问题
In a retail scenario where each stores report their daily transaction to the backend system at the end of the day. Today a file consisting of the daily transactions and some other meta information is transferred from the stores to the backend using FTP. I’m currently investigating replacing FTP with something else. MSMQ has been suggested as an alternative transport mechanism. So my question is, do we need to write a custom windows service that sticks the daily transactions file into a message object and sends it on its way or is there any out the box mechanism in MSMQ to handle this?
Also, since the files we want to transfer can reach 5-6 Mb for large stores should we rule out MSMQ? In that case is there any other suggested technologies we should investigate?
Cheers!
回答1:
NServiceBus provides a nice abstraction over MSMQ for situations like this. You get the reliable messaging aspects of MSMQ, along with a very nice programming model for defining your messages.
MSMQ is limited to a 4MB message size, however, and there are two ways you could deal with this in NServiceBus:
- NServiceBus has a concept called the Data Bus, which takes the large attachments in your messages and transmits them reliably using another method. This is handled by the infrastructure and as far as your message handlers are concerned, the data is just there.
- You could break up the payload into smaller atomic messages and send them as normal messages. The NServiceBus infrastructure would ensure that they all arrive at their destination and are processed. I would recommend this method unless it's absolutely critical that the entire huge data dump is processed as one atomic transaction.
One other thing to note is that the fact that you do nightly dumps is probably a limitation of a previous system. With NServiceBus it may be possible to change the system so that these bits of information are sent in a more immediate fashion, which will result in much more up-to-date data all the time, which may be a big win for the business.
回答2:
You can look at IBM Sterling Managed File Transfer and WebSphere MQ Managed File Transfer products.
You can consider WebSphere MQ MFT if you require both messaging and file transfer capabilities. On the other hand if your requirement is just file transfer then you can look at Sterling MFT.
回答3:
Sending files over a messaging transport is not trivial. If you put the entire file into a single message you can have the atomicity you need but tuning the messaging provider for wide variance in message sizes can be challenging. If all the files are of about the same size, one per message is about the simplest solution.
On the other hand, you can split the files into multiple messages but then you've got to reassemble them, in the right order, include a protocol to detect and resend missing segments, integrity-check the file received against the file sent, etc. You also probably want to check that the files on either end did not change during the transmission.
With any of these systems you also need the system to be smart enough to manage the disposition of sending and receiving files under normal and exception conditions, log the transfers, etc.
So when considering whether to move to messaging the two best options are either to move natively to messaging and give up files altogether, or to use an enterprise managed file transfer solution that runs atop the messaging provider that you choose. None of the off-the-shelf MFT products will cost as much in the long run as developing it yourself if you wish to do it right with robust exception handling and reporting.
回答4:
If the stores are on separate networks and communicating over the internet, then MSMQ is not really an option. NServiceBus provides a concept of a gateway, which allows to asynchronously transport MSMQ messages over HTTP or HTTPS.
来源：https://stackoverflow.com/questions/12580230/sending-files-over-msmq