {
		fmt.Println("Fetch feeds: ", time.Now().Format(time.RFC3339))
		for _, actor := range actors {
			fmt.Println(actor.feed)
			articles, err := allFeedItems(actor.feed)
			if err != nil {
				fmt.Println(actor.feed, err.Error())
				continue
			}
			// Post or update latest 5 article
			for _, article := range (*articles)[0:int(math.Min(float64(len(*articles)-1), 4))] {
				err = actor.PostArticle(article)
				if err != nil {
					fmt.Println("Posting", article, "failed")
				}
			}
		}
	}

	webfingerHandler := func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("content-type", "application/jrd+json; charset=utf-8")
		name := r.URL.Query().Get("resource") // should be something like acct:user@example.com
		urlBaseUrl, _ := url.Parse(baseURL)
		re := regexp.MustCompile(`^acct:(.*)@` + regexp.QuoteMeta(urlBaseUrl.Host) + `$`)
		name = re.ReplaceAllString(name, "$1")
		actor := actors[name]
		if actor == nil && len(defaultActor) > 0 {
			// return default actor
			actor = actors[defaultActor]
		} else if actor == nil {
			// error out if this actor does not exist
			w.WriteHeader(http.StatusNotFound)
			return
		}
		responseMap := make(map[string]interface{})
		responseMap["subject"] = "acct:" + actor.Name + "@" + urlBaseUrl.Host
		// links is a json array with a single element
		var links [1]map[string]string
		link1 := make(map[string]string)
		link1["rel"] = "self"
		link1["type"] = ContentTypeAs2
		link1["href"] = actor.iri
		links[0] = link1
		responseMap["links"] = links
		_ = json.NewEncoder(w).Encode(responseMap)
	}

	inboxHandler := func(w http.ResponseWriter, r *http.Request) {
		activity := make(map[string]interface{})
		err := json.NewDecoder(r.Body).Decode(&activity)
		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		actor := actors[mux.Vars(r)["actor"]]
		if actor == nil {
			// actor doesn't exist
			w.WriteHeader(http.StatusNotFound)
			return
		}
		switch activity["type"] {
		case "Follow":
			actor.Accept(&activity)
		case "Undo":
			{
				if object, ok := activity["object"].(map[string]interface{}); ok {
					if objectType, ok := object["type"].(string); ok && objectType == "Follow" {
						if iri, ok := object["actor"].(string); ok && iri == activity["actor"] {
							_ = actor.RemoveFollower(iri)
							fmt.Println(iri, "unfollowed")
						}
					}
				}
			}
		case "Create":
			{
				if object, ok := activity["object"].(map[string]interface{}); ok {
					inReplyTo, hasReplyToString := object["inReplyTo"].(string)
					id, hasId := object["id"].(string)
					if hasReplyToString && hasId && len(inReplyTo) > 0 && len(id) > 0 && strings.Contains(inReplyTo, actor.iri) {
						// It's an ActivityPub reply
						fmt.Println("Received reply to:", inReplyTo)
						webmentionClient := webmention.New(nil)
						sendWebmention(webmentionClient, actor, id, inReplyTo)
					} else if hasId && len(id) > 0 {
						// May be a mention
						webmentionClient := webmention.New(nil)
						dl, err := webmentionClient.DiscoverLinks(id, "")
						if err != nil {
							return
						}
						// Send Webmentions
						for _, link := range dl {
							sendWebmention(webmentionClient, actor, id, link)
						}
					}
				}
			}
		case "Delete":
			{
				if object, ok := activity["object"].(string); ok && len(object) > 0 && activity["actor"] == object {
					_ = actor.RemoveFollower(object)
				}
			}
		default:
			// Log inbox request
			logInbox(actor, &activity)
		}
		// Return 201
		w.WriteHeader(http.StatusCreated)
	}

	// Add the handlers to a HTTP server
	gorilla := mux.NewRouter()
	gorilla.HandleFunc("/hook", hookHandler).Methods(http.MethodPost)
	gorilla.HandleFunc("/.well-known/webfinger", webfingerHandler)
	gorilla.PathPrefix("/{actor}/inbox").HandlerFunc(inboxHandler).Methods(http.MethodPost)
	http.Handle("/", gorilla)

	log.Fatal(http.ListenAndServe(":8081", nil))
}

func logInbox(actor *Actor, activity *map[string]interface{}) {
	f, err := os.OpenFile(storage+slash+"actors"+slash+actor.Name+slash+"inbox", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return
	}
	defer func() { _ = f.Close() }()
	_ = json.NewEncoder(f).Encode(activity)
	_, _ = f.WriteString("\n---\n")
}

func sendWebmention(client *webmention.Client, actor *Actor, mentioningLink, mentionedLink string) {
	if !strings.Contains(mentionedLink, actor.iri) {
		// Not mention of blog
		return
	}
	endpoint, err := client.DiscoverEndpoint(mentionedLink)
	if err != nil || len(endpoint) < 1 {
		return
	}
	_, err = client.SendWebmention(endpoint, mentioningLink, mentionedLink)
	if err != nil {
		log.Println("Sending webmention to " + mentionedLink + " failed")
		return
	}
	log.Println("Sent webmention to " + mentionedLink)
}