RFC 2244
ACAP -- Application Configuration Access Protocol
4. Namespace Conventions 4.1. Dataset Namespace The dataset namespace is a slash-separated hierarchy. The first component of the dataset namespace is a dataset class. Dataset classes MUST have a vendor prefix (vendor.<vendor/product>) or be specified in a standards track or IESG approved experimental RFC. See section 7.3 for the registration template. The second component of the dataset name is "site", "group", "host", or "user" referring to server-wide data, administrative group data, per-host data and per-user data respectively. For "group", "host", and "user" areas, the third component of the path is the group name, the fully qualified host domain name, or the user name. A path of the form "/<dataset-class>/~/" is a convenient abbreviation for "/<dataset-class>/user/<current-user>/". Dataset names which begin with "/byowner/" are reserved as an alternate view of the namespace. This provides a way to see all the dataset classes which a particular owner uses. For example, "/byowner/~/<dataset-class>/" is an alternate name for "/<dataset-class>/~/". Byowner provides a way to view a list of dataset classes owned by a given user; this is done using the dataset "/byowner/user/<current-user>/" with the NOINHERIT SEARCH modifier. The dataset "/" may be used to find all dataset classes visible to the current user. A dataset of the form "/<dataset-class>/user/" may be used to find all users which have made a dataset or entry of that class visible to the current user. The formal syntax for a dataset name is defined by the "dataset-name" rule in section 4.3. 4.2. Attribute Namespace Attribute names which do not contain a dot (".") are reserved for standardized attributes which have meaning in any dataset. In order to simplify client implementations, the attribute namespace is intended to be unique across all datasets. To achieve this, attribute names are prefixed with the dataset class name followed by a dot ("."). Attributes which affect management of the dataset are prefixed with "dataset.". In addition, a subtree of the "vendor." attribute namespace may be registered with IANA according to the rules in section 7.4. ACAP implementors are encouraged to help define interoperable dataset classes specifications rather than using the private attribute namespace.
Some users or sites may wish to add their own private attributes to certain dataset classes. In order to enable this, the "user.<user- name>." and "site." subtrees of the attribute namespace are reserved for user-specific and site-specific attributes respectively and will not be standardized. Such attributes are not interoperable so are discouraged in favor of defining standard attributes. A future extension is expected to permit discovery of syntax for user or site-specific attributes. Clients wishing to support display of user or site-specific attributes should display the value of any non-NIL single-valued "user.<user-name>." or "site." attribute which has valid UTF-8 syntax. The formal syntax for an attribute name is defined by the "attribute-name" rule in the next section. 4.3. Formal Syntax for Dataset and Attribute Namespace The naming conventions for datasets and attributes are defined by the following ABNF. Note that this grammar is not part of the ACAP protocol syntax in section 8, as dataset names and attribute names are encoded as strings within the ACAP protocol. attribute-dacl = "dataset.acl" *("." name-component) attribute-dset = dataset-std 1*("." name-component) ;; MUST be defined in a dataset class specification attribute-name = attribute-std / attr-site / attr-user / vendor-name attribute-std = "entry" / "subdataset" / "modtime" / "dataset.inherit" / attribute-dacl / attribute-dset attr-site = "site" 1*("." name-component) attr-user = "user." name-component 1*("." name-component) byowner = "/byowner/" owner "/" [dataset-class "/" dataset-sub] dataset-class = dataset-std / vendor-name dataset-normal = "/" [dataset-class "/" (owner-prefix / dataset-tail)] dataset-name = byowner / dataset-normal
dataset-std = name-component
;; MUST be registered with IANA and the spec MUST
;; be published as a standards track or
;; IESG-approved experimental RFC
dataset-sub = *(dname-component "/")
;; The rules for this portion of the namespace may
;; be further restricted by the dataset class
;; specification.
dataset-tail = owner "/" dataset-sub
dname-component = 1*UTF8-CHAR
;; MUST NOT begin with "." or contain "/"
name-component = 1*UTF8-CHAR
;; MUST NOT contain ".", "/", "%", or "*"
owner = "site" / owner-host / owner-group /
owner-user / "~"
owner-group = "group/" dname-component
owner-host = "host/" dname-component
owner-prefix = "group/" / "host/" / "user/"
owner-user = "user/" dname-component
vendor-name = vendor-token *("." name-component)
vendor-token = "vendor." name-component
;; MUST be registered with IANA
5. Dataset Management
The entry with an empty name ("") in the dataset is used to hold
management information for the dataset as a whole.
5.1. Dataset Inheritance
It is possible for one dataset to inherit data from another. The
dataset from which the data is inherited is called the base dataset.
Data in the base dataset appears in the inheriting dataset, except
when overridden by a STORE to the inheriting dataset.
