Extended services are only supported when accessing the Zebra server using the Z39.50 protocol. The SRU protocol does not support extended services.
The extended services are not enabled by default in zebra - due to the
fact that they modify the system. Zebra can be configured
to allow anybody to
search, and to allow only updates for a particular admin user
in the main zebra configuration file zebra.cfg.
For user admin, you could use:
perm.anonymous: r
perm.admin: rw
passwd: passwordfile
And in the password file
passwordfile, you have to specify users and
encrypted passwords as colon separated strings.
Use a tool like htpasswd
to maintain the encrypted passwords.
admin:secret
It is essential to configure Zebra to store records internally, and to support modifications and deletion of records:
storeData: 1
storeKeys: 1
The general record type should be set to any record filter which is able to parse XML records, you may use any of the two declarations (but not both simultaneously!)
recordType: dom.filter_dom_conf.xml
# recordType: grs.xml
Notice the difference to the specific instructions
recordType.xml: dom.filter_dom_conf.xml
# recordType.xml: grs.xml
which only work when indexing XML files from the filesystem using
the *.xml naming convention.
To enable transaction safe shadow indexing, which is extra important for this kind of operation, set
shadow: directoryname: size (e.g. 1000M)
See Section 2, “The Zebra Configuration File” for additional information on these configuration options.
It is not possible to carry information about record types or similar to Zebra when using extended services, due to limitations of the Z39.50 protocol. Therefore, indexing filters can not be chosen on a per-record basis. One and only one general XML indexing filter must be defined.
The Z39.50 standard allows servers to accept special binary extended services protocol packages, which may be used to insert, update and delete records into servers. These carry control and update information to the servers, which are encoded in seven package fields:
Table 6.1. Extended services Z39.50 Package Fields
| Parameter | Value | Notes |
|---|---|---|
type | 'update' | Must be set to trigger extended services |
action | string |
Extended service action type with
one of four possible values: recordInsert,
recordReplace,
recordDelete,
and specialUpdate
|
record | XML string | An XML formatted string containing the record |
syntax | 'xml' | XML/SUTRS/MARC. GRS-1 not supported. The default filter (record type) as given by recordType in zebra.cfg is used to parse the record. |
recordIdOpaque | string | Optional client-supplied, opaque record identifier used under insert operations. |
recordIdNumber | positive number | Zebra's internal system number,
not allowed for recordInsert or
specialUpdate actions which result in fresh
record inserts.
|
databaseName | database identifier | The name of the database to which the extended services should be applied. |
The action parameter can be any of
recordInsert (will fail if the record already exists),
recordReplace (will fail if the record does not exist),
recordDelete (will fail if the record does not
exist), and
specialUpdate (will insert or update the record
as needed, record deletion is not possible).
During all actions, the
usual rules for internal record ID generation apply, unless an
optional recordIdNumber Zebra internal ID or a
recordIdOpaque string identifier is assigned.
The default ID generation is
configured using the recordId: from
zebra.cfg.
See Section 2, “The Zebra Configuration File”.
Setting of the recordIdNumber parameter,
which must be an existing Zebra internal system ID number, is not
allowed during any recordInsert or
specialUpdate action resulting in fresh record
inserts.
When retrieving existing
records indexed with GRS-1 indexing filters, the Zebra internal
ID number is returned in the field
/*/id:idzebra/localnumber in the namespace
xmlns:id="http://www.indexdata.dk/zebra/",
where it can be picked up for later record updates or deletes.
A new element set for retrieval of internal record
data has been added, which can be used to access minimal records
containing only the recordIdNumber Zebra
internal ID, or the recordIdOpaque string
identifier. This works for any indexing filter used.
See Section 4, “Retrieval of Zebra internal record data”.
The recordIdOpaque string parameter
is an client-supplied, opaque record
identifier, which may be used under
insert, update and delete operations. The
client software is responsible for assigning these to
records. This identifier will
replace zebra's own automagic identifier generation with a unique
mapping from recordIdOpaque to the
Zebra internal recordIdNumber.
The opaque recordIdOpaque string
identifiers
are not visible in retrieval records, nor are
searchable, so the value of this parameter is
questionable. It serves mostly as a convenient mapping from
application domain string identifiers to Zebra internal ID's.
We can now start a yaz-client admin session and create a database:
$ yaz-client localhost:9999 -u admin/secret
Z> adm-create
Now the Default database was created,
we can insert an XML file (esdd0006.grs
from example/gils/records) and index it:
Z> update insert id1234 esdd0006.grs
The 3rd parameter - id1234 here -
is the recordIdOpaque package field.
Actually, we should have a way to specify "no opaque record id" for yaz-client's update command.. We'll fix that.
The newly inserted record can be searched as usual:
Z> f utah
Sent searchRequest.
Received SearchResponse.
Search was a success.
Number of hits: 1, setno 1
SearchResult-1: term=utah cnt=1
records returned: 0
Elapsed: 0.014179
Let's delete the beast, using the same
recordIdOpaque string parameter:
Z> update delete id1234
No last record (update ignored)
Z> update delete 1 esdd0006.grs
Got extended services response
Status: done
Elapsed: 0.072441
Z> f utah
Sent searchRequest.
Received SearchResponse.
Search was a success.
Number of hits: 0, setno 2
SearchResult-1: term=utah cnt=0
records returned: 0
Elapsed: 0.013610
If shadow register is enabled in your
zebra.cfg,
you must run the adm-commit command
Z> adm-commit
after each update session in order write your changes from the shadow to the life register space.
Extended services are also available from the YAZ PHP client layer. An example of an YAZ-PHP extended service transaction is given here:
$record = '<record><title>A fine specimen of a record</title></record>';
$options = array('action' => 'recordInsert',
'syntax' => 'xml',
'record' => $record,
'databaseName' => 'mydatabase'
);
yaz_es($yaz, 'update', $options);
yaz_es($yaz, 'commit', array());
yaz_wait();
if ($error = yaz_error($yaz))
echo "$error";
When debugging ES over PHP we recommend the following order of tests:
Make sure you have a nice record on your filesystem, which you can index from the filesystem by use of the zebraidx command. Do it exactly as you planned, using one of the GRS-1 filters, or the DOMXML filter. When this works, proceed.
Check that your server setup is OK before you even coded one single
line PHP using ES.
Take the same record form the file system, and send as ES via
yaz-client like described in
Section 10.2, “Extended services from yaz-client”,
and
remember the -a option which tells you what
goes over the wire! Notice also the section on permissions:
try
perm.anonymous: rw
in zebra.cfg to make sure you do not run into
permission problems (but never expose such an insecure setup on the
internet!!!). Then, make sure to set the general
recordType instruction, pointing correctly
to the GRS-1 filters,
or the DOMXML filters.
If you insist on using the sysno in the
recordIdNumber setting,
please make sure you do only updates and deletes. Zebra's internal
system number is not allowed for
recordInsert or
specialUpdate actions
which result in fresh record inserts.
If shadow register is enabled in your
zebra.cfg, you must remember running the
Z> adm-commit
command as well.
If this works, then proceed to do the same thing in your PHP script.