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@ -2,8 +2,8 @@
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Internet-Draft D. Boreham, Bozeman Pass
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LDAPext Working Group J. Sermersheim, Novell
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Intended Category: Standards Track A. Kashi, Microsoft
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<draft-ietf-ldapext-ldapv3-vlv-06.txt>
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Expires: Nov 2002 May 2002
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<draft-ietf-ldapext-ldapv3-vlv-09.txt>
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Expires: Jun 2003 Nov 2002
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LDAP Extensions for Scrolling View Browsing of Search Results
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@ -37,16 +37,16 @@ Expires: Nov 2002 May 2002
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2. Abstract
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This document describes a Virtual List View control extension for the
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This document describes a Virtual List View extension for the
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Lightweight Directory Access Protocol (LDAP) Search operation. This
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control is designed to allow the "virtual list box" feature, common
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extension is designed to allow the "virtual list box" feature, common
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in existing commercial e-mail address book applications, to be
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supported efficiently by LDAP servers. LDAP servers' inability to
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support this client feature is a significant impediment to LDAP
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replacing proprietary protocols in commercial e-mail systems.
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The control allows a client to specify that the server return, for a
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given LDAP search with associated sort keys, a contiguous subset of
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The extension allows a client to specify that the server return, for
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a given LDAP search with associated sort keys, a contiguous subset of
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the search result set. This subset is specified in terms of offsets
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into the ordered list, or in terms of a greater than or equal
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comparison value.
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@ -54,13 +54,32 @@ Expires: Nov 2002 May 2002
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Boreham et al Internet-Draft 1
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LDAP Extensions for Scrolling View May 2002
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LDAP Extensions for Scrolling View Nov 2002
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Browsing of Search Results
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3. Conventions used in this document
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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"SHOULD", "SHOULD NOT", "RECOMMENDED", and "MAY" in this document are
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to be interpreted as described in RFC 2119 [Bradner97].
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The key words "MUST", "SHALL", "SHOULD", "SHOULD NOT", and "MAY" in
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this document are to be interpreted as described in RFC 2119
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[Bradner97].
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Protocol elements are described using ASN.1 [X.680]. The term "BER-
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encoded" means the element is to be encoded using the Basic Encoding
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Rules [X.690] under the restrictions detailed in Section 5.1 of
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[LDAPPROT].
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The phrase "subsequent virtual list request" is used in this document
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to describe a search request accompanied by a VirtualListViewRequest
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control, where the search base, scope, and filter are the same as a
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previous search request also accompanied by a VirtualListViewRequest
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control, and where the contextID of the subsequent
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VirtualListViewRequest control, is set to that of the contextID in
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the VirtualListViewResponse control that accompanied the previous
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search response.
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The phrase "contiguous virtual list request" is used to describe a
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subsequent virtual list request which is requesting search results
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adjoining or overlapping the result returned from the prior virtual
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list request.
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4. Background
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@ -80,14 +99,21 @@ Expires: Nov 2002 May 2002
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only that information which is required to display the part of the
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list currently in view is fetched. The subject of this document is
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the interaction between client and server required to implement this
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functionality in the context of the results from a sorted LDAP search
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request.
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functionality in the context of the results from an ordered [SSS]
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Lightweight Directory Access Protocol (LDAP) search operation
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[LDAPPROT].
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For example, suppose an e-mail address book application displays a
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list view onto the list containing the names of all the holders of e-
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mail accounts at a large university. The list is sorted
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mail accounts at a large university. The list is ordered
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alphabetically. While there may be tens of thousands of entries in
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this list, the address book list view displays only 20 such accounts
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Boreham et al Internet-Draft 2
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LDAP Extensions for Scrolling View Nov 2002
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Browsing of Search Results
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at any one time. The list has an accompanying scroll bar and text
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input window for type-down. When first displayed, the list view shows
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the first 20 entries in the list, and the scroll bar slider is
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|
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@ -109,12 +135,6 @@ Expires: Nov 2002 May 2002
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"B". When this happens, the scroll bar slider should also be updated
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to reflect the new relative location within the list.
