Update doc/schema/claims/attributes.txt

Change-Id: I6f7bcce136b38ad33f991e20289e67e2d184353e

doc/schema/claims/attributes.txt

@@ -1,6 +1,54 @@
-Description of the attributes a permanode can get
------
+Permanode Attributes
+
+While a permanode can have any arbitrary attributes and values (and
+each value can be single-valued or multi-valued), the following are
+the conventional attributes and values used by the various tools,
+search, FUSE, and web UI.
+
+"tag": (multi-valued)
+
+    a set of zero or more keywords (or phrases) indexed completely, for
+    searching by tag. No HTML.
+
+"title": (single-valued)
+
+    A name given to the permanode. No HTML.
+
+"description": (single-valued)
+
+    An account of the permanode. It may include but is not limited to:
+    an abstract, a table of contents, or a free-text account of the
+    resource. No HTML.  As of 2013-12-28, not very defined yet.
+
+"camliContent": (single-valued)
+
+    when a permanode is a file, the camliContent is set to the fileref
+    (the blobref of the "file" schema blob)
+
+"camliMember": (multi-valued)
+
+    when the permanode represents a set (unordered, unkeyed), the
+    parent permanode (the container set) has a camliMember set to the
+    permanode of each child element.
+
+"camliPath:$dirent_name" (single-valued)
+
+    when the permanode represents an associative container, each keyed
+    child permanode blobref is pointed to by the "camliPath:$key"
+    attribute on the parent.  This is used by the FUSE client, and
+    respected in the UI (browser, publishing code), etc.
+
+"camliNodeType" (single-valued)
+
+    when the application needs to note the type of a permanode before
+    any other attributes (like those above) are added which would otherwise
+    imply its type, the camliNodeType lets applications be specific.
+    This should only be used if another attribute can't imply it.
+    Currently only used by FUSE to indicate the difference between a new
+    file and a new directory permanode.  Known values include:
+
+        * "directory". this permanode will have "camliPath:$key"
+          attributes later.
+        * "file". this permanode will have a "camliContent" later. for
+          now, it should be treated as if it's an empty, 0-byte file.
 
-"tag": a set of zero or more keywords (or phrases) indexed completely, for searching by tag. No HTML.
-"title": A name given to the permanode. No HTML.
-"description": An account of the permanode. It may include but is not limited to: an abstract, a table of contents, or a free-text account of the resource. No HTML.