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你可能喜欢nginx_http_push_module - Comet For The People
NGINX HTTP Push Module is now obsolete. It has been remolded, reworked, and rebooted into , which is 99% backwards compatible with the Push Module.
unless you don't want to.
This module turns Nginx into an adept
It takes care of all the ,
and exposes a simple interface to broadcast messages to clients via plain old HTTP requests.
This lets you write live-updating asynchronous web applications as easily as their oldschool
classic counterparts, since your code does not need to manage requests with delayed responses.
NHPM fully implements the
, a no-frills publisher/subscriber protocol
centered on uniquely identifiable channels. It is an order of magnitude
simpler and more basic than similar protocols (such as ).
However, this basic functionality together with the flexibility of the server configuration
make it possible to reformulate most HTTP Push use cases in Basic HTTP Push Relay Protocol
language with very little application- and client-side programming overhead.
You're writing a live-updating web application. Maybe it's some sort of chat, a multiplayer Flash game, a live feed reader,
or maybe it's a realtime
controller.
Either way, you won't have status updates come only when the user refreshes a page, and polling the server every couple of seconds
seems to you ugly and insufficient. But you don't quite want to commit to writing your application in any of the available
frameworks.
You're also not crazy about , maybe because you think the Bayeux protocol is overkill.
You , , and
the module.
you implement a subscriber client, and with nothing else
but an HTTP request from your application to the server (maybe with curl, maybe with something else),
you send live messages to long-polling subscribers.
The latest
(October 2 2015). ()
d25cfe12dd8ea3ce91ec
b8d017c668a3bd8ddf
Nginx HTTP Push Module is distrbuted under the
Modules are added by compiling them along with the Nginx source.
the push module, untar, and run
./configure --add-module=path/to/nginx_http_push_module ...
Install via make install
NHPM is compatible with Nginx versions 0.8 and above (tested up to 1.8).
A token uniquely identifying a communication channel. Must be present in the
context of the push_subscriber and push_publisher directives.
set $push_channel_id $arg_
#channel id is now the url query string parameter "id"
#(/foo/bar?id=channel_id_string)
[ long-poll | interval-poll
default: long-poll
context: server, location
Defines a server or location as a subscriber. This location represents a
subscriber's interface to a channel's message queue. The queue is traversed
automatically via entity-caching request headers (If-Modified-Since and
If-None-Match), beginning with the oldest available message. Requests for
upcoming messages are handled in accordance with the setting provided.
for a detailed description.
The directive value controls server behavior when a subscriber requests a message that has
yet to arrive. Naturally, long-poll long-polls the request, while
interval-poll is responded to immediately with a 304 Not Modified
status code until the requested message becomes available.
[ last | first | broadcast ]
default: broadcast
context: http, server, location
Controls how multiple subscriber requests to a channel (identified by
some common ) are handled.
The values work as follows:
broadcast:
any number of concurrent subscriber requests may be held.
only the most recent subscriber request is kept, all others get a 409 Conflict response.
only the oldest subscriber request is kept, all others get a 409 Conflict response.
default: none
context: server, location
Defines a server or location as a message publisher. Requests to a publisher
location are treated as messages to be sent to subscribers. See the
for a detailed description.
[ on | off ]
default: on
context: http, server, location
Whether or not message queuing is enabled. "Off" is equivalent to the setting
default: 32M
context: http
The size of the memory chunk this module will use for all message queuing and buffering.
[ number ]
default: 1
context: http, server, location
The minimum number of messages to store per channel. A channel's message
buffer will retain at least this many most recent messages.
[ number ]
default: 10
context: http, server, location
The maximum number of messages to store per channel. A channel's message
buffer will retain at most this many most recent messages.
[ number ]
default: off
context: http, server, location
The exact number of messages to store per channel. Sets both
to this value.
default: 0
context: http, server, location
When enabled, as soon as the oldest message in a channel's message queue has
been received by a subscriber, it is deleted -- provided there are more than
messages in the channel's message buffer. Recommend avoiding this directive as it
violates subscribers' assumptions of GET request idempotence.
default: 1h
context: http, server, location
The length of time a message may be queued before it is considered expired.
If you do not want messages to expire, set this to 0.
Applicable only if a
is present in
this or a child context.
[ on | off ]
default: off
context: http, server, location
Whether or not a subscriber may create a channel by making a request to a
location. If set to on, a
publisher must send a POST or PUT
request before a subscriber can request messages on the channel. Otherwise,
all subscriber requests to nonexistent channels will get a 403 Forbidden response.
[ string ]
default: none
context: server, location
Because settings are bound to locations and not individual channels,
it is useful to be able to have channels that can be reached only from some
locations and never others. That's where this setting comes in. Think of it
as a prefix string for the .
[ number ]
default: 512
context: main, server, location
Maximum permissible
length (number of characters). Longer ids will be truncated.
[ number ]
default: 0 (unlimited)
context: main, server, location
Maximum concurrent subscribers. Pretty self-explanatory.
For an overview and some configuration examples, take a look at this
by Ilya Grigorik.
This section will be expanded further. Sit tight.
Make sure your subscriber clients handle caching headers correctly, and are not confused by the Vary header.
(I'm looking at you, Internet Explorer.) For maximum cross-browser compliance, you may wish to forward
the Last-Modified and Etag headers manually
for an example).
When using $arg_PARAMETER
, keep in mind that Nginx does not parse the value if it is
Be careful writing a subscriber client with jQuery & it has the inexplicable tendency of adding
a random parameter to the query string, which understandably confuses the browser trying to forward caching headers.
Make sure to turn off this weird behavior.
If your application makes publisher requests, make sure to use keep-alive connections in your production environment.
Otherwise, it will bear the (slight but perhaps meaningful) overhead of a TCP/IP handshake for every publisher request.
This section will be expanded further. Sit tight.
Nginx is .
Using this module adds a small amount of overhead -- a dozen or so bytes per channel, and around a hundred per each open subscriber
request (depending, of course, on the size of the request).
Channel messages are stored either in memory or, when they exceed some reasonable size threshold, in temporary files. If you
intend to have millions of channels open with millions of messages that take weeks to expire and be purged, consider increasing
CPU usage should be completely unnoticeable. Channels are stored in a red-black tree, and have an O(log(N)) retrieval cost.
All other NHPM operations are constant-time, so things should scale quite well.
Oh, hi there. I'm Leo.
Got questions? A successful large-scale deployment? A failing one? Found a bug?
Want to submit a patch? Send money? ...Cake?
Email me at
or get in touch with me on .
Here's an example chat application. It's made entirely with
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