Message handlers fail after client error

[paulgrav]

Summary

I’m currently evaluating Redis+Socket.io and I’m coming across a situation where my
message event handlers stop firing events. I was seeing this after leaving my node.js server
running for a few hours, but now I can always reproduce by publishing a malformatted
message to my Redis server. My work around is to restart my server which is far from
ideal.

Steps to Reproduce

1. Download this code: https://gist.github.com/3293884
2. Setup a local Redis instance.
3. Run the downloaded code in node.js
4. Send “publish football.match.event foo” to the redis instance.
5. Send “publish football.match.event "{"foo":"bar"}"” to the redis instance.
6. Send “publish football.match.event foo” to the redis instance.

Expected Results

The client error handler (line #9) should fire 3 times so I should see this error
repeated 3 times in my logs.

error event - localhost:6379 - SyntaxError: Unexpected token o

Actual Results

I see the above mentioned error message only once. doMessageListen() is never called again.

Notes:

I have redis.debug_mode set to true. When I publish the messages I can see them in my
redis debugging. The following output appears twice in my logs.

net read localhost:6379 id 1: *3
$7
message
$20
football.match.event
$3
foo

[DTrejo]

So after sending a malformed command to your redis server, you expect it not to fail?

Please elaborate on what portion of this problem you believe to be an issue with node_redis, and we'll go from there.

Thank you,
D

[paulgrav]

Malformed in that I send a plaintext message instead of one containing JSON. I expect that a non-JSON message to cause JSON.parse() on line #44 to error, for client.on(‘error’) on line #9 to call it’s handler but for subsequent messages to be processed.

The message handlers on lines #40 and #34 are handlers for Redis messages which are no longer called following a single client error. This is why I think it’s a node_redis issue and not node.js or socket.io.

[paulgrav]

I’ve attempted to reduce the issue. https://gist.github.com/3302796
Using the code in that Gist for a node instances. Then sending the following messages. It’s message #3 where I expect to see output receive from sending message #1.

Message #1:

redis-cli publish football.match.event "{\"foo\": \"bar\"}"

produces this output in node.js:

XXX
{ foo: 'bar' }

Message #2

redis-cli publish football.match.event foo

produces this output in node.js:

XXX
error event - localhost:6379 - SyntaxError: Unexpected token o
connected: true

Message #3

redis-cli publish football.match.event "{\"foo\": \"bar\"}"

produces no output in node.js

[paulgrav]

I’ve done a bit of debugging. After sending message #2 the function RedisReplyParser.prototype.execute() is still being called but this.emit(“reply”… never gets called. Now, prior to sending message #3, if I stick a break point on line 72 of node_modules/redis/lib/parser/javascript.js and then manually call RedisReplyParser.prototype.reset() then everything works.

I don’t really understand exactly what’s going on in RedisReplyParser, but it looks like it’s being left in an inconsistent state where it’s unable to process subsequent messages.

[paulgrav]

I’m running node.js on a Mac and it seems that hiredis isn’t being installed/compiled correctly. So I’m using the javascript parser.

On a Solaris box that has hiredis is being used and everything works fine.

[DTrejo]

Happy to hear it works well on solaris :)

If you'd like to submit a failing test as well as something that fixes it, I'd be very happy.

Also, make sure you try out master before you do the above, as it may have fixed your issue. There are a lot of commits not yet on npm.

Cheers,
D

[paulgrav]

Why did you close the ticket?

[DTrejo]

I get trigger happy sometimes, apologies.

[BridgeAR]

This is a parser bug that is fixed in newer versions