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Boreham et al Internet-Draft 2
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|
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LDAP Extensions for Scrolling View May 2002
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Browsing of Search Results
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This document defines a request control which extends the LDAP search
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operation. Always used in conjunction with the server side sorting
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control [SSS], this allows a client to retrieve selected portions of
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|
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@ -125,21 +145,32 @@ Expires: Nov 2002 May 2002
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5. Client-Server Interaction
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The Virtual List View control extends a regular LDAP Search operation
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which must also include a server-side sorting control [SSS]. Rather
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which MUST also include a server-side sorting control [SSS]. Rather
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than returning the complete set of appropriate SearchResultEntry
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messages, the server is instructed to return a contiguous subset of
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those entries, taken from the sorted result set, centered around a
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those entries, taken from the ordered result set, centered around a
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particular target entry. Henceforth, in the interests of brevity, the
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sorted search result set will be referred to as "the list".
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ordered search result set will be referred to as "the list".
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The sort control MAY contain any sort specification valid for the
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The sort control may contain any sort specification valid for the
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server. The attributeType field in the first SortKeyList sequence
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element has special significance for "typedown".
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element has special significance for "typedown". The Virtual List
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View control acts upon a set of ordered entries and this order must
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be repeatable for all subsequent virtual list requests. The server-
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side sorting control is intended to aid in this ordering, but other
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mechanisms may need to be employed to produce a repeatable order--
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especially for entries that don't have a value of the sort key.
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The desired target entry and the number of entries to be returned,
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both before and after that target entry in the list, are determined
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by the client's VirtualListViewRequest control.
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Boreham et al Internet-Draft 3
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LDAP Extensions for Scrolling View Nov 2002
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Browsing of Search Results
|
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|
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When the server returns the set of entries to the client, it attaches
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a VirtualListViewResponse control to the SearchResultDone message.
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The server returns in this control: its current estimate for the list
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|
|
@ -165,12 +196,6 @@ Expires: Nov 2002 May 2002
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entries in the list, and to take account of cases where the list size
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is changing during the time the user browses the list, and because
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the client needs a way to indicate specific list targets "beginning"
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|
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Boreham et al Internet-Draft 3
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|
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LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
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|
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and "end", offsets within the list are transmitted between client and
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server as ratios---offset to content count. The server sends its
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latest estimate as to the number of entries in the list (content
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|
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@ -197,11 +222,17 @@ Expires: Nov 2002 May 2002
|
|||
offset and content count:
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- an offset of one and a content count of non-one (Ci = 1, Cc != 1)
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indicates that the target is the first entry in the list.
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|
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Boreham et al Internet-Draft 4
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LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
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- equivalent values (Ci = Cc) indicate that the target is the last
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entry in the list.
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- a content count of zero, and a non-zero offset (Cc = 0, Ci != 0)
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means the client has no idea what the content count is, the server
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MUST use its own content count estimate in place of the client's.
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- a content count of zero (Cc = 0, Ci != 0) means the client has no
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idea what the content count is, the server MUST use its own
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content count estimate in place of the client's.
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Because the server always returns contentCount and targetPosition,
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the client can always determine which of the returned entries is the
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|
|
@ -209,7 +240,7 @@ Expires: Nov 2002 May 2002
|
|||
number requested, the client is able to identify the target by simple
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arithmetic. Where the number of entries returned is not the same as
|
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the number requested (because the requested range crosses the
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beginning or end of the list, or both), the client must use the
|
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beginning or end of the list, or both), the client MUST use the
|
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target position and content count values returned by the server to
|
||||
identify the target entry. For example, suppose that 10 entries
|
||||
before and 10 after the target were requested, but the server returns
|
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|
|
@ -218,18 +249,11 @@ Expires: Nov 2002 May 2002
|
|||
the list, therefore the 13 entries returned are the first 13 entries
|
||||
in the list, and the target is the third one.
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|
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A server-generated context identifier MAY be returned to clients. A
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client receiving a context identifier SHOULD return it unchanged in a
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subsequent request which relates to the same list. The purpose of
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|
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|
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Boreham et al Internet-Draft 4
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
||||
|
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this interaction is to enhance the performance and effectiveness of
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servers which employ approximate positioning.
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A server-generated contextID MAY be returned to clients. A client
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receiving a contextID MUST return it unchanged or not return it at
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all, in a subsequent request which relates to the same list. The
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purpose of this interaction is to maintain state information between
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the client and server.
