chore: init

pkg/webfinger/host_meta.go

@@ -0,0 +1,51 @@
+package webfinger
+
+import (
+	"encoding/json"
+	"net/url"
+)
+
+type HostMeta struct {
+	JSON []byte
+	XML  []byte
+}
+
+func NewHostMeta(baseURL *url.URL) HostMeta {
+	template := &url.URL{Path: "/.well-known/webfinger?resource={uri}"}
+	template = baseURL.ResolveReference(template)
+
+	return HostMeta{
+		JSON: generateJSONHostMeta(template),
+		XML:  generateXMLHostMeta(template),
+	}
+}
+
+func generateXMLHostMeta(template *url.URL) []byte {
+	return []byte(`<?xml version="1.0"?>
+	<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
+	<Link rel="lrdd" template="` + template.String() + `" />
+	</XRD>`)
+}
+
+func generateJSONHostMeta(template *url.URL) []byte {
+	b, err := json.Marshal(hostMetaStruct{
+		Links: []hostMetaLink{{
+			Rel:      "lrdd",
+			Template: template.String(),
+		}},
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	return b
+}
+
+type hostMetaStruct struct {
+	Links []hostMetaLink `json:"links"`
+}
+
+type hostMetaLink struct {
+	Rel      string `json:"rel"`
+	Template string `json:"template"`
+}

pkg/webfinger/webfinger.go

@@ -0,0 +1,72 @@
+package webfinger
+
+import (
+	"errors"
+	"net/url"
+	"strings"
+)
+
+var (
+	ErrInvalidSyntax = errors.New("must follow the format \"acct:<ID|Username>@<DOMAIN>\"")
+)
+
+func ParseResource(res string) (*UserID, error) {
+	if !strings.HasPrefix(res, "acct:") {
+		return nil, ErrInvalidSyntax
+	}
+
+	if !strings.Contains(res, "@") {
+		return nil, ErrInvalidSyntax
+	}
+
+	spl := strings.Split(res, "@")
+	if len(spl) != 2 {
+		return nil, ErrInvalidSyntax
+	}
+
+	userID := strings.TrimPrefix(spl[0], "acct:")
+	domain := spl[1]
+
+	return &UserID{userID, domain}, nil
+}
+
+type UserID struct {
+	ID     string
+	Domain string
+}
+
+func (u UserID) String() string {
+	return u.ID + "@" + u.Domain
+}
+
+type Response struct {
+	Subject string `json:"subject,omitempty"`
+	Links   []Link `json:"links,omitempty"`
+
+	Error *string `json:"error,omitempty"`
+}
+
+type Link struct {
+	Relation string `json:"rel"`
+	Type     any    `json:"type"`
+	Link     string `json:"href"`
+}
+
+type User struct {
+	UserID
+
+	URI *url.URL
+
+	Avatar         *url.URL
+	AvatarMIMEType string
+}
+
+func (u User) WebFingerResource() Response {
+	return Response{
+		Subject: "acct:" + u.String(),
+		Links: []Link{
+			{"self", "application/json", u.URI.String()},
+			{"avatar", u.AvatarMIMEType, u.Avatar.String()},
+		},
+	}
+}