Update KnownHosts documentation

Use (*ResponseWriter).WriteHeader instead.

cert.go

@@ -2,21 +2,28 @@ package gemini
 
 import (
 	"crypto"
+	"crypto/ecdsa"
 	"crypto/ed25519"
+	"crypto/elliptic"
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
 	"math/big"
 	"net"
+	"os"
 	"path/filepath"
 	"strings"
 	"time"
 )
 
-// CertificateStore maps hostnames to certificates.
+// CertificateStore maps certificate scopes to certificates.
 // The zero value of CertificateStore is an empty store ready to use.
 type CertificateStore struct {
 	store map[string]tls.Certificate
+	dir   bool
+	path  string
 }
 
 // Add adds a certificate for the given scope to the store.
@@ -35,17 +42,22 @@ func (c *CertificateStore) Add(scope string, cert tls.Certificate) {
 	c.store[scope] = cert
 }
 
+// Write writes the provided certificate to the certificate directory.
+func (c *CertificateStore) Write(scope string, cert tls.Certificate) error {
+	if c.dir {
+		certPath := filepath.Join(c.path, scope+".crt")
+		keyPath := filepath.Join(c.path, scope+".key")
+		if err := WriteCertificate(cert, certPath, keyPath); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // Lookup returns the certificate for the given scope.
-func (c *CertificateStore) Lookup(scope string) (*tls.Certificate, error) {
+func (c *CertificateStore) Lookup(scope string) (tls.Certificate, bool) {
 	cert, ok := c.store[scope]
-	if !ok {
-		return nil, ErrCertificateUnknown
-	}
-	// Ensure that the certificate is not expired
-	if cert.Leaf != nil && cert.Leaf.NotAfter.Before(time.Now()) {
-		return &cert, ErrCertificateExpired
-	}
-	return &cert, nil
+	return cert, ok
 }
 
 // Load loads certificates from the given path.
@@ -53,6 +65,7 @@ func (c *CertificateStore) Lookup(scope string) (*tls.Certificate, error) {
 // in the form scope.crt and scope.key.
 // For example, the hostname "localhost" would have the corresponding files
 // localhost.crt (certificate) and localhost.key (private key).
+// New certificates will be written to this directory.
 func (c *CertificateStore) Load(path string) error {
 	matches, err := filepath.Glob(filepath.Join(path, "*.crt"))
 	if err != nil {
@@ -67,14 +80,42 @@ func (c *CertificateStore) Load(path string) error {
 		scope := strings.TrimSuffix(filepath.Base(crtPath), ".crt")
 		c.Add(scope, cert)
 	}
+	c.dir = true
+	c.path = path
 	return nil
 }
 
-// CertificateOptions configures how a certificate is created.
+// SetOutput sets the directory that new certificates will be written to.
+func (c *CertificateStore) SetOutput(path string) {
+	c.dir = true
+	c.path = path
+}
+
+// CertificateOptions configures the creation of a certificate.
 type CertificateOptions struct {
+	// Subject Alternate Name values.
+	// Should contain the IP addresses that the certificate is valid for.
 	IPAddresses []net.IP
-	DNSNames    []string
-	Duration    time.Duration
+
+	// Subject Alternate Name values.
+	// Should contain the DNS names that this certificate is valid for.
+	// E.g. example.com, *.example.com
+	DNSNames []string
+
+	// Subject specifies the certificate Subject.
+	//
+	// Subject.CommonName can contain the DNS name that this certificate
+	// is valid for. Server certificates should specify both a Subject
+	// and a Subject Alternate Name.
+	Subject pkix.Name
+
+	// Duration specifies the amount of time that the certificate is valid for.
+	Duration time.Duration
+
+	// Ed25519 specifies whether to generate an Ed25519 key pair.
+	// If false, an ECDSA key will be generated instead.
+	// Ed25519 is not as widely supported as ECDSA.
+	Ed25519 bool
 }
 
 // CreateCertificate creates a new TLS certificate.
@@ -92,15 +133,27 @@ func CreateCertificate(options CertificateOptions) (tls.Certificate, error) {
 
 // newX509KeyPair creates and returns a new certificate and private key.
 func newX509KeyPair(options CertificateOptions) (*x509.Certificate, crypto.PrivateKey, error) {
-	// Generate an ED25519 private key
-	_, priv, err := ed25519.GenerateKey(rand.Reader)
-	if err != nil {
-		return nil, nil, err
+	var pub crypto.PublicKey
+	var priv crypto.PrivateKey
+	if options.Ed25519 {
+		// Generate an Ed25519 private key
+		var err error
+		pub, priv, err = ed25519.GenerateKey(rand.Reader)
+		if err != nil {
+			return nil, nil, err
+		}
+	} else {
+		// Generate an ECDSA private key
+		private, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+		if err != nil {
+			return nil, nil, err
+		}
+		priv = private
+		pub = &private.PublicKey
 	}
-	public := priv.Public()
 
-	// ED25519 keys should have the DigitalSignature KeyUsage bits set
-	// in the x509.Certificate template
+	// ECDSA and Ed25519 keys should have the DigitalSignature KeyUsage bits
+	// set in the x509.Certificate template
 	keyUsage := x509.KeyUsageDigitalSignature
 
 	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
@@ -121,9 +174,10 @@ func newX509KeyPair(options CertificateOptions) (*x509.Certificate, crypto.Priva
 		BasicConstraintsValid: true,
 		IPAddresses:           options.IPAddresses,
 		DNSNames:              options.DNSNames,
+		Subject:               options.Subject,
 	}
 
-	crt, err := x509.CreateCertificate(rand.Reader, &template, &template, public, priv)
+	crt, err := x509.CreateCertificate(rand.Reader, &template, &template, pub, priv)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -133,3 +187,30 @@ func newX509KeyPair(options CertificateOptions) (*x509.Certificate, crypto.Priva
 	}
 	return cert, priv, nil
 }
+
+// WriteCertificate writes the provided certificate and private key
+// to certPath and keyPath respectively.
+func WriteCertificate(cert tls.Certificate, certPath, keyPath string) error {
+	certOut, err := os.OpenFile(certPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer certOut.Close()
+	if err := pem.Encode(certOut, &pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: cert.Leaf.Raw,
+	}); err != nil {
+		return err
+	}
+
+	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer keyOut.Close()
+	privBytes, err := x509.MarshalPKCS8PrivateKey(cert.PrivateKey)
+	if err != nil {
+		return err
+	}
+	return pem.Encode(keyOut, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
+}

client.go

@@ -4,10 +4,12 @@ import (
 	"bufio"
 	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"net"
 	"net/url"
 	"path"
 	"strings"
+	"time"
 )
 
 // Client is a Gemini client.
@@ -18,28 +20,45 @@ type Client struct {
 	// Certificates stores client-side certificates.
 	Certificates CertificateStore
 
+	// Timeout specifies a time limit for requests made by this
+	// Client. The timeout includes connection time and reading
+	// the response body. The timer remains running after
+	// Get and Do return and will interrupt reading of the Response.Body.
+	//
+	// A Timeout of zero means no timeout.
+	Timeout time.Duration
+
+	// InsecureSkipTrust specifies whether the client should trust
+	// any certificate it receives without checking KnownHosts
+	// or calling TrustCertificate.
+	// Use with caution.
+	InsecureSkipTrust bool
+
 	// GetInput is called to retrieve input when the server requests it.
 	// If GetInput is nil or returns false, no input will be sent and
 	// the response will be returned.
 	GetInput func(prompt string, sensitive bool) (input string, ok bool)
 
 	// CheckRedirect determines whether to follow a redirect.
-	// If CheckRedirect is nil, a default policy of no more than 5 consecutive
-	// redirects will be enforced.
+	// If CheckRedirect is nil, redirects will not be followed.
 	CheckRedirect func(req *Request, via []*Request) error
 
 	// CreateCertificate is called to generate a certificate upon
 	// the request of a server.
 	// If CreateCertificate is nil or the returned error is not nil,
 	// the request will not be sent again and the response will be returned.
-	CreateCertificate func(hostname, path string) (tls.Certificate, error)
+	CreateCertificate func(scope, path string) (tls.Certificate, error)
 