The base dataset is usually a system-wide or group-wide set of defaults. A system-wide dataset usually has one inheriting dataset per user, allowing each user to add to or modify the defaults as appropriate. An entry which exists in both the inheriting and base dataset inherits a modtime equal to the greater of the two modtimes. An attribute in such an entry is inherited from the base dataset if it was never modified by a STORE command in the inheriting dataset or if DEFAULT was stored to that attribute. This permits default entries to be amended rather than replaced in the inheriting dataset. The "subdataset" attribute is not directly inherited. If the base dataset includes a "subdataset" attribute and the inheriting dataset does not, then the "subdataset" attribute will inherit a virtual value of a list containing a ".". The subdataset at that node is said to be a "virtual" dataset as it is simply a virtual copy of the appropriate base dataset with all "subdataset" attributes changed to a list containing a ".". A virtual dataset is not visible if NOINHERIT is specified on the SEARCH command. Servers MUST support at least two levels of inheritance. This permits a user's dataset such as "/options/user/fred/common" to inherit from a group dataset such as "/options/group/dinosaur operators/common" which in turn inherits from a server-wide dataset such as "/options/site/common". 5.2. Dataset Attributes The following attributes apply to management of the dataset when stored in the "" entry of a dataset. These attributes are not inherited. dataset.acl This holds the default access control list for the dataset. This attribute is validated, so an invalid access control list in a STORE command will result in a NO response with an INVALID response code. dataset.acl.<attribute> This holds the default access control list for an attribute within the dataset. This attribute is validated, so an invalid access control list in a STORE command will result in a NO response with an INVALID response code. dataset.inherit This holds the name of a dataset from which to inherit according to the rules in the previous section. This attribute MAY refer
to a non-existent dataset, in which case nothing is inherited.
This attribute is validated, so illegal dataset syntax or an
attempt to store a multi-value will result in a NO response with
an INVALID response code.
5.3. Dataset Creation
When a dataset is first created (by storing a "." in the subdataset
attribute or storing an entry in a previously non-existent dataset),
the dataset attributes are initialized with the values from the
parent dataset in the "/byowner/" hierarchy. In the case of the
"dataset.inherit" attribute, the appropriate hierarchy component is
added. For example, given the following entry (note that \t refers
to the US-ASCII horizontal tab character):
entry path "/byowner/user/joe/"
dataset.acl ("joe\txrwia" "fred\txr")
dataset.inherit "/byowner/site"
If a new dataset class "/byowner/user/joe/new" is created, it will
have the following dataset attributes:
entry path "/byowner/user/joe/new/"
dataset.acl ("joe\txrwia" "fred\txr")
dataset.inherit "/byowner/site/new"
Note that the dataset "/byowner/user/joe/new/" is equivalent to
"/new/user/joe/".
5.4. Dataset Class Capabilities
Certain dataset classes or dataset class features may only be useful
if there is an active updating client or integrated server support
for the feature. The dataset class "capability" is reserved to allow
clients or servers to advertise such features. The "entry" attribute
within this dataset class is the name of the dataset class whose
features are being described. The attributes are prefixed with
"capability.<dataset-class>." and are defined by the appropriate
dataset class specification.
Since it is possible for an unprivileged user to run an active client
for himself, a per-user capability dataset is useful. The dataset
"/capability/~/" holds information about all features available to
the user (via inheritance), and the dataset "/capability/site/" holds
information about all features supported by the site.
5.5. Dataset Quotas Management and scope of quotas is implementation dependent. Clients can check the applicable quota limit and usage (in bytes) with the GETQUOTA command. Servers can notify the client of a low quota situation with the QUOTA untagged response. 6. Command and Response Specifications ACAP commands and responses are described in this section. Commands are organized first by the state in which the command is permitted, then by a general category of command type. Command arguments, identified by "Arguments:" in the command descriptions below, are described by function, not by syntax. The precise syntax of command arguments is described in the Formal Syntax section. Some commands cause specific server data to be returned; these are identified by "Data:" in the command descriptions below. See the response descriptions in the Responses section for information on these responses, and the Formal Syntax section for the precise syntax of these responses. It is possible for server data to be transmitted as a result of any command; thus, commands that do not specifically require server data specify "no specific data for this command" instead of "none". The "Result:" in the command description refers to the possible tagged status responses to a command, and any special interpretation of these status responses. 6.1. Initial Connection Upon session startup, the server sends one of two untagged responses: ACAP or BYE. The untagged BYE response is described in section 6.2.8. 6.1.1. ACAP Untagged Response Data: capability list The untagged ACAP response indicates the session is ready to accept commands and contains a space-separated listing of capabilities that the server supports. Each capability is represented by a list containing the capability name optionally followed by capability specific string arguments.
ACAP capability names MUST be registered with IANA according to
the rules in section 7.1.
Client implementations SHOULD NOT require any capability name
beyond those defined in this specification, and MUST tolerate any
unknown capability names. A client implementation MAY be
configurable to require SASL mechanisms other than CRAM-MD5
[CRAM-MD5] for site security policy reasons.
The following initial capabilities are defined:
CONTEXTLIMIT
The CONTEXTLIMIT capability has one argument which is a
number describing the maximum number of contexts the server
supports per connection. The number 0 indicates the server
has no limit, otherwise this number MUST be greater than
100.
IMPLEMENTATION
The IMPLEMENTATION capability has one argument which is a
string describing the server implementation. ACAP clients
MUST NOT alter their behavior based on this value. It is
intended primarily for debugging purposes.
SASL The SASL capability includes a list of the authentication
mechanisms supported by the server. See section 6.3.1.
Example: S: * ACAP (IMPLEMENTATION "ACME v3.5")
(SASL "CRAM-MD5") (CONTEXTLIMIT "200")
6.2. Any State
The following commands and responses are valid in any state.
6.2.1. NOOP Command
Arguments: none
Data: no specific data for this command (but see below)
Result: OK - noop completed
BAD - command unknown or arguments invalid
The NOOP command always succeeds. It does nothing. It can be
used to reset any inactivity auto-logout timer on the server.
