examples/client: Fix fingerprint check

cert.go

@@ -2,33 +2,44 @@ package gemini
 
 import (
 	"crypto"
+	"crypto/ecdsa"
 	"crypto/ed25519"
+	"crypto/elliptic"
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
+	"crypto/x509/pkix"
 	"encoding/pem"
-	"log"
 	"math/big"
 	"net"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"time"
 )
 
-// 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
+// CertificateDir maps certificate scopes to certificates.
+type CertificateStore map[string]tls.Certificate
+
+// CertificateDir represents a certificate store optionally loaded from a directory.
+// The zero value of CertificateDir is an empty store ready to use.
+//
+// CertificateDir is safe for concurrent use by multiple goroutines.
+type CertificateDir struct {
+	CertificateStore
 	dir  bool
 	path string
+	mu   sync.RWMutex
 }
 
 // Add adds a certificate for the given scope to the store.
 // It tries to parse the certificate if it is not already parsed.
-func (c *CertificateStore) Add(scope string, cert tls.Certificate) {
-	if c.store == nil {
-		c.store = map[string]tls.Certificate{}
+func (c *CertificateDir) Add(scope string, cert tls.Certificate) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.CertificateStore == nil {
+		c.CertificateStore = CertificateStore{}
 	}
 	// Parse certificate if not already parsed
 	if cert.Leaf == nil {
@@ -37,29 +48,31 @@ func (c *CertificateStore) Add(scope string, cert tls.Certificate) {
 			cert.Leaf = parsed
 		}
 	}
+	c.CertificateStore[scope] = cert
+}
+
+// Write writes the provided certificate to the certificate directory.
+func (c *CertificateDir) Write(scope string, cert tls.Certificate) error {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
 	if c.dir {
-		// Write certificates
-		log.Printf("gemini: Writing certificate for %s to %s", scope, c.path)
+		// Escape slash character
+		scope = strings.ReplaceAll(scope, "/", ":")
 		certPath := filepath.Join(c.path, scope+".crt")
 		keyPath := filepath.Join(c.path, scope+".key")
 		if err := WriteCertificate(cert, certPath, keyPath); err != nil {
-			log.Printf("gemini: Failed to write certificate for %s: %s", scope, err)
+			return err
 		}
 	}
-	c.store[scope] = cert
+	return nil
 }
 
 // Lookup returns the certificate for the given scope.
-func (c *CertificateStore) Lookup(scope string) (*tls.Certificate, error) {
-	cert, ok := c.store[scope]
-	if !ok {
-		return nil, ErrCertificateNotFound
-	}
-	// Ensure that the certificate is not expired
-	if cert.Leaf != nil && cert.Leaf.NotAfter.Before(time.Now()) {
-		return &cert, ErrCertificateExpired
-	}
-	return &cert, nil
+func (c *CertificateDir) Lookup(scope string) (tls.Certificate, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	cert, ok := c.CertificateStore[scope]
+	return cert, ok
 }
 
 // Load loads certificates from the given path.
@@ -68,7 +81,7 @@ func (c *CertificateStore) Lookup(scope string) (*tls.Certificate, error) {
 // 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 {
+func (c *CertificateDir) Load(path string) error {
 	matches, err := filepath.Glob(filepath.Join(path, "*.crt"))
 	if err != nil {
 		return err
@@ -80,18 +93,47 @@ func (c *CertificateStore) Load(path string) error {
 			continue
 		}
 		scope := strings.TrimSuffix(filepath.Base(crtPath), ".crt")
+		// Unescape slash character
+		scope = strings.ReplaceAll(scope, ":", "/")
 		c.Add(scope, cert)
 	}
-	c.dir = true
-	c.path = path
+	c.SetDir(path)
 	return nil
 }
 
-// CertificateOptions configures how a certificate is created.
+// SetDir sets the directory that new certificates will be written to.
+func (c *CertificateDir) SetDir(path string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	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
+
+	// 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.
@@ -109,15 +151,27 @@ 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)
+	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
 		}
-	public := priv.Public()
+	} 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
+	}
 
-	// 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)
@@ -138,9 +192,10 @@ 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
 	}

client.go

@@ -2,22 +2,23 @@ package gemini
 
 import (
 	"bufio"
+	"context"
 	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"net"
-	"net/url"
-	"path"
 	"strings"
 	"time"
 )
 
 // Client is a Gemini client.
 type Client struct {
-	// KnownHosts is a list of known hosts.
-	KnownHosts KnownHosts
-
-	// Certificates stores client-side certificates.
-	Certificates CertificateStore
+	// TrustCertificate is called to determine whether the client
+	// should trust the certificate provided by the server.
+	// If TrustCertificate is nil, the client will accept any certificate.
+	// If the returned error is not nil, the certificate will not be trusted
+	// and the request will be aborted.
+	TrustCertificate func(hostname string, cert *x509.Certificate) error
 
 	// Timeout specifies a time limit for requests made by this
 	// Client. The timeout includes connection time and reading
@@ -26,42 +27,9 @@ type Client struct {
 	//
 	// 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.
-	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)
-
-	// 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.
+// Get performs a Gemini request for the given URL.
 func (c *Client) Get(url string) (*Response, error) {
 	req, err := NewRequest(url)
 	if err != nil {
@@ -72,130 +40,59 @@ func (c *Client) Get(url string) (*Response, error) {
 
 // Do performs a Gemini request and returns a Gemini response.
 func (c *Client) Do(req *Request) (*Response, error) {
-	return c.do(req, nil)
-}
+	// Extract hostname
+	colonPos := strings.LastIndex(req.Host, ":")
+	if colonPos == -1 {
+		colonPos = len(req.Host)
+	}
+	hostname := req.Host[:colonPos]
 
