commit 53f4629963069b1872a368c23e3e67c6e76a13e6
Author: Matt Baer <matt@write.as>
Date:   Mon Jul 23 19:49:38 2018 +0200

    Create nodeinfo library

diff --git a/nodeinfo.go b/nodeinfo.go
new file mode 100644
index 0000000..f80b248
--- /dev/null
+++ b/nodeinfo.go
@@ -0,0 +1,80 @@
+package nodeinfo
+
+type (
+	NodeProtocol string
+	NodeService  string
+)
+
+const (
+	// Protocols that can be supported by this node.
+	ProtocolActivityPub NodeProtocol = "activitypub"
+	ProtocolOStatus                  = "ostatus"
+
+	// Services that can be supported (inbound or outbound) by this node's API.
+	ServiceTwitter NodeService = "twitter"
+	ServiceTumblr              = "tumblr"
+)
+
+type Config struct {
+	InfoURL   string
+	Metadata  Metadata
+	Protocols []NodeProtocol
+	Services  Services
+	Software  SoftwareInfo
+}
+
+type (
+	// NodeInfo includes all required node info.
+	NodeInfo struct {
+		Metadata          Metadata       `json:"metadata"`
+		OpenRegistrations bool           `json:"openRegistrations"`
+		Protocols         []NodeProtocol `json:"protocols"`
+		Services          Services       `json:"services"`
+		Software          SoftwareInfo   `json:"software"`
+		Usage             Usage          `json:"usage"`
+		Version           string         `json:"version"`
+	}
+
+	// Metadata for nodeinfo. Properties are based on what Pleroma uses.
+	//
+	// From the spec: Free form key value pairs for software specific values.
+	// Clients should not rely on any specific key present.
+	Metadata struct {
+		NodeName        string `json:"nodeName,omitempty"`
+		NodeDescription string `json:"nodeDescription,omitempty"`
+		Private         bool   `json:"private,omitempty"`
+	}
+
+	Services struct {
+		Inbound  []NodeService `json:"inbound"`
+		Outbound []NodeService `json:"outbound"`
+	}
+
+	SoftwareInfo struct {
+		// Name (canonical) of this server software.
+		Name string `json:"name"`
+		// Version of this server software.
+		Version string `json:"version"`
+	}
+
+	// Usage is usage statistics for this server.
+	Usage struct {
+		Users         UsageUsers `json:"users"`
+		LocalPosts    int        `json:"localPosts,omitempty"`
+		LocalComments int        `json:"localComments,omitempty"`
+	}
+
+	UsageUsers struct {
+		Total          int `json:"total,omitempty"`
+		ActiveHalfYear int `json:"activeHalfyear,omitempty"`
+		ActiveMonth    int `json:"activeMonth,omitempty"`
+	}
+)
+
+func (s Service) BuildInfo() NodeInfo {
+	ni := s.Info
+	ni.OpenRegistrations, _ = s.resolver.IsOpenRegistration()
+	ni.Usage, _ = s.resolver.Usage()
+	ni.Version = profileVer
+	return ni
+}
diff --git a/resolver.go b/resolver.go
new file mode 100644
index 0000000..4fc4bf7
--- /dev/null
+++ b/resolver.go
@@ -0,0 +1,8 @@
+package nodeinfo
+
+type Resolver interface {
+	// IsOpenRegistration returns whether or not registration is open on this node.
+	IsOpenRegistration() (bool, error)
+	// Usage returns usage stats for this node.
+	Usage() (Usage, error)
+}
diff --git a/routes.go b/routes.go
new file mode 100644
index 0000000..dd11b45
--- /dev/null
+++ b/routes.go
@@ -0,0 +1,64 @@
+package nodeinfo
+
+import (
+	"encoding/json"
+	"github.com/writeas/go-webfinger"
+	"log"
+	"net/http"
+)
+
+// NodeInfoPath defines the default path of the nodeinfo handler.
+const NodeInfoPath = "/.well-known/nodeinfo"
+
+type discoverInfo struct {
+	Links []webfinger.Link `json:"links"`
+}
+
+func (s *Service) NodeInfoDiscover(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json; charset=UTF-8")
+
+	i := discoverInfo{
+		Links: []webfinger.Link{
+			{
+				Rel:  profile,
+				HRef: s.InfoURL,
+			},
+		},
+	}
+
+	body, err := json.Marshal(i)
+	if err != nil {
+		log.Printf("Unable to marshal nodeinfo discovery: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+
+	_, err = w.Write(body)
+	if err != nil {
+		log.Printf("Unable to write body: %v", err)
+		return
+	}
+}
+
+func (s *Service) NodeInfo(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json; profile="+profile+"#")
+
+	i := s.BuildInfo()
+
+	body, err := json.Marshal(i)
+	if err != nil {
+		log.Printf("Unable to marshal nodeinfo: %v", err)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+
+	_, err = w.Write(body)
+	if err != nil {
+		log.Printf("Unable to write body: %v", err)
+		return
+	}
+}
diff --git a/service.go b/service.go
new file mode 100644
index 0000000..52c6293
--- /dev/null
+++ b/service.go
@@ -0,0 +1,26 @@
+package nodeinfo
+
+const (
+	profileVer = "2.0"
+	profile    = "http://nodeinfo.diaspora.software/ns/schema/" + profileVer
+)
+
+type Service struct {
+	InfoURL string
+	Info    NodeInfo
+
+	resolver Resolver
+}
+
+func NewService(cfg Config, r Resolver) *Service {
+	return &Service{
+		InfoURL: cfg.InfoURL,
+		Info: NodeInfo{
+			Metadata:  cfg.Metadata,
+			Protocols: cfg.Protocols,
+			Services:  cfg.Services,
+			Software:  cfg.Software,
+		},
+		resolver: r,
+	}
+}