Example: C: a002 NOOP
S: a002 OK "NOOP completed"
6.2.2. LANG Command
Arguments: list of language preferences
Data: intermediate response: LANG
Result: OK - lang completed
NO - no matching language available
BAD - command unknown or arguments invalid
One or more arguments are supplied to indicate the client's
preferred languages [LANG-TAGS] for error messages. The server
will match each client preference in order against its internal
table of available error string languages. For a client
preference to match a server language, the client's language tag
MUST be a prefix of the server's tag and match up to a "-" or the
end of string. If a match is found, the server returns an
intermediate LANG response and an OK response. The LANG response
indicates the actual language selected and appropriate comparators
for use with the languages listed in the LANG command.
If no LANG command is issued, all error text strings MUST be in
the registered language "i-default" [CHARSET-LANG-POLICY],
intended for an international audience.
Example: C: A003 LANG "fr-ca" "fr" "en-ca" "en-uk"
S: A003 LANG "fr-ca" "i;octet" "i;ascii-numeric"
"i;ascii-casemap" "en;primary" "fr;primary"
S: A003 OK "Bonjour"
6.2.3. LANG Intermediate Response
Data: language for error responses
appropriate comparators
The LANG response indicates the language which will be used for
error responses and the comparators which are appropriate for the
languages listed in the LANG command. The comparators SHOULD be
in approximate order from most efficient (usually "i;octet") to
most appropriate for human text in the preferred language.
6.2.4. LOGOUT Command Arguments: none Data: mandatory untagged response: BYE Result: OK - logout completed BAD - command unknown or arguments invalid The LOGOUT command informs the server that the client is done with the session. The server must send a BYE untagged response before the (tagged) OK response, and then close the network connection. Example: C: A023 LOGOUT S: * BYE "ACAP Server logging out" S: A023 OK "LOGOUT completed" (Server and client then close the connection) 6.2.5. OK Response Data: optional response code human-readable text The OK response indicates an information message from the server. When tagged, it indicates successful completion of the associated command. The human-readable text may be presented to the user as an information message. The untagged form indicates an information-only message; the nature of the information MAY be indicated by a response code. Example: S: * OK "Master ACAP server is back up" 6.2.6. NO Response Data: optional response code human-readable text The NO response indicates an operational error message from the server. When tagged, it indicates unsuccessful completion of the associated command. The untagged form indicates a warning; the command may still complete successfully. The human-readable text describes the condition. Example: C: A010 SEARCH "/addressbook/" DEPTH 3 RETURN ("*") EQUAL "entry" "+i;octet" "bozo" S: * NO "Master ACAP server is down, your data may
be out of date."
S: A010 OK "search done"
...
C: A222 STORE ("/folder/site/comp.mail.misc"
"folder.creation-time" "19951206103412")
S: A222 NO (PERMISSION ("/folder/site/")) "Permission
denied"
6.2.7. BAD Response
Data: optional response code
human-readable text
The BAD response indicates an error message from the server. When
tagged, it reports a protocol-level error in the client's command;
the tag indicates the command that caused the error. The untagged
form indicates a protocol-level error for which the associated
command can not be determined; it may also indicate an internal
server failure. The human-readable text describes the condition.
Example: C: ...empty line...
S: * BAD "Empty command line"
C: A443 BLURDYBLOOP
S: A443 BAD "Unknown command"
C: A444 NOOP Hello
S: A444 BAD "invalid arguments"
6.2.8. BYE Untagged Response
Data: optional response code
human-readable text
The untagged BYE response indicates that the server is about to
close the connection. The human-readable text may be displayed to
the user in a status report by the client. The BYE response may
be sent as part of a normal logout sequence, or as a panic
shutdown announcement by the server. It is also used by some
server implementations as an announcement of an inactivity auto-
logout.
This response is also used as one of two possible greetings at
session startup. It indicates that the server is not willing to
accept a session from this client.
Example: S: * BYE "Auto-logout; idle for too long"
6.2.9. ALERT Untagged Response Data: optional response code human-readable text The human-readable text contains a special human generated alert message that MUST be presented to the user in a fashion that calls the user's attention to the message. This is intended to be used for vital messages from the server administrator to the user, such as a warning that the server will soon be shut down for maintenance. Example: S: * ALERT "This ACAP server will be shut down in 10 minutes for system maintenance." 6.3. Non-Authenticated State In non-authenticated state, the AUTHENTICATE command establishes authentication and enters authenticated state. The AUTHENTICATE command provides a general mechanism for a variety of authentication techniques. Server implementations may allow non-authenticated access to certain information by supporting the SASL ANONYMOUS [SASL-ANON] mechanism. Once authenticated (including as anonymous), it is not possible to re-enter non-authenticated state. Only the any-state commands (NOOP, LANG and LOGOUT) and the AUTHENTICATE command are valid in non-authenticated state. 6.3.1. AUTHENTICATE Command Arguments: SASL mechanism name optional initial response Data: continuation data may be requested Result: OK - authenticate completed, now in authenticated state NO - authenticate failure: unsupported authentication mechanism, credentials rejected BAD - command unknown or arguments invalid, authentication exchange cancelled
The AUTHENTICATE command indicates a SASL [SASL] authentication
mechanism to the server. If the server supports the requested
authentication mechanism, it performs an authentication protocol
exchange to authenticate and identify the user. Optionally, it
also negotiates a security layer for subsequent protocol
interactions. If the requested authentication mechanism is not
supported, the server rejects the AUTHENTICATE command by sending
a tagged NO response.
