add chat handlers and only allow POST methods

8 files changed, 236 insertions, 128 deletions

diff --git a/srv/api/api.go b/srv/api/api.go
index bbb677a..6ba7ce0 100644
--- a/srv/api/api.go
+++ b/srv/api/api.go
@@ -26,7 +26,7 @@ type Params struct {
 	PowManager       pow.Manager
 	MailingList      mailinglist.MailingList
 	GlobalRoom       chat.Room
-	UserIDCalculator chat.UserIDCalculator
+	UserIDCalculator *chat.UserIDCalculator
 
 	// ListenProto and ListenAddr are passed into net.Listen to create the
 	// API's listener. Both "tcp" and "unix" protocols are explicitly
@@ -165,7 +165,14 @@ func (a *api) handler() http.Handler {
 	apiMux.Handle("/mailinglist/finalize", a.mailingListFinalizeHandler())
 	apiMux.Handle("/mailinglist/unsubscribe", a.mailingListUnsubscribeHandler())
 
+	apiMux.Handle("/chat/global/", http.StripPrefix("/chat/global", newChatHandler(
+		a.params.GlobalRoom,
+		a.params.UserIDCalculator,
+		a.requirePowMiddleware,
+	)))
+
 	var apiHandler http.Handler = apiMux
+	apiHandler = allowedMethod("POST", apiHandler)
 	apiHandler = checkCSRFMiddleware(apiHandler)
 	apiHandler = logMiddleware(a.params.Logger, apiHandler)
 	apiHandler = annotateMiddleware(apiHandler)
diff --git a/srv/api/apiutils/apiutils.go b/srv/api/apiutils/apiutils.go
new file mode 100644
index 0000000..223c2b9
--- /dev/null
+++ b/srv/api/apiutils/apiutils.go
@@ -0,0 +1,112 @@
+// Package apiutils contains utilities which are useful for implementing api
+// endpoints.
+package apiutils
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
+)
+
+type loggerCtxKey int
+
+// SetRequestLogger sets the given Logger onto the given Request's Context,
+// returning a copy.
+func SetRequestLogger(r *http.Request, logger *mlog.Logger) *http.Request {
+	ctx := r.Context()
+	ctx = context.WithValue(ctx, loggerCtxKey(0), logger)
+	return r.WithContext(ctx)
+}
+
+// GetRequestLogger returns the Logger which was set by SetRequestLogger onto
+// this Request, or nil.
+func GetRequestLogger(r *http.Request) *mlog.Logger {
+	ctx := r.Context()
+	logger, _ := ctx.Value(loggerCtxKey(0)).(*mlog.Logger)
+	if logger == nil {
+		logger = mlog.Null
+	}
+	return logger
+}
+
+// JSONResult writes the JSON encoding of the given value as the response body.
+func JSONResult(rw http.ResponseWriter, r *http.Request, v interface{}) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		InternalServerError(rw, r, err)
+		return
+	}
+	b = append(b, '\n')
+
+	rw.Header().Set("Content-Type", "application/json")
+	rw.Write(b)
+}
+
+// BadRequest writes a 400 status and a JSON encoded error struct containing the
+// given error as the response body.
+func BadRequest(rw http.ResponseWriter, r *http.Request, err error) {
+	GetRequestLogger(r).Warn(r.Context(), "bad request", err)
+
+	rw.WriteHeader(400)
+	JSONResult(rw, r, struct {
+		Error string `json:"error"`
+	}{
+		Error: err.Error(),
+	})
+}
+
+// InternalServerError writes a 500 status and a JSON encoded error struct
+// containing a generic error as the response body (though it will log the given
+// one).
+func InternalServerError(rw http.ResponseWriter, r *http.Request, err error) {
+	GetRequestLogger(r).Error(r.Context(), "internal server error", err)
+
+	rw.WriteHeader(500)
+	JSONResult(rw, r, struct {
+		Error string `json:"error"`
+	}{
+		Error: "internal server error",
+	})
+}
+
+// StrToInt parses the given string as an integer, or returns the given default
+// integer if the string is empty.
+func StrToInt(str string, defaultVal int) (int, error) {
+	if str == "" {
+		return defaultVal, nil
+	}
+	return strconv.Atoi(str)
+}
+
+// GetCookie returns the namd cookie's value, or the given default value if the
+// cookie is not set.
+//
+// This will only return an error if there was an unexpected error parsing the
+// Request's cookies.
+func GetCookie(r *http.Request, cookieName, defaultVal string) (string, error) {
+	c, err := r.Cookie(cookieName)
+	if errors.Is(err, http.ErrNoCookie) {
+		return defaultVal, nil
+	} else if err != nil {
+		return "", fmt.Errorf("reading cookie %q: %w", cookieName, err)
+	}
+
+	return c.Value, nil
+}
+
+// RandStr returns a human-readable random string with the given number of bytes
+// of randomness.
+func RandStr(numBytes int) string {
+	b := make([]byte, numBytes)
+	if _, err := rand.Read(b); err != nil {
+		panic(err)
+	}
+	return hex.EncodeToString(b)
+}
diff --git a/srv/api/chat.go b/srv/api/chat.go
index 55d9d02..4ac32e4 100644
--- a/srv/api/chat.go
+++ b/srv/api/chat.go
@@ -7,32 +7,57 @@ import (
 	"strings"
 	"unicode"
 
