Add initial login logic

cmd/koushin/main.go

@@ -1,12 +1,22 @@
 package main
 
 import (
+	"fmt"
+	"os"
+
 	"git.sr.ht/~emersion/koushin"
 	"github.com/labstack/echo/v4/middleware"
 )
 
 func main() {
-	e := koushin.New()
+	if len(os.Args) != 2 {
+		fmt.Println("usage: koushin imaps://<host>:<port>")
+		return
+	}
+
+	url := os.Args[1]
+
+	e := koushin.New(url)
 	e.Use(middleware.Logger())
 	e.Use(middleware.Recover())
 	e.Logger.Fatal(e.Start(":1323"))

conn_pool.go

@@ -0,0 +1,58 @@
+package koushin
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+
+	imapclient "github.com/emersion/go-imap/client"
+)
+
+func generateToken() (string, error) {
+	b := make([]byte, 32)
+	_, err := rand.Read(b)
+	if err != nil {
+		return "", err
+	}
+	return base64.URLEncoding.EncodeToString(b), nil
+}
+
+var ErrSessionExpired = errors.New("session expired")
+
+// TODO: expiration timer
+type ConnPool struct {
+	// TODO: add synchronization
+	conns map[string]*imapclient.Client
+}
+
+func NewConnPool() *ConnPool {
+	return &ConnPool{
+		conns: make(map[string]*imapclient.Client),
+	}
+}
+
+func (pool *ConnPool) Get(token string) (*imapclient.Client, error) {
+	conn, ok := pool.conns[token]
+	if !ok {
+		return nil, ErrSessionExpired
+	}
+	return conn, nil
+}
+
+func (pool *ConnPool) Put(conn *imapclient.Client) (token string, err error) {
+	for {
+		var err error
+		token, err = generateToken()
+		if err != nil {
+			conn.Logout()
+			return "", err
+		}
+
+		if _, ok := pool.conns[token]; !ok {
+			break
+		}
+	}
+
+	pool.conns[token] = conn
+	return token, nil
+}

go.mod

@@ -2,4 +2,7 @@ module git.sr.ht/~emersion/koushin
 
 go 1.13
 
-require github.com/labstack/echo/v4 v4.1.11
+require (
+	github.com/emersion/go-imap v1.0.1
+	github.com/labstack/echo/v4 v4.1.11
+)

go.sum

@@ -1,11 +1,18 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
+github.com/emersion/go-imap v1.0.1 h1:J3duplefIrglQtE63hCGYdGLgMjYWqHvkUUEbimbXY8=
+github.com/emersion/go-imap v1.0.1/go.mod h1:MEiDDwwQFcZ+L45Pa68jNGv0qU9kbW+SJzwDpvSfX1s=
+github.com/emersion/go-message v0.10.4-0.20190609165112-592ace5bc1ca/go.mod h1:3h+HsGTCFHmk4ngJ2IV/YPhdlaOcR6hcgqM3yca9v7c=
+github.com/emersion/go-sasl v0.0.0-20190520160400-47d427600317 h1:tYZxAY8nu3JJQKios9f27Sbvbkfm4XHXT476gVtszu0=
+github.com/emersion/go-sasl v0.0.0-20190520160400-47d427600317/go.mod h1:G/dpzLu16WtQpBfQ/z3LYiYJn3ZhKSGWn83fyoyQe/k=
+github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
 github.com/labstack/echo v3.3.10+incompatible h1:pGRcYk231ExFAyoAjAfD85kQzRJCRI8bbnE7CX5OEgg=
 github.com/labstack/echo/v4 v4.1.11 h1:z0BZoArY4FqdpUEl+wlHp4hnr/oSR6MTmQmv8OHSoww=
 github.com/labstack/echo/v4 v4.1.11/go.mod h1:i541M3Fj6f76NZtHSj7TXnyM8n2gaodfvfxNnFqi74g=
 github.com/labstack/gommon v0.3.0 h1:JEeO0bvc78PKdyHxloTKiF8BD5iGrH8T6MSeGvSgob0=
 github.com/labstack/gommon v0.3.0/go.mod h1:MULnywXg0yavhxWKc+lOruYdAhDwPK9wf0OL7NoOu+k=
+github.com/martinlindhe/base36 v0.0.0-20190418230009-7c6542dfbb41/go.mod h1:+AtEs8xrBpCeYgSLoY/aJ6Wf37jtBuR0s35750M27+8=
 github.com/mattn/go-colorable v0.1.2 h1:/bC9yWikZXAL9uJdulbSfyVNIR3n3trXl+v8+1sx8mU=
 github.com/mattn/go-colorable v0.1.2/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hdxcsrc5s=
@@ -30,5 +37,8 @@ golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a h1:aYOabOQFp6Vj6W1F80affTUvO
 golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

public/login.html

@@ -0,0 +1,14 @@
+{{template "head"}}
+
+<h1>koushin</h1>
+
+<form method="post" action="/login">
+	<p>Username:</p>
+	<input type="text" name="username">
+	<p>Password:</p>
+	<input type="password" name="password">
+	<br><br>
+	<input type="submit" value="Login">
+</form>
+
+{{template "foot"}}

server.go

@@ -1,24 +1,171 @@
 package koushin
 
 import (
+	"fmt"
 	"net/http"
+	"net/url"
+	"time"
 