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6. The Controls
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|
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@ -242,56 +266,89 @@ Expires: Nov 2002 May 2002
|
|||
|
||||
This control is included in the SearchRequest message as part of the
|
||||
controls field of the LDAPMessage, as defined in Section 4.1.12 of
|
||||
[LDAPv3]. The controlType is set to "2.16.840.1.113730.3.4.9". The
|
||||
criticality SHOULD be set to TRUE. If this control is included in a
|
||||
SearchRequest message, a Server Side Sorting request control [SSS]
|
||||
MUST also be present in the message. The controlValue is an OCTET
|
||||
STRING whose value is the BER-encoding of the following SEQUENCE:
|
||||
[LDAPPROT]. The controlType is set to "2.16.840.1.113730.3.4.9". If
|
||||
this control is included in a SearchRequest message, a Server Side
|
||||
Sorting request control [SSS] MUST also be present in the message.
|
||||
The controlValue, an OCTET STRING, is the BER-encoding of the
|
||||
following SEQUENCE:
|
||||
|
||||
VirtualListViewRequest ::= SEQUENCE {
|
||||
beforeCount INTEGER (0..maxInt),
|
||||
afterCount INTEGER (0..maxInt),
|
||||
CHOICE {
|
||||
byoffset [0] SEQUENCE {
|
||||
offset INTEGER (0 .. maxInt),
|
||||
target CHOICE {
|
||||
byOffset [0] SEQUENCE {
|
||||
offset INTEGER (1 .. maxInt),
|
||||
contentCount INTEGER (0 .. maxInt) },
|
||||
|
||||
Boreham et al Internet-Draft 5
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
greaterThanOrEqual [1] AssertionValue },
|
||||
contextID OCTET STRING OPTIONAL }
|
||||
|
||||
beforeCount indicates how many entries before the target entry the
|
||||
client wants the server to send. afterCount indicates the number of
|
||||
entries after the target entry the client wants the server to send.
|
||||
client wants the server to send.
|
||||
|
||||
afterCount indicates the number of entries after the target entry the
|
||||
client wants the server to send.
|
||||
|
||||
offset and contentCount identify the target entry as detailed in
|
||||
section 4. greaterThanOrEqual is an attribute assertion value defined
|
||||
in [LDAPv3]. If present, the value supplied in greaterThanOrEqual is
|
||||
used to determine the target entry by comparison with the values of
|
||||
the attribute specified as the primary sort key. The first list entry
|
||||
section 5.
|
||||
|
||||
greaterThanOrEqual is a matching rule assertion value defined in
|
||||
[LDAPPROT]. The assertion value is encoded according to the ORDERING
|
||||
matching rule for the attributeDescription in the sort control [SSS].
|
||||
If present, the value supplied in greaterThanOrEqual is used to
|
||||
determine the target entry by comparison with the values of the
|
||||
attribute specified as the primary sort key. The first list entry
|
||||
who's value is no less than (less than or equal to when the sort
|
||||
order is reversed) the supplied value is the target entry. If
|
||||
present, the contextID field contains the value of the most recently
|
||||
received contextID field from a VirtualListViewResponse control. The
|
||||
type AssertionValue and value maxInt are defined in [LDAPv3].
|
||||
contextID values have no validity outwith the connection on which
|
||||
they were received. That is, a client should not submit a contextID
|
||||
which it received from another connection, a connection now closed,
|
||||
or a different server.
|
||||
order is reversed) the supplied value is the target entry.
|
||||
|
||||
If present, the contextID field contains the value of the most
|
||||
recently received contextID field from a VirtualListViewResponse
|
||||
control for the same list view. If the contextID is not known because
|
||||
no contextID has been sent by the server in a VirtualListViewResponse
|
||||
control, it SHALL be omitted. If the server receives a contextID that
|
||||
is invalid, it SHALL fail the search operation and indicate the
|
||||
failure with a protocolError (3) value in the virtualListViewResult
|
||||
field of the VirtualListViewResponse. The contextID provides state
|
||||
information between the client and server. This state information is
|
||||
used by the server to ensure continuity contiguous virtual list
|
||||
requests. When a server receives a VirtualListViewRequest control
|
||||
that includes a contextID, it SHALL determine whether the client has
|
||||
sent a contiguous virtual list request and SHALL provide contiguous
|
||||
entries if possible. If a valid contextID is sent, and the server is
|
||||
unable to determine whether contiguous data is requested, or is
|
||||
unable to provide requested contiguous data, it SHALL fail the search
|
||||
operation and indicate the failure with an unwillingToPerform (53)
|
||||
value in the virtualListViewResult field of the
|
||||
VirtualListViewResponse. contextID values have no validity outside
|
||||
the connection and query with which they were received. A client MUST
|
||||
NOT submit a contextID which it received from a different connection,
|
||||
a different query, or a different server.