-	// TrustCertificate determines whether the client should trust
-	// the provided certificate.
-	// If the returned error is not nil, the connection will be aborted.
-	// If TrustCertificate is nil, the client will check KnownHosts
-	// for the certificate.
-	TrustCertificate func(hostname string, cert *x509.Certificate, knownHosts *KnownHosts) error
+	// TrustCertificate is called to determine whether the client
+	// should trust a certificate it has not seen before.
+	// If TrustCertificate is nil, the certificate will not be trusted
+	// and the connection will be aborted.
+	//
+	// If TrustCertificate returns TrustOnce, the certificate will be added
+	// to the client's list of known hosts.
+	// If TrustCertificate returns TrustAlways, the certificate will also be
+	// written to the known hosts file.
+	TrustCertificate func(hostname string, cert *x509.Certificate) Trust
 }
 
 // Get performs a Gemini request for the given url.
@@ -72,7 +91,10 @@ func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 	if err != nil {
 		return nil, err
 	}
-	// TODO: Set connection deadline
+	// Set connection deadline
+	if d := c.Timeout; d != 0 {
+		conn.SetDeadline(time.Now().Add(d))
+	}
 
 	// Write the request
 	w := bufio.NewWriter(conn)
@@ -86,6 +108,7 @@ func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 	if err := resp.read(conn); err != nil {
 		return nil, err
 	}
+	resp.Request = req
 	// Store connection state
 	resp.TLS = conn.ConnectionState()
 
@@ -103,9 +126,10 @@ func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 				return resp, err
 			}
 			c.Certificates.Add(hostname+path, cert)
+			req.Certificate = &cert
 			return c.do(req, via)
 		}
-		return resp, ErrCertificateRequired
+		return resp, nil
 
 	case resp.Status.Class() == StatusClassInput:
 		if c.GetInput != nil {
@@ -116,7 +140,7 @@ func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 				return c.do(req, via)
 			}
 		}
-		return resp, ErrInputRequired
+		return resp, nil
 
 	case resp.Status.Class() == StatusClassRedirect:
 		if via == nil {
@@ -129,23 +153,16 @@ func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 			return resp, err
 		}
 		target = req.URL.ResolveReference(target)
-		redirect, err := NewRequestFromURL(target)
-		if err != nil {
-			return resp, err
-		}
 
+		redirect := NewRequestFromURL(target)
 		if c.CheckRedirect != nil {
 			if err := c.CheckRedirect(redirect, via); err != nil {
 				return resp, err
 			}
-		} else if len(via) > 5 {
-			// Default policy of no more than 5 redirects
-			return resp, ErrTooManyRedirects
+			return c.do(redirect, via)
 		}
-		return c.do(redirect, via)
 	}
 
-	resp.Request = req
 	return resp, nil
 }
 
@@ -158,11 +175,14 @@ func (c *Client) getClientCertificate(req *Request) (*tls.Certificate, error) {
 	// Search recursively for the certificate
 	scope := req.URL.Hostname() + strings.TrimSuffix(req.URL.Path, "/")
 	for {
-		cert, err := c.Certificates.Lookup(scope)
-		if err == nil {
-			return cert, err
-		}
-		if err == ErrCertificateExpired {
+		cert, ok := c.Certificates.Lookup(scope)
+		if ok {
+			// Ensure that the certificate is not expired
+			if cert.Leaf != nil && !time.Now().After(cert.Leaf.NotAfter) {
+				// Store the certificate
+				req.Certificate = &cert
+				return &cert, nil
+			}
 			break
 		}
 		scope = path.Dir(scope)
@@ -186,12 +206,33 @@ func (c *Client) verifyConnection(req *Request, cs tls.ConnectionState) error {
 	if err := verifyHostname(cert, hostname); err != nil {
 		return err
 	}
-	// Check that the client trusts the certificate
-	var err error
-	if c.TrustCertificate != nil {
-		return c.TrustCertificate(hostname, cert, &c.KnownHosts)
-	} else {
-		err = c.KnownHosts.Lookup(hostname, cert)
+	if c.InsecureSkipTrust {
+		return nil
 	}
-	return err
+
+	// Check the known hosts
+	knownHost, ok := c.KnownHosts.Lookup(hostname)
+	if !ok || time.Now().Unix() >= knownHost.Expires {
+		// See if the client trusts the certificate
+		if c.TrustCertificate != nil {
+			switch c.TrustCertificate(hostname, cert) {
+			case TrustOnce:
+				fingerprint := NewFingerprint(cert.Raw, cert.NotAfter)
+				c.KnownHosts.Add(hostname, fingerprint)
+				return nil
+			case TrustAlways:
+				fingerprint := NewFingerprint(cert.Raw, cert.NotAfter)
+				c.KnownHosts.Add(hostname, fingerprint)
+				c.KnownHosts.Write(hostname, fingerprint)
+				return nil
+			}
+		}
+		return errors.New("gemini: certificate not trusted")
+	}
+
+	fingerprint := NewFingerprint(cert.Raw, cert.NotAfter)
+	if knownHost.Hex == fingerprint.Hex {
+		return nil
+	}
+	return errors.New("gemini: fingerprint does not match")
 }

doc.go

@@ -1,82 +0,0 @@
-/*
-Package gemini implements the Gemini protocol.
-
-Get makes a Gemini request:
-
-	resp, err := gemini.Get("gemini://example.com")
-	if err != nil {
-		// handle error
-	}
-	// ...
-
-The client must close the response body when finished with it:
-
-	resp, err := gemini.Get("gemini://example.com")
-	if err != nil {
-		// handle error
-	}
-	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
-	// ...
-
-For control over client behavior, create a Client:
-
-	var client gemini.Client
-	resp, err := client.Get("gemini://example.com")
-	if err != nil {
-		// handle error
-	}
-	// ...
-
-Clients can load their own list of known hosts:
-
-	err := client.KnownHosts.Load("path/to/my/known_hosts")
-	if err != nil {
-		// handle error
-	}
-
-Clients can control when to trust certificates with TrustCertificate:
-
-	client.TrustCertificate = func(hostname string, cert *x509.Certificate, knownHosts *gemini.KnownHosts) error {
-		return knownHosts.Lookup(hostname, cert)
-	}
-
-Clients can create client certificates upon the request of a server:
-
-	client.CreateCertificate = func(hostname, path string) (tls.Certificate, error) {
-		return gemini.CreateCertificate(gemini.CertificateOptions{
-			Duration: time.Hour,
-		})
-	}
-
-Server is a Gemini server.
-
-	var server gemini.Server
-
-Servers must be configured with certificates:
-
-	err := server.Certificates.Load("/var/lib/gemini/certs")
-	if err != nil {
-		// handle error
-	}
-
-Servers can accept requests for multiple hosts and schemes:
-
-	server.RegisterFunc("example.com", func(w *gemini.ResponseWriter, r *gemini.Request) {
-		fmt.Fprint(w, "Welcome to example.com")
-	})
-	server.RegisterFunc("example.org", func(w *gemini.ResponseWriter, r *gemini.Request) {
-		fmt.Fprint(w, "Welcome to example.org")
-	})
-	server.RegisterFunc("http://example.net", func(w *gemini.ResponseWriter, r *gemini.Request) {
-		fmt.Fprint(w, "Proxied content from http://example.net")
-	})
-
-To start the server, call ListenAndServe:
-
-	err := server.ListenAndServe()
-	if err != nil {
-		// handle error
-	}
-*/
-package gemini

examples/auth.go

@@ -3,9 +3,12 @@
 package main
 
 import (
+	"crypto/tls"
 	"crypto/x509"
+	"crypto/x509/pkix"
 	"fmt"
 	"log"
+	"time"
 
 	"git.sr.ht/~adnano/go-gemini"
 )
@@ -44,6 +47,15 @@ func main() {
 	if err := server.Certificates.Load("/var/lib/gemini/certs"); err != nil {
 		log.Fatal(err)
 	}
+	server.CreateCertificate = func(hostname string) (tls.Certificate, error) {
+		return gemini.CreateCertificate(gemini.CertificateOptions{
+			Subject: pkix.Name{
+				CommonName: hostname,
+			},
+			DNSNames: []string{hostname},
+			Duration: time.Hour,
+		})
+	}
 	server.Register("localhost", &mux)
 
 	if err := server.ListenAndServe(); err != nil {
@@ -51,68 +63,73 @@ func main() {
 	}
 }
 
