Initial QSfera import

Server/services/webfinger/pkg/relations/qsfera_instance.go

@@ -0,0 +1,88 @@
+package relations
+
+import (
+	"context"
+	"net/url"
+	"regexp"
+	"strings"
+	"text/template"
+
+	"github.com/qsfera/server/pkg/oidc"
+	"github.com/qsfera/server/services/webfinger/pkg/config"
+	"github.com/qsfera/server/services/webfinger/pkg/service/v0"
+	"github.com/qsfera/server/services/webfinger/pkg/webfinger"
+)
+
+const (
+	QsferaInstanceRel = "http://webfinger.qsfera/rel/server-instance"
+)
+
+type compiledInstance struct {
+	config.Instance
+	compiledRegex *regexp.Regexp
+	hrefTemplate  *template.Template
+}
+
+type qsferaInstance struct {
+	instances    []compiledInstance
+	qsferaURL    string
+	instanceHost string
+}
+
+// QsferaInstance adds one or more КуСфера instance relations
+func QsferaInstance(instances []config.Instance, qsferaURL string) (service.RelationProvider, error) {
+	compiledInstances := make([]compiledInstance, 0, len(instances))
+	var err error
+	for _, instance := range instances {
+		compiled := compiledInstance{Instance: instance}
+		compiled.compiledRegex, err = regexp.Compile(instance.Regex)
+		if err != nil {
+			return nil, err
+		}
+		compiled.hrefTemplate, err = template.New(instance.Claim + ":" + instance.Regex + ":" + instance.Href).Parse(instance.Href)
+		if err != nil {
+			return nil, err
+		}
+		compiledInstances = append(compiledInstances, compiled)
+	}
+
+	u, err := url.Parse(qsferaURL)
+	if err != nil {
+		return nil, err
+	}
+	return &qsferaInstance{
+		instances:    compiledInstances,
+		qsferaURL:    qsferaURL,
+		instanceHost: u.Host + u.Path,
+	}, nil
+}
+
+func (l *qsferaInstance) Add(ctx context.Context, _ string, jrd *webfinger.JSONResourceDescriptor) {
+	if jrd == nil {
+		jrd = &webfinger.JSONResourceDescriptor{}
+	}
+	if claims := oidc.FromContext(ctx); claims != nil {
+		if value, ok := claims[oidc.PreferredUsername].(string); ok {
+			jrd.Subject = "acct:" + value + "@" + l.instanceHost
+		} else if value, ok := claims[oidc.Email].(string); ok {
+			jrd.Subject = "mailto:" + value
+		}
+		// allow referencing QSFERA_URL in the template
+		claims["QSFERA_URL"] = l.qsferaURL
+		claims["OC_URL"] = l.qsferaURL
+		for _, instance := range l.instances {
+			if value, ok := claims[instance.Claim].(string); ok && instance.compiledRegex.MatchString(value) {
+				var tmplWriter strings.Builder
+				instance.hrefTemplate.Execute(&tmplWriter, claims)
+				jrd.Links = append(jrd.Links, webfinger.Link{
+					Rel:    QsferaInstanceRel,
+					Href:   tmplWriter.String(),
+					Titles: instance.Titles,
+				})
+				if instance.Break {
+					break
+				}
+			}
+		}
+	}
+}