separate public key handler (#64)

internal/api/s2s/user/publickeyget.go

@@ -0,0 +1,45 @@
+package user
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/sirupsen/logrus"
+)
+
+// PublicKeyGETHandler should be served at eg https://example.org/users/:username/main-key.
+//
+// The goal here is to return a MINIMAL activitypub representation of an account
+// in the form of a vocab.ActivityStreamsPerson. The account will only contain the id,
+// public key, username, and type of the account.
+func (m *Module) PublicKeyGETHandler(c *gin.Context) {
+	l := m.log.WithFields(logrus.Fields{
+		"func": "PublicKeyGETHandler",
+		"url":  c.Request.RequestURI,
+	})
+
+	requestedUsername := c.Param(UsernameKey)
+	if requestedUsername == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "no username specified in request"})
+		return
+	}
+
+	// make sure this actually an AP request
+	format := c.NegotiateFormat(ActivityPubAcceptHeaders...)
+	if format == "" {
+		c.JSON(http.StatusNotAcceptable, gin.H{"error": "could not negotiate format with given Accept header(s)"})
+		return
+	}
+	l.Tracef("negotiated format: %s", format)
+
+	// make a copy of the context to pass along so we don't break anything
+	cp := c.Copy()
+	user, err := m.processor.GetFediUser(requestedUsername, cp.Request) // GetFediUser handles auth as well
+	if err != nil {
+		l.Info(err.Error())
+		c.JSON(err.Code(), gin.H{"error": err.Safe()})
+		return
+	}
+
+	c.JSON(http.StatusOK, user)
+}

internal/api/s2s/user/user.go

@@ -40,6 +40,8 @@ const (
 	// Use this anywhere you need to know the username of the user being queried.
 	// Eg https://example.org/users/:username
 	UsersBasePathWithUsername = UsersBasePath + "/:" + UsernameKey
+	// UsersPublicKeyPath is a path to a user's public key, for serving bare minimum AP representations.
+	UsersPublicKeyPath = UsersBasePathWithUsername + "/" + util.PublicKeyPath
 	// UsersInboxPath is for serving POST requests to a user's inbox with the given username key.
 	UsersInboxPath = UsersBasePathWithUsername + "/" + util.InboxPath
 	// UsersFollowersPath is for serving GET request's to a user's followers list, with the given username key.
@@ -80,5 +82,6 @@ func (m *Module) Route(s router.Router) error {
 	s.AttachHandler(http.MethodGet, UsersFollowersPath, m.FollowersGETHandler)
 	s.AttachHandler(http.MethodGet, UsersFollowingPath, m.FollowingGETHandler)
 	s.AttachHandler(http.MethodGet, UsersStatusPath, m.StatusGETHandler)
+	s.AttachHandler(http.MethodGet, UsersPublicKeyPath, m.PublicKeyGETHandler)
 	return nil
 }