The authentication protocol exchange consists of a series of
server challenges and client answers that are specific to the
authentication mechanism. A server challenge consists of a
command continuation request with the "+" token followed by a
string. The client answer consists of a line consisting of a
string. If the client wishes to cancel an authentication
exchange, it should issue a line with a single unquoted "*". If
the server receives such an answer, it must reject the
AUTHENTICATE command by sending a tagged BAD response.
The optional initial-response argument to the AUTHENTICATE command
is used to save a round trip when using authentication mechanisms
that are defined to send no data in the initial challenge. When
the initial-response argument is used with such a mechanism, the
initial empty challenge is not sent to the client and the server
uses the data in the initial-response argument as if it were sent
in response to the empty challenge. If the initial-response
argument to the AUTHENTICATE command is used with a mechanism that
sends data in the initial challenge, the server rejects the
AUTHENTICATE command by sending a tagged NO response.
The service name specified by this protocol's profile of SASL is
"acap".
If a security layer is negotiated through the SASL authentication
exchange, it takes effect immediately following the CRLF that
concludes the authentication exchange for the client, and the CRLF
of the tagged OK response for the server.
All ACAP implementations MUST implement the CRAM-MD5 SASL
mechanism [CRAM-MD5], although they MAY offer a configuration
option to disable it if site security policy dictates. The
example below is the same example described in the CRAM-MD5
specification.
If an AUTHENTICATE command fails with a NO response, the client
may try another authentication mechanism by issuing another
AUTHENTICATE command. In other words, the client may request
authentication types in decreasing order of preference.
Example: S: * ACAP (IMPLEMENTATION "Blorfysoft v3.5")
(SASL "CRAM-MD5" "KERBEROS_V4")
C: A001 AUTHENTICATE "CRAM-MD5"
S: + "<1896.697170952@postoffice.reston.mci.net>"
C: "tim b913a602c7eda7a495b4e6e7334d3890"
S: A001 OK "CRAM-MD5 authentication successful"
6.4. Searching
This section describes the SEARCH command, for retrieving data from
datasets.
6.4.1. SEARCH Command
Arguments: dataset or context name
optional list of modifiers
search criteria
Data: intermediate responses: ENTRY, MODTIME, REFER
untagged responses: ADDTO, REMOVEFROM, CHANGE, MODTIME
Result: OK - search completed
NO - search failure: can't perform search
BAD - command unknown or arguments invalid
The SEARCH command identifies a subset of entries in a dataset and
returns information on that subset to the client. Inherited
entries and attributes are included in the search unless the
NOINHERIT search modifier is included or the user does not have
permission to read the attributes in the base dataset.
The first argument to SEARCH identifies what is to be searched.
If the string begins with a slash ("/"), it is the name of a
dataset to be searched, otherwise it is a name of a context that
was created by a SEARCH command given previously in the session.
A successful SEARCH command MAY result in intermediate ENTRY
responses and MUST result in a MODTIME intermediate response.
Following that are zero or more modifiers to the search. Each
modifier may be specified at most once. The defined modifiers
are:
DEPTH number
The SEARCH command will traverse the dataset tree up to the
specified depth. ENTRY responses will include the full path
to the entry. A value of "0" indicates that the search
should traverse the entire tree. A value of "1" is the
default and indicates only the specified dataset should be
searched. If a dataset is traversed which is not located on
the current server, then a REFER intermediate response is
returned for that subtree and the search continues.
HARDLIMIT number
If the SEARCH command would result in more than number
entries, the SEARCH fails with a NO completion result with a
WAYTOOMANY response code.
LIMIT number number
Limits the number of intermediate ENTRY responses that the
search may generate. The first numeric argument specifies
the limit, the second number specifies the number of entries
to return if the number of matches exceeds the limit. If the
limit is exceeded, the SEARCH command still succeeds,
returning the total number of matches in a TOOMANY response
code in the tagged OK response.
MAKECONTEXT [ENUMERATE] [NOTIFY] context
Causes the SEARCH command to create a context with the name
given in the argument to refer to the matching entries. If
the SEARCH is successful, the context name may then be given
as an argument to subsequent SEARCH commands to search the
set of matching entries. If a context with the specified
name already exists, it is first freed. If a new context may
not be created due to the server's limit on the number of
existing contexts, the command fails, returning a
TRYFREECONTEXT response code in the NO completion response.
The optional "ENUMERATE" and "NOTIFY" arguments may be
included to request enumeration of the context (for virtual
scroll bars) or change notifications for the context. If
"NOTIFY" is not requested, the context represents a snapshot
of the entries at the time the SEARCH was issued.
ENUMERATE requests that the contents of the context be
ordered according to the SORT modifier and that sequential
numbers, starting with one, be assigned to the entries in the
context. This permits the RANGE modifier to be used to fetch
portions of the ordered context.
NOTIFY requests that the server send untagged ADDTO,
REMOVEFROM, CHANGE, and MODTIME responses while the context
created by this SEARCH command exists. The server MAY issue
untagged ADDTO, REMOVEFROM, CHANGE and MODTIME notifications
for a context at any time between the issuing of the SEARCH
command with MAKECONTEXT NOTIFY and the completion of a
FREECONTEXT command for the context. Notifications are only
issued for changes which occur after the server receives the
SEARCH command which created the context. After issuing a
sequence of ADDTO, REMOVEFROM or CHANGE notifications, the
server MUST issue an untagged MODTIME notification indicating
that the client has all updates to the entries in the context
up to and including the given modtime value. Servers are
permitted a reasonable delay to batch change notifications
before sending them to the client.