-func getSession(crt *x509.Certificate) (*session, bool) {
-	fingerprint := gemini.Fingerprint(crt)
-	session, ok := sessions[fingerprint]
+func getSession(cert *x509.Certificate) (*session, bool) {
+	fingerprint := gemini.NewFingerprint(cert.Raw, cert.NotAfter)
+	session, ok := sessions[fingerprint.Hex]
 	return session, ok
 }
 
 func login(w *gemini.ResponseWriter, r *gemini.Request) {
-	cert, ok := gemini.Certificate(w, r)
-	if !ok {
+	if r.Certificate == nil {
+		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	username, ok := gemini.Input(w, r, "Username")
+	username, ok := gemini.Input(r)
 	if !ok {
+		w.WriteHeader(gemini.StatusInput, "Username")
 		return
 	}
-	fingerprint := gemini.Fingerprint(cert)
-	sessions[fingerprint] = &session{
+	cert := r.Certificate.Leaf
+	fingerprint := gemini.NewFingerprint(cert.Raw, cert.NotAfter)
+	sessions[fingerprint.Hex] = &session{
 		username: username,
 	}
-	gemini.Redirect(w, "/password")
+	w.WriteHeader(gemini.StatusRedirect, "/password")
 }
 
 func loginPassword(w *gemini.ResponseWriter, r *gemini.Request) {
-	cert, ok := gemini.Certificate(w, r)
-	if !ok {
+	if r.Certificate == nil {
+		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	session, ok := getSession(cert)
+	session, ok := getSession(r.Certificate.Leaf)
 	if !ok {
 		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
 		return
 	}
 
-	password, ok := gemini.SensitiveInput(w, r, "Password")
+	password, ok := gemini.Input(r)
 	if !ok {
+		w.WriteHeader(gemini.StatusSensitiveInput, "Password")
 		return
 	}
 	expected := logins[session.username].password
 	if password == expected {
 		session.authorized = true
-		gemini.Redirect(w, "/profile")
+		w.WriteHeader(gemini.StatusRedirect, "/profile")
 	} else {
-		gemini.SensitiveInput(w, r, "Wrong password. Try again")
+		w.WriteHeader(gemini.StatusSensitiveInput, "Password")
 	}
 }
 
 func logout(w *gemini.ResponseWriter, r *gemini.Request) {
-	cert, ok := gemini.Certificate(w, r)
-	if !ok {
+	if r.Certificate == nil {
+		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	fingerprint := gemini.Fingerprint(cert)
-	delete(sessions, fingerprint)
+	cert := r.Certificate.Leaf
+	fingerprint := gemini.NewFingerprint(cert.Raw, cert.NotAfter)
+	delete(sessions, fingerprint.Hex)
 	fmt.Fprintln(w, "Successfully logged out.")
+	fmt.Fprintln(w, "=> / Index")
 }
 
 func profile(w *gemini.ResponseWriter, r *gemini.Request) {
-	cert, ok := gemini.Certificate(w, r)
-	if !ok {
+	if r.Certificate == nil {
+		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	session, ok := getSession(cert)
+	session, ok := getSession(r.Certificate.Leaf)
 	if !ok {
 		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
 		return
@@ -124,11 +141,11 @@ func profile(w *gemini.ResponseWriter, r *gemini.Request) {
 }
 
 func admin(w *gemini.ResponseWriter, r *gemini.Request) {
-	cert, ok := gemini.Certificate(w, r)
-	if !ok {
+	if r.Certificate == nil {
+		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	session, ok := getSession(cert)
+	session, ok := getSession(r.Certificate.Leaf)
 	if !ok {
 		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
 		return

examples/cert.go

@@ -3,10 +3,7 @@
 package main
 
 import (
-	"bytes"
-	"crypto/tls"
-	"crypto/x509"
-	"encoding/pem"
+	"crypto/x509/pkix"
 	"fmt"
 	"log"
 	"os"
@@ -26,6 +23,9 @@ func main() {
 		log.Fatal(err)
 	}
 	options := gemini.CertificateOptions{
+		Subject: pkix.Name{
+			CommonName: host,
+		},
 		DNSNames: []string{host},
 		Duration: duration,
 	}
@@ -33,63 +33,9 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := writeCertificate(host, cert); err != nil {
+	certPath := host + ".crt"
+	keyPath := host + ".key"
+	if err := gemini.WriteCertificate(cert, certPath, keyPath); err != nil {
 		log.Fatal(err)
 	}
 }
-
-// writeCertificate writes the provided certificate and private key
-// to path.crt and path.key respectively.
-func writeCertificate(path string, cert tls.Certificate) error {
-	crt, err := marshalX509Certificate(cert.Leaf.Raw)
-	if err != nil {
-		return err
-	}
-	key, err := marshalPrivateKey(cert.PrivateKey)
-	if err != nil {
-		return err
-	}
-
-	// Write the certificate
-	crtPath := path + ".crt"
-	crtOut, err := os.OpenFile(crtPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
-	if _, err := crtOut.Write(crt); err != nil {
-		return err
-	}
-
-	// Write the private key
-	keyPath := path + ".key"
-	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
-	if _, err := keyOut.Write(key); err != nil {
-		return err
-	}
-	return nil
-}
-
-// marshalX509Certificate returns a PEM-encoded version of the given raw certificate.
-func marshalX509Certificate(cert []byte) ([]byte, error) {
-	var b bytes.Buffer
-	if err := pem.Encode(&b, &pem.Block{Type: "CERTIFICATE", Bytes: cert}); err != nil {
-		return nil, err
-	}
-	return b.Bytes(), nil
-}
-
-// marshalPrivateKey returns PEM encoded versions of the given certificate and private key.
-func marshalPrivateKey(priv interface{}) ([]byte, error) {
-	var b bytes.Buffer
-	privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
-	if err != nil {
-		return nil, err
-	}
-	if err := pem.Encode(&b, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes}); err != nil {
-		return nil, err
-	}
-	return b.Bytes(), nil
-}

examples/client.go

@@ -8,43 +8,44 @@ import (
 	"crypto/x509"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
+	"path/filepath"
 	"time"
 
 	"git.sr.ht/~adnano/go-gemini"
+	"git.sr.ht/~adnano/go-xdg"
 )
 
+const trustPrompt = `The certificate offered by %s is of unknown trust. Its fingerprint is:
+%s
+
+If you knew the fingerprint to expect in advance, verify that this matches.
+Otherwise, this should be safe to trust.
+
+[t]rust always; trust [o]nce; [a]bort
+=> `
+
 var (
 	scanner = bufio.NewScanner(os.Stdin)
 	client  = &gemini.Client{}
 )
 
 func init() {
-	client.KnownHosts.LoadDefault()
-	client.TrustCertificate = func(hostname string, cert *x509.Certificate, knownHosts *gemini.KnownHosts) error {
-		err := knownHosts.Lookup(hostname, cert)
-		if err != nil {
-			switch err {
-			case gemini.ErrCertificateNotTrusted:
-				// Alert the user that the certificate is not trusted
-				fmt.Printf("Warning: Certificate for %s is not trusted!\n", hostname)
-				fmt.Println("This could indicate a Man-in-the-Middle attack.")
-			case gemini.ErrCertificateUnknown:
-				// Prompt the user to trust the certificate
-				trust := trustCertificate(cert)
-				switch trust {
-				case trustOnce:
-					// Temporarily trust the certificate
-					knownHosts.AddTemporary(hostname, cert)
-					return nil
-				case trustAlways:
-					// Add the certificate to the known hosts file
-					knownHosts.Add(hostname, cert)
-					return nil
-				}
-			}
+	client.Timeout = 30 * time.Second
+	client.KnownHosts.Load(filepath.Join(xdg.DataHome(), "gemini", "known_hosts"))
+	client.TrustCertificate = func(hostname string, cert *x509.Certificate) gemini.Trust {
+		fingerprint := gemini.NewFingerprint(cert.Raw, cert.NotAfter)
+		fmt.Printf(trustPrompt, hostname, fingerprint.Hex)
+		scanner.Scan()
+		switch scanner.Text() {
+		case "t":
+			return gemini.TrustAlways
+		case "o":
+			return gemini.TrustOnce
+		default:
+			return gemini.TrustNone
 		}
-		return err
 	}
 	client.CreateCertificate = func(hostname, path string) (tls.Certificate, error) {
 		fmt.Println("Generating client certificate for", hostname, path)
@@ -59,54 +60,6 @@ func init() {
 	}
 }
 
