Redbean getstatus and more (#308)

* Add GetBody() Lua API to redbean.
   This improves consistency with RFC 7230 terminology and
   should be favored over the old GetPayload function.
* Add GetStatus() API to redbean.
   This is useful to get status after it's changed/set by Redbean,
   for example if 505 or 508 is set when ServeRedirect is called.
* Introduce GetAssetComment() API to redbean.
   This function should be favored over the old name GetComment().
* Introduce IsLoopbackClient() API to redbean
* Limit redbean reason to 128 chars when set instead of reporting an error

tool/net/help.txt

@@ -597,6 +597,10 @@ FUNCTIONS
            Turns integer like 0x01020304 into a string like 1.2.3.4. See also
            ParseIp for the inverse operation.
 
+   GetAssetComment(path:str) → str
+           Returns comment text associated with asset in the ZIP central
+           directory. Also available as GetComment (deprecated).
+
    GetAssetMode(path:str) → int
            Returns UNIX-style octal mode for ZIP asset (or local file if the
            -D flag is used)
@@ -605,9 +609,9 @@ FUNCTIONS
            Returns byte size of uncompressed contents of ZIP asset (or local
            file if the -D flag is used)
 
-   GetComment(path:str) → str
+   GetBody() → str
-           Returns comment text associated with asset in the ZIP central
+           Returns the request message body if present or an empty string.
-           directory.
+           Also available as GetPayload (deprecated).
 
    GetCookie(name:str) → str
            Returns cookie value.
@@ -714,13 +718,13 @@ FUNCTIONS
    GetScheme() → str
            Returns scheme from Request-URL, if any.
 
+   GetStatus() → int
+           Returns current status (as set by an earlier SetStatus call) or
+           `nil` if the status hasn't been set yet.
+
    GetTime() → seconds:number
            Returns current time as a UNIX timestamp with 0.0001s precision.
 
-   GetPayload() → str
-           Returns the request message payload, or empty string if there
-           isn't one.
-
    GetUrl() → str
            Returns the effective Request-URL as an ASCII string, where
            illegal characters or UTF-8 is guaranteed to be percent encoded,
@@ -763,6 +767,10 @@ FUNCTIONS
            Returns true if IP address is part of a private network
            (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16).
 
+   IsLoopbackClient() → bool
+           Returns true if the client IP address (returned by GetRemoteAddr)
+           is part of the localhost network (127.0.0.0/8).
+
    IsLoopbackIp(uint32) → bool
            Returns true if IP address is part of the localhost network
            (127.0.0.0/8).

tool/net/redbean.c

@@ -3143,7 +3143,7 @@ static int LuaRespond(lua_State *L, char *R(unsigned, const char *)) {
     luaheaderp = R(code, GetHttpReason(code));
   } else {
     reason = lua_tolstring(L, 2, &reasonlen);
-    if (reasonlen < 128 && (p = EncodeHttpHeaderValue(reason, reasonlen, 0))) {
+    if ((p = EncodeHttpHeaderValue(reason, MIN(reasonlen, 128), 0))) {
       luaheaderp = R(code, p);
       free(p);
     } else {
@@ -3158,6 +3158,15 @@ static int LuaSetStatus(lua_State *L) {
   return LuaRespond(L, SetStatus);
 }
 
+static int LuaGetStatus(lua_State *L) {
+  OnlyCallDuringRequest(L, "GetStatus");
+  if (!luaheaderp)
+    lua_pushnil(L);
+  else
+    lua_pushinteger(L, statuscode);
+  return 1;
+}
+
 static int LuaServeError(lua_State *L) {
   return LuaRespond(L, ServeError);
 }
@@ -3971,6 +3980,12 @@ static int LuaIsLoopbackIp(lua_State *L) {
   return LuaIsIp(L, IsLoopbackIp);
 }
 
+static int LuaIsLoopbackClient(lua_State *L) {
+  OnlyCallDuringRequest(L, "IsLoopbackClient");
+  lua_pushboolean(L, IsLoopbackClient());
+  return 1;
+}
+
 static int LuaCategorizeIp(lua_State *L) {
   lua_pushstring(L, GetIpCategoryName(CategorizeIp(luaL_checkinteger(L, 1))));
   return 1;
@@ -4088,7 +4103,7 @@ static int LuaParseHttpDateTime(lua_State *L) {
   return 1;
 }
 
-static int LuaGetPayload(lua_State *L) {
+static int LuaGetBody(lua_State *L) {
   lua_pushlstring(L, inbuf.p + hdrsize, payloadlength);
   return 1;
 }
@@ -5083,7 +5098,7 @@ static int LuaIsDaemon(lua_State *L) {
   return 1;
 }
 
-static int LuaGetComment(lua_State *L) {
+static int LuaGetAssetComment(lua_State *L) {
   struct Asset *a;
   const char *path;
   size_t pathlen, m;
@@ -5316,10 +5331,13 @@ static const luaL_Reg kLuaFuncs[] = {
     {"Fetch", LuaFetch},                                        //
     {"FormatHttpDateTime", LuaFormatHttpDateTime},              //
     {"FormatIp", LuaFormatIp},                                  //
+    {"GetAssetComment", LuaGetAssetComment},                    //
+    {"GetComment", LuaGetAssetComment},                         //
     {"GetAssetMode", LuaGetAssetMode},                          //
     {"GetAssetSize", LuaGetAssetSize},                          //
+    {"GetBody", LuaGetBody},                                    //
+    {"GetPayload", LuaGetBody},                                 //
     {"GetClientAddr", LuaGetClientAddr},                        //
-    {"GetComment", LuaGetComment},                              //
     {"GetCookie", LuaGetCookie},                                //
     {"GetDate", LuaGetDate},                                    //
     {"GetEffectivePath", LuaGetEffectivePath},                  //
@@ -5338,13 +5356,13 @@ static const luaL_Reg kLuaFuncs[] = {
     {"GetParams", LuaGetParams},                                //
     {"GetPass", LuaGetPass},                                    //
     {"GetPath", LuaGetPath},                                    //
-    {"GetPayload", LuaGetPayload},                              //
     {"GetPort", LuaGetPort},                                    //
     {"GetRandomBytes", LuaGetRandomBytes},                      //
     {"GetRedbeanVersion", LuaGetRedbeanVersion},                //
     {"GetRemoteAddr", LuaGetRemoteAddr},                        //
     {"GetScheme", LuaGetScheme},                                //
     {"GetServerAddr", LuaGetServerAddr},                        //
+    {"GetStatus", LuaGetStatus},                                //
     {"GetTime", LuaGetTime},                                    //
     {"GetUrl", LuaGetUrl},                                      //
     {"GetUser", LuaGetUser},                                    //
@@ -5359,6 +5377,7 @@ static const luaL_Reg kLuaFuncs[] = {
     {"IsCompressed", LuaIsCompressed},                          //
     {"IsDaemon", LuaIsDaemon},                                  //
     {"IsHiddenPath", LuaIsHiddenPath},                          //
+    {"IsLoopbackClient", LuaIsLoopbackClient},                  //
     {"IsLoopbackIp", LuaIsLoopbackIp},                          //
     {"IsPrivateIp", LuaIsPrivateIp},                            //
     {"IsPublicIp", LuaIsPublicIp},                              //