-func (c *Client) do(req *Request, via []*Request) (*Response, error) {
 	// Connect to the host
 	config := &tls.Config{
 		InsecureSkipVerify: true,
 		MinVersion:         tls.VersionTLS12,
 		GetClientCertificate: func(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) {
-			return c.getClientCertificate(req)
+			if req.Certificate != nil {
+				return req.Certificate, nil
+			}
+			return &tls.Certificate{}, nil
 		},
 		VerifyConnection: func(cs tls.ConnectionState) error {
 			return c.verifyConnection(req, cs)
 		},
+		ServerName: hostname,
 	}
-	conn, err := tls.Dial("tcp", req.Host, config)
+	// Set connection context
+	ctx := req.Context
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	netConn, err := (&net.Dialer{}).DialContext(ctx, "tcp", req.Host)
 	if err != nil {
 		return nil, err
 	}
+	conn := tls.Client(netConn, config)
 	// Set connection deadline
-	if d := c.Timeout; d != 0 {
-		conn.SetDeadline(time.Now().Add(d))
+	if c.Timeout != 0 {
+		conn.SetDeadline(time.Now().Add(c.Timeout))
 	}
 
 	// Write the request
 	w := bufio.NewWriter(conn)
-	req.write(w)
+	req.Write(w)
 	if err := w.Flush(); err != nil {
 		return nil, err
 	}
 
 	// Read the response
-	resp := &Response{}
-	if err := resp.read(conn); err != nil {
+	resp, err := ReadResponse(conn)
+	if err != nil {
 		return nil, err
 	}
 	// Store connection state
 	resp.TLS = conn.ConnectionState()
 
-	switch {
-	case resp.Status == StatusCertificateRequired:
-		// Check to see if a certificate was already provided to prevent an infinite loop
-		if req.Certificate != nil {
 	return resp, nil
-		}
-
-		hostname, path := req.URL.Hostname(), strings.TrimSuffix(req.URL.Path, "/")
-		if c.CreateCertificate != nil {
-			cert, err := c.CreateCertificate(hostname, path)
-			if err != nil {
-				return resp, err
-			}
-			c.Certificates.Add(hostname+path, cert)
-			return c.do(req, via)
-		}
-		return resp, ErrCertificateRequired
-
-	case resp.Status.Class() == StatusClassInput:
-		if c.GetInput != nil {
-			input, ok := c.GetInput(resp.Meta, resp.Status == StatusSensitiveInput)
-			if ok {
-				req.URL.ForceQuery = true
-				req.URL.RawQuery = url.QueryEscape(input)
-				return c.do(req, via)
-			}
-		}
-		return resp, ErrInputRequired
-
-	case resp.Status.Class() == StatusClassRedirect:
-		if via == nil {
-			via = []*Request{}
-		}
-		via = append(via, req)
-
-		target, err := url.Parse(resp.Meta)
-		if err != nil {
-			return resp, err
-		}
-		target = req.URL.ResolveReference(target)
-		redirect, err := NewRequestFromURL(target)
-		if err != nil {
-			return resp, err
-		}
-
-		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)
-	}
-
-	resp.Request = req
-	return resp, nil
-}
-
-func (c *Client) getClientCertificate(req *Request) (*tls.Certificate, error) {
-	// Request certificates have the highest precedence
-	if req.Certificate != nil {
-		return req.Certificate, nil
-	}
-
-	// Search recursively for the certificate
-	scope := req.URL.Hostname() + strings.TrimSuffix(req.URL.Path, "/")
-	for {
-		cert, err := c.Certificates.Lookup(scope)
-		if err == nil {
-			// Store the certificate
-			req.Certificate = cert
-			return cert, err
-		}
-		if err == ErrCertificateExpired {
-			break
-		}
-		scope = path.Dir(scope)
-		if scope == "." {
-			break
-		}
-	}
-
-	return &tls.Certificate{}, nil
 }
 
 func (c *Client) verifyConnection(req *Request, cs tls.ConnectionState) error {
@@ -210,25 +107,14 @@ func (c *Client) verifyConnection(req *Request, cs tls.ConnectionState) error {
 	if err := verifyHostname(cert, hostname); err != nil {
 		return err
 	}
-	if c.InsecureSkipTrust {
-		return nil
+	// Check expiration date
+	if !time.Now().Before(cert.NotAfter) {
+		return errors.New("gemini: certificate expired")
 	}
-	// Check the known hosts
-	err := c.KnownHosts.Lookup(hostname, cert)
-	switch err {
-	case ErrCertificateExpired, ErrCertificateNotFound:
+
 	// See if the client trusts the certificate
 	if c.TrustCertificate != nil {
-			switch c.TrustCertificate(hostname, cert) {
-			case TrustOnce:
-				c.KnownHosts.AddTemporary(hostname, cert)
+		return c.TrustCertificate(hostname, cert)
+	}
 	return nil
-			case TrustAlways:
-				c.KnownHosts.Add(hostname, cert)
-				return nil
-			}
-		}
-		return ErrCertificateNotTrusted
-	}
-	return err
 }

doc.go

@@ -1,55 +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
-	}
-	defer resp.Body.Close()
-	// ...
-
-For control over client behavior, create a Client:
-
-	client := &gemini.Client{}
-	resp, err := client.Get("gemini://example.com")
-	if err != nil {
-		// handle error
-	}
-	// ...
-
-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

examples/auth.go

@@ -3,8 +3,10 @@
 package main
 
 import (
+	"crypto/sha512"
 	"crypto/tls"
 	"crypto/x509"
+	"crypto/x509/pkix"
 	"fmt"
 	"log"
 	"time"
@@ -12,35 +14,19 @@ import (
 	"git.sr.ht/~adnano/go-gemini"
 )
 