|
||||
|
||||
The type AssertionValue and value maxInt are defined in [LDAPPROT].
|
||||
|
||||
|
||||
6.2. Response Control
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 5
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 6
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
This control is included in the SearchResultDone message as part of
|
||||
the controls field of the LDAPMessage, as defined in Section 4.1.12
|
||||
of [LDAPv3].
|
||||
If the request control is serviced, this response control is included
|
||||
in the SearchResultDone message as part of the controls field of the
|
||||
LDAPMessage, as defined in Section 4.1.12 of [LDAPPROT].
|
||||
|
||||
The controlType is set to "2.16.840.1.113730.3.4.10". The criticality
|
||||
is FALSE (MAY be absent). The controlValue is an OCTET STRING, whose
|
||||
value is the BER encoding of a value of the following SEQUENCE:
|
||||
The controlType is set to "2.16.840.1.113730.3.4.10". The
|
||||
controlValue, an OCTET STRING, is the BER-encoding of the following
|
||||
SEQUENCE:
|
||||
|
||||
VirtualListViewResponse ::= SEQUENCE {
|
||||
targetPosition INTEGER (0 .. maxInt),
|
||||
|
|
@ -299,128 +356,137 @@ Expires: Nov 2002 May 2002
|
|||
virtualListViewResult ENUMERATED {
|
||||
success (0),
|
||||
operationsError (1),
|
||||
protocolError (3),
|
||||
unwillingToPerform (53),
|
||||
insufficientAccessRights (50),
|
||||
busy (51),
|
||||
timeLimitExceeded (3),
|
||||
adminLimitExceeded (11),
|
||||
innapropriateMatching (18),
|
||||
sortControlMissing (60),
|
||||
offsetRangeError (61),
|
||||
other (80) },
|
||||
other(80),
|
||||
... },
|
||||
contextID OCTET STRING OPTIONAL }
|
||||
|
||||
targetPosition gives the list offset for the target entry.
|
||||
|
||||
contentCount gives the server's estimate of the current number of
|
||||
entries in the list. Together these give sufficient information for
|
||||
the client to update a list box slider position to match the newly
|
||||
retrieved entries and identify the target entry. The contentCount
|
||||
value returned SHOULD be used in a subsequent VirtualListViewRequest
|
||||
control. contextID is a server-defined octet string. If present, the
|
||||
contents of the contextID field SHOULD be returned to the server by a
|
||||
client in a subsequent VirtualListViewRequest control.
|
||||
control.
|
||||
|
||||
contextID is a server-defined octet string. If present, the contents
|
||||
of the contextID field SHOULD be returned to the server by a client
|
||||
in a subsequent virtual list request. The presence of a contextID
|
||||
here indicates that the server is willing to return contiguous data
|
||||
from a subsequent search request which uses the same search criteria,
|
||||
accompanied by a VirtualListViewRequest which indicates that the
|
||||
client wishes to receive an adjoining page of data.
|
||||
|
||||
The virtualListViewResult codes which are common to the LDAP
|
||||
searchResponse (adminLimitExceeded, timeLimitExceeded, busy,
|
||||
operationsError, unwillingToPerform, insufficientAccessRights) have
|
||||
the same meanings as defined in [LDAPv3], but they pertain
|
||||
specifically to the VLV operation. For example, the server could
|
||||
exceed an administration limit processing a SearchRequest with a
|
||||
VirtualListViewRequest control. However, the same administration
|
||||
limit would not be exceeded should the same SearchRequest be
|
||||
submitted by the client without the VirtualListViewRequest control.
|
||||
In this case, the client can determine that an administration limit
|
||||
has been exceeded in servicing the VLV request, and can if it chooses
|
||||
resubmit the SearchRequest without the VirtualListViewRequest
|
||||
control.
|
||||
searchResultDone (adminLimitExceeded, timeLimitExceeded,
|
||||
operationsError, unwillingToPerform, insufficientAccessRights,
|
||||
success, other) have the same meanings as defined in [LDAPPROT], but
|
||||
they pertain specifically to the VLV operation. For example, the
|
||||
server could exceed a VLV-specific administrative limit while
|
||||
processing a SearchRequest with a VirtualListViewRequest control.
