Manifest files are discovered and downloaded in exactly the same way that RSD files are. Beginning from the weblog homepage URL, writer first looks for a file named “wlwmanifest.xml” within the weblog’s root directory. For example:
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Weblog URL: http://www.myblog.com
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Manifest URL: http://www.myblog.com/wlwmanifest.xml
If this probe is not successful then Writer downloads the weblog homepage contents and looks within the <head> for a <link> tag which points to a manifest. For example (RSD link tag also included to illustrate the similarity in method):
<head>
<title>Weblog homepage</title>
<link rel="EditURI" type="application/rsd+xml"
href="stuff/rsd.xml" />
<link rel="wlwmanifest" type="application/wlwmanifest+xml"
href="stuff/wlwmanifest.xml" />
</head>After successfully discovering a manifest, its URL is cached so that subsequent retrievals do not require discovery (however if the manifest URL is not available Writer will automatically attempt to re-discover the URL).
Writer attempts to discover and download a manifest file at the following times:
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When running the Add Weblog Account Wizard
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When running the Update Account Configuration Wizard
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When executing the Update Weblog Style command
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During Auto-Update (described below)
After discovery and download, the manifest file is read and its contents are used to update Writer’s configuration (registry settings, template files, etc).
Auto-Update
In addition to using manifest files during weblog configuration, Writer can also download a weblog’s manifest each time the weblog is activated within Writer. Auto-update is enabled for all weblogs by default, however can be disabled by either:
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The user disabling the feature globally (for all accounts) using the Accounts preferences panel.
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The weblog provider disabling auto-update using the <supportsAutoUpdate> option (described in the “Options” section below).
If enabled, Auto-Update is triggered for a weblog whenever:
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A new post which targets the weblog is created
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A post associated with the weblog is opened
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The user switches to the weblog while authoring a post
To avoid latency, Auto-Update is performed in a delayed background thread. If the Auto-Update succeeds then an event is fired notifying the user-interface to update its state based on the new settings. If the Auto-Update fails then it does so silently (but logs any errors encountered to the Writer log file).
Some additional notes on Auto-Update:
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Caching headers (Expires, Last-Modified, and ETag) are respected for Auto-Update manifest downloads.
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Editing templates (<view> elements) are not included in Auto-Update processing.
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In addition to downloading the manifest, Writer also refreshes the list of categories for the weblog.