 	"github.com/labstack/echo/v4"
+	imapclient "github.com/emersion/go-imap/client"
 )
 
-func New() *echo.Echo {
+const cookieName = "koushin_session"
+
+type Server struct {
+	imap struct {
+		host string
+		tls bool
+		insecure bool
+
+		pool *ConnPool
+	}
+}
+
+func NewServer(imapURL string) (*Server, error) {
+	u, err := url.Parse(imapURL)
+	if err != nil {
+		return nil, err
+	}
+
+	s := &Server{}
+	s.imap.host = u.Host
+	switch u.Scheme {
+	case "imap":
+		// This space is intentionally left blank
+	case "imaps":
+		s.imap.tls = true
+	case "imap+insecure":
+		s.imap.insecure = true
+	default:
+		return nil, fmt.Errorf("unrecognized IMAP URL scheme: %s", u.Scheme)
+	}
+
+	s.imap.pool = NewConnPool()
+
+	return s, nil
+}
+
+func (s *Server) connectIMAP() (*imapclient.Client, error) {
+	var c *imapclient.Client
+	var err error
+	if s.imap.tls {
+		c, err = imapclient.DialTLS(s.imap.host, nil)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		c, err = imapclient.Dial(s.imap.host)
+		if err != nil {
+			return nil, err
+		}
+		if !s.imap.insecure {
+			if err := c.StartTLS(nil); err != nil {
+				c.Close()
+				return nil, err
+			}
+		}
+	}
+
+	return c, err
+}
+
+type context struct {
+	echo.Context
+	server *Server
+	conn *imapclient.Client
+}
+
+var aLongTimeAgo = time.Unix(233431200, 0)
+
+func (c *context) setToken(token string) {
+	cookie := http.Cookie{
+		Name: cookieName,
+		Value: token,
+		HttpOnly: true,
+		// TODO: domain, secure
+	}
+	if token == "" {
+		cookie.Expires = aLongTimeAgo // unset the cookie
+	}
+	c.SetCookie(&cookie)
+}
+
+func handleLogin(ectx echo.Context) error {
+	ctx := ectx.(*context)
+	username := ctx.FormValue("username")
+	password := ctx.FormValue("password")
+	if username != "" && password != "" {
+		conn, err := ctx.server.connectIMAP()
+		if err != nil {
+			return err
+		}
+
+		if err := conn.Login(username, password); err != nil {
+			conn.Logout()
+			return ctx.Render(http.StatusOK, "login.html", nil)
+		}
+
+		token, err := ctx.server.imap.pool.Put(conn)
+		if err != nil {
+			return err
+		}
+		ctx.setToken(token)
+
+		return ctx.Redirect(http.StatusFound, "/")
+	}
+
+	return ctx.Render(http.StatusOK, "login.html", nil)
+}
+
+func New(imapURL string) *echo.Echo {
 	e := echo.New()
 
-	var err error
+	s, err := NewServer(imapURL)
+	if err != nil {
+		e.Logger.Fatal(err)
+	}
+
+	e.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(ectx echo.Context) error {
+			ctx := &context{Context: ectx, server: s}
+
+			cookie, err := ctx.Cookie(cookieName)
+			if err == http.ErrNoCookie {
+				return next(ctx)
+			} else if err != nil {
+				return err
+			}
+
+			ctx.conn, err = ctx.server.imap.pool.Get(cookie.Value)
+			if err == ErrSessionExpired {
+				ctx.setToken("")
+				return ctx.Redirect(http.StatusFound, "/login")
+			} else if err != nil {
+				return err
+			}
+
+			return next(ctx)
+		}
+	})
+
 	e.Renderer, err = loadTemplates()
 	if err != nil {
 		e.Logger.Fatal("Failed to load templates:", err)
 	}
 
-	e.GET("/", func(c echo.Context) error {
+	e.GET("/", func(ectx echo.Context) error {
-		return c.Render(http.StatusOK, "index.html", nil)
+		ctx := ectx.(*context)
+		if ctx.conn == nil {
+			return ctx.Redirect(http.StatusFound, "/login")
+		}
+
+		return ctx.Render(http.StatusOK, "index.html", nil)
 	})
 
+	e.GET("/login", handleLogin)
+	e.POST("/login", handleLogin)
+
 	e.Static("/assets", "public/assets")
 
 	return e