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/chat"
 )
 
-func (a *api) chatHistoryHandler() http.Handler {
+type chatHandler struct {
+	*http.ServeMux
+
+	room       chat.Room
+	userIDCalc *chat.UserIDCalculator
+}
+
+func newChatHandler(
+	room chat.Room, userIDCalc *chat.UserIDCalculator,
+	requirePowMiddleware func(http.Handler) http.Handler,
+) http.Handler {
+	c := &chatHandler{
+		ServeMux:   http.NewServeMux(),
+		room:       room,
+		userIDCalc: userIDCalc,
+	}
+
+	c.Handle("/history", c.historyHandler())
+	c.Handle("/user-id", requirePowMiddleware(c.userIDHandler()))
+	c.Handle("/append", requirePowMiddleware(c.appendHandler()))
+
+	return c
+}
+
+func (c *chatHandler) historyHandler() http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
-		limit, err := strToInt(r.FormValue("limit"), 0)
+		limit, err := apiutils.StrToInt(r.PostFormValue("limit"), 0)
 		if err != nil {
-			badRequest(rw, r, fmt.Errorf("invalid limit parameter: %w", err))
+			apiutils.BadRequest(rw, r, fmt.Errorf("invalid limit parameter: %w", err))
 			return
 		}
 
-		cursor := r.FormValue("cursor")
+		cursor := r.PostFormValue("cursor")
 
-		cursor, msgs, err := a.params.GlobalRoom.History(r.Context(), chat.HistoryOpts{
+		cursor, msgs, err := c.room.History(r.Context(), chat.HistoryOpts{
 			Limit:  limit,
 			Cursor: cursor,
 		})
 
 		if argErr := (chat.ErrInvalidArg{}); errors.As(err, &argErr) {
-			badRequest(rw, r, argErr.Err)
+			apiutils.BadRequest(rw, r, argErr.Err)
 			return
 		} else if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 		}
 
-		jsonResult(rw, r, struct {
+		apiutils.JSONResult(rw, r, struct {
 			Cursor   string         `json:"cursor"`
 			Messages []chat.Message `json:"messages"`
 		}{
@@ -42,7 +67,7 @@ func (a *api) chatHistoryHandler() http.Handler {
 	})
 }
 
-func (a *api) getUserID(r *http.Request) (chat.UserID, error) {
+func (c *chatHandler) userID(r *http.Request) (chat.UserID, error) {
 	name := r.PostFormValue("name")
 	if l := len(name); l == 0 {
 		return chat.UserID{}, errors.New("name is required")
@@ -68,21 +93,58 @@ func (a *api) getUserID(r *http.Request) (chat.UserID, error) {
 		return chat.UserID{}, errors.New("password too long")
 	}
 
