[user_external] cache username and password

[kriztan]

Affected apps

user_external; IMAP

Expected behaviour

It would be nice to cache the username and password for a configurable period of time e.g. 24 h to limit the number of connections to IMAP server.

Actual behaviour

Every login starts a new connection to the IMAP server. Users with at least 2 clients syncing calendars, files and contacts periodically causing hundreds of connections to the IMAP server. Sometimes the IMAP server is blocking more connections and the authentication fails.

Steps to reproduce

Start syncing calendars, contacts, files, notes from multiple clients at the same time.

Server configuration

Operating system: CentOS

Web server: Apache 2.2.15

Database: MySQL

PHP version: 5.6.20

ownCloud version: 9.0

Thanks!