The position arguments of the ADDTO, REMOVEFROM and CHANGE
notifications are 0 if ENUMERATE is not requested.
NOINHERIT
This causes the SEARCH command to operate without
inheritance. It can be used to tell which values are
explicit overrides. If MAKECONTEXT is also specified, the
created context is also not affected by inheritance.
RETURN (metadata...)
Specifies what is to be returned in intermediate ENTRY
responses. If this modifier is not specified, no
intermediate ENTRY responses are returned.
Inside the parentheses is an optional list of attributes,
each optionally followed by a parenthesized list of metadata.
If the parenthesized list of metadata is not specified, it
defaults to "(value)".
An attribute name with a trailing "*" requests all attributes
with that prefix. A "*" by itself requests all attributes.
If the parenthesized list of metadata is not specified for an
attribute with a trailing "*", it defaults to "(attribute
value)". Results matching such an attribute pattern are
grouped in parentheses.
Following the last intermediate ENTRY response, the server
returns a single intermediate MODTIME response.
SORT (attribute comparator ...)
Specifies the order in which any resulting ENTRY replies are
to be returned to the client. The SORT modifier takes as an
argument a parenthesized list of one or more
attribute/comparator pairs. Attribute lists the attribute to
sort on, comparator specifies the name of the collation rule
to apply to the values of the attribute. Successive
attribute/comparator pairs are used to order two entries only
when all preceding pairs indicate the two entries collate the
same.
If the SORT modifier is used in conjunction with the
MAKECONTEXT modifier, the SORT modifier specifies the
ordering of entries in the created context.
If no SORT modifier is specified, or none of the
attribute/comparator pairs indicates an order for the two
entries, the server uses the order of the entries that exists
in the context or dataset being searched.
Following the modifiers is the search criteria. Searching
criteria consist of one or more search keys. Search keys may be
combined using the AND, and OR search keys. For example, the
criteria (the newline is for readability and not part of the
criteria):
AND COMPARE "modtime" "+i;octet" "19951206103400"
COMPARE "modtime" "-i;octet" "19960112000000"
refers to all entries modified between 10:34 December 6 1995 and
midnight January 12, 1996 UTC.
The currently defined search keys are as follows.
ALL This matches all entries.
AND search-key1 search-key2
Entries that match both search keys.
COMPARE attribute comparator value
Entries for which the value of the specified attribute
collates using the specified comparator the same or later
than the specified value.
COMPARESTRICT attribute comparator value
Entries for which the specified attribute collates using the
specified comparator later than the specified value.
EQUAL attribute comparator value
Entries for which the value of the attribute is equal to the
specified value using the specified comparator.
NOT search-key
Entries that do not match the specified search key.
OR search-key1 search-key2
Entries that match either search key.
PREFIX attribute comparator value
Entries which begin with the specified value using the
specified comparator. If the specified comparator doesn't
support substring matching, a BAD response is returned.
RANGE start end time
Entries which are within the specified range of the
enumerated context's ordering. The lowest-ordered entry in
the context is assigned number one, the next lowest entry is
assigned number two, and so on. The numeric arguments
specify the lowest and highest numbers to match. The time
specifies that the client has processed notifications for the
context up to the specified time. If the context has been
modified since then, the server MUST either return a NO with
a MODIFIED response code, or return the results that the
SEARCH would have returned if none of the changes since that
time had been made.
RANGE is only permitted on enumerated contexts. If RANGE is
used with a dataset or non-enumerated context, the server
MUST return a BAD response.
SUBSTRING attribute comparator value
Entries which contain the specified value, using the
specified comparator. If the specified comparator doesn't
support substring matching, a BAD response is returned.
6.4.2. ENTRY Intermediate Response
Data: entry name
entry data
The ENTRY intermediate response occurs as a result of a SEARCH or
STORE command. This is the means by which dataset entries are
returned to the client.
The ENTRY response begins with the entry name, if a SEARCH command
without the DEPTH modifier was issued, or the entry path in other
cases. This is followed by a set of zero or more items, one for
each metadata item in the RETURN search modifier. Results
matching an attribute pattern or returning multiple metadata items
are grouped in parentheses.
6.4.3. MODTIME Intermediate Response
Data: modtime value
The MODTIME intermediate response occurs as a result of a SEARCH
command. It indicates that the just created context or the
previously returned ENTRY responses include all updates to the
returned entries up to and including the modtime value in the
argument.
6.4.4. REFER Intermediate Response
Data: dataset path
relative ACAP URLs
The REFER intermediate response occurs as a result of a
multi-level SEARCH where one of the levels is located on a
different server. The response indicates the dataset which is not
located on the current server and one or more relative ACAP URLs
for where that dataset may be found.