-func doRequest(req *gemini.Request) error {
-	resp, err := client.Do(req)
-	if err != nil {
-		return err
-	}
-
-	if resp.Status.Class() == gemini.StatusClassSuccess {
-		body, err := ioutil.ReadAll(resp.Body)
-		resp.Body.Close()
-		if err != nil {
-			return err
-		}
-		fmt.Print(string(body))
-		return nil
-	}
-	return fmt.Errorf("request failed: %d %s: %s", resp.Status, resp.Status.Message(), resp.Meta)
-}
-
-type trust int
-
-const (
-	trustAbort trust = iota
-	trustOnce
-	trustAlways
-)
-
-const trustPrompt = `The certificate offered by this server is of unknown trust. Its fingerprint is:
-%s
-
-If you knew the fingerprint to expect in advance, verify that this matches.
-Otherwise, this should be safe to trust.
-
-[t]rust always; trust [o]nce; [a]bort
-=> `
-
-func trustCertificate(cert *x509.Certificate) trust {
-	fmt.Printf(trustPrompt, gemini.Fingerprint(cert))
-	scanner.Scan()
-	switch scanner.Text() {
-	case "t":
-		return trustAlways
-	case "o":
-		return trustOnce
-	default:
-		return trustAbort
-	}
-}
-
 func main() {
 	if len(os.Args) < 2 {
 		fmt.Printf("usage: %s gemini://... [host]", os.Args[0])
@@ -124,8 +77,20 @@ func main() {
 		req.Host = os.Args[2]
 	}
 
-	if err := doRequest(req); err != nil {
+	resp, err := client.Do(req)
+	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
+
+	if resp.Status.Class() == gemini.StatusClassSuccess {
+		defer resp.Body.Close()
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Print(string(body))
+	} else {
+		fmt.Printf("request failed: %d %s: %s", resp.Status, resp.Status.Message(), resp.Meta)
+	}
 }

examples/html.go

@@ -37,11 +37,10 @@ func textToHTML(text gemini.Text) string {
 			list = false
 			fmt.Fprint(&b, "</ul>\n")
 		}
-		switch l.(type) {
+		switch l := l.(type) {
 		case gemini.LineLink:
-			link := l.(gemini.LineLink)
-			url := html.EscapeString(link.URL)
-			name := html.EscapeString(link.Name)
+			url := html.EscapeString(l.URL)
+			name := html.EscapeString(l.Name)
 			if name == "" {
 				name = url
 			}
@@ -54,29 +53,22 @@ func textToHTML(text gemini.Text) string {
 				fmt.Fprint(&b, "</pre>\n")
 			}
 		case gemini.LinePreformattedText:
-			text := string(l.(gemini.LinePreformattedText))
-			fmt.Fprintf(&b, "%s\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "%s\n", html.EscapeString(string(l)))
 		case gemini.LineHeading1:
-			text := string(l.(gemini.LineHeading1))
-			fmt.Fprintf(&b, "<h1>%s</h1>\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "<h1>%s</h1>\n", html.EscapeString(string(l)))
 		case gemini.LineHeading2:
-			text := string(l.(gemini.LineHeading2))
-			fmt.Fprintf(&b, "<h2>%s</h2>\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "<h2>%s</h2>\n", html.EscapeString(string(l)))
 		case gemini.LineHeading3:
-			text := string(l.(gemini.LineHeading3))
-			fmt.Fprintf(&b, "<h3>%s</h3>\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "<h3>%s</h3>\n", html.EscapeString(string(l)))
 		case gemini.LineListItem:
-			text := string(l.(gemini.LineListItem))
-			fmt.Fprintf(&b, "<li>%s</li>\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "<li>%s</li>\n", html.EscapeString(string(l)))
 		case gemini.LineQuote:
-			text := string(l.(gemini.LineQuote))
-			fmt.Fprintf(&b, "<blockquote>%s</blockquote>\n", html.EscapeString(text))
+			fmt.Fprintf(&b, "<blockquote>%s</blockquote>\n", html.EscapeString(string(l)))
 		case gemini.LineText:
-			text := string(l.(gemini.LineText))
-			if text == "" {
+			if l == "" {
 				fmt.Fprint(&b, "<br>\n")
 			} else {
-				fmt.Fprintf(&b, "<p>%s</p>\n", html.EscapeString(text))
+				fmt.Fprintf(&b, "<p>%s</p>\n", html.EscapeString(string(l)))
 			}
 		}
 	}

examples/server.go

@@ -3,14 +3,9 @@
 package main
 
 import (
-	"crypto"
 	"crypto/tls"
-	"crypto/x509"
-	"encoding/pem"
-	"fmt"
-	"io"
+	"crypto/x509/pkix"
 	"log"
-	"os"
 	"time"
 
 	"git.sr.ht/~adnano/go-gemini"
@@ -18,20 +13,19 @@ import (
 
 func main() {
 	var server gemini.Server
+	server.ReadTimeout = 30 * time.Second
+	server.WriteTimeout = 1 * time.Minute
 	if err := server.Certificates.Load("/var/lib/gemini/certs"); err != nil {
 		log.Fatal(err)
 	}
 	server.CreateCertificate = func(hostname string) (tls.Certificate, error) {
-		fmt.Println("Generating certificate for", hostname)
-		cert, err := gemini.CreateCertificate(gemini.CertificateOptions{
+		return gemini.CreateCertificate(gemini.CertificateOptions{
+			Subject: pkix.Name{
+				CommonName: hostname,
+			},
 			DNSNames: []string{hostname},
 			Duration: time.Minute, // for testing purposes
 		})
-		if err == nil {
-			// Write the new certificate to disk
-			err = writeCertificate("/var/lib/gemini/certs/"+hostname, cert)
-		}
-		return cert, err
 	}
 
 	var mux gemini.ServeMux
@@ -42,39 +36,3 @@ func main() {
 		log.Fatal(err)
 	}
 }
-
-// writeCertificate writes the provided certificate and private key
-// to path.crt and path.key respectively.
-func writeCertificate(path string, cert tls.Certificate) error {
-	// Write the certificate
-	crtPath := path + ".crt"
-	crtOut, err := os.OpenFile(crtPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
-	if err := marshalX509Certificate(crtOut, cert.Leaf.Raw); err != nil {
-		return err
-	}
-
-	// Write the private key
-	keyPath := path + ".key"
-	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
-	return marshalPrivateKey(keyOut, cert.PrivateKey)
-}
-
-// marshalX509Certificate writes a PEM-encoded version of the given certificate.
-func marshalX509Certificate(w io.Writer, cert []byte) error {
-	return pem.Encode(w, &pem.Block{Type: "CERTIFICATE", Bytes: cert})
-}
-
-// marshalPrivateKey writes a PEM-encoded version of the given private key.
-func marshalPrivateKey(w io.Writer, priv crypto.PrivateKey) error {
-	privBytes, err := x509.MarshalPKCS8PrivateKey(priv)
-	if err != nil {
-		return err
-	}
-	return pem.Encode(w, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
-}

fs.go

@@ -33,7 +33,7 @@ func (fsh fsHandler) Respond(w *ResponseWriter, r *Request) {
 	// Detect mimetype
 	ext := path.Ext(p)
 	mimetype := mime.TypeByExtension(ext)
-	w.SetMimetype(mimetype)
+	w.SetMediaType(mimetype)
 	// Copy file to response writer
 	io.Copy(w, f)
 }
@@ -72,7 +72,7 @@ func ServeFile(w *ResponseWriter, fs FS, name string) {
 	// Detect mimetype
 	ext := path.Ext(name)
 	mimetype := mime.TypeByExtension(ext)
-	w.SetMimetype(mimetype)
+	w.SetMediaType(mimetype)
 	// Copy file to response writer
 	io.Copy(w, f)
 }
@@ -96,9 +96,9 @@ func openFile(p string) (File, error) {
 			if stat.Mode().IsRegular() {
 				return f, nil
 			}
-			return nil, ErrNotAFile
+			return nil, os.ErrNotExist
 		} else if !stat.Mode().IsRegular() {
-			return nil, ErrNotAFile
+			return nil, os.ErrNotExist
 		}
 	}
 	return f, nil

