Blackberry BROWSER VERSION 4.7.0 - FUNDAMENTALS GUIDE Fundamentals - Page 35
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Fundamentals Guide
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Pushing content to a browser channel: This method delivers content to the browser cache and adds an icon on the Home
screen as entry point to the content. Clicking the icon opens the pushed content in the browser.
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Pushing content to the message list: This method delivers content to the message list, where it appears as an item in the
list. Clicking the item in the message list displays the pushed content in the browser.
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Pushing content to the browser cache: This method delivers content to the cache, but provides no notification to the user.
The next time the user accesses the content, the updated cached content is displayed.
The default amount of time that pushed content is stored in cache memory depends on the version of the BlackBerry® Device
Software is running on the device. In BlackBerry Device Software version 3.8 or later, pushed content is cleared from the cache
after 12 hours. On devices running an earlier version of the BlackBerry Device Software, pushed content expires and is cleared
from the cache after 29 days.
To increase or decrease the time content is stored in cache memory, you can specify a date and time in the HTTP header of the
push request with the Expires header. For example, the following header will store content in cache until December 31, 2018 at
12PM GMT.
Expires: Wed, 31 Dec 2018 24:00:00 GMT
Content might be cleared from the cache prior to the value specified in the Expires header. If the BlackBerry device runs low on
flash memory, the browser cache might be cleared to free up space, or the user might choose to manually clear the pushed
content cache.
Pushed content supported by the BlackBerry Internet Service Browsing network gateway
You can push content to BlackBerry® device users through the BlackBerry Internet Service Browsing network gateway by creating
web signals. Web signals enable you to push content to the BlackBerry® Browser using the BlackBerry Internet Service Browsing
as the network gateway. Users subscribe to the web signal(s) you offer and receive an icon on their Home screen. To the user,
the web signal appears like any other application. When they click the web signal icon, the Internet Browser configuration opens
and retrieves the content through the BlackBerry Internet Service Browsing.
To push content to users, you must first register one or more web signals with Research In Motion. Users can subscribe to receive
your web signal(s) on their BlackBerry devices.
Creating content for a web signal can be simple or complex. At its simplest, a web signal requires a subscription web page, two
icons used to identify the web signal on the BlackBerry device Home screen (the standard icon, displayed when no new content
is available, and the other notification icon, displayed when new content is available), and a web page that contains the content
that subscribed users can view.
When you want to alert web signal subscribers to new content, you can submit an HTTP POST request to the BlackBerry®
Infrastructure. A parameter in the POST request lists the subscribed users to whom the URLs should be sent. The BlackBerry
Infrastructure receives the request and queues it, then delivers the URLs of the icons and the content to the BlackBerry devices.
Pushed content delivery
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