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Diffstat (limited to 'src/modules/helloworld.c')
| -rw-r--r-- | src/modules/helloworld.c | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/src/modules/helloworld.c b/src/modules/helloworld.c new file mode 100644 index 000000000..8598de895 --- /dev/null +++ b/src/modules/helloworld.c @@ -0,0 +1,334 @@ +#include "../redismodule.h" +#include <stdio.h> +#include <stdlib.h> +#include <ctype.h> + +/* HELLO.SIMPLE is among the simplest commands you can implement. + * It just returns the currently selected DB id, a functionality which is + * missing in Redis. The command uses two important API calls: one to + * fetch the currently selected DB, the other in order to send the client + * an integer reply as response. */ +int HelloSimple_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + RedisModule_ReplyWithLongLong(ctx,RedisModule_GetSelectedDb(ctx)); + return REDISMODULE_OK; +} + +/* HELLO.PUSH.NATIVE re-implements RPUSH, and shows the low level modules API + * where you can "open" keys, make low level operations, create new keys by + * pushing elements into non-existing keys, and so forth. + * + * You'll find this command to be roughly as fast as the actual RPUSH + * command. */ +int HelloPushNative_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) +{ + if (argc != 3) return RedisModule_WrongArity(ctx); + + RedisModuleKey *key = RedisModule_OpenKey(ctx,argv[1], + REDISMODULE_READ|REDISMODULE_WRITE); + + RedisModule_ListPush(key,REDISMODULE_LIST_TAIL,argv[2]); + size_t newlen = RedisModule_ValueLength(key); + RedisModule_CloseKey(key); + RedisModule_ReplyWithLongLong(ctx,newlen); + return REDISMODULE_OK; +} + +/* HELLO.PUSH.CALL implements RPUSH using an higher level approach, calling + * a Redis command instead of working with the key in a low level way. This + * approach is useful when you need to call Redis commands that are not + * available as low level APIs, or when you don't need the maximum speed + * possible but instead prefer implementation simplicity. */ +int HelloPushCall_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) +{ + if (argc != 3) return RedisModule_WrongArity(ctx); + + RedisModuleCallReply *reply; + + reply = RedisModule_Call(ctx,"RPUSH","ss",argv[1],argv[2]); + long long len = RedisModule_CallReplyInteger(reply); + RedisModule_FreeCallReply(reply); + RedisModule_ReplyWithLongLong(ctx,len); + return REDISMODULE_OK; +} + +/* HELLO.LIST.SUM.LEN returns the total length of all the items inside + * a Redis list, by using the high level Call() API. + * This command is an example of the array reply access. */ +int HelloListSumLen_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) +{ + if (argc != 2) return RedisModule_WrongArity(ctx); + + RedisModuleCallReply *reply; + + reply = RedisModule_Call(ctx,"LRANGE","sll",argv[1],(long long)0,(long long)-1); + size_t strlen = 0; + size_t items = RedisModule_CallReplyLength(reply); + size_t j; + for (j = 0; j < items; j++) { + RedisModuleCallReply *ele = RedisModule_CallReplyArrayElement(reply,j); + strlen += RedisModule_CallReplyLength(ele); + } + RedisModule_FreeCallReply(reply); + RedisModule_ReplyWithLongLong(ctx,strlen); + return REDISMODULE_OK; +} + +/* HELLO.LIST.SPLICE srclist dstlist count + * Moves 'count' elements from the tail of 'srclist' to the head of + * 'dstlist'. If less than count elements are available, it moves as much + * elements as possible. */ +int HelloListSplice_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + if (argc != 4) return RedisModule_WrongArity(ctx); + + RedisModuleKey *srckey = RedisModule_OpenKey(ctx,argv[1], + REDISMODULE_READ|REDISMODULE_WRITE); + RedisModuleKey *dstkey = RedisModule_OpenKey(ctx,argv[2], + REDISMODULE_READ|REDISMODULE_WRITE); + + /* Src and dst key must be empty or lists. */ + if ((RedisModule_KeyType(srckey) != REDISMODULE_KEYTYPE_LIST && + RedisModule_KeyType(srckey) != REDISMODULE_KEYTYPE_EMPTY) || + (RedisModule_KeyType(dstkey) != REDISMODULE_KEYTYPE_LIST && + RedisModule_KeyType(dstkey) != REDISMODULE_KEYTYPE_EMPTY)) + { + RedisModule_CloseKey(srckey); + RedisModule_CloseKey(dstkey); + return RedisModule_ReplyWithError(ctx,REDISMODULE_ERRORMSG_WRONGTYPE); + } + + long long count; + if (RedisModule_StringToLongLong(argv[3],&count) != REDISMODULE_OK) { + RedisModule_CloseKey(srckey); + RedisModule_CloseKey(dstkey); + return RedisModule_ReplyWithError(ctx,"ERR invalid count"); + } + + while(count-- > 0) { + RedisModuleString *ele; + + ele = RedisModule_ListPop(srckey,REDISMODULE_LIST_TAIL); + if (ele == NULL) break; + RedisModule_ListPush(dstkey,REDISMODULE_LIST_HEAD,ele); + RedisModule_FreeString(ctx,ele); + } + + size_t len = RedisModule_ValueLength(srckey); + RedisModule_CloseKey(srckey); + RedisModule_CloseKey(dstkey); + RedisModule_ReplyWithLongLong(ctx,len); + return REDISMODULE_OK; +} + +/* Like the HELLO.LIST.SPLICE above, but uses automatic memory management + * in order to avoid freeing stuff. */ +int HelloListSpliceAuto_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + if (argc != 4) return RedisModule_WrongArity(ctx); + + RedisModule_AutoMemory(ctx); + + RedisModuleKey *srckey = RedisModule_OpenKey(ctx,argv[1], + REDISMODULE_READ|REDISMODULE_WRITE); + RedisModuleKey *dstkey = RedisModule_OpenKey(ctx,argv[2], + REDISMODULE_READ|REDISMODULE_WRITE); + + /* Src and dst key must be empty or lists. */ + if ((RedisModule_KeyType(srckey) != REDISMODULE_KEYTYPE_LIST && + RedisModule_KeyType(srckey) != REDISMODULE_KEYTYPE_EMPTY) || + (RedisModule_KeyType(dstkey) != REDISMODULE_KEYTYPE_LIST && + RedisModule_KeyType(dstkey) != REDISMODULE_KEYTYPE_EMPTY)) + { + return RedisModule_ReplyWithError(ctx,REDISMODULE_ERRORMSG_WRONGTYPE); + } + + long long count; + if (RedisModule_StringToLongLong(argv[3],&count) != REDISMODULE_OK) + return RedisModule_ReplyWithError(ctx,"ERR invalid count"); + + while(count-- > 0) { + RedisModuleString *ele; + + ele = RedisModule_ListPop(srckey,REDISMODULE_LIST_TAIL); + if (ele == NULL) break; + RedisModule_ListPush(dstkey,REDISMODULE_LIST_HEAD,ele); + } + + size_t len = RedisModule_ValueLength(srckey); + RedisModule_ReplyWithLongLong(ctx,len); + return REDISMODULE_OK; +} + +/* HELLO.RAND.ARRAY <count> + * Shows how to generate arrays as commands replies. + * It just outputs <count> random numbers. */ +int HelloRandArray_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + if (argc != 2) return RedisModule_WrongArity(ctx); + long long count; + if (RedisModule_StringToLongLong(argv[1],&count) != REDISMODULE_OK || + count < 0) + return RedisModule_ReplyWithError(ctx,"ERR invalid count"); + + /* To reply with an array, we call RedisModule_ReplyWithArray() followed + * by other "count" calls to other reply functions in order to generate + * the elements of the array. */ + RedisModule_ReplyWithArray(ctx,count); + while(count--) RedisModule_ReplyWithLongLong(ctx,rand()); + return REDISMODULE_OK; +} + +/* This is a simple command to test replication. Because of the "!" modified + * in the RedisModule_Call() call, the two INCRs get replicated. + * Also note how the ECHO is replicated in an unexpected position (check + * comments the function implementation). */ +int HelloRepl1_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) +{ + RedisModuleCallReply *reply; + RedisModule_AutoMemory(ctx); + + /* This will be replicated *after* the two INCR statements, since + * the Call() replication has precedence, so the actual replication + * stream will be: + * + * MULTI + * INCR foo + * INCR bar + * ECHO c foo + * EXEC + */ + RedisModule_Replicate(ctx,"ECHO","c","foo"); + + /* Using the "!" modifier we replicate the command if it + * modified the dataset in some way. */ + reply = RedisModule_Call(ctx,"INCR","c!","foo"); + reply = RedisModule_Call(ctx,"INCR","c!","bar"); + + RedisModule_ReplyWithLongLong(ctx,0); + + return REDISMODULE_OK; +} + +/* Another command to show replication. In this case, we call + * RedisModule_ReplicateVerbatim() to mean we want just the command to be + * propagated to slaves / AOF exactly as it was called by the user. + * + * This command also shows how to work with string objects. + * It takes a list, and increments all the elements (that must have + * a numerical value) by 1, returning the sum of all the elements + * as reply. + * + * Usage: HELLO.REPL2 <list-key> */ +int HelloRepl2_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + if (argc != 2) return RedisModule_WrongArity(ctx); + + RedisModule_AutoMemory(ctx); /* Use automatic memory management. */ + RedisModuleKey *key = RedisModule_OpenKey(ctx,argv[1], + REDISMODULE_READ|REDISMODULE_WRITE); + + if (RedisModule_KeyType(key) != REDISMODULE_KEYTYPE_LIST) + return RedisModule_ReplyWithError(ctx,REDISMODULE_ERRORMSG_WRONGTYPE); + + size_t listlen = RedisModule_ValueLength(key); + long long sum = 0; + + /* Rotate and increment. */ + while(listlen--) { + RedisModuleString *ele = RedisModule_ListPop(key,REDISMODULE_LIST_TAIL); + long long val; + if (RedisModule_StringToLongLong(ele,&val) != REDISMODULE_OK) val = 0; + val++; + sum += val; + RedisModuleString *newele = RedisModule_CreateStringFromLongLong(ctx,val); + RedisModule_ListPush(key,REDISMODULE_LIST_HEAD,newele); + } + RedisModule_ReplyWithLongLong(ctx,sum); + RedisModule_ReplicateVerbatim(ctx); + return REDISMODULE_OK; +} + +/* This is an example of strings DMA access. Given a key containing a string + * it toggles the case of each character from lower to upper case or the + * other way around. + * + * No automatic memory management is used in this example (for the sake + * of variety). + * + * HELLO.TOGGLE.CASE key */ +int HelloToggleCase_RedisCommand(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) { + if (argc != 2) return RedisModule_WrongArity(ctx); + + RedisModuleKey *key = RedisModule_OpenKey(ctx,argv[1], + REDISMODULE_READ|REDISMODULE_WRITE); + + int keytype = RedisModule_KeyType(key); + if (keytype != REDISMODULE_KEYTYPE_STRING && + keytype != REDISMODULE_KEYTYPE_EMPTY) + { + RedisModule_CloseKey(key); + return RedisModule_ReplyWithError(ctx,REDISMODULE_ERRORMSG_WRONGTYPE); + } + + if (keytype == REDISMODULE_KEYTYPE_STRING) { + size_t len, j; + char *s = RedisModule_StringDMA(key,&len,REDISMODULE_WRITE); + for (j = 0; j < len; j++) { + if (isupper(s[j])) { + s[j] = tolower(s[j]); + } else { + s[j] = toupper(s[j]); + } + } + } + + RedisModule_CloseKey(key); + RedisModule_ReplyWithSimpleString(ctx,"OK"); + RedisModule_ReplicateVerbatim(ctx); + 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) { + if (RedisModule_Init(ctx,"helloworld",1,REDISMODULE_APIVER_1) + == REDISMODULE_ERR) return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.simple", + HelloSimple_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.push.native", + HelloPushNative_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.push.call", + HelloPushCall_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.list.sum.len", + HelloListSumLen_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.list.splice", + HelloListSplice_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.list.splice.auto", + HelloListSpliceAuto_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.rand.array", + HelloRandArray_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.repl1", + HelloRepl1_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.repl2", + HelloRepl2_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + if (RedisModule_CreateCommand(ctx,"hello.toggle.case", + HelloToggleCase_RedisCommand) == REDISMODULE_ERR) + return REDISMODULE_ERR; + + return REDISMODULE_OK; +} |