Communication with remote clients

Question

Delphi

There is a task to organize software for collecting information - there will be a certain number of clients, each with its own database (about 30 pieces). on clients this base which parts should merge in the general base in the central storage is stuffed. customers are in fields with weak intermittent Internet access via mobile network.
What methods of information exchange can be used? feedback, I would also like the server to send a dump to the client if something happens.
so far, only ftp with file naming according to the client number and postfixes in the form of a package number / random value

is seen. is there anything without a link to your dropbox-type server, but on other clients it is not necessary to receive data from other clients?

Answer 1

CouchDB is suitable for your conditions . Replication/synchronization is already implemented. This database is available on many platforms, simple and clear API

Answer 2

Another way to exchange information is E-Mail. The client prepared the stuffed data, attached it to the letter, connected to the network and sent it, and the server received, processed and sent back a message that such and such records were received and processed, there is no need to send them anymore. In this scenario, the server does not need a permanent ip-address on the Internet - it is enough to start a virtual hosting with the required number of mailboxes or even some Mail.ru. Disadvantages - possible delay of letters by antispam and not so hot what security.