MQTT的学习研究（九）基于HTTP GET MQTT 抓取消息服务端使用

官方参看文档：

HTTP GET 接收主题请求协议和响应协议

http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com.ibm.mq.csqzau.doc/ts21230_.htm

HTTP POST 发布主题请求协议和响应协议

http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com.ibm.mq.csqzau.doc/ts21220_.htm

HTTP DELETE 订阅主题请求协议和响应协议

http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com.ibm.mq.csqzau.doc/ts21240_.htm

请求响应头各个字段的含义的讲解

http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com.ibm.mq.csqzau.doc/ts21250_.htm

响应错误处理

http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com.ibm.mq.csqzau.doc/ts21340_.htm

HTTP GET: WebSphere MQ bridge for HTTP command

The HTTP GET operation gets a message from a WebSphere® MQ queue. The message is left on the queue. The HTTP GET operation is equivalent to browsing a WebSphere MQ
queue.

Syntax

Request

>>-+-DELETE-+-- --| Path |-- --HTTP version--CRLF--------------->
'-GET----'

.-CRLF---------------.  .-CRLF---------------.
V                    |  V                    |
>----+----------------+-+----+----------------+-+--------------->
'-general-header-'      '-request-header-'

.-CRLF----------------------------.
V                                 |
>----+-----------------------------+-+-------------------------><
'-| Entity-header (Request) |-'

Path

|--/--contextRoot--/-------------------------------------------->

>--msg/--+-queue/--queueName--+-------------+-+--/--------------|
|                    '-@--qMgrName-' |
'-topic/--topicName------------------'

entity-header (Request)

|--+----------------------------------------------+-------------|
+-standard entity-header-- --entity-value------+
+-x-msg-correlId - --correlation ID------------+
+-x-msg-msgId - --message ID-------------------+
+-x-msg-range-- --range------------------------+
+-x-msg-require-headers-- --entity header name-+
'-x-msg-wait - --wait time---------------------'

Note:

If a question mark (?) is used it must be substituted with %3f. For example, orange?topic should be specified as orange%3ftopic.
@qMgrName is only valid on an HTTP POST

Response

>>-HTTP version-- --HTTP Status-Code-- --HTTP Reason-Phrase--CRLF-->

.-CRLF---------------.  .-CRLF----------------.
V                    |  V                     |
>----+----------------+-+----+-----------------+-+-------------->
'-general-header-'      '-response-header-'

.-CRLF-----------------------------.
V                                  |
>----+------------------------------+-+--+---------------+-----><
'-| Entity-header (Response) |-'    '-CRLF--Message-'

entity-header (Response)

|--+-----------------------------------------+------------------|
+-standard entity-header-- --entity-value-+
+-x-msg-class-- --message type------------+
+-x-msg-correlId-- --correlation ID-------+
+-x-msg-encoding-- --encoding type--------+
+-x-msg-expiry-- --duration---------------+
+-x-msg-format-- --message format---------+
+-x-msg-msgId-- --message ID--------------+
+-x-msg-persistence-- --persistence-------+
+-x-msg-priority-- --priority class-------+
+-x-msg-replyTo-- --reply-to queue--------+
+-x-msg-timestamp-- --HTTP-date-----------+
'-x-msg-usr-- --user properties-----------'

HTTP GET example

HTTP GET gets a message from a queue. The message remains on the queue. In WebSphere MQ terms, HTTP GET is a browse request. You could create an HTTP DELETE request
using a Java client, a browser form, or an AJAX toolkit.

Figure 1 is an HTTP request to browse the next message on queue called myQueue.

The request contains the HTTP request header x-msg-wait, which instructs WebSphere MQ bridge for HTTP how long to wait for a message to arrive on the queue. The request also contains the x-msg-require-headersrequest
header, which specifies that the client is to receive the message correlation ID in the response.
Figure 1. Example of an HTTP GET request

GET /msg/queue/myQueue/ HTTP/1.1
Host: www.example.org
x-msg-wait: 10
x-msg-require-headers: correlID

Figure 2 is the response returned to the client. The correlation ID is returned to the client, as requested in x-msg-require-headers of
the request.
Figure 2. Example of an HTTP GET response

HTTP/1.1 200 OK
Date: Wed, 2 Jan 2007 22:38:34 GMT
Server: Apache-Coyote/1.1 WMQ-HTTP/1.1 JEE-Bridge/1.1
Content-Length: 50
Content-Type: text/plain; charset=utf-8
x-msg-correlId: 1234567890

Here's my message body that will appear on the queue.