-type user struct {
-	password string // TODO: use hashes
-	admin    bool
-}
-
-type session struct {
-	username   string
-	authorized bool // whether or not the password was supplied
+type User struct {
+	Name string
 }
 
 var (
-	// Map of usernames to user data
-	logins = map[string]user{
-		"admin": {"p@ssw0rd", true}, // NOTE: These are bad passwords!
-		"user1": {"password1", false},
-		"user2": {"password2", false},
-	}
-
-	// Map of certificate fingerprints to sessions
-	sessions = map[string]*session{}
+	// Map of certificate hashes to users
+	users = map[string]*User{}
 )
 
 func main() {
 	var mux gemini.ServeMux
-	mux.HandleFunc("/", login)
-	mux.HandleFunc("/password", loginPassword)
-	mux.HandleFunc("/profile", profile)
-	mux.HandleFunc("/admin", admin)
-	mux.HandleFunc("/logout", logout)
+	mux.HandleFunc("/", profile)
+	mux.HandleFunc("/username", changeUsername)
 
 	var server gemini.Server
 	if err := server.Certificates.Load("/var/lib/gemini/certs"); err != nil {
@@ -48,6 +34,9 @@ func main() {
 	}
 	server.CreateCertificate = func(hostname string) (tls.Certificate, error) {
 		return gemini.CreateCertificate(gemini.CertificateOptions{
+			Subject: pkix.Name{
+				CommonName: hostname,
+			},
 			DNSNames: []string{hostname},
 			Duration: time.Hour,
 		})
@@ -59,62 +48,9 @@ func main() {
 	}
 }
 
-func getSession(cert *x509.Certificate) (*session, bool) {
-	fingerprint := gemini.Fingerprint(cert)
-	session, ok := sessions[fingerprint]
-	return session, ok
-}
-
-func login(w *gemini.ResponseWriter, r *gemini.Request) {
-	if r.Certificate == nil {
-		w.WriteStatus(gemini.StatusCertificateRequired)
-		return
-	}
-	username, ok := gemini.Input(r)
-	if !ok {
-		w.WriteHeader(gemini.StatusInput, "Username")
-		return
-	}
-	fingerprint := gemini.Fingerprint(r.Certificate.Leaf)
-	sessions[fingerprint] = &session{
-		username: username,
-	}
-	w.WriteHeader(gemini.StatusRedirect, "/password")
-}
-
-func loginPassword(w *gemini.ResponseWriter, r *gemini.Request) {
-	if r.Certificate == nil {
-		w.WriteStatus(gemini.StatusCertificateRequired)
-		return
-	}
-	session, ok := getSession(r.Certificate.Leaf)
-	if !ok {
-		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
-		return
-	}
-
-	password, ok := gemini.Input(r)
-	if !ok {
-		w.WriteHeader(gemini.StatusSensitiveInput, "Password")
-		return
-	}
-	expected := logins[session.username].password
-	if password == expected {
-		session.authorized = true
-		w.WriteHeader(gemini.StatusRedirect, "/profile")
-	} else {
-		w.WriteHeader(gemini.StatusSensitiveInput, "Wrong password. Try again")
-	}
-}
-
-func logout(w *gemini.ResponseWriter, r *gemini.Request) {
-	if r.Certificate == nil {
-		w.WriteStatus(gemini.StatusCertificateRequired)
-		return
-	}
-	fingerprint := gemini.Fingerprint(r.Certificate.Leaf)
-	delete(sessions, fingerprint)
-	fmt.Fprintln(w, "Successfully logged out.")
+func fingerprint(cert *x509.Certificate) string {
+	b := sha512.Sum512(cert.Raw)
+	return string(b[:])
 }
 
 func profile(w *gemini.ResponseWriter, r *gemini.Request) {
@@ -122,31 +58,33 @@ func profile(w *gemini.ResponseWriter, r *gemini.Request) {
 		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	session, ok := getSession(r.Certificate.Leaf)
+	fingerprint := fingerprint(r.Certificate.Leaf)
+	user, ok := users[fingerprint]
 	if !ok {
-		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
-		return
+		user = &User{}
+		users[fingerprint] = user
 	}
-	user := logins[session.username]
-	fmt.Fprintln(w, "Username:", session.username)
-	fmt.Fprintln(w, "Admin:", user.admin)
-	fmt.Fprintln(w, "=> /logout Logout")
+	fmt.Fprintln(w, "Username:", user.Name)
+	fmt.Fprintln(w, "=> /username Change username")
 }
 
-func admin(w *gemini.ResponseWriter, r *gemini.Request) {
+func changeUsername(w *gemini.ResponseWriter, r *gemini.Request) {
 	if r.Certificate == nil {
 		w.WriteStatus(gemini.StatusCertificateRequired)
 		return
 	}
-	session, ok := getSession(r.Certificate.Leaf)
+
+	username, err := gemini.QueryUnescape(r.URL.RawQuery)
+	if err != nil || username == "" {
+		w.WriteHeader(gemini.StatusInput, "Username")
+		return
+	}
+	fingerprint := fingerprint(r.Certificate.Leaf)
+	user, ok := users[fingerprint]
 	if !ok {
-		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
-		return
+		user = &User{}
+		users[fingerprint] = user
 	}
-	user := logins[session.username]
-	if !user.admin {
-		w.WriteStatus(gemini.StatusCertificateNotAuthorized)
-		return
-	}
-	fmt.Fprintln(w, "Welcome to the admin portal.")
+	user.Name = username
+	w.WriteHeader(gemini.StatusRedirect, "/")
 }

examples/cert.go

@@ -1,8 +1,11 @@
 // +build ignore
 
+// This example illustrates a certificate generation tool.
+
 package main
 
 import (
+	"crypto/x509/pkix"
 	"fmt"
 	"log"
 	"os"
@@ -22,6 +25,9 @@ func main() {
 		log.Fatal(err)
 	}
 	options := gemini.CertificateOptions{
+		Subject: pkix.Name{
+			CommonName: host,
+		},
 		DNSNames: []string{host},
 		Duration: duration,
 	}

examples/client.go

@@ -1,20 +1,41 @@
 // +build ignore
 
+// This example illustrates a Gemini client.
+
 package main
 
 import (
 	"bufio"
-	"crypto/tls"
 	"crypto/x509"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"log"
+	"net/url"
 	"os"
+	"path/filepath"
 	"time"
 