|
||||
Obviously, the same administrative limit would not be exceeded should
|
||||
|
||||
Boreham et al Internet-Draft 7
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
the same SearchRequest be submitted by the client without the
|
||||
VirtualListViewRequest control. In this case, the client can
|
||||
determine that the administrative limit has been exceeded in
|
||||
servicing the VLV request, and can if it chooses resubmit the
|
||||
SearchRequest without the VirtualListViewRequest control, or with
|
||||
different parameters.
|
||||
|
||||
insufficientAccessRights means that the server denied the client
|
||||
permission to perform the VLV operation.
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 6
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
||||
|
||||
If the server determines that the results of the search presented
|
||||
exceed the range specified in INTEGER values, it MUST return
|
||||
offsetRangeError.
|
||||
exceed the range specified in INTEGER values, or if the client
|
||||
specifies an invalid offset or contentCount, the server MUST set the
|
||||
virtualListViewResult value to offsetRangeError.
|
||||
|
||||
6.2.1 virtualListViewError
|
||||
|
||||
A new LDAP error is introduced called virtualListViewError. Its value
|
||||
is 76.
|
||||
[Note to the IESG/IANA/RFC Editor: the value 76 has been suggested by
|
||||
experts, had expert review, and is currently being used by some
|
||||
implementations. The intent is to have this number designated as an
|
||||
official IANA assigned LDAP Result Code (see draft-ietf-ldapbis-iana-
|
||||
xx.txt, Section 3.5)]
|
||||
|
||||
If the server returns any code other than success (0) for
|
||||
virtualListViewResult, then the server SHOULD return
|
||||
virtualListViewError as the resultCode of the SearchResultDone
|
||||
message.
|
||||
is 76. This error indicates that the search operation failed due to
|
||||
the inclusion of the VirtualListViewRequest control.
|
||||
|
||||
If the resultCode in the SearchResultDone message is set to
|
||||
virtualListViewError (76), then the virtualListViewResult value MUST
|
||||
NOT be success (as virtualListViewResult indicates the specific error
|
||||
condition). If resultCode in the SearchResultDone message is not set
|
||||
to virtualListViewError (76), then the virtualListViewResult value
|
||||
SHOULD be success (0) and its value MUST be ignored.
|
||||
|
||||
7. Protocol Example
|
||||
|
||||
Here we walk through the client-server interaction for a specific
|
||||
virtual list view example: The task is to display a list of all 78564
|
||||
people in the US company "Ace Industry". This will be done by
|
||||
persons in the US company "Ace Industry". This will be done by
|
||||
creating a graphical user interface object to display the list
|
||||
contents, and by repeatedly sending different versions of the same
|
||||
virtual list view search request to the server. The list view
|
||||
displays 20 entries on the screen at a time.
|
||||
|
||||
We form a search with baseDN "o=Ace Industry, c=us"; search scope
|
||||
subtree; filter "objectClass=inetOrgPerson". We attach a server sort
|
||||
order control to the search, specifying ascending sort on attribute
|
||||
"cn". To this base search, we attach a virtual list view request
|
||||
control with contents determined by the user activity and send the
|
||||
search to the server. We display the results from each search in the
|
||||
list window and update the slider position.
|
||||
We form a search with baseObject of "o=Ace Industry,c=us"; scope of
|
||||
wholeSubtree; and filter of "(objectClass=person)". We attach a
|
||||
server-side sort control [SSS] to the search request, specifying
|
||||
ascending sort on attribute "cn". To this search request, we attach a
|
||||
virtual list view request control with contents determined by the
|
||||
user activity and send the search request to the server. We display
|
||||
the results from each search result entry in the list window and
|
||||
update the slider position.
|
||||
|
||||
When the list view is first displayed, we want to initialize the
|
||||
contents showing the beginning of the list. Therefore, we set
|
||||
beforeCount = 0, afterCount = 19, contentCount = 0, offset = 1 and
|
||||
send the request to the server. The server duly returns the first 20
|
||||
entries in the list, plus the content count = 78564 and
|
||||
targetPosition = 1. We therefore leave the scroll bar slider at its
|
||||
beforeCount to 0, afterCount to 19, contentCount to 0, offset to 1
|
||||
and send the request to the server. The server duly returns the first
|
||||
|
||||
Boreham et al Internet-Draft 8
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
20 entries in the list, plus a content count of 78564 and
|
||||
targetPosition of 1. We therefore leave the scroll bar slider at its
|
||||
current location (the top of its range).