gemini.go

@@ -1,59 +1,63 @@
+/*
+Package gemini implements the Gemini protocol.
+
+Client is a Gemini client.
+
+	client := &gemini.Client{}
+	resp, err := client.Get("gemini://example.com")
+	if err != nil {
+		// handle error
+	}
+	if resp.Status.Class() == gemini.StatusClassSucess {
+		defer resp.Body.Close()
+		// ...
+	}
+	// ...
+
+Server is a Gemini server.
+
+	server := &gemini.Server{
+		ReadTimeout:    10 * time.Second,
+		WriteTimeout:   10 * time.Second,
+	}
+
+Servers should be configured with certificates:
+
+	err := server.Certificates.Load("/var/lib/gemini/certs")
+	if err != nil {
+		// handle error
+	}
+
+Servers can accept requests for multiple hosts and schemes:
+
+	server.RegisterFunc("example.com", func(w *gemini.ResponseWriter, r *gemini.Request) {
+		fmt.Fprint(w, "Welcome to example.com")
+	})
+	server.RegisterFunc("example.org", func(w *gemini.ResponseWriter, r *gemini.Request) {
+		fmt.Fprint(w, "Welcome to example.org")
+	})
+	server.RegisterFunc("http://example.net", func(w *gemini.ResponseWriter, r *gemini.Request) {
+		fmt.Fprint(w, "Proxied content from http://example.net")
+	})
+
+To start the server, call ListenAndServe:
+
+	err := server.ListenAndServe()
+	if err != nil {
+		// handle error
+	}
+*/
 package gemini
 
 import (
-	"crypto/tls"
-	"crypto/x509"
 	"errors"
-	"sync"
-	"time"
 )
 
 var crlf = []byte("\r\n")
 
 // Errors.
 var (
-	ErrInvalidURL            = errors.New("gemini: invalid URL")
-	ErrInvalidResponse       = errors.New("gemini: invalid response")
-	ErrCertificateUnknown    = errors.New("gemini: unknown certificate")
-	ErrCertificateExpired    = errors.New("gemini: certificate expired")
-	ErrCertificateNotTrusted = errors.New("gemini: certificate is not trusted")
-	ErrNotAFile              = errors.New("gemini: not a file")
-	ErrNotAGeminiURL         = errors.New("gemini: not a Gemini URL")
-	ErrBodyNotAllowed        = errors.New("gemini: response status code does not allow for body")
-	ErrTooManyRedirects      = errors.New("gemini: too many redirects")
-	ErrInputRequired         = errors.New("gemini: input required")
-	ErrCertificateRequired   = errors.New("gemini: certificate required")
+	ErrInvalidURL      = errors.New("gemini: invalid URL")
+	ErrInvalidResponse = errors.New("gemini: invalid response")
+	ErrBodyNotAllowed  = errors.New("gemini: response body not allowed")
 )
-
-// DefaultClient is the default client. It is used by Get and Do.
-//
-// On the first request, DefaultClient loads the default list of known hosts.
-var DefaultClient Client
-
-// Get performs a Gemini request for the given url.
-//
-// Get is a wrapper around DefaultClient.Get.
-func Get(url string) (*Response, error) {
-	return DefaultClient.Get(url)
-}
-
-// Do performs a Gemini request and returns a Gemini response.
-//
-// Do is a wrapper around DefaultClient.Do.
-func Do(req *Request) (*Response, error) {
-	return DefaultClient.Do(req)
-}
-
-var defaultClientOnce sync.Once
-
-func init() {
-	DefaultClient.TrustCertificate = func(hostname string, cert *x509.Certificate, knownHosts *KnownHosts) error {
-		defaultClientOnce.Do(func() { knownHosts.LoadDefault() })
-		return knownHosts.Lookup(hostname, cert)
-	}
-	DefaultClient.CreateCertificate = func(hostname, path string) (tls.Certificate, error) {
-		return CreateCertificate(CertificateOptions{
-			Duration: time.Hour,
-		})
-	}
-}

mux.go

@@ -138,14 +138,14 @@ func (mux *ServeMux) Respond(w *ResponseWriter, r *Request) {
 	// If the given path is /tree and its handler is not registered,
 	// redirect for /tree/.
 	if u, ok := mux.redirectToPathSlash(path, r.URL); ok {
-		Redirect(w, u.String())
+		w.WriteHeader(StatusRedirect, u.String())
 		return
 	}
 
 	if path != r.URL.Path {
 		u := *r.URL
 		u.Path = path
-		Redirect(w, u.String())
+		w.WriteHeader(StatusRedirect, u.String())
 		return
 	}
 

request.go

@@ -19,7 +19,9 @@ type Request struct {
 
 	// Certificate specifies the TLS certificate to use for the request.
 	// Request certificates take precedence over client certificates.
-	// This field is ignored by the server.
+	//
+	// On the server side, if the client provided a certificate then
+	// Certificate.Leaf is guaranteed to be non-nil.
 	Certificate *tls.Certificate
 
 	// RemoteAddr allows servers and other software to record the network
@@ -39,15 +41,12 @@ func NewRequest(rawurl string) (*Request, error) {
 	if err != nil {
 		return nil, err
 	}
-	return NewRequestFromURL(u)
+	return NewRequestFromURL(u), nil
 }
 
 // NewRequestFromURL returns a new request for the given URL.
 // The host is inferred from the URL.
-func NewRequestFromURL(url *url.URL) (*Request, error) {
-	if url.Scheme != "" && url.Scheme != "gemini" {
-		return nil, ErrNotAGeminiURL
-	}
+func NewRequestFromURL(url *url.URL) *Request {
 	host := url.Host
 	if url.Port() == "" {
 		host += ":1965"
@@ -55,7 +54,7 @@ func NewRequestFromURL(url *url.URL) (*Request, error) {
 	return &Request{
 		URL:  url,
 		Host: host,
-	}, nil
+	}
 }
 
 // write writes the Gemini request to the provided buffered writer.

response.go

@@ -9,7 +9,7 @@ import (
 
 // Response is a Gemini response.
 type Response struct {
-	// Status represents the response status.
+	// Status contains the response status code.
 	Status Status
 
 	// Meta contains more information related to the response status.
@@ -21,7 +21,7 @@ type Response struct {
 	// Body contains the response body for successful responses.
 	Body io.ReadCloser
 
-	// Request is the request that was sent to obtain this Response.
+	// Request is the request that was sent to obtain this response.
 	Request *Request
 
 	// TLS contains information about the TLS connection on which the response
@@ -68,6 +68,10 @@ func (resp *Response) read(rc io.ReadCloser) error {
 	if len(meta) > 1024 {
 		return ErrInvalidResponse
 	}
+	// Default mime type of text/gemini; charset=utf-8
+	if statusClass == StatusClassSuccess && meta == "" {
+		meta = "text/gemini; charset=utf-8"
+	}
 	resp.Meta = meta
 
 	// Read terminating newline

server.go

@@ -3,7 +3,7 @@ package gemini
 import (
 	"bufio"
 	"crypto/tls"
-	"crypto/x509"
+	"errors"
 	"log"
 	"net"
 	"net/url"
@@ -18,6 +18,13 @@ type Server struct {
 	// If Addr is empty, the server will listen on the address ":1965".
 	Addr string
 
+	// ReadTimeout is the maximum duration for reading a request.
+	ReadTimeout time.Duration
+
+	// WriteTimeout is the maximum duration before timing out
+	// writes of the response.
+	WriteTimeout time.Duration
+
 	// Certificates contains the certificates used by the server.
 	Certificates CertificateStore
 
@@ -25,27 +32,26 @@ type Server struct {
 	// if the current one is expired or missing.
 	CreateCertificate func(hostname string) (tls.Certificate, error)
 
+	// ErrorLog specifies an optional logger for errors accepting connections
+	// and file system errors.
+	// If nil, logging is done via the log package's standard logger.
+	ErrorLog *log.Logger
+
 	// registered responders
 	responders map[responderKey]Responder
+	hosts      map[string]bool
 }
 
 type responderKey struct {
 	scheme   string
 	hostname string
-	wildcard bool
 }
 