 	"git.sr.ht/~adnano/go-gemini"
+	"git.sr.ht/~adnano/go-xdg"
 )
 
+var (
+	hosts   gemini.KnownHostsFile
+	scanner *bufio.Scanner
+)
+
+func init() {
+	// Load known hosts file
+	path := filepath.Join(xdg.DataHome(), "gemini", "known_hosts")
+	err := hosts.Load(path)
+	if err != nil {
+		log.Println(err)
+	}
+
+	scanner = bufio.NewScanner(os.Stdin)
+}
+
 const trustPrompt = `The certificate offered by %s is of unknown trust. Its fingerprint is:
 %s
 
@@ -24,48 +45,85 @@ 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 trustCertificate(hostname string, cert *x509.Certificate) error {
+	fingerprint := gemini.NewFingerprint(cert.Raw, cert.NotAfter)
+	knownHost, ok := hosts.Lookup(hostname)
+	if ok && time.Now().Before(knownHost.Expires) {
+		// Check fingerprint
+		if knownHost.Hex == fingerprint.Hex {
+			return nil
+		}
+		return errors.New("error: fingerprint does not match!")
+	}
 
-func init() {
-	client.Timeout = 30 * time.Second
-	client.KnownHosts.LoadDefault()
-	client.TrustCertificate = func(hostname string, cert *x509.Certificate) gemini.Trust {
-		fmt.Printf(trustPrompt, hostname, gemini.Fingerprint(cert))
+	fmt.Printf(trustPrompt, hostname, fingerprint.Hex)
 	scanner.Scan()
 	switch scanner.Text() {
 	case "t":
-			return gemini.TrustAlways
+		hosts.Add(hostname, fingerprint)
+		hosts.Write(hostname, fingerprint)
+		return nil
 	case "o":
-			return gemini.TrustOnce
+		hosts.Add(hostname, fingerprint)
+		return nil
 	default:
-			return gemini.TrustNone
+		return errors.New("certificate not trusted")
 	}
-	}
-	client.CreateCertificate = func(hostname, path string) (tls.Certificate, error) {
-		fmt.Println("Generating client certificate for", hostname, path)
-		return gemini.CreateCertificate(gemini.CertificateOptions{
-			Duration: time.Hour,
-		})
-	}
-	client.GetInput = func(prompt string, sensitive bool) (string, bool) {
-		fmt.Printf("%s: ", prompt)
+}
+
+func getInput(prompt string, sensitive bool) (input string, ok bool) {
+	fmt.Printf("%s ", prompt)
 	scanner.Scan()
 	return scanner.Text(), true
+}
+
+func do(req *gemini.Request, via []*gemini.Request) (*gemini.Response, error) {
+	client := gemini.Client{
+		TrustCertificate: trustCertificate,
 	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return resp, err
+	}
+
+	switch resp.Status.Class() {
+	case gemini.StatusClassInput:
+		input, ok := getInput(resp.Meta, resp.Status == gemini.StatusSensitiveInput)
+		if !ok {
+			break
+		}
+		req.URL.ForceQuery = true
+		req.URL.RawQuery = gemini.QueryEscape(input)
+		return do(req, via)
+
+	case gemini.StatusClassRedirect:
+		via = append(via, req)
+		if len(via) > 5 {
+			return resp, errors.New("too many redirects")
+		}
+
+		target, err := url.Parse(resp.Meta)
+		if err != nil {
+			return resp, err
+		}
+		target = req.URL.ResolveReference(target)
+		redirect := *req
+		redirect.URL = target
+		return do(&redirect, via)
+	}
+
+	return resp, err
 }
 
 func main() {
 	if len(os.Args) < 2 {
-		fmt.Printf("usage: %s gemini://... [host]", os.Args[0])
+		fmt.Printf("usage: %s <url> [host]\n", os.Args[0])
 		os.Exit(1)
 	}
 
+	// Do the request
 	url := os.Args[1]
 	req, err := gemini.NewRequest(url)
-
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
@@ -73,21 +131,22 @@ func main() {
 	if len(os.Args) == 3 {
 		req.Host = os.Args[2]
 	}
-
-	resp, err := client.Do(req)
+	resp, err := do(req, nil)
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}
-	defer resp.Body.Close()
 
+	// Handle response
 	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)
+		fmt.Printf("%d %s: %s\n", resp.Status, resp.Status.Message(), resp.Meta)
+		os.Exit(1)
 	}
 }

examples/html.go

@@ -7,76 +7,77 @@ package main
 import (
 	"fmt"
 	"html"
-	"strings"
+	"io"
+	"os"
 
 	"git.sr.ht/~adnano/go-gemini"
 )
 
 func main() {
-	text := gemini.Text{
-		gemini.LineHeading1("Hello, world!"),
-		gemini.LineText("This is a gemini text document."),
+	hw := HTMLWriter{
+		out: os.Stdout,
 	}
-
-	html := textToHTML(text)
-	fmt.Print(html)
+	gemini.ParseLines(os.Stdin, hw.Handle)
+	hw.Finish()
 }
 
