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Modules: hellodict example WIP #3: KEYRANGE.

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antirez 2018-09-27 17:01:32 +02:00
parent 0aecb135c9
commit 5aa347b377
1 changed files with 40 additions and 0 deletions
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40
src/modules/hellodict.c
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@ -68,6 +68,42 @@ int cmd_GET(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
}
}
/* 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 amitted array len. */
RedisModule_ReplyWithArray(ctx,REDISMODULE_POSTPONED_ARRAY_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) {
@ -85,6 +121,10 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
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 dictionray. Here we'll set our keys and values. */
Keyspace = RedisModule_CreateDict(NULL);