# fakeredis - a fake redis for node.js This module provides easy-to-use simulated instances of Redis to which you appear to be connected via the [redis](https://github.com/mranney/node_redis) client by [Matt Ranney](https://github.com/mranney). **It helps with writing tests** in two ways: your tests won't require an actual redis instance and you'll be able to safely run as many tests in parallel as you want. [![NPM Version](https://nodei.co/npm/fakeredis.png?downloads=true)](https://npmjs.org/package/fakeredis) [![Build Status](https://secure.travis-ci.org/hdachev/fakeredis.png?branch=master)](http://travis-ci.org/hdachev/fakeredis) ## Usage Install: npm install fakeredis You can use fakeredis as you would use node_redis, just changing the module name from `redis` to `fakeredis`: ```javascript var client = require("fakeredis").createClient(port, host); ``` Both parameters are optional, and only serve to determine if you want to reuse a an existing fakeredis instance or not. You can also just name your backends arbitrarily: ```javascript // Create a connection to a fresh fakeredis instance: var client = fakeredis.createClient("social stuff"); // Connect to the same backend via another simulated connection: var concurrentClient = fakeredis.createClient("social stuff"); ``` By omitting both parameters, you simply create a new blank slate fakeredis instance: ```javascript var client = require("fakeredis").createClient(); ``` In other words, every time you create a client specifying the same port and/or name you reuse the same simulated backend. This makes most sense when you need a concurrent client setup for some test, say because you need to publish / subscribe, or because you want to test something that's based on `MULTI`/`EXEC` and uses optimistic locking with `WATCH`/`UNWATCH`. In any case, fakeredis is great for testing because you can run as many tests in parallel as you wish, and that's also why you'll generally be naming your clients in a way that ensures tests don't collide. ## Intended differences from a true Redis One key difference is that the output of some commands, such as `SMEMBERS`, `HKEYS`, `HVALS`, comes out sorted lexicographically to provide for simpler testing. This means that some tests that make use of undocumented Redis behaviours such as the chronological order of retrieval for members in a set may fail when attempted with fakeredis. To solve this, whenever there is no documented sort order for a given Redis command's multi-bulk reply, sort the output before asserting equality to ensure your tests run everywhere. Another major difference is that commands that accept modifier parameters, such as `SORT key [BY pattern] [LIMIT offset count] [GET pattern [GET pattern ...]] [ASC|DESC] [ALPHA] [STORE destination]` currently only accept these parameters in the order that is stated in the documentation. For example, in Redis it appears to be perfectly legitimate to have `SORT myset ALPHA LIMIT 0 5`, but in fakeredis this will currently return a syntax error. I'm totally open to discussion on both points. ### Implemented subset: All string, list, hash, set and sorted set commands, most keyspace commands, and some connection and server commands. Pubsub, transactions with optimistic locking are also fully implemented. List of **available** commands: Keyspace: DBSIZE EXISTS EXPIRE EXPIREAT FLUSHDB KEYS PERSIST DEL RANDOMKEY RENAME RENAMENX SORT TTL TYPE Strings: APPEND DECR DECRBY GET GETBIT GETRANGE GETSET INCR INCRBY MGET MSET MSETNX SET SETBIT SETEX SETNX SETRANGE Hashes: HDEL HEXISTS HGET HGETALL HINCRBY HKEYS HLEN HMGET HMSET HSET HSETNX HVALS Lists: BLPOP BRPOP BRPOPLPUSH LINDEX LINSERT LLEN LPOP LPUSH LPUSHX LRANGE LREM LSET LTRIM RPOP RPOPLPUSH RPUSH RPUSHX Sets: SADD SCARD SDIFF SDIFFSTORE SINTER SINTERSTORE SISMEMBER SMEMBERS SMOVE SPOP SRANDMEMBER SREM STRLEN SUNION SUNIONSTORE Sorted Sets: ZADD ZCARD ZCOUNT ZINCRBY ZINTERSTORE ZRANGE ZRANGEBYSCORE ZRANK ZREM ZREMRANGEBYRANK ZREMRANGEBYSCORE