-// textToHTML returns the Gemini text response as HTML.
-func textToHTML(text gemini.Text) string {
-	var b strings.Builder
-	var pre bool
-	var list bool
-	for _, l := range text {
-		if _, ok := l.(gemini.LineListItem); ok {
-			if !list {
-				list = true
-				fmt.Fprint(&b, "<ul>\n")
+type HTMLWriter struct {
+	out  io.Writer
+	pre  bool
+	list bool
+}
+
+func (h *HTMLWriter) Handle(line gemini.Line) {
+	if _, ok := line.(gemini.LineListItem); ok {
+		if !h.list {
+			h.list = true
+			fmt.Fprint(h.out, "<ul>\n")
 		}
-		} else if list {
-			list = false
-			fmt.Fprint(&b, "</ul>\n")
+	} else if h.list {
+		h.list = false
+		fmt.Fprint(h.out, "</ul>\n")
 	}
-		switch l := l.(type) {
+	switch line := line.(type) {
 	case gemini.LineLink:
-			url := html.EscapeString(l.URL)
-			name := html.EscapeString(l.Name)
+		url := html.EscapeString(line.URL)
+		name := html.EscapeString(line.Name)
 		if name == "" {
 			name = url
 		}
-			fmt.Fprintf(&b, "<p><a href='%s'>%s</a></p>\n", url, name)
+		fmt.Fprintf(h.out, "<p><a href='%s'>%s</a></p>\n", url, name)
 	case gemini.LinePreformattingToggle:
-			pre = !pre
-			if pre {
-				fmt.Fprint(&b, "<pre>\n")
+		h.pre = !h.pre
+		if h.pre {
+			fmt.Fprint(h.out, "<pre>\n")
 		} else {
-				fmt.Fprint(&b, "</pre>\n")
+			fmt.Fprint(h.out, "</pre>\n")
 		}
 	case gemini.LinePreformattedText:
-			fmt.Fprintf(&b, "%s\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "%s\n", html.EscapeString(string(line)))
 	case gemini.LineHeading1:
-			fmt.Fprintf(&b, "<h1>%s</h1>\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "<h1>%s</h1>\n", html.EscapeString(string(line)))
 	case gemini.LineHeading2:
-			fmt.Fprintf(&b, "<h2>%s</h2>\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "<h2>%s</h2>\n", html.EscapeString(string(line)))
 	case gemini.LineHeading3:
-			fmt.Fprintf(&b, "<h3>%s</h3>\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "<h3>%s</h3>\n", html.EscapeString(string(line)))
 	case gemini.LineListItem:
-			fmt.Fprintf(&b, "<li>%s</li>\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "<li>%s</li>\n", html.EscapeString(string(line)))
 	case gemini.LineQuote:
-			fmt.Fprintf(&b, "<blockquote>%s</blockquote>\n", html.EscapeString(string(l)))
+		fmt.Fprintf(h.out, "<blockquote>%s</blockquote>\n", html.EscapeString(string(line)))
 	case gemini.LineText:
-			if l == "" {
-				fmt.Fprint(&b, "<br>\n")
+		if line == "" {
+			fmt.Fprint(h.out, "<br>\n")
 		} else {
-				fmt.Fprintf(&b, "<p>%s</p>\n", html.EscapeString(string(l)))
+			fmt.Fprintf(h.out, "<p>%s</p>\n", html.EscapeString(string(line)))
 		}
 	}
-	}
-	if pre {
-		fmt.Fprint(&b, "</pre>\n")
-	}
-	if list {
-		fmt.Fprint(&b, "</ul>\n")
-	}
-	return b.String()
+}
+
+func (h *HTMLWriter) Finish() {
+	if h.pre {
+		fmt.Fprint(h.out, "</pre>\n")
+	}
+	if h.list {
+		fmt.Fprint(h.out, "</ul>\n")
+	}
 }

examples/server.go

@@ -1,9 +1,12 @@
 // +build ignore
 
+// This example illustrates a Gemini server.
+
 package main
 
 import (
 	"crypto/tls"
+	"crypto/x509/pkix"
 	"log"
 	"time"
 
@@ -19,8 +22,11 @@ func main() {
 	}
 	server.CreateCertificate = func(hostname string) (tls.Certificate, error) {
 		return gemini.CreateCertificate(gemini.CertificateOptions{
+			Subject: pkix.Name{
+				CommonName: hostname,
+			},
 			DNSNames: []string{hostname},
-			Duration: time.Minute, // for testing purposes
+			Duration: 365 * 24 * time.Hour,
 		})
 	}
 

examples/stream.go

@@ -0,0 +1,44 @@
+// +build ignore
+
+// This example illustrates a streaming Gemini server.
+
+package main
+
+import (
+	"crypto/tls"
+	"crypto/x509/pkix"
+	"fmt"
+	"log"
+	"time"
+
+	"git.sr.ht/~adnano/go-gemini"
+)
+
+func main() {
+	var server gemini.Server
+	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: 365 * 24 * time.Hour,
+		})
+	}
+
+	server.RegisterFunc("localhost", stream)
+	if err := server.ListenAndServe(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func stream(w *gemini.ResponseWriter, r *gemini.Request) {
+	for {
+		fmt.Fprintln(w, time.Now().UTC())
+		w.Flush()
+		time.Sleep(time.Second)
+	}
+}

