Gopher: initial request handling.

src/Makefile

@@ -164,7 +164,7 @@ endif
 
 REDIS_SERVER_NAME=redis-server
 REDIS_SENTINEL_NAME=redis-sentinel
-REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o acl.o
+REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o acl.o gopher.o
 REDIS_CLI_NAME=redis-cli
 REDIS_CLI_OBJ=anet.o adlist.o dict.o redis-cli.o zmalloc.o release.o anet.o ae.o crc64.o siphash.o crc16.o
 REDIS_BENCHMARK_NAME=redis-benchmark

src/gopher.c

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2019, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "server.h"
+
+/* Emit an item in Gopher directory listing format:
+ * <type><descr><TAB><selector><TAB><hostname><TAB><port>
+ * If descr or selector are NULL, then the "(NULL)" string is used instead. */
+void addReplyGopherItem(client *c, const char *type, const char *descr,
+                        const char *selector, const char *hostname, int port)
+{
+    sds item = sdscatfmt(sdsempty(),"%s%s\t%s\t%s\t%i\r\n",
+                         type, descr,
+                         selector ? selector : "(NULL)",
+                         hostname ? hostname : "(NULL)",
+                         port);
+    addReplyProto(c,item,sdslen(item));
+    sdsfree(item);
+}
+
+/* This is called by processInputBuffer() when an inline request is processed
+ * with Gopher mode enabled, and the request happens to have zero or just one
+ * argument. In such case we get the relevant key and reply using the Gopher
+ * protocol. */
+void processGopherRequest(client *c) {
+    robj *keyname = c->argc == 0 ? createStringObject("/",1) : c->argv[1];
+    robj *o = lookupKeyRead(c->db,keyname);
+
+    /* If there is no such key, return with a Gopher error. */
+    if (o == NULL || o->type != OBJ_STRING) {
+        char *errstr;
+        if (o == NULL)
+            errstr = "Error: no content at the specified key";
+        else
+            errstr = "Error: selected key type is invalid "
+                     "for Gopher output";
+        addReplyGopherItem(c,"i",errstr,NULL,NULL,0);
+        addReplyGopherItem(c,"i","Redis Gopher server",NULL,NULL,0);
+    } else {
+    }
+
+    /* Cleanup, also make sure to emit the final ".CRLF" line. Note that
+     * the connection will be closed immediately after this because the client
+     * will be flagged with CLIENT_CLOSE_AFTER_REPLY, in accordance with the
+     * Gopher protocol. */
+    if (c->argc == 0) decrRefCount(keyname);
+    addReplyProto(c,".\r\n",3);
+}

src/networking.c

@@ -1564,6 +1564,14 @@ void processInputBuffer(client *c) {
 
         if (c->reqtype == PROTO_REQ_INLINE) {
             if (processInlineBuffer(c) != C_OK) break;
+            /* If the Gopher mode and we got zero or one argument, process
+             * the request in Gopher mode. */
+            if (server.gopher_enabled && (c->argc == 1 || c->argc == 0)) {
+                processGopherRequest(c);
+                resetClient(c);
+                c->flags |= CLIENT_CLOSE_AFTER_REPLY;
+                break;
+            }
         } else if (c->reqtype == PROTO_REQ_MULTIBULK) {
             if (processMultibulkBuffer(c) != C_OK) break;
         } else {

src/server.h

@@ -1514,6 +1514,7 @@ void setDeferredAttributeLen(client *c, void *node, long length);
 void setDeferredPushLen(client *c, void *node, long length);
 void processInputBuffer(client *c);
 void processInputBufferAndReplicate(client *c);
+void processGopherRequest(client *c);
 void acceptHandler(aeEventLoop *el, int fd, void *privdata, int mask);
 void acceptTcpHandler(aeEventLoop *el, int fd, void *privdata, int mask);
 void acceptUnixHandler(aeEventLoop *el, int fd, void *privdata, int mask);