-	return a.params.UserIDCalculator.Calculate(name, password), nil
+	return c.userIDCalc.Calculate(name, password), nil
 }
 
-func (a *api) getUserIDHandler() http.Handler {
+func (c *chatHandler) userIDHandler() http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
-		userID, err := a.getUserID(r)
+		userID, err := c.userID(r)
 		if err != nil {
-			badRequest(rw, r, err)
+			apiutils.BadRequest(rw, r, err)
 			return
 		}
 
-		jsonResult(rw, r, struct {
+		apiutils.JSONResult(rw, r, struct {
 			UserID chat.UserID `json:"userID"`
 		}{
 			UserID: userID,
 		})
 	})
 }
+
+func (c *chatHandler) appendHandler() http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		userID, err := c.userID(r)
+		if err != nil {
+			apiutils.BadRequest(rw, r, err)
+			return
+		}
+
+		body := r.PostFormValue("body")
+
+		if l := len(body); l == 0 {
+			apiutils.BadRequest(rw, r, errors.New("body is required"))
+			return
+
+		} else if l > 300 {
+			apiutils.BadRequest(rw, r, errors.New("body too long"))
+			return
+		}
+
+		msg, err := c.room.Append(r.Context(), chat.Message{
+			UserID: userID,
+			Body:   body,
+		})
+
+		if err != nil {
+			apiutils.InternalServerError(rw, r, err)
+			return
+		}
+
+		apiutils.JSONResult(rw, r, struct {
+			MessageID string `json:"messageID"`
+		}{
+			MessageID: msg.ID,
+		})
+	})
+}
diff --git a/srv/api/csrf.go b/srv/api/csrf.go
index d705adb..0802d8a 100644
--- a/srv/api/csrf.go
+++ b/srv/api/csrf.go
@@ -3,6 +3,8 @@ package api
 import (
 	"errors"
 	"net/http"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
 )
 
 const (
@@ -13,16 +15,16 @@ const (
 func setCSRFMiddleware(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
-		csrfTok, err := getCookie(r, csrfTokenCookieName, "")
+		csrfTok, err := apiutils.GetCookie(r, csrfTokenCookieName, "")
 
 		if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 			return
 
 		} else if csrfTok == "" {
 			http.SetCookie(rw, &http.Cookie{
 				Name:   csrfTokenCookieName,
-				Value:  randStr(32),
+				Value:  apiutils.RandStr(32),
 				Secure: true,
 			})
 		}
@@ -34,14 +36,14 @@ func setCSRFMiddleware(h http.Handler) http.Handler {
 func checkCSRFMiddleware(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
-		csrfTok, err := getCookie(r, csrfTokenCookieName, "")
+		csrfTok, err := apiutils.GetCookie(r, csrfTokenCookieName, "")
 
 		if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 			return
 
 		} else if csrfTok == "" || r.Header.Get(csrfTokenHeaderName) != csrfTok {
-			badRequest(rw, r, errors.New("invalid CSRF token"))
+			apiutils.BadRequest(rw, r, errors.New("invalid CSRF token"))
 			return
 		}
 
diff --git a/srv/api/mailinglist.go b/srv/api/mailinglist.go
index 2ddfbe6..d89fe2a 100644
--- a/srv/api/mailinglist.go
+++ b/srv/api/mailinglist.go
@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
 	"github.com/mediocregopher/blog.mediocregopher.com/srv/mailinglist"
 )
 
@@ -15,7 +16,7 @@ func (a *api) mailingListSubscribeHandler() http.Handler {
 			parts[0] == "" ||
 			parts[1] == "" ||
 			len(email) >= 512 {
-			badRequest(rw, r, errors.New("invalid email"))
+			apiutils.BadRequest(rw, r, errors.New("invalid email"))
 			return
 		}
 