ZREVRANGE ZREVRANGEBYSCORE ZREVRANK ZSCORE ZUNIONSTORE Pub/Sub: PSUBSCRIBE PUBLISH PUNSUBSCRIBE SUBSCRIBE UNSUBSCRIBE Transactions: DISCARD EXEC MULTI UNWATCH WATCH Connection and Server: ECHO PING QUIT SELECT These do nothing but return `OK`: AUTH BGREWRITEAOF BGSAVE SAVE ### What's missing: Most notably, `MONITOR` is still missing. Also note that **none of the node_redis client constructor options are available**, which means no `detect_buffers` and `return_buffers`. Command arguments are always stringified at the fake connection level, and replies are always returned as `null`, `String`, `Number` or `Array`. Finally, none of the `ready`, `connect`, `error`, `end`, `drain` and `idle` client events are currently implemented. List of **missing** commands (will throw upon attempt to use): Connection and Server: CONFIG GET CONFIG SET CONFIG RESETSTAT DEBUG OBJECT DEBUG SEGFAULT FLUSHALL INFO LASTSAVE MONITOR MOVE OBJECT SHUTDOWN SLAVEOF SYNC ## Helpers To facilitate development and testing, fakeredis provides some additional methods on the client object. ### Prettyprinting: ```javascript fakeredisClient.pretty(); fakeredisClient.pretty("p*tte?n"); fakeredisClient.pretty(options); ``` `.pretty()` will prettyprint to stdout the entire keyspace or a subset of keys specificed with a redis pattern of the same kind that's used for `KEYS` and `PSUBSCRIBE`. Keep in mind .pretty() is async, because it works as a normal client command and hence needs to respect the command order, fake pipelining and latency and all, so that you can do stuff like: ```javascript var client = require("fakeredis").createClient(); client.SADD('hello', 'world', 'Jenny', 'Sam'); client.LPUSH('mylist', 'hey', 'ho', 'letsgo'); client.pretty({label: "my stuff", pattern: "*"}); ``` Which would print *(in color!)* my stuff: set hello -1 Jenny, Sam, world list mylist -1 letsgo, ho, hey ### Keyspace dumps: ```javascript fakeredisClient.getKeypsace(callback); fakeredisClient.getKeypsace("p*tte?n", callback); fakeredisClient.getKeyspace(options, callback); ``` Will `callback(err, data)` with an array that enumerates the whole keyspace, or the requested subset, in the following manner: ```javascript [ key1, ttl1, type1, value1 , key2, ttl2, type2, value2 , ... ] ``` The keyspace is sorted lexicographically by key, string values are strings, list values are the output of `LRANGE 0 -1`, hashes come out as the output of `HGETALL` for hashes (no syntactic sugar though, so an Array of `[field, value, field, value, ...]`), `SMEMBERS` output is used for sets, and `ZRANGE 0 -1 WITHSCORES` for sorted sets, each of which is sorted lexicographically in a way that makes sense, so that the final result is simple enough to assert deep equality against. In any case, you'll probably need to reformat these keyspace dumps to a format that makes more sense for your testing needs. There are a couple of transforms that are included out of the box: ```javascript fakeredisClient.getKeypsace({pattern: "myz*", map: true}, callback); ``` If you only care about the key and value of each entry, you can set the **map** option to a truthy value, you will instead receive the keyspace dump as a key-value map of the kind: ```javascript { key1: value1, key2: value2, ... } ``` This means you're skipping ttl and key type info though. You can also do: ```javascript fakeredisClient.getKeypsace({pattern: "myz*", group: true}, callback); ``` Which will return an `Array` of `Array`s, one for each keyspace entry, so that you end up with: ```javascript [ [ key1, ttl1, type1, value1 ] , [ key2, ttl2, type2, value2 ] , ... ] ``` The benefit of this option is that you can sort the outer array as you like more easily. ## Similar projects You might also want to check out these similar implementations in [python](https://github.com/jamesls/fakeredis) and [ruby](https://github.com/guilleiguaran/fakeredis). ## MIT License Copyright (c) 2012 Hristo Dachev Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.