|
||||
|
||||
Say that next the user drags the scroll bar slider down to the bottom
|
||||
of its range. We now wish to display the last 20 entries in the list,
|
||||
so we set beforeCount = 19, afterCount = 0, contentCount = 78564,
|
||||
offset = 78564 and send the request to the server. The server returns
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 7
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
||||
|
||||
the last 20 entries in the list, plus the content count = 78564 and
|
||||
targetPosition = 78564.
|
||||
so we set beforeCount to 19, afterCount to 0, contentCount to 78564,
|
||||
offset to 78564 and send the request to the server. The server
|
||||
returns the last 20 entries in the list, plus a content count of
|
||||
78564 and a targetPosition of 78564.
|
||||
|
||||
Next the user presses a page up key. Our page size is 20, so we set
|
||||
beforeCount = 0, afterCount = 19, contentCount = 78564, offset =
|
||||
beforeCount to 0, afterCount to 19, contentCount to 78564, offset to
|
||||
78564-19-20 and send the request to the server. The server returns
|
||||
the preceding 20 entries in the list, plus the content count = 78564
|
||||
and targetPosition = 78525.
|
||||
the preceding 20 entries in the list, plus a content count of 78564
|
||||
and a targetPosition of 78525.
|
||||
|
||||
Now the user grabs the scroll bar slider and drags it to 68% of the
|
||||
way down its travel. 68% of 78564 is 53424 so we set beforeCount = 9,
|
||||
afterCount = 10, contentCount = 78564, offset = 53424 and send the
|
||||
request to the server. The server returns the preceding 20 entries in
|
||||
the list, plus the content count = 78564 and targetPosition = 53424.
|
||||
way down its travel. 68% of 78564 is 53424 so we set beforeCount to
|
||||
9, afterCount to 10, contentCount to 78564, offset to 53424 and send
|
||||
the request to the server. The server returns the preceding 20
|
||||
entries in the list, plus a content count of 78564 and a
|
||||
targetPosition of 53424.
|
||||
|
||||
Lastly, the user types the letter "B". We set beforeCount = 9,
|
||||
afterCount = 10 and greaterThanOrEqual = "B". The server finds the
|
||||
Lastly, the user types the letter "B". We set beforeCount to 9,
|
||||
afterCount to 10 and greaterThanOrEqual to "B". The server finds the
|
||||
first entry in the list not less than "B", let's say "Babs Jensen",
|
||||
and returns the nine preceding entries, the target entry, and the
|
||||
proceeding 10 entries. The server returns content count = 78564 and
|
||||
targetPosition = 5234 and so the client updates its scroll bar slider
|
||||
to 6.7% of full scale.
|
||||
proceeding 10 entries. The server returns a content count of 78564
|
||||
and a targetPosition of 5234 and so the client updates its scroll bar
|
||||
slider to 6.7% of full scale.
|
||||
|
||||
|
||||
8. Notes for Implementers
|
||||
|
|
@ -440,40 +506,44 @@ Expires: Nov 2002 May 2002
|
|||
information received from the list view code to match the format of
|
||||
the virtual list view request and response controls.
|
||||
|
||||
Client implementers should note that any offset value returned by the
|
||||
server may be approximate. Do not design clients > which only operate
|
||||
correctly when offsets are exact.
|
||||
|
||||
Server implementers using indexing technology which features
|
||||
approximate positioning should consider returning context identifiers
|
||||
to clients. The use of a context identifier will allow the server to
|
||||
distinguish between client requests which relate to different
|
||||
displayed lists on the client. Consequently the server can decide
|
||||
more intelligently whether to reposition an existing database cursor
|
||||
|
||||
Boreham et al Internet-Draft 8
|
||||
Boreham et al Internet-Draft 9
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
accurately to within a short distance of its current position, or to
|
||||
reposition to an approximate position. Thus the client will see
|
||||
precise offsets for "short" repositioning (e.g. paging up or down),
|
||||
but approximate offsets for a "long" reposition (e.g. a slider
|
||||
movement).
