Nginx Http Push Module 消息推送

Http Server Push是一種推送技術，服務器主動向瀏覽器發送數據。

 

1. 下載安裝

1) 下載源代碼包
Nginx：http://nginx.org/
Nginx Http Push Module：http://pushmodule.slact.net/

2) 解壓縮
tar zxvf nginx-1.0.14.tar.gz
tar zxvf nginx_http_push_module-0.692.tar.gz

3) 編譯安裝
編譯Nginx，configure指定待添加模塊的路徑
./configure --add-module=path/to/nginx_http_push_module ...
make && make install

 

2. 配置

關於推送配置說明，可參考推送模塊源碼包內的README，

推送協議可參考protocol.txt，或訪問http://pushmodule.slact.net/protocol.html，

在Nginx配置文件中添加一個基本的推送配置，

可參考自帶的用於測試的配置文件nginx_http_push_module-0.692/tests/nginx.conf，將其中配置部分附加到Nginx配置文件的http結構中：

server {
    listen       8082;
    location / { 
        location = /sub {
            set $push_channel_id $arg_id;
            push_subscriber;
            push_subscriber_concurrency broadcast;
            push_channel_group broadcast;
        }   
        location = /pub {
            set $push_channel_id $arg_id;
            push_publisher;
            push_min_message_buffer_length 5;
            push_max_message_buffer_length 20; 
            push_message_timeout 5s; 
            push_channel_group broadcast;
        }   
    }   
}

 

3. 調試

啟動Nginx，使用curl進行推送測試

1) subscriber請求數據：
curl -X GET localhost:8082/sub?id=1
向channel1請求數據，當前channel無數據，等待數據生成

2) publisher推送數據：
curl -X POST -d "data_to_push" localhost:8082/pub?id=1
向channel1推送數據，subscriber收到數據並返回

 

4. 總結

Http服務器需要使用一個或一組url指定發布服務和訂閱服務（publisher and subscriber locations，我翻譯的不太合理）。

所有發送到發布服務的請求被視為發布請求，所有發送到訂閱服務的請求被視為訂閱請求。

通道（channel）需要使用唯一id進行標識，推薦使用url指定具體通道，如 localhost:8082/sub?id=1。

發布請求（publisher request）通過POST向服務器傳輸數據，並通知其向某些通道某些用戶發送數據，

訂閱請求（subscriber request）通過GET向服務器請求數據，通知其該用戶想要接收數據。

 

附上一個Python腳本

#!/usr/bin/python
#
# file  : nginx_http_push.py
# author: caosiyang
#

import httplib


#send publisher request
def publish(host, url, data_to_push):
    '''Send publisher request.

    description: push data.'''
    pubconn = httplib.HTTPConnection(host)
    pubconn.request('POST', url, data_to_push)
    pubconn.close()


#send subscriber request
def subscribe(host, url, header):
    '''Send subscriber request.

    description: receive data.'''
    subconn = httplib.HTTPConnection(host)
    subconn.request('GET', url, '', header)
    resp = subconn.getresponse()
    last_modified = ''
    etag = ''
    if resp.status == 200:
        header = resp.getheaders()
        for item in header:
            if (item[0] == 'last-modified'):
                last_modified = item[1]
                continue
            if (item[0] == 'etag'):
                etag = item[1]
                continue
    #print 'last-modified: %s' % last_modified
    #print 'etag         : %s' % etag
    #print 'receive data : %s' % resp.read()
    #print ''
    print 'last-modified: %s\n' \
          'etag         : %s\n' \
          'receive data : %s\n' % (last_modified, etag, resp.read())
    subconn.close()
    return (last_modified, etag)


#script starts
host = 'localhost:8082'
for i in range(0, 10):
    publish(host, '/pub?id=1', 'test_data_%d' % i)

header = {'If-Modified-Since': '', 'If-None-Match': ''}
for i in range(0, 10):
    tuple = subscribe(host, '/sub?id=1', header)
    header['If-Modified-Since'] = tuple[0]
    header['If-None-Match'] = tuple[1]

 

其輸出如下

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 0
receive data : test_data_0

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 1
receive data : test_data_1

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 2
receive data : test_data_2

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 3
receive data : test_data_3

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 4
receive data : test_data_4

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 5
receive data : test_data_5

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 6
receive data : test_data_6

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 7
receive data : test_data_7

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 8
receive data : test_data_8

last-modified: Thu, 05 Apr 2012 04:55:29 GMT
etag         : 9
receive data : test_data_9