actual initial thoughts

.gitignore

@@ -0,0 +1 @@
+config.json

finger.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Resource struct {
+	Subject    string            `json:"subject"`
+	Aliases    []string          `json:"aliases,omitempty"`
+	Properties map[string]string `json:"properties,omitempty"`
+	Links      []Links           `json:"links,omitempty"`
+}
+
+type Links struct {
+	Rel  string `json:"rel"`
+	Type string `json:"type,omitempty"`
+	Href string `json:"href,omitempty"`
+}
+
+type Webfinger struct {
+	domain      string
+	username    string
+	accountName string
+}
+
+func NewWebfinger(username string, domain string, aliases ...string) (*Webfinger, error) {
+	return &Webfinger{
+		username:    username,
+		domain:      domain,
+		accountName: fmt.Sprintf("acct:%s@%s", username, domain),
+	}, nil
+}
+
+func (w *Webfinger) FingerResource(name string) (Resource, error) {
+	if !strings.EqualFold(w.accountName, name) {
+		return Resource{}, fmt.Errorf("account not found")
+	}
+	return Resource{
+		Subject: w.accountName,
+		Links: []Links{
+			{
+				Rel:  "self",
+				Type: "application/activity+json",
+				Href: fmt.Sprintf("https://%s/users/%s", w.domain, w.username),
+			},
+		},
+	}, nil
+}

go.mod

@@ -1,3 +1,5 @@
 module git.yetaga.in/alazyreader/friend
 
-go 1.18
+go 1.19
+
+require github.com/go-chi/chi/v5 v5.0.7

go.sum

@@ -0,0 +1,2 @@
+github.com/go-chi/chi/v5 v5.0.7 h1:rDTPXLDHGATaeHvVlLcR4Qe0zftYethFucbjVQ1PxU8=
+github.com/go-chi/chi/v5 v5.0.7/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=

handlers.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+)
+
+func WebFingerHandler(wf *Webfinger) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		requestedResource := r.URL.Query().Get("resource")
+		res, err := wf.FingerResource(requestedResource)
+		if err != nil {
+			w.WriteHeader(http.StatusNotFound)
+			w.Write([]byte(`{"error": "account not found"}`))
+			return
+		}
+		b, err := json.Marshal(res)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		w.Write(b)
+	}
+}
+
+func ProfileHandler(pp *ProfileProvider) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		userID := chi.URLParam(r, "user")
+		res, err := pp.Get(userID)
+		if err != nil {
+			w.WriteHeader(http.StatusNotFound)
+			w.Write([]byte(`{"error": "account not found"}`))
+			return
+		}
+		b, err := json.Marshal(res)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		w.Write(b)
+	}
+}

main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+)
+
+func main() {
+	wf, err := NewWebfinger("dma", "hello.yetaga.in")
+	if err != nil {
+		log.Fatalln(err)
+	}
+	pp, err := NewProfileProvider("hello.yetaga.in")
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	r := chi.NewRouter()
+	r.Get("/.well-known/webfinger", WebFingerHandler(wf))
+	r.Get("/users/{user}", ProfileHandler(pp))
+
+	log.Println("listening on http://0.0.0.0:8008")
+	err = http.ListenAndServe(":8008", r)
+	if err != nil {
+		log.Fatalln(err)
+	}
+}

profile.go

@@ -0,0 +1,68 @@
+package main
+
+import "fmt"
+
+type Actor struct {
+	ID                string `json:"id"`
+	Type              string `json:"type"`
+	URL               string `json:"url"`
+	Name              string `json:"name"`
+	PreferredUsername string `json:"preferredUsername,omitempty"`
+	Summary           string `json:"summary,omitempty"`
+
+	PublicKey PublicKey `json:"publicKey,omitempty"`
+
+	Inbox     string `json:"inbox,omitempty"`
+	Outbox    string `json:"outbo,omitempty"`
+	Followers string `json:"followers,omitempty"`
+	Following string `json:"following,omitempty"`
+
+	Icon  *Link `json:"icon,omitempty"`
+	Image *Link `json:"image,omitempty"`
+
+	Endpoints map[string]string `json:"endpoints,omitempty"`
+}
+
+type Link struct {
+	Type      string `json:"type"`
+	MediaType string `json:"mediaType"`
+	URL       string `json:"url"`
+}
+
+type PublicKey struct {
+	ID           string `json:"id"`
+	Owner        string `json:"owner"`
+	PublicKeyPem string `json:"publicKeyPem"`
+}
+
+type ProfileProvider struct {
+	domain string
+}
+
+func NewProfileProvider(domain string) (*ProfileProvider, error) {
+	return &ProfileProvider{
+		domain: domain,
+	}, nil
+}
+
+func (pp *ProfileProvider) Get(userID string) (*Actor, error) {
+	userRoot := fmt.Sprintf("https://%s/users/%s", pp.domain, userID)
+	return &Actor{
+		ID:        userRoot,
+		Type:      "Person",
+		URL:       fmt.Sprintf("https://%s/@%s", pp.domain, userID),
+		Name:      userID,
+		Inbox:     userRoot + "/inbox",
+		Outbox:    userRoot + "/outbox",
+		Followers: userRoot + "/followers",
+		Following: userRoot + "/following",
+		Endpoints: map[string]string{
+			"sharedInbox": fmt.Sprintf("https://%s/inbox", pp.domain),
+		},
+		PublicKey: PublicKey{
+			ID:           userRoot + "#main-key",
+			Owner:        userRoot,
+			PublicKeyPem: "-----BEGIN PUBLIC KEY-----...-----END PUBLIC KEY-----",
+		},
+	}, nil
+}

signature.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"crypto"
+	"crypto/rand"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+type Signer struct {
+	key   crypto.Signer
+	keyID string
+}
+
+// Sign modifies the request, computing and setting the Signature header, and setting the Date header to the provided time.
+func (s Signer) Sign(r *http.Request, date time.Time) error {
+	host := r.URL.Host
+	path := r.URL.Path
+	method := strings.ToLower(r.Method)
+	stringToSign := fmt.Sprintf("(request-target): %s %s\nhost: %s\ndate: %s", method, path, host, date.Format(time.RFC1123))
+	sig, err := s.key.Sign(rand.Reader, []byte(stringToSign), nil)
+	if err != nil {
+		return err
+	}
+	r.Header.Set("Date", date.Format(time.RFC1123))
+	r.Header.Set("Signature", fmt.Sprintf(`keyId="%s",headers="(request-target) host date",signature="%s"`, s.keyID, sig))
+	return nil
+}

streams.go

@@ -0,0 +1,38 @@
+package main
+
+import "time"
+
+type Stream struct {
+	Context    string     `json:"@context"`
+	ID         string     `json:"id"`
+	Type       string     `json:"type"`
+	TotalItems int        `json:"totalItems"`
+	Items      []struct{} `json:"items"`
+}
+
+type Activity struct {
+	Context   string    `json:"@context"`
+	Summary   string    `json:"summary"`
+	Type      string    `json:"type"`
+	Published time.Time `json:"published"`
+	Actor     Actor     `json:"actor"`
+	Object    *Object   `json:"object,omitempty"`
+	Target    *Object   `json:"target,omitempty"`
+}
+
+type Object struct {
+	ID   string `json:"id"`
+	Type string `json:"type"`
+	URL  string `json:"url"`
+	Name string `json:"name"`
+}
+
+type Streams struct{}
+
+func (s *Streams) Inbox()
+
+func (s *Streams) Outbox()
+
+func (s *Streams) Followers()
+
+func (s *Streams) Followed()