|
||||
Client implementers MUST be aware that any offset value returned by
|
||||
the server might be approximate. Do not design clients that only
|
||||
operate correctly when offsets are exact. However, if contextIDs are
|
||||
used, and adjoining pages of information are requested, the server
|
||||
will return contiguous data.
|
||||
|
||||
Server implementers are free to return status code unwillingToPerform
|
||||
should their server be unable to service any particular VLV search.
|
||||
This might be because the resolution of the search is computationally
|
||||
infeasible, or because excessive server resources would be required
|
||||
to service the search.
|
||||
Server implementers using indexing technology which features
|
||||
approximate positioning should consider returning contextIDs to
|
||||
clients. The use of a contextID will allow the server to distinguish
|
||||
between client requests which relate to different displayed lists on
|
||||
the client. Consequently the server can decide more intelligently
|
||||
whether to reposition an existing database cursor accurately to
|
||||
within a short distance of its current position, or to reposition to
|
||||
an approximate position. Thus the client will see precise offsets for
|
||||
"short" repositioning (e.g. paging up or down), but approximate
|
||||
offsets for a "long" reposition (e.g. a slider movement).
|
||||
|
||||
Server implementers are free to return an LDAP result code of
|
||||
virtualListViewError and a virtualListViewResult of
|
||||
unwillingToPerform should their server be unable to service any
|
||||
particular VLV search. This might be because the resolution of the
|
||||
search is computationally infeasible, or because excessive server
|
||||
resources would be required to service the search.
|
||||
|
||||
Client implementers should note that this control is only defined on
|
||||
a client interaction with a single server. If a server returns
|
||||
referrals as a part of its response to the search request, the client
|
||||
is responsible for deciding when and how to apply this control to the
|
||||
referred-to servers, and how to collate the results from multiple
|
||||
servers.
|
||||
a client interaction with a single server. If a search scope spans
|
||||
multiple naming contexts that are not held locally, search result
|
||||
references will be returned, and may occur at any point in the search
|
||||
operation. The client is responsible for deciding when and how to
|
||||
apply this control to the referred-to servers, and how to collate the
|
||||
results from multiple servers.
|
||||
|
||||
|
||||
9. Relationship to "Simple Paged Results"
|
||||
|
|
@ -494,7 +564,13 @@ Expires: Nov 2002 May 2002
|
|||
Server implementers may wish to consider whether clients are able to
|
||||
consume excessive server resources in requesting virtual list
|
||||
operations. Access control to the feature itself; configuration
|
||||
options limiting the featureÆs use to certain predetermined search
|
||||
|
||||
Boreham et al Internet-Draft 10
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
options limiting the feature's use to certain predetermined search
|
||||
base DNs and filters; throttling mechanisms designed to limit the
|
||||
ability for one client to soak up server resources, may be
|
||||
appropriate.
|
||||
|
|
@ -503,43 +579,68 @@ Expires: Nov 2002 May 2002
|
|||
retrieve the complete contents, or a significant subset of the
|
||||
complete contents of the directory using this feature. This may be
|
||||
undesirable in some circumstances and consequently it may be
|
||||
necessary to enforce some access control.
|
||||
necessary to enforce some access control or administrative limit.
|
||||
|
||||
Clients can, using this control, determine how many entries match a
|
||||
particular filter, before the entries are returned to the client.
|
||||
This may require special processing in servers which perform access
|
||||
control checks on entries to determine whether the existence of the
|
||||
entry can be disclosed to the client.
|
||||
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 9
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
||||
|
||||
Clients can, using this control, determine how many entries are
|
||||
contained within a portion of the DIT. This may constitute a security
|
||||
hazard. Again, access controls may be appropriate.
|
||||
|
||||
Server implementers SHOULD exercise caution concerning the content of
|
||||
Server implementers should exercise caution concerning the content of
|
||||
the contextID. Should the contextID contain internal server state, it
|
||||
may be possible for a malicious client to use that information to
|
||||
gain unauthorized access to information.