6.4.5. Search Examples
Here are some SEARCH command exchanges between the client and server:
C: A046 SEARCH "/addressbook/" DEPTH 3 RETURN ("addressbook.Alias"
"addressbook.Email" "addressbook.List") OR NOT EQUAL
"addressbook.Email" "i;octet" NIL NOT EQUAL
"addressbook.List" "i;octet" NIL
S: A046 ENTRY "/addressbook/user/joe/A0345" "fred"
"fred@stone.org" NIL
S: A046 ENTRY "/addressbook/user/fred/A0537" "joe" "joe@stone.org"
NIL
S: A046 ENTRY "/addressbook/group/Dinosaur Operators/A423"
"saurians" NIL "1"
S: A046 MODTIME "19970728105252"
S: A046 OK "SEARCH completed"
C: A047 SEARCH "/addressbook/user/fred/" RETURN ("*") EQUAL "entry"
"i;octet" "A0345"
S: A047 ENTRY "A0345" (("modtime" "19970728102226")
("addressbook.Alias" "fred") ("addressbook.Email"
"fred@stone.org") ("addressbook.CommonName"
"Fred Flintstone") ("addressbook.Surname" "Flintstone")
("addressbook.GivenName" "Fred"))
S: A047 MODTIME "19970728105258"
S: A047 OK "SEARCH completed"
C: A048 SEARCH "/options/~/vendor.example/" RETURN
("option.value"("size" "value" "myrights"))
SORT ("entry" "i;octet") COMPARE "modtime" "i;octet"
"19970727123225"
S: A048 ENTRY "blurdybloop" (5 "ghoti" "rwia")
S: A048 ENTRY "buckybits" (2 "10" "rwia")
S: A048 ENTRY "windowSize" (7 "100x100" "rwia")
S: A048 MODTIME "19970728105304"
S: A048 OK "SEARCH completed"
C: A049 SEARCH "/addressbook/~/public" RETURN ("addressbook.Alias"
"addressbook.Email") MAKECONTEXT ENUMERATE "blob" LIMIT 100 1
SORT ("addressbook.Alias" "i;octet") NOT EQUAL
"addressbook.Email" NIL
S: A049 ENTRY "A437" "aaguy" "aaguy@stone.org"
S: A049 MODTIME "19970728105308"
S: A049 OK (TOOMANY 347) "Context 'blob' created"
C: A050 SEARCH "blob" RANGE 2 2 "19970728105308" ALL
S: A050 ENTRY "A238" "abguy" "abguy@stone.org"
S: A050 MODTIME "19970728105310"
S: A050 OK "SEARCH Completed"
6.5. Contexts
The following commands use contexts created by a SEARCH command with
a MAKECONTEXT modifier.
6.5.1. FREECONTEXT Command
Arguments: context name
Data: no specific data for this command
Result: OK - freecontext completed
NO - freecontext failure: no such context
BAD - command unknown or arguments invalid
The FREECONTEXT command causes the server to free all state
associated with the named context. The context may no longer be
searched and the server will no longer issue any untagged
responses for the context. The context is no longer counted
against the server's limit on the number of contexts.
Example: C: A683 FREECONTEXT "blurdybloop"
S: A683 OK "Freecontext completed"
6.5.2. UPDATECONTEXT Command
Arguments: list of context names
Data: untagged responses: ADDTO REMOVEFROM CHANGE MODTIME
Result: OK - Updatecontext completed: all updates completed
NO - Updatecontext failed: no such context
not a notify context
BAD - command unknown or arguments invalid
The UPDATECONTEXT command causes the server to ensure that the
client is notified of all changes known to the server for the
contexts listed as arguments up to the current time. The contexts
listed in the arguments must have been previously given to a
successful SEARCH command with a MAKECONTEXT NOTIFY modifier. A
MODTIME untagged response MUST be returned if any read-write
metadata in the context changed since the last MODTIME for that
context. This includes metadata which is not listed in the RETURN
modifier for the context.
While a server may issue untagged ADDTO, REMOVEFROM, CHANGE, and
MODTIME at any time, the UPDATECONTEXT command is used to "prod"
the server to send any notifications it has not sent yet.
The UPDATECONTEXT command SHOULD NOT be used to poll for updates.
Example: C: Z4S9 UPDATECONTEXT "blurdybloop" "blarfl"
S: Z4S9 OK "client has been notified of all changes"
6.5.3. ADDTO Untagged Response
Data: context name
entry name
position
metadata list
The untagged ADDTO response informs the client that an entry has
been added to a context. The response includes the position
number of the added entry (the first entry in the context is
numbered 1) and those metadata contained in the entry which match
the RETURN statement when the context was created.
For enumerated contexts, the ADDTO response implicitly adds one to
the position of all members of the context which had position
numbers that were greater than or equal to the ADDTO position
number. For non-enumerated contexts, the position field is always
0.
Example: S: * ADDTO "blurdybloop" "fred" 15
("addressbook.Email" "fred@stone.org")
6.5.4. REMOVEFROM Untagged Response
Data: context name
entry name
old position
The untagged REMOVEFROM response informs the client that an entry
has been removed from a context. The response includes the
position number that the removed entry used to have (the first
entry in the context is numbered 1).
For enumerated contexts, the REMOVEFROM response implicitly
subtracts one from the position numbers of all members of the
context which had position numbers greater than the REMOVEFROM
position number. For non-enumerated contexts, the position field
is always 0.
Example: S: * REMOVEFROM "blurdybloop" "fred" 15
6.5.5. CHANGE Untagged Response
Data: context name
entry name
old position
new position
metadata list
The untagged CHANGE response informs the client that an entry in a
context has either changed position in the context or has changed
the values of one or more of the attributes specified in the
RETURN modifier when the context was created.
The response includes the previous and current position numbers of
the entry (which are 0 if ENUMERATE was not specified on the
context) and the attribute metadata requested in the RETURN
modifier when the context was created.
For enumerated contexts, the CHANGE response implicitly changes
the position numbers of all entries which had position numbers
between the old and new position. If old position is less than
new position, than one is subtracted from all entries which had
position numbers in that range. Otherwise one is added to all
entries which had position numbers in that range. If the old
position and new position are the same, then no implicit position
renumbering occurs.