 // Register registers a responder for the given pattern.
 //
-// Patterns must be in the form of hostname or scheme://hostname
-// (e.g. gemini://example.com).
-// If no scheme is specified, a default scheme of gemini:// is assumed.
-//
-// Wildcard patterns are supported (e.g. *.example.com).
-// To register a certificate for a wildcard hostname, call Certificates.Add:
-//
-//     var s gemini.Server
-//     s.Certificates.Add("*.example.com", cert)
+// Patterns must be in the form of "hostname" or "scheme://hostname".
+// If no scheme is specified, a scheme of "gemini://" is implied.
+// Wildcard patterns are supported (e.g. "*.example.com").
 func (s *Server) Register(pattern string, responder Responder) {
 	if pattern == "" {
 		panic("gemini: invalid pattern")
@@ -55,6 +61,7 @@ func (s *Server) Register(pattern string, responder Responder) {
 	}
 	if s.responders == nil {
 		s.responders = map[responderKey]Responder{}
+		s.hosts = map[string]bool{}
 	}
 
 	split := strings.SplitN(pattern, "://", 2)
@@ -66,16 +73,12 @@ func (s *Server) Register(pattern string, responder Responder) {
 		key.scheme = "gemini"
 		key.hostname = split[0]
 	}
-	split = strings.SplitN(key.hostname, ".", 2)
-	if len(split) == 2 && split[0] == "*" {
-		key.hostname = split[1]
-		key.wildcard = true
-	}
 
 	if _, ok := s.responders[key]; ok {
 		panic("gemini: multiple registrations for " + pattern)
 	}
 	s.responders[key] = responder
+	s.hosts[key.hostname] = true
 }
 
 // RegisterFunc registers a responder function for the given pattern.
@@ -120,7 +123,7 @@ func (s *Server) Serve(l net.Listener) error {
 				if max := 1 * time.Second; tempDelay > max {
 					tempDelay = max
 				}
-				log.Printf("gemini: Accept error: %v; retrying in %v", err, tempDelay)
+				s.logf("gemini: Accept error: %v; retrying in %v", err, tempDelay)
 				time.Sleep(tempDelay)
 				continue
 			}
@@ -135,22 +138,49 @@ func (s *Server) Serve(l net.Listener) error {
 }
 
 func (s *Server) getCertificate(h *tls.ClientHelloInfo) (*tls.Certificate, error) {
-	cert, err := s.Certificates.Lookup(h.ServerName)
-	switch err {
-	case ErrCertificateExpired, ErrCertificateUnknown:
-		if s.CreateCertificate != nil {
-			cert, err := s.CreateCertificate(h.ServerName)
-			if err == nil {
-				s.Certificates.Add(h.ServerName, cert)
-			}
-			return &cert, err
+	cert, err := s.getCertificateFor(h.ServerName)
+	if err != nil {
+		// Try wildcard
+		wildcard := strings.SplitN(h.ServerName, ".", 2)
+		if len(wildcard) == 2 {
+			cert, err = s.getCertificateFor("*." + wildcard[1])
 		}
 	}
 	return cert, err
 }
 
+func (s *Server) getCertificateFor(hostname string) (*tls.Certificate, error) {
+	if _, ok := s.hosts[hostname]; !ok {
+		return nil, errors.New("hostname not registered")
+	}
+
+	// Generate a new certificate if it is missing or expired
+	cert, ok := s.Certificates.Lookup(hostname)
+	if !ok || cert.Leaf != nil && cert.Leaf.NotAfter.Before(time.Now()) {
+		if s.CreateCertificate != nil {
+			cert, err := s.CreateCertificate(hostname)
+			if err == nil {
+				s.Certificates.Add(hostname, cert)
+				if err := s.Certificates.Write(hostname, cert); err != nil {
+					s.logf("gemini: Failed to write new certificate for %s: %s", hostname, err)
+				}
+			}
+			return &cert, err
+		}
+		return nil, errors.New("no certificate")
+	}
+	return &cert, nil
+}
+
 // respond responds to a connection.
 func (s *Server) respond(conn net.Conn) {
+	if d := s.ReadTimeout; d != 0 {
+		conn.SetReadDeadline(time.Now().Add(d))
+	}
+	if d := s.WriteTimeout; d != 0 {
+		conn.SetWriteDeadline(time.Now().Add(d))
+	}
+
 	r := bufio.NewReader(conn)
 	w := newResponseWriter(conn)
 	// Read requested URL
@@ -162,25 +192,39 @@ func (s *Server) respond(conn net.Conn) {
 	if b, err := r.ReadByte(); err != nil {
 		return
 	} else if b != '\n' {
-		w.WriteHeader(StatusBadRequest, "Bad request")
+		w.WriteStatus(StatusBadRequest)
 	}
 	// Trim carriage return
 	rawurl = rawurl[:len(rawurl)-1]
 	// Ensure URL is valid
 	if len(rawurl) > 1024 {
-		w.WriteHeader(StatusBadRequest, "Bad request")
+		w.WriteStatus(StatusBadRequest)
 	} else if url, err := url.Parse(rawurl); err != nil || url.User != nil {
 		// Note that we return an error status if User is specified in the URL
-		w.WriteHeader(StatusBadRequest, "Bad request")
+		w.WriteStatus(StatusBadRequest)
 	} else {
 		// If no scheme is specified, assume a default scheme of gemini://
 		if url.Scheme == "" {
 			url.Scheme = "gemini"
 		}
+
+		// Store information about the TLS connection
+		connState := conn.(*tls.Conn).ConnectionState()
+		var cert *tls.Certificate
+		if len(connState.PeerCertificates) > 0 {
+			peerCert := connState.PeerCertificates[0]
+			// Store the TLS certificate
+			cert = &tls.Certificate{
+				Certificate: [][]byte{peerCert.Raw},
+				Leaf:        peerCert,
+			}
+		}
+
 		req := &Request{
-			URL:        url,
-			RemoteAddr: conn.RemoteAddr(),
-			TLS:        conn.(*tls.Conn).ConnectionState(),
+			URL:         url,
+			RemoteAddr:  conn.RemoteAddr(),
+			TLS:         connState,
+			Certificate: cert,
 		}
 		resp := s.responder(req)
 		if resp != nil {
@@ -194,24 +238,32 @@ func (s *Server) respond(conn net.Conn) {
 }
 
 func (s *Server) responder(r *Request) Responder {
-	if h, ok := s.responders[responderKey{r.URL.Scheme, r.URL.Hostname(), false}]; ok {
+	if h, ok := s.responders[responderKey{r.URL.Scheme, r.URL.Hostname()}]; ok {
 		return h
 	}
 	wildcard := strings.SplitN(r.URL.Hostname(), ".", 2)
 	if len(wildcard) == 2 {
-		if h, ok := s.responders[responderKey{r.URL.Scheme, wildcard[1], true}]; ok {
+		if h, ok := s.responders[responderKey{r.URL.Scheme, "*." + wildcard[1]}]; ok {
 			return h
 		}
 	}
 	return nil
 }
 
+func (s *Server) logf(format string, args ...interface{}) {
+	if s.ErrorLog != nil {
+		s.ErrorLog.Printf(format, args...)
+	} else {
+		log.Printf(format, args...)
+	}
+}
+
 // ResponseWriter is used by a Gemini handler to construct a Gemini response.
 type ResponseWriter struct {
 	b           *bufio.Writer
 	bodyAllowed bool
 	wroteHeader bool
-	mimetype    string
+	mediatype   string
 }
 
 func newResponseWriter(conn net.Conn) *ResponseWriter {
@@ -244,32 +296,31 @@ func (w *ResponseWriter) WriteHeader(status Status, meta string) {
 }
 
 // WriteStatus writes the response header with the given status code.
+//
+// WriteStatus is equivalent to WriteHeader(status, status.Message())
 func (w *ResponseWriter) WriteStatus(status Status) {
 	w.WriteHeader(status, status.Message())
 }
 
-// SetMimetype sets the mimetype that will be written for a successful response.
-// The provided mimetype will only be used if Write is called without calling
-// WriteHeader.
+// SetMediaType sets the media type that will be written for a successful response.
 // If the mimetype is not set, it will default to "text/gemini".
-func (w *ResponseWriter) SetMimetype(mimetype string) {
-	w.mimetype = mimetype
+func (w *ResponseWriter) SetMediaType(mediatype string) {
+	w.mediatype = mediatype
 }
 