|
||||
|
||||
11. IANA Considerations
|
||||
|
||||
11. Acknowledgements
|
||||
11.1 Request for LDAP Result Code
|
||||
|
||||
In accordance with section 3.6 of [LDAPIANA], it is requested that
|
||||
IANA register the LDAP result code virtualListViewError (76) upon
|
||||
Standards Action by the IESG. The value 76 has been suggested by
|
||||
experts, had expert review, and is currently being used by some
|
||||
implementations. If 76 is unavailable on not chosen, the value in the
|
||||
paragraphs in Section 6.2.1 will need to be updated. The following
|
||||
registration template is suggested:
|
||||
|
||||
Subject: LDAP Result Code Registration
|
||||
Person & email address to contact for further information: Jim
|
||||
Sermersheim
|
||||
Result Code Name: virtualListViewError
|
||||
Specification: RFCXXXX
|
||||
Author/Change Controller: IESG
|
||||
Comments: request LDAP result codes be assigned
|
||||
|
||||
|
||||
|
||||
12. Acknowledgements
|
||||
|
||||
Chris Weider, Anoop Anantha, and Michael Armijo of Microsoft co-
|
||||
authored previous versions of this document.
|
||||
|
||||
|
||||
12. References
|
||||
|
||||
|
||||
[LDAPv3] Wahl, M., Kille, S. and T. Howes, "Lightweight Directory
|
||||
Boreham et al Internet-Draft 11
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
13. Normative References
|
||||
|
||||
|
||||
[X.680] ITU-T Rec. X.680, "Abstract Syntax Notation One (ASN.1) -
|
||||
Specification of Basic Notation", 1994.
|
||||
|
||||
[X.690] ITU-T Rec. X.690, "Specification of ASN.1 encoding rules:
|
||||
Basic, Canonical, and Distinguished Encoding Rules",
|
||||
1994.
|
||||
|
||||
[LDAPPROT] Wahl, M., Kille, S. and T. Howes, "Lightweight Directory
|
||||
Access Protocol (v3)", Internet Standard, RFC 2251,
|
||||
December, 1997.
|
||||
|
||||
[SPaged] Weider, C., Herron, A., Anantha, A. and T. Howes, "LDAP
|
||||
Control Extension for Simple Paged Results Manipulation",
|
||||
RFC2696, September 1999.
|
||||
|
||||
[SSS] Wahl, M., Herron, A. and T. Howes, "LDAP Control
|
||||
Extension for Server Side Sorting of Search Results",
|
||||
RFC 2891, August, 2000.
|
||||
|
|
@ -547,30 +648,18 @@ Expires: Nov 2002 May 2002
|
|||
[Bradner97] Bradner, S., "Key Words for use in RFCs to Indicate
|
||||
Requirement Levels", BCP 14, RFC 2119, March 1997.
|
||||
|
||||
[LDAPIANA] Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
|
||||
Considerations for the Lightweight Directory Access
|
||||
Protocol (LDAP)", RFC 3383, September 2002.
|
||||
|
||||
14. Informative References
|
||||
|
||||
[SPaged] Weider, C., Herron, A., Anantha, A. and T. Howes, "LDAP
|
||||
Control Extension for Simple Paged Results Manipulation",
|
||||
RFC2696, September 1999.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 10
|
||||
|
||||
LDAP Extensions for Scrolling View May 2002
|
||||
Browsing of Search Results
|
||||
|
||||
13. Authors' Addresses
|
||||
15. Authors' Addresses
|
||||
|
||||
David Boreham
|
||||
Bozeman Pass, Inc
|
||||
|
|
@ -578,7 +667,7 @@ Expires: Nov 2002 May 2002
|
|||
david@bozemanpass.com
|
||||
|
||||
Jim Sermersheim
|
||||
Novell, Inc
|
||||
Novell
|
||||
1800 South Novell Place
|
||||
Provo, Utah 84606, USA
|
||||
jimse@novell.com
|
||||
|
|
@ -590,8 +679,14 @@ Expires: Nov 2002 May 2002
|
|||
+1 425 882-8080
|
||||
asafk@microsoft.com
|
||||
|
||||
Boreham et al Internet-Draft 12
|
||||
|
||||
LDAP Extensions for Scrolling View Nov 2002
|
||||
Browsing of Search Results
|
||||
|
||||
14. Full Copyright Statement
|
||||
|
||||
|
||||
16. Full Copyright Statement
|
||||
|
||||
Copyright (C) The Internet Society (2002). All Rights Reserved.
|
||||
This document and translations of it may be copied and furnished to
|
||||
|
|
@ -622,4 +717,23 @@ Expires: Nov 2002 May 2002
|
|||
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 11
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Boreham et al Internet-Draft 13
|
||||
|
|
|
|||
Loading…
Reference in a new issue