CHANGE responses are not issued for entries which have changed
position implicitly due to another ADDTO, REMOVEFROM or CHANGE
response.
Example: S: * CHANGE "blurdybloop" "fred" 15 10
("addressbook.Email" "fred@stone.org")
6.5.6. MODTIME Untagged Response
Data: context name
modtime value
The untagged MODTIME response informs the client that it has
received all updates to entries in the context which have modtime
values less than or equal to the modtime value in the argument.
Example: S: * MODTIME mycontext "19970320162338"
6.6. Dataset modification
The following commands and responses handle modification of datasets.
6.6.1. STORE Command Arguments: entry store list Data: intermediate responses: ENTRY Result: OK - store completed NO - store failure: can't store that name UNCHANGEDSINCE specified and entry changed BAD - command unknown or arguments invalid invalid UTF-8 syntax in attribute name Creates, modifies, or deletes the named entries in the named datasets. The values of metadata not specified in the command are not changed. Setting the "value" metadata of an attribute to NIL removes that attribute from the entry. Setting the "value" of the "entry" attribute to NIL removes that entry from the dataset and cancels inheritance for the entire entry. Setting the "value" of the "entry" attribute to DEFAULT removes that entry from the inheriting dataset and reverts the entry and its attributes to inherited values, if any. Changing the value of the "entry" attribute renames the entry. Storing DEFAULT to the "value" metadata of an attribute is equivalent to storing NIL, except that inheritance is enabled for that attribute. If a non-NIL value is inherited then an ENTRY intermediate response is generated to notify the client of the this change. The ENTRY response includes the entry-path and the attribute name and value metadata for each attribute which reverted to a non-NIL inherited setting. Storing NIL to the "value" metadata of an attribute MAY be treated equivalent to storing DEFAULT to that "value" if there is a NIL value in the base dataset. The STORE command is followed by one or more entry store lists. Each entry store list begins with an entry path followed by STORE modifiers, followed by zero or more attribute store items. Each attribute store item is made up of the attribute name followed by NIL (to remove the attribute's value), DEFAULT (to revert the item to any inherited value), a single value (to set the attribute's single value), or a list of metadata items to modify. The following STORE modifiers may be specified:
NOCREATE
By default, the server MUST create any datasets necessary to
store the entry, including multiple hierarchy levels. If
NOCREATE is specified, the STORE command will fail with a
NOEXIST error unless the parent dataset already exists.
UNCHANGEDSINCE
If the "modtime" of the entry is later than the
unchangedsince time, then the store fails with a MODIFIED
response code. Use of UNCHANGEDSINCE with a time of
"00000101000000" will always fail if the entry exists.
Clients writing to a shared dataset are encouraged to use
UNCHANGEDSINCE when modifying an existing entry.
The server MUST either make all the changes specified in a single
STORE command or make none of them. If successful, the server
MUST update the "modtime" attribute for every entry which was
changed.
It is illegal to list any metadata item within an attribute twice,
any attribute within an entry twice or any entry path twice. The
server MUST return a BAD response if this happens.
The server MAY re-order the strings in a multi-value on STORE and
MAY remove duplicate strings. However, SEARCH MUST return multi-
values and the associated size list metadata in a consistant
order.
Example: C: A342 STORE ("/addressbook/user/fred/ABC547"
"addressbook.TelephoneNumber" "555-1234"
"addressbook.CommonName" "Barney Rubble"
"addressbook.AlternateNames" ("value"
("Barnacus Rubble" "Coco Puffs Thief"))
"addressbook.Email" NIL)
S: A342 OK "Store completed"
C: A343 STORE ("/addressbook/user/joe/ABD42"
UNCHANGEDSINCE "19970320162338"
"user.joe.hair-length" "10 inches")
S: A343 NO (MODIFIED) "'ABD42' has been changed
by somebody else."
C: A344 STORE ("/addressbook/group/Developers/ACD54"
"entry" NIL)
S: A344 OK "Store completed"
C: A345 STORE ("/option/~/common/SMTPserver"
"option.value" DEFAULT)
S: A345 ENTRY "/option/~/common/SMTPserver"
"option.value" "smtp.server.do.main"
S: A345 OK "Store completed"
C: A347 STORE ("/addressbook/~/" "dataset.inherit"
"/addressbook/group/Developers")
S: A347 OK "Store completed"
6.6.2. DELETEDSINCE Command
Arguments: dataset name
time
Data: intermediate response: DELETED
Result: OK - DELETEDSINCE completed
NO - DELETEDSINCE failure: can't read dataset
date too far in the past
BAD - command unknown or arguments invalid
The DELETEDSINCE command returns in intermediate DELETED replies
the names of entries that have been deleted from the named dataset
since the given time.
Servers may impose a limit on the number or age of deleted entry
names they keep track of. If the server does not have information
going back to the specified time, the command fails, returning a
TOOOLD response code in the tagged NO response.
Example: C: Z4S9 DELETEDSINCE "/folder/site/" 19951205103412
S: Z4S9 DELETED "blurdybloop"
S: Z4S9 DELETED "anteaters"
S: Z4S9 OK "DELETEDSINCE completed"
C: Z4U3 DELETEDSINCE "/folder/site/" 19951009040854
S: Z4U3 NO (TOOOLD) "Don't have that information"
6.6.3. DELETED Intermediate Response
Data: entry name
The intermediate DELETED response occurs as a result of a
DELETEDSINCE command. It returns an entry that has been deleted
from the dataset specified in the DELETEDSINCE command.