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

@@ -1,8 +1,56 @@
+/*
+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 (
 	"errors"
-	"sync"
 )
 
 var crlf = []byte("\r\n")
@@ -10,37 +58,7 @@ var crlf = []byte("\r\n")
 // Errors.
 var (
 	ErrInvalidURL      = errors.New("gemini: invalid URL")
+	ErrInvalidRequest  = errors.New("gemini: invalid request")
 	ErrInvalidResponse = errors.New("gemini: invalid response")
-	ErrCertificateExpired    = errors.New("gemini: certificate expired")
-	ErrCertificateNotFound   = errors.New("gemini: certificate not found")
-	ErrCertificateNotTrusted = errors.New("gemini: certificate not trusted")
-	ErrCertificateRequired   = errors.New("gemini: certificate required")
-	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")
+	ErrBodyNotAllowed  = errors.New("gemini: response body not allowed")
 )
-
-// defaultClient is the default client. It is used by Get and Do.
-var defaultClient Client
-
-// Get performs a Gemini request for the given url.
-func Get(url string) (*Response, error) {
-	setupDefaultClientOnce()
-	return defaultClient.Get(url)
-}
-
-// Do performs a Gemini request and returns a Gemini response.
-func Do(req *Request) (*Response, error) {
-	setupDefaultClientOnce()
-	return defaultClient.Do(req)
-}
-
-var defaultClientOnce sync.Once
-
-func setupDefaultClientOnce() {
-	defaultClientOnce.Do(func() {
-		defaultClient.KnownHosts.LoadDefault()
-	})
-}

query.go

@@ -0,0 +1,18 @@
+package gemini
+
+import (
+	"net/url"
+	"strings"
+)
+
+// QueryEscape escapes a string for use in a Gemini URL query.
+// It is like url.PathEscape except that it also replaces plus signs
+// with their percent-encoded counterpart.
+func QueryEscape(query string) string {
+	return strings.ReplaceAll(url.PathEscape(query), "+", "%2B")
+}
+
+// QueryUnescape is identical to url.PathUnescape.
+func QueryUnescape(query string) (string, error) {
+	return url.PathUnescape(query)
+}

request.go

@@ -2,7 +2,9 @@ package gemini
 
 import (
 	"bufio"
+	"context"
 	"crypto/tls"
+	"io"
 	"net"
 	"net/url"
 )
@@ -14,6 +16,7 @@ type Request struct {
 
 	// For client requests, Host specifies the host on which the URL is sought.
 	// Host must contain a port.
+	//
 	// This field is ignored by the server.
 	Host string
 
@@ -26,13 +29,19 @@ type Request struct {
 
 	// RemoteAddr allows servers and other software to record the network
 	// address that sent the request.
+	//
 	// This field is ignored by the client.
 	RemoteAddr net.Addr
 
 	// TLS allows servers and other software to record information about the TLS
 	// connection on which the request was received.
+	//
 	// This field is ignored by the client.
 	TLS tls.ConnectionState
+
+	// Context specifies the context to use for client requests.
+	// If Context is nil, the background context will be used.
+	Context context.Context
 }
 
 // NewRequest returns a new request. The host is inferred from the URL.
@@ -41,15 +50,15 @@ 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
-	}
+//
+// Callers should be careful that the URL query is properly escaped.
+// See the documentation for QueryEscape for more information.
+func NewRequestFromURL(url *url.URL) *Request {
 	host := url.Host
 	if url.Port() == "" {
 		host += ":1965"
@@ -57,11 +66,42 @@ func NewRequestFromURL(url *url.URL) (*Request, error) {
 	return &Request{
 		URL:  url,
 		Host: host,
-	}, nil
+	}
 }
 
-// write writes the Gemini request to the provided buffered writer.
-func (r *Request) write(w *bufio.Writer) error {
+// ReadRequest reads a Gemini request from the provided io.Reader
+func ReadRequest(r io.Reader) (*Request, error) {
+	// Read URL
+	br := bufio.NewReader(r)
+	rawurl, err := br.ReadString('\r')
+	if err != nil {
+		return nil, err
+	}
+	// Read terminating line feed
+	if b, err := br.ReadByte(); err != nil {
+		return nil, err
+	} else if b != '\n' {
+		return nil, ErrInvalidRequest
+	}
+	// Trim carriage return
+	rawurl = rawurl[:len(rawurl)-1]
+	// Validate URL
+	if len(rawurl) > 1024 {
+		return nil, ErrInvalidRequest
+	}
+	u, err := url.Parse(rawurl)
+	if err != nil {
+		return nil, err
+	}
+	if u.User != nil {
+		// User is not allowed
+		return nil, ErrInvalidURL
+	}
+	return &Request{URL: u}, nil
+}
+
+// Write writes the Gemini request to the provided buffered writer.
+func (r *Request) Write(w *bufio.Writer) error {
 	url := r.URL.String()
 	// User is invalid
 	if r.URL.User != nil || len(url) > 1024 {

response.go

@@ -2,10 +2,8 @@ package gemini
 
 import (
 	"bufio"
-	"bytes"
 	"crypto/tls"
 	"io"
-	"io/ioutil"
 	"strconv"
 )
 
@@ -21,28 +19,26 @@ type Response struct {
 	Meta string
 
 	// Body contains the response body for successful responses.
-	// Body is guaranteed to be non-nil.
 	Body io.ReadCloser
 
-	// Request is the request that was sent to obtain this response.
-	Request *Request
-
 	// TLS contains information about the TLS connection on which the response
 	// was received.
 	TLS tls.ConnectionState
 }
 
-// read reads a Gemini response from the provided io.ReadCloser.
-func (resp *Response) read(rc io.ReadCloser) error {
+// ReadResponse reads a Gemini response from the provided io.ReadCloser.
+func ReadResponse(rc io.ReadCloser) (*Response, error) {
+	resp := &Response{}
 	br := bufio.NewReader(rc)
+
 	// Read the status
 	statusB := make([]byte, 2)
 	if _, err := br.Read(statusB); err != nil {
-		return err
+		return nil, err
 	}
 	status, err := strconv.Atoi(string(statusB))
 	if err != nil {
-		return err
+		return nil, err
 	}
 	resp.Status = Status(status)
 
