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| Sun Java System Portal Server 6 2004Q2 Developer's Guide | |
Chapter 23
About the RDM APIThis chapter
IntroductionThis chapter describes the use of the search engine Resource Description Manager (RDM) API to access the search engine and its database. The RDM API provides routines to parse, modify, and create resource description messages (RDMs) using C.
The robot generates RDs and saves them to the search engine database. You can retrieve the RDs in SOIF format, use the RDM API to modify them, and then have the search engine import them back.
The RDM API is defined in the rdm.h file in the following directory in your search engine installation directory:
portal-server-install-root/SUNWps/sdk/rdm/include
This chapter is restricted to discussing the use of C functions that come with the search engine RDM API. Therefore, it is strongly recommended that you have a basic understanding of the C programming language.
rdm.h FileThe file rdm.h defines structures and functions for creating RDMs. The intent of these functions is to construct queries and instructions that can be output as RDM and sent via the sendrdm program to a search engine for processing. These queries and instructions are created in the C programming language.
The basic structures are:
To support each of these main structures, there are additional structures like RDMViewAttributes, RDMViewOrder, and RDMViewHit which are used to represent attributes in an RDMQuery.
The RDM API defined in rdm.h file provides functions for creating and modifying these structures. For example, the following statement:
RDMQuery *myquery = RDMQuery_Create("varrius");
creates an RDMQuery that corresponds to the following SOIF:
The following statement:
RDMQuery_SetViewAttr(myquery, "URL,Title");
modifies the RDMQuery so that it corresponds to the following SOIF:
Both the RDMHeader and RDMQuery structures have soif fields, which contain the SOIF data for the header or the query. To extract SOIF data from RDMHeader or RDMQuery, you can access the soif field. Thus, you can also use the RDM SOIF API to create and modify RDMHeader and RDMQuery objects.
API ReferenceThis section describes the RDM API, located in directory portal-server-install-root/SUNWps/sdk/rdm/include/rdm.h.
Finding the RDM Version
RDM_Version
NSAPI_PUBLIC const char *RDM_Version(void);
Returns the version of the RDM library.
Creating and Freeing RDM Structures
For most RDMX structures, such as RDMRequest, RDMQuery, and so on, there are two or more creation functions. There is usually an RDMX_Parse() function, which takes SOIF arguments, and an RDMX_Create() function, which takes non-SOIF arguments.
There is also an RDMX_Free() function, which releases the object.
Several RDM structures also have an RDMX_merge() function, which merges data from a SOIF object into an existing RDMX structure.
RDMHeader
An RDMHeader represents the header of an RDM. An RDMHeader structure has one public field, soif, which is a SOIF containing a collection of attribute-value pairs. The allowable attribute names of the attribute-value pairs in the SOIF are:
- rdm-version (required) - This is set automatically if you use RDMHeader_CreateRequest() or RDMHeader_CreateResponse() to create the RDMHeader.
- rdm-type (required)
- catalog-service-id (recommended) - This indicates which search engine instance to send the RDM request to).
- rdm-query-language (required for a request) - For communicating with the search engine, you can specify "search".
Response RDMs also have several attributes, and you can find them in rdm.h.
The following statements create an RDMHeader whose RDMType is RDM_RD_REQ, and whose query language is search. This RDM will be sent to the search engine instance search1 of the search engine at http://budgie.siroe.com:6714.
CSID *csid = CSID_Parse("x-catalog://budgie.siroe.com:6714/search1");
RDMHeader *myheader = RDMHeader_CreateRequest(RDM_RD_REQ, "search", csid);
The following table describes the allowable values for RDM-Type in the first (left) column and a includes a description of the corresponding RDM-Type value in the second (right) column:
You can use the following macros to get and set the string values of the attributes:
RDMHeader_GetType(RDMHeader) /* returns RDMType */
RDMHeader_GetVersion(RDMHeader)
RDMHeader_GetQueryLanguage(RDMHeader)
RDMHeader_GetCSID(RDMHeader)
RDMHeader_GetResponseInterpret(RDMHeader)
RDMHeader_GetErrorMessage(RDMHeader)
RDMHeader_GetErrorNumber(RDMHeