1 files changed, 111 insertions, 0 deletions
diff --git a/examples/redis-unstable/src/modules/hellodict.c b/examples/redis-unstable/src/modules/hellodict.c
new file mode 100644
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+++ b/examples/redis-unstable/src/modules/hellodict.c
@@ -0,0 +1,111 @@
+/* Hellodict -- An example of modules dictionary API
+ *
+ * This module implements a volatile key-value store on top of the
+ * dictionary exported by the Redis modules API.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Copyright (c) 2018-Present, Redis Ltd.
+ * All rights reserved.
+ *
+ * Licensed under your choice of (a) the Redis Source Available License 2.0
+ * (RSALv2); or (b) the Server Side Public License v1 (SSPLv1); or (c) the
+ * GNU Affero General Public License v3 (AGPLv3).
+ */
+
+#include "../redismodule.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+
+static RedisModuleDict *Keyspace;
+
+/* HELLODICT.SET <key> <value>
+ *
+ * Set the specified key to the specified value. */
+int cmd_SET(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 3) return RedisModule_WrongArity(ctx);
+    RedisModule_DictSet(Keyspace,argv[1],argv[2]);
+    /* We need to keep a reference to the value stored at the key, otherwise
+     * it would be freed when this callback returns. */
+    RedisModule_RetainString(NULL,argv[2]);
+    return RedisModule_ReplyWithSimpleString(ctx, "OK");
+}
+
+/* HELLODICT.GET <key>
+ *
+ * Return the value of the specified key, or a null reply if the key
+ * is not defined. */
+int cmd_GET(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 2) return RedisModule_WrongArity(ctx);
+    RedisModuleString *val = RedisModule_DictGet(Keyspace,argv[1],NULL);
+    if (val == NULL) {
+        return RedisModule_ReplyWithNull(ctx);
+    } else {
+        return RedisModule_ReplyWithString(ctx, val);
+    }
+}
+
+/* HELLODICT.KEYRANGE <startkey> <endkey> <count>
+ *
+ * Return a list of matching keys, lexicographically between startkey
+ * and endkey. No more than 'count' items are emitted. */
+int cmd_KEYRANGE(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    if (argc != 4) return RedisModule_WrongArity(ctx);
+
+    /* Parse the count argument. */
+    long long count;
+    if (RedisModule_StringToLongLong(argv[3],&count) != REDISMODULE_OK) {
+        return RedisModule_ReplyWithError(ctx,"ERR invalid count");
+    }
+
+    /* Seek the iterator. */
+    RedisModuleDictIter *iter = RedisModule_DictIteratorStart(
+        Keyspace, ">=", argv[1]);
+
+    /* Reply with the matching items. */
+    char *key;
+    size_t keylen;
+    long long replylen = 0; /* Keep track of the emitted array len. */
+    RedisModule_ReplyWithArray(ctx,REDISMODULE_POSTPONED_LEN);
+    while((key = RedisModule_DictNextC(iter,&keylen,NULL)) != NULL) {
+        if (replylen >= count) break;
+        if (RedisModule_DictCompare(iter,"<=",argv[2]) == REDISMODULE_ERR)
+            break;
+        RedisModule_ReplyWithStringBuffer(ctx,key,keylen);
+        replylen++;
+    }
+    RedisModule_ReplySetArrayLength(ctx,replylen);
+
+    /* Cleanup. */
+    RedisModule_DictIteratorStop(iter);
+    return REDISMODULE_OK;
+}
+
+/* This function must be present on each Redis module. It is used in order to
+ * register the commands into the Redis server. */
+int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
+    REDISMODULE_NOT_USED(argv);
+    REDISMODULE_NOT_USED(argc);
+
+    if (RedisModule_Init(ctx,"hellodict",1,REDISMODULE_APIVER_1)
+        == REDISMODULE_ERR) return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"hellodict.set",
+        cmd_SET,"write deny-oom",1,1,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"hellodict.get",
+        cmd_GET,"readonly",1,1,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    if (RedisModule_CreateCommand(ctx,"hellodict.keyrange",
+        cmd_KEYRANGE,"readonly",1,1,0) == REDISMODULE_ERR)
+        return REDISMODULE_ERR;
+
+    /* Create our global dictionary. Here we'll set our keys and values. */
+    Keyspace = RedisModule_CreateDict(NULL);
+
+    return REDISMODULE_OK;
+}