 // Write writes the response body.
 // If the response status does not allow for a response body, Write returns
 // ErrBodyNotAllowed.
 //
-// If WriteHeader has not yet been called, Write calls
-// WriteHeader(StatusSuccess, mimetype) where mimetype is the mimetype set in
-// SetMimetype. If no mimetype is set, a default of "text/gemini" will be used.
+// If the response header has not yet been written, Write calls WriteHeader
+// with StatusSuccess and the mimetype set in SetMimetype.
 func (w *ResponseWriter) Write(b []byte) (int, error) {
 	if !w.wroteHeader {
-		mimetype := w.mimetype
-		if mimetype == "" {
-			mimetype = "text/gemini"
+		mediatype := w.mediatype
+		if mediatype == "" {
+			mediatype = "text/gemini"
 		}
-		w.WriteHeader(StatusSuccess, mimetype)
+		w.WriteHeader(StatusSuccess, mediatype)
 	}
 	if !w.bodyAllowed {
 		return 0, ErrBodyNotAllowed
@@ -283,51 +334,29 @@ type Responder interface {
 	Respond(*ResponseWriter, *Request)
 }
 
-// Input returns the request query.
-// If no input is provided, it responds with StatusInput.
-func Input(w *ResponseWriter, r *Request, prompt string) (string, bool) {
-	if r.URL.ForceQuery || r.URL.RawQuery != "" {
-		query, err := url.QueryUnescape(r.URL.RawQuery)
-		return query, err == nil
-	}
-	w.WriteHeader(StatusInput, prompt)
-	return "", false
-}
-
-// SensitiveInput returns the request query.
-// If no input is provided, it responds with StatusSensitiveInput.
-func SensitiveInput(w *ResponseWriter, r *Request, prompt string) (string, bool) {
-	if r.URL.ForceQuery || r.URL.RawQuery != "" {
-		query, err := url.QueryUnescape(r.URL.RawQuery)
-		return query, err == nil
-	}
-	w.WriteHeader(StatusSensitiveInput, prompt)
-	return "", false
-}
-
-// Redirect replies to the request with a redirect to the given URL.
-func Redirect(w *ResponseWriter, url string) {
-	w.WriteHeader(StatusRedirect, url)
-}
-
-// PermanentRedirect replies to the request with a permanent redirect to the given URL.
-func PermanentRedirect(w *ResponseWriter, url string) {
-	w.WriteHeader(StatusRedirectPermanent, url)
-}
-
-// Certificate returns the request certificate. If one is not provided,
-// it returns nil and responds with StatusCertificateRequired.
-func Certificate(w *ResponseWriter, r *Request) (*x509.Certificate, bool) {
-	if len(r.TLS.PeerCertificates) == 0 {
-		w.WriteStatus(StatusCertificateRequired)
-		return nil, false
-	}
-	return r.TLS.PeerCertificates[0], true
-}
-
 // ResponderFunc is a wrapper around a bare function that implements Responder.
 type ResponderFunc func(*ResponseWriter, *Request)
 
 func (f ResponderFunc) Respond(w *ResponseWriter, r *Request) {
 	f(w, r)
 }
+
+// Input returns the request query.
+// If the query is invalid or no query is provided, ok will be false.
+//
+// Example:
+//
+//    input, ok := gemini.Input(req)
+//    if !ok {
+//        w.WriteHeader(gemini.StatusInput, "Prompt")
+//        return
+//    }
+//    // ...
+//
+func Input(r *Request) (query string, ok bool) {
+	if r.URL.ForceQuery || r.URL.RawQuery != "" {
+		query, err := url.QueryUnescape(r.URL.RawQuery)
+		return query, err == nil
+	}
+	return "", false
+}

status.go

@@ -8,7 +8,7 @@ const (
 	StatusSensitiveInput           Status = 11
 	StatusSuccess                  Status = 20
 	StatusRedirect                 Status = 30
-	StatusRedirectPermanent        Status = 31
+	StatusPermanentRedirect        Status = 31
 	StatusTemporaryFailure         Status = 40
 	StatusServerUnavailable        Status = 41
 	StatusCGIError                 Status = 42
@@ -52,7 +52,7 @@ func (s Status) Message() string {
 		return "Success"
 	case StatusRedirect:
 		return "Redirect"
-	case StatusRedirectPermanent:
+	case StatusPermanentRedirect:
 		return "Permanent redirect"
 	case StatusTemporaryFailure:
 		return "Temporary failure"

text.go

@@ -87,58 +87,68 @@ func (l LineText) line()                {}
 // Text represents a Gemini text response.
 type Text []Line
 
-// Parse parses Gemini text from the provided io.Reader.
-func Parse(r io.Reader) Text {
-	const spacetab = " \t"
+// ParseText parses Gemini text from the provided io.Reader.
+func ParseText(r io.Reader) Text {
 	var t Text
+	ParseLines(r, func(line Line) {
+		t = append(t, line)
+	})
+	return t
+}
+
+// ParseLines parses Gemini text from the provided io.Reader.
+// It calls handler with each line that it parses.
+func ParseLines(r io.Reader, handler func(Line)) {
+	const spacetab = " \t"
 	var pre bool
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
-		line := scanner.Text()
-		if strings.HasPrefix(line, "```") {
+		var line Line
+		text := scanner.Text()
+		if strings.HasPrefix(text, "```") {
 			pre = !pre
-			line = line[3:]
-			t = append(t, LinePreformattingToggle(line))
+			text = text[3:]
+			line = LinePreformattingToggle(text)
 		} else if pre {
-			t = append(t, LinePreformattedText(line))
-		} else if strings.HasPrefix(line, "=>") {
-			line = line[2:]
-			line = strings.TrimLeft(line, spacetab)
-			split := strings.IndexAny(line, spacetab)
+			line = LinePreformattedText(text)
+		} else if strings.HasPrefix(text, "=>") {
+			text = text[2:]
+			text = strings.TrimLeft(text, spacetab)
+			split := strings.IndexAny(text, spacetab)
 			if split == -1 {
-				// line is a URL
-				t = append(t, LineLink{URL: line})
+				// text is a URL
+				line = LineLink{URL: text}
 			} else {
-				url := line[:split]
-				name := line[split:]
+				url := text[:split]
+				name := text[split:]
 				name = strings.TrimLeft(name, spacetab)
-				t = append(t, LineLink{url, name})
+				line = LineLink{url, name}
 			}
-		} else if strings.HasPrefix(line, "*") {
-			line = line[1:]
-			line = strings.TrimLeft(line, spacetab)
-			t = append(t, LineListItem(line))
-		} else if strings.HasPrefix(line, "###") {
-			line = line[3:]
-			line = strings.TrimLeft(line, spacetab)
-			t = append(t, LineHeading3(line))
-		} else if strings.HasPrefix(line, "##") {
-			line = line[2:]
-			line = strings.TrimLeft(line, spacetab)
-			t = append(t, LineHeading2(line))
-		} else if strings.HasPrefix(line, "#") {
-			line = line[1:]
-			line = strings.TrimLeft(line, spacetab)
-			t = append(t, LineHeading1(line))
-		} else if strings.HasPrefix(line, ">") {
-			line = line[1:]
-			line = strings.TrimLeft(line, spacetab)
-			t = append(t, LineQuote(line))
+		} else if strings.HasPrefix(text, "*") {
+			text = text[1:]
+			text = strings.TrimLeft(text, spacetab)
+			line = LineListItem(text)
+		} else if strings.HasPrefix(text, "###") {
+			text = text[3:]
+			text = strings.TrimLeft(text, spacetab)
+			line = LineHeading3(text)
+		} else if strings.HasPrefix(text, "##") {
+			text = text[2:]
+			text = strings.TrimLeft(text, spacetab)
+			line = LineHeading2(text)
+		} else if strings.HasPrefix(text, "#") {
+			text = text[1:]
+			text = strings.TrimLeft(text, spacetab)
+			line = LineHeading1(text)
+		} else if strings.HasPrefix(text, ">") {
+			text = text[1:]
+			text = strings.TrimLeft(text, spacetab)
+			line = LineQuote(text)
 		} else {
-			t = append(t, LineText(line))
+			line = LineText(text)
 		}
+		handler(line)
 	}
-	return t
 }
 
 // String writes the Gemini text response to a string and returns it.

tofu.go

@@ -3,45 +3,76 @@ package gemini
 import (
 	"bufio"
 	"crypto/sha512"
-	"crypto/x509"
 	"fmt"
 	"io"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
 )
 
+// Trust represents the trustworthiness of a certificate.
+type Trust int
+
+const (
+	TrustNone   Trust = iota // The certificate is not trusted.
+	TrustOnce                // The certificate is trusted once.
+	TrustAlways              // The certificate is trusted always.
+)
+
 // KnownHosts represents a list of known hosts.
 // The zero value for KnownHosts is an empty list ready to use.
 type KnownHosts struct {
-	hosts map[string]certInfo
-	file  *os.File
+	hosts map[string]Fingerprint
+	out   io.Writer
 }
 