@@ -50,26 +46,26 @@ func (resp *Response) read(rc io.ReadCloser) error {
 	const minStatus, maxStatus = 1, 6
 	statusClass := resp.Status.Class()
 	if statusClass < minStatus || statusClass > maxStatus {
-		return ErrInvalidResponse
+		return nil, ErrInvalidResponse
 	}
 
 	// Read one space
 	if b, err := br.ReadByte(); err != nil {
-		return err
+		return nil, err
 	} else if b != ' ' {
-		return ErrInvalidResponse
+		return nil, ErrInvalidResponse
 	}
 
 	// Read the meta
 	meta, err := br.ReadString('\r')
 	if err != nil {
-		return err
+		return nil, err
 	}
 	// Trim carriage return
 	meta = meta[:len(meta)-1]
 	// Ensure meta is less than or equal to 1024 bytes
 	if len(meta) > 1024 {
-		return ErrInvalidResponse
+		return nil, ErrInvalidResponse
 	}
 	// Default mime type of text/gemini; charset=utf-8
 	if statusClass == StatusClassSuccess && meta == "" {
@@ -79,17 +75,15 @@ func (resp *Response) read(rc io.ReadCloser) error {
 
 	// Read terminating newline
 	if b, err := br.ReadByte(); err != nil {
-		return err
+		return nil, err
 	} else if b != '\n' {
-		return ErrInvalidResponse
+		return nil, ErrInvalidResponse
 	}
 
 	if resp.Status.Class() == StatusClassSuccess {
 		resp.Body = newReadCloserBody(br, rc)
-	} else {
-		resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
 	}
-	return nil
+	return resp, nil
 }
 
 type readCloserBody struct {

server.go

@@ -3,9 +3,10 @@ package gemini
 import (
 	"bufio"
 	"crypto/tls"
+	"errors"
+	"io"
 	"log"
 	"net"
-	"net/url"
 	"strconv"
 	"strings"
 	"time"
@@ -25,12 +26,17 @@ type Server struct {
 	WriteTimeout time.Duration
 
 	// Certificates contains the certificates used by the server.
-	Certificates CertificateStore
+	Certificates CertificateDir
 
 	// CreateCertificate, if not nil, will be called to create a new certificate
 	// 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
@@ -117,7 +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
 			}
@@ -145,26 +151,30 @@ func (s *Server) getCertificate(h *tls.ClientHelloInfo) (*tls.Certificate, error
 
 func (s *Server) getCertificateFor(hostname string) (*tls.Certificate, error) {
 	if _, ok := s.hosts[hostname]; !ok {
-		return nil, ErrCertificateNotFound
+		return nil, errors.New("hostname not registered")
 	}
-	cert, err := s.Certificates.Lookup(hostname)
 
-	switch err {
-	case ErrCertificateNotFound, ErrCertificateExpired:
+	// 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, err
+	return &cert, nil
 }
 
 // respond responds to a connection.
 func (s *Server) respond(conn net.Conn) {
+	defer conn.Close()
 	if d := s.ReadTimeout; d != 0 {
 		conn.SetReadDeadline(time.Now().Add(d))
 	}
@@ -172,60 +182,33 @@ func (s *Server) respond(conn net.Conn) {
 		conn.SetWriteDeadline(time.Now().Add(d))
 	}
 
-	r := bufio.NewReader(conn)
-	w := newResponseWriter(conn)
-	// Read requested URL
-	rawurl, err := r.ReadString('\r')
+	w := NewResponseWriter(conn)
+	defer w.b.Flush()
+
+	req, err := ReadRequest(conn)
 	if err != nil {
-		return
-	}
-	// Read terminating line feed
-	if b, err := r.ReadByte(); err != nil {
-		return
-	} else if b != '\n' {
-		w.WriteStatus(StatusBadRequest)
-	}
-	// Trim carriage return
-	rawurl = rawurl[:len(rawurl)-1]
-	// Ensure URL is valid
-	if len(rawurl) > 1024 {
-		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.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]
+		if tlsConn, ok := conn.(*tls.Conn); ok {
+			req.TLS = tlsConn.ConnectionState()
+			if len(req.TLS.PeerCertificates) > 0 {
+				peerCert := req.TLS.PeerCertificates[0]
 				// Store the TLS certificate
-			cert = &tls.Certificate{
+				req.Certificate = &tls.Certificate{
 					Certificate: [][]byte{peerCert.Raw},
 					Leaf:        peerCert,
 				}
 			}
-
-		req := &Request{
-			URL:         url,
-			RemoteAddr:  conn.RemoteAddr(),
-			TLS:         connState,
-			Certificate: cert,
 		}
+	}
+
 	resp := s.responder(req)
 	if resp != nil {
 		resp.Respond(w, req)
 	} else {
 		w.WriteStatus(StatusNotFound)
 	}
-	}
-	w.b.Flush()
-	conn.Close()
 }
 
 func (s *Server) responder(r *Request) Responder {
@@ -241,17 +224,26 @@ func (s *Server) responder(r *Request) Responder {
 	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 {
+// NewResponseWriter returns a ResponseWriter that uses the provided io.Writer.
+func NewResponseWriter(w io.Writer) *ResponseWriter {
 	return &ResponseWriter{
-		b: bufio.NewWriter(conn),
+		b: bufio.NewWriter(w),
 	}
 }
 
@@ -285,13 +277,13 @@ func (w *ResponseWriter) WriteStatus(status Status) {
 	w.WriteHeader(status, status.Message())
 }
 