6.7. Access Control List Commands
The commands in this section are used to manage access control lists.
6.7.1. SETACL Command Arguments: acl object authentication identifier access rights Data: no specific data for this command Result: OK - setacl completed NO - setacl failure: can't set acl BAD - command unknown or arguments invalid The SETACL command changes the access control list on the specified object so that the specified identifier is granted the permissions enumerated in rights. If the object did not previously have an access control list, one is created. Example: C: A123 SETACL ("/addressbook/~/public/") "anyone" "r" S: A123 OK "Setacl complete" C: A124 SETACL ("/folder/site/") "B1FF" "rwa" S: A124 NO (PERMISSION ("/folder/site/")) "'B1FF' not permitted to modify access rights for '/folder/site/'" 6.7.2. DELETEACL Command Arguments: acl object optional authentication identifier Data: no specific data for this command Result: OK - deleteacl completed NO - deleteacl failure: can't delete acl BAD - command unknown or arguments invalid If given the optional identifier argument, the DELETEACL command removes any portion of the access control list on the specified object for the specified identifier. If not given the optional identifier argument, the DELETEACL command removes the ACL from the object entirely, causing access to be controlled by a higher-level default ACL. This form of the DELETEACL command is not permitted on the default ACL for a dataset and servers MUST return a BAD.
Example: C: A223 DELETEACL ("/addressbook/~/public") "anyone"
S: A223 OK "Deleteacl complete"
C: A224 DELETEACL ("/folder/site")
S: A224 BAD "Can't delete ACL from dataset"
C: A225 DELETEACL ("/addressbook/user/fred"
"addressbook.Email" "barney")
S: A225 OK "Deleteacl complete"
6.7.3. MYRIGHTS Command
Arguments: acl object
Data: intermediate responses: MYRIGHTS
Result: OK - myrights completed
NO - myrights failure: can't get rights
BAD - command unknown or arguments invalid
The MYRIGHTS command returns the set of rights that the client has
to the given dataset or dataset attribute.
Example: C: A003 MYRIGHTS ("/folder/site")
S: A003 MYRIGHTS "r"
S: A003 OK "Myrights complete"
6.7.4. MYRIGHTS Intermediate Response
Data: rights
The MYRIGHTS response occurs as a result of a MYRIGHTS command.
The argument is the set of rights that the client has for the
object referred to in the MYRIGHTS command.
6.7.5. LISTRIGHTS Command
Arguments: acl object
authentication identifier
Data: untagged responses: LISTRIGHTS
Result: OK - listrights completed
NO - listrights failure: can't get rights list
BAD - command unknown or arguments invalid
The LISTRIGHTS command takes an object and an identifier and
returns information about what rights the current user may revoke
or grant to that identifier in the ACL for that object.
Example: C: a001 LISTRIGHTS ("/folder/~/") "smith"
S: a001 LISTRIGHTS "xra" "w" "i"
S: a001 OK Listrights completed
C: a005 LISTRIGHTS ("/folder/site/archive/imap") "anyone"
S: a005 LISTRIGHTS "" "x" "r" "w" "i"
S: a005 OK Listrights completed
6.7.6. LISTRIGHTS Intermediate Response
Data: required rights
list of optional rights
The LISTRIGHTS response occurs as a result of a LISTRIGHTS
command. The first argument is a string containing the (possibly
empty) set of rights the identifier will always be granted on the
dataset or attribute.
Following this are zero or more strings each containing a single
right which the current user may revoke or grant to the identifier
in the dataset or attribute.
The same right MUST NOT be listed more than once in the LISTRIGHTS
response.
6.8. Quotas
The section defines the commands and responses relating to quotas.
6.8.1. GETQUOTA Command
Arguments: dataset
Data: untagged responses: QUOTA
Result: OK - Quota information returned
NO - Quota failure: can't access resource limit
no resource limit
BAD - command unknown or arguments invalid
The GETQUOTA command takes the name of a dataset, and returns in
an untagged QUOTA response the name of the dataset, quota limit in
bytes that applies to that dataset and the quota usage within that
limit. The scope of a quota limit is implementation dependent.
Example: C: A043 GETQUOTA "/option/user/fred/common"
S: * QUOTA "/option/user/fred/common" 1048576 2475
S: A043 OK "Getquota completed"
6.8.3. QUOTA Untagged Response
Data: dataset
quota limit in bytes
amount of quota limit used
extension data
The QUOTA untagged response is generated as a result of a GETQUOTA
command or MAY be generated by the server in response to a SEARCH
or STORE command to warn about high usage of a quota. It includes
the name of the applicable dataset, the quota limit in bytes, the
quota usage and some optional extension data. Clients MUST
tolerate the extension data as its use is reserved for a future
extension.
6.9. Extensions
In order to simplify the process of extending the protocol, clients
MUST tolerate unknown server responses which meet the syntax of
response-extend. In addition, clients MUST tolerate unknown server
response codes which meet the syntax of resp-code-ext. Availability
of new commands MUST be announced via a capability on the initial
greeting line and such commands SHOULD meet the syntax of
command-extend.
Servers MUST respond to unknown commands with a BAD command
completion result. Servers MUST skip over non-synchronizing literals
contained in an unknown command. This may be done by assuming the
unknown command matches the command-extend syntax, or by reading a
line at a time and checking for the non-synchronizing literal syntax
at the end of the line.
(page 53 continued on part 3)