-// LoadDefault loads the known hosts from the default known hosts path, which is
-// $XDG_DATA_HOME/gemini/known_hosts.
-// It creates the path and any of its parent directories if they do not exist.
-// KnownHosts will append to the file whenever a certificate is added.
-func (k *KnownHosts) LoadDefault() error {
-	path, err := defaultKnownHostsPath()
-	if err != nil {
-		return err
+// SetOutput sets the output to which new known hosts will be written to.
+func (k *KnownHosts) SetOutput(w io.Writer) {
+	k.out = w
+}
+
+// Add adds a known host to the list of known hosts.
+func (k *KnownHosts) Add(hostname string, fingerprint Fingerprint) {
+	if k.hosts == nil {
+		k.hosts = map[string]Fingerprint{}
 	}
-	return k.Load(path)
+	k.hosts[hostname] = fingerprint
 }
 
-// Load loads the known hosts from the provided path.
-// It creates the path and any of its parent directories if they do not exist.
-// KnownHosts will append to the file whenever a certificate is added.
-func (k *KnownHosts) Load(path string) error {
-	if dir := filepath.Dir(path); dir != "." {
-		err := os.MkdirAll(dir, 0755)
-		if err != nil {
+// Lookup returns the fingerprint of the certificate corresponding to
+// the given hostname.
+func (k *KnownHosts) Lookup(hostname string) (Fingerprint, bool) {
+	c, ok := k.hosts[hostname]
+	return c, ok
+}
+
+// Write writes a known hosts entry to the configured output.
+func (k *KnownHosts) Write(hostname string, fingerprint Fingerprint) {
+	if k.out != nil {
+		k.writeKnownHost(k.out, hostname, fingerprint)
+	}
+}
+
+// WriteAll writes all of the known hosts to the provided io.Writer.
+func (k *KnownHosts) WriteAll(w io.Writer) error {
+	for h, c := range k.hosts {
+		if _, err := k.writeKnownHost(w, h, c); err != nil {
 			return err
 		}
 	}
+	return nil
+}
+
+// writeKnownHost writes a known host to the provided io.Writer.
+func (k *KnownHosts) writeKnownHost(w io.Writer, hostname string, f Fingerprint) (int, error) {
+	return fmt.Fprintf(w, "%s %s %s %d\n", hostname, f.Algorithm, f.Hex, f.Expires)
+}
+
+// Load loads the known hosts from the provided path.
+// It creates the file if it does not exist.
+// New known hosts will be appended to the file.
+func (k *KnownHosts) Load(path string) error {
 	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDONLY, 0644)
 	if err != nil {
 		return err
@@ -53,66 +84,15 @@ func (k *KnownHosts) Load(path string) error {
 	if err != nil {
 		return err
 	}
-	k.file = f
+	k.out = f
 	return nil
 }
 
-// Add adds a certificate to the list of known hosts.
-// If KnownHosts was loaded from a file, Add will append to the file.
-func (k *KnownHosts) Add(hostname string, cert *x509.Certificate) {
-	k.add(hostname, cert, true)
-}
-
-// AddTemporary adds a certificate to the list of known hosts
-// without writing it to the known hosts file.
-func (k *KnownHosts) AddTemporary(hostname string, cert *x509.Certificate) {
-	k.add(hostname, cert, false)
-}
-
-func (k *KnownHosts) add(hostname string, cert *x509.Certificate, write bool) {
-	if k.hosts == nil {
-		k.hosts = map[string]certInfo{}
-	}
-	info := certInfo{
-		Algorithm:   "SHA-512",
-		Fingerprint: Fingerprint(cert),
-		Expires:     cert.NotAfter.Unix(),
-	}
-	k.hosts[hostname] = info
-	// Append to the file
-	if write && k.file != nil {
-		appendKnownHost(k.file, hostname, info)
-	}
-}
-
-// Lookup looks for the provided certificate in the list of known hosts.
-// If the hostname is in the list, but the fingerprint differs,
-// Lookup returns ErrCertificateNotTrusted.
-// If the hostname is not in the list, Lookup returns ErrCertificateUnknown.
-// If the certificate is found and the fingerprint matches, error will be nil.
-func (k *KnownHosts) Lookup(hostname string, cert *x509.Certificate) error {
-	now := time.Now().Unix()
-	fingerprint := Fingerprint(cert)
-	if c, ok := k.hosts[hostname]; ok {
-		if c.Expires <= now {
-			// Certificate is expired
-			return ErrCertificateUnknown
-		}
-		if c.Fingerprint != fingerprint {
-			// Fingerprint does not match
-			return ErrCertificateNotTrusted
-		}
-		// Certificate is trusted
-		return nil
-	}
-	return ErrCertificateUnknown
-}
-
 // Parse parses the provided reader and adds the parsed known hosts to the list.
-// Invalid lines are ignored.
+// Invalid entries are ignored.
 func (k *KnownHosts) Parse(r io.Reader) {
 	if k.hosts == nil {
-		k.hosts = map[string]certInfo{}
+		k.hosts = map[string]Fingerprint{}
 	}
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
@@ -128,39 +108,30 @@ func (k *KnownHosts) Parse(r io.Reader) {
 			continue
 		}
 		fingerprint := parts[2]
+
 		expires, err := strconv.ParseInt(parts[3], 10, 0)
 		if err != nil {
 			continue
 		}
 
-		k.hosts[hostname] = certInfo{
-			Algorithm:   algorithm,
-			Fingerprint: fingerprint,
-			Expires:     expires,
+		k.hosts[hostname] = Fingerprint{
+			Algorithm: algorithm,
+			Hex:       fingerprint,
+			Expires:   expires,
 		}
 	}
 }
 
-// Write writes the known hosts to the provided io.Writer.
-func (k *KnownHosts) Write(w io.Writer) {
-	for h, c := range k.hosts {
-		appendKnownHost(w, h, c)
-	}
+// Fingerprint represents a fingerprint using a certain algorithm.
+type Fingerprint struct {
+	Algorithm string // fingerprint algorithm e.g. SHA-512
+	Hex       string // fingerprint in hexadecimal, with ':' between each octet
+	Expires   int64  // unix time of the fingerprint expiration date
 }
 
-type certInfo struct {
-	Algorithm   string // fingerprint algorithm e.g. SHA-512
-	Fingerprint string // fingerprint in hexadecimal, with ':' between each octet
-	Expires     int64  // unix time of certificate notAfter date
-}
-
-func appendKnownHost(w io.Writer, hostname string, c certInfo) (int, error) {
-	return fmt.Fprintf(w, "%s %s %s %d\n", hostname, c.Algorithm, c.Fingerprint, c.Expires)
-}
-
-// Fingerprint returns the SHA-512 fingerprint of the provided certificate.
-func Fingerprint(cert *x509.Certificate) string {
-	sum512 := sha512.Sum512(cert.Raw)
+// NewFingerprint returns the SHA-512 fingerprint of the provided raw data.
+func NewFingerprint(raw []byte, expires time.Time) Fingerprint {
+	sum512 := sha512.Sum512(raw)
 	var b strings.Builder
 	for i, f := range sum512 {
 		if i > 0 {
@@ -168,29 +139,9 @@ func Fingerprint(cert *x509.Certificate) string {
 		}
 		fmt.Fprintf(&b, "%02X", f)
 	}
-	return b.String()
-}
-
-// defaultKnownHostsPath returns the default known_hosts path.
-// The default path is $XDG_DATA_HOME/gemini/known_hosts
-func defaultKnownHostsPath() (string, error) {
-	dataDir, err := userDataDir()
-	if err != nil {
-		return "", err
+	return Fingerprint{
+		Algorithm: "SHA-512",
+		Hex:       b.String(),
+		Expires:   expires.Unix(),
 	}
-	return filepath.Join(dataDir, "gemini", "known_hosts"), nil
-}
-
-// userDataDir returns the user data directory.
-func userDataDir() (string, error) {
-	dataDir, ok := os.LookupEnv("XDG_DATA_HOME")
-	if ok {
-		return dataDir, nil
-	}
-
-	home, err := os.UserHomeDir()
-	if err != nil {
-		return "", err
-	}
-	return filepath.Join(home, ".local", "share"), nil
 }