@@ -25,11 +26,11 @@ func (a *api) mailingListSubscribeHandler() http.Handler {
 			// just eat the error, make it look to the user like the
 			// verification email was sent.
 		} else if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 			return
 		}
 
-		jsonResult(rw, r, struct{}{})
+		apiutils.JSONResult(rw, r, struct{}{})
 	})
 }
 
@@ -39,25 +40,25 @@ func (a *api) mailingListFinalizeHandler() http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 		subToken := r.PostFormValue("subToken")
 		if l := len(subToken); l == 0 || l > 128 {
-			badRequest(rw, r, errInvalidSubToken)
+			apiutils.BadRequest(rw, r, errInvalidSubToken)
 			return
 		}
 
 		err := a.params.MailingList.FinalizeSubscription(subToken)
 
 		if errors.Is(err, mailinglist.ErrNotFound) {
-			badRequest(rw, r, errInvalidSubToken)
+			apiutils.BadRequest(rw, r, errInvalidSubToken)
 			return
 
 		} else if errors.Is(err, mailinglist.ErrAlreadyVerified) {
 			// no problem
 
 		} else if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 			return
 		}
 
-		jsonResult(rw, r, struct{}{})
+		apiutils.JSONResult(rw, r, struct{}{})
 	})
 }
 
@@ -67,21 +68,21 @@ func (a *api) mailingListUnsubscribeHandler() http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 		unsubToken := r.PostFormValue("unsubToken")
 		if l := len(unsubToken); l == 0 || l > 128 {
-			badRequest(rw, r, errInvalidUnsubToken)
+			apiutils.BadRequest(rw, r, errInvalidUnsubToken)
 			return
 		}
 
 		err := a.params.MailingList.Unsubscribe(unsubToken)
 
 		if errors.Is(err, mailinglist.ErrNotFound) {
-			badRequest(rw, r, errInvalidUnsubToken)
+			apiutils.BadRequest(rw, r, errInvalidUnsubToken)
 			return
 
 		} else if err != nil {
-			internalServerError(rw, r, err)
+			apiutils.InternalServerError(rw, r, err)
 			return
 		}
 
-		jsonResult(rw, r, struct{}{})
+		apiutils.JSONResult(rw, r, struct{}{})
 	})
 }
diff --git a/srv/api/middleware.go b/srv/api/middleware.go
index e3e85bb..2605d93 100644
--- a/srv/api/middleware.go
+++ b/srv/api/middleware.go
@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mctx"
 	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
 )
@@ -57,7 +58,7 @@ func (lrw *logResponseWriter) WriteHeader(statusCode int) {
 func logMiddleware(logger *mlog.Logger, h http.Handler) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 
-		r = setRequestLogger(r, logger)
+		r = apiutils.SetRequestLogger(r, logger)
 
 		lrw := newLogResponseWriter(rw)
 
@@ -76,3 +77,15 @@ func logMiddleware(logger *mlog.Logger, h http.Handler) http.Handler {
 		logger.Info(ctx, "handled HTTP request")
 	})
 }
+
+func allowedMethod(method string, h http.Handler) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		if r.Method == method {
+			h.ServeHTTP(rw, r)
+			return
+		}
+
+		apiutils.GetRequestLogger(r).WarnString(r.Context(), "method not allowed")
+		rw.WriteHeader(405)
+	})
+}
diff --git a/srv/api/pow.go b/srv/api/pow.go
index 096e252..6d11061 100644
--- a/srv/api/pow.go
+++ b/srv/api/pow.go
@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/api/apiutils"
 )
 
 func (a *api) newPowChallengeHandler() http.Handler {
@@ -12,7 +14,7 @@ func (a *api) newPowChallengeHandler() http.Handler {
 
 		challenge := a.params.PowManager.NewChallenge()
 
-		jsonResult(rw, r, struct {
+		apiutils.JSONResult(rw, r, struct {
 			Seed   string `json:"seed"`
 			Target uint32 `json:"target"`
 		}{
@@ -28,21 +30,21 @@ func (a *api) requirePowMiddleware(h http.Handler) http.Handler {
 		seedHex := r.PostFormValue("powSeed")
 		seed, err := hex.DecodeString(seedHex)
 		if err != nil || len(seed) == 0 {
-			badRequest(rw, r, errors.New("invalid powSeed"))
+			apiutils.BadRequest(rw, r, errors.New("invalid powSeed"))
 			return
 		}
 
 		solutionHex := r.PostFormValue("powSolution")
 		solution, err := hex.DecodeString(solutionHex)
 		if err != nil || len(seed) == 0 {
-			badRequest(rw, r, errors.New("invalid powSolution"))
+			apiutils.BadRequest(rw, r, errors.New("invalid powSolution"))
 			return
 		}
 
 		err = a.params.PowManager.CheckSolution(seed, solution)
 
 		if err != nil {
-			badRequest(rw, r, fmt.Errorf("checking proof-of-work solution: %w", err))
+			apiutils.BadRequest(rw, r, fmt.Errorf("checking proof-of-work solution: %w", err))
 			return
 		}
 
diff --git a/srv/api/utils.go b/srv/api/utils.go
deleted file mode 100644
index 2cf40b6..0000000
--- a/srv/api/utils.go
+++ /dev/null
@@ -1,91 +0,0 @@
-package api
-
-import (
-	"context"
-	"crypto/rand"
-	"encoding/hex"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net/http"
-	"strconv"
-
-	"github.com/mediocregopher/mediocre-go-lib/v2/mlog"
-)
-
-type loggerCtxKey int
-
-func setRequestLogger(r *http.Request, logger *mlog.Logger) *http.Request {
-	ctx := r.Context()
-	ctx = context.WithValue(ctx, loggerCtxKey(0), logger)
-	return r.WithContext(ctx)
-}
-
-func getRequestLogger(r *http.Request) *mlog.Logger {
-	ctx := r.Context()
-	logger, _ := ctx.Value(loggerCtxKey(0)).(*mlog.Logger)
-	if logger == nil {
-		logger = mlog.Null
-	}
-	return logger
-}
-
-func jsonResult(rw http.ResponseWriter, r *http.Request, v interface{}) {
-	b, err := json.Marshal(v)
-	if err != nil {
-		internalServerError(rw, r, err)
-		return
-	}
-	b = append(b, '\n')
-
-	rw.Header().Set("Content-Type", "application/json")
-	rw.Write(b)
-}
-
-func badRequest(rw http.ResponseWriter, r *http.Request, err error) {
-	getRequestLogger(r).Warn(r.Context(), "bad request", err)
-
-	rw.WriteHeader(400)
-	jsonResult(rw, r, struct {
-		Error string `json:"error"`
-	}{
-		Error: err.Error(),
-	})
-}
-
-func internalServerError(rw http.ResponseWriter, r *http.Request, err error) {
-	getRequestLogger(r).Error(r.Context(), "internal server error", err)
-
-	rw.WriteHeader(500)
-	jsonResult(rw, r, struct {
-		Error string `json:"error"`
-	}{
-		Error: "internal server error",
-	})
-}
-
-func strToInt(str string, defaultVal int) (int, error) {
-	if str == "" {
-		return defaultVal, nil
-	}
-	return strconv.Atoi(str)
-}
-
-func getCookie(r *http.Request, cookieName, defaultVal string) (string, error) {
-	c, err := r.Cookie(cookieName)
-	if errors.Is(err, http.ErrNoCookie) {
-		return defaultVal, nil
-	} else if err != nil {
-		return "", fmt.Errorf("reading cookie %q: %w", cookieName, err)
-	}
-
-	return c.Value, nil
-}
-
-func randStr(numBytesEntropy int) string {
-	b := make([]byte, numBytesEntropy)
-	if _, err := rand.Read(b); err != nil {
-		panic(err)
-	}
-	return hex.EncodeToString(b)
-}