-// SetMimetype sets the mimetype that will be written for a successful response.
+// 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.
+// Write writes data to the connection as part of the response body.
 // If the response status does not allow for a response body, Write returns
 // ErrBodyNotAllowed.
 //
@@ -299,11 +291,11 @@ func (w *ResponseWriter) SetMimetype(mimetype string) {
 // 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
@@ -311,6 +303,11 @@ func (w *ResponseWriter) Write(b []byte) (int, error) {
 	return w.b.Write(b)
 }
 
+// Flush writes any buffered data to the underlying io.Writer.
+func (w *ResponseWriter) Flush() error {
+	return w.b.Flush()
+}
+
 // A Responder responds to a Gemini request.
 type Responder interface {
 	// Respond accepts a Request and constructs a Response.
@@ -323,23 +320,3 @@ 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
-}

tofu.go

@@ -3,124 +3,100 @@ package gemini
 import (
 	"bufio"
 	"crypto/sha512"
-	"crypto/x509"
 	"fmt"
 	"io"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
-// Trust represents the trustworthiness of a certificate.
-type Trust int
+// KnownHosts maps hosts to fingerprints.
+type KnownHosts map[string]Fingerprint
 
-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
+// KnownHostsFile represents a list of known hosts optionally loaded from a file.
+// The zero value for KnownHostsFile represents an empty list ready to use.
+//
+// KnownHostsFile is safe for concurrent use by multiple goroutines.
+type KnownHostsFile struct {
+	KnownHosts
+	out io.Writer
+	mu  sync.RWMutex
 }
 
-// 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 {
+// SetOutput sets the output to which new known hosts will be written to.
+func (k *KnownHostsFile) SetOutput(w io.Writer) {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+	k.out = w
+}
+
+// Add adds a known host to the list of known hosts.
+func (k *KnownHostsFile) Add(hostname string, fingerprint Fingerprint) {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+	if k.KnownHosts == nil {
+		k.KnownHosts = KnownHosts{}
+	}
+	k.KnownHosts[hostname] = fingerprint
+}
+
+// Lookup returns the fingerprint of the certificate corresponding to
+// the given hostname.
+func (k *KnownHostsFile) Lookup(hostname string) (Fingerprint, bool) {
+	k.mu.RLock()
+	defer k.mu.RUnlock()
+	c, ok := k.KnownHosts[hostname]
+	return c, ok
+}
+
+// Write writes a known hosts entry to the configured output.
+func (k *KnownHostsFile) Write(hostname string, fingerprint Fingerprint) {
+	k.mu.RLock()
+	defer k.mu.RUnlock()
+	if k.out != nil {
+		k.writeKnownHost(k.out, hostname, fingerprint)
+	}
+}
+
+// WriteAll writes all of the known hosts to the provided io.Writer.
+func (k *KnownHostsFile) WriteAll(w io.Writer) error {
+	k.mu.RLock()
+	defer k.mu.RUnlock()
+	for h, c := range k.KnownHosts {
+		if _, err := k.writeKnownHost(w, h, c); err != nil {
 			return err
 		}
-	return k.Load(path)
+	}
+	return nil
+}
+
+// writeKnownHost writes a known host to the provided io.Writer.
+func (k *KnownHostsFile) 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.Unix())
 }
 
 // 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 {
-			return err
-		}
-	}
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDONLY, 0644)
+// It creates the file if it does not exist.
+// New known hosts will be appended to the file.
+func (k *KnownHostsFile) Load(path string) error {
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0644)
 	if err != nil {
 		return err
 	}
 	k.Parse(f)
-	f.Close()
-	// Open the file for append-only use
-	f, err = os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
-	if err != nil {
-		return err
-	}
-	k.file = f
+	k.SetOutput(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 not in the list, Lookup returns ErrCertificateNotFound.
-// If the fingerprint doesn't match, Lookup returns ErrCertificateNotTrusted.
-// Otherwise, Lookup returns 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 ErrCertificateExpired
-		}
-		if c.Fingerprint != fingerprint {
-			// Fingerprint does not match
-			return ErrCertificateNotTrusted
-		}
-		// Certificate is found
-		return nil
-	}
-	return ErrCertificateNotFound
-}
-
 // Parse parses the provided reader and adds the parsed known hosts to the list.
-// Invalid lines are ignored.
-func (k *KnownHosts) Parse(r io.Reader) {
-	if k.hosts == nil {
-		k.hosts = map[string]certInfo{}
+// Invalid entries are ignored.
+func (k *KnownHostsFile) Parse(r io.Reader) {
+	k.mu.Lock()
+	defer k.mu.Unlock()
+	if k.KnownHosts == nil {
+		k.KnownHosts = map[string]Fingerprint{}
 	}
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
@@ -135,40 +111,32 @@ func (k *KnownHosts) Parse(r io.Reader) {
 		if algorithm != "SHA-512" {
 			continue
 		}
-		fingerprint := parts[2]
-		expires, err := strconv.ParseInt(parts[3], 10, 0)
+		hex := parts[2]
+
+		unix, err := strconv.ParseInt(parts[3], 10, 0)
 		if err != nil {
 			continue
 		}
+		expires := time.Unix(unix, 0)
 
-		k.hosts[hostname] = certInfo{
+		k.KnownHosts[hostname] = Fingerprint{
 			Algorithm: algorithm,
-			Fingerprint: fingerprint,
+			Hex:       hex,
 			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)
-	}
-}
-
-type certInfo struct {
+// Fingerprint represents a fingerprint using a certain algorithm.
+type Fingerprint 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
+	Hex       string    // fingerprint in hexadecimal, with ':' between each octet
+	Expires   time.Time // unix time of the fingerprint expiration 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 {
@@ -176,29 +144,9 @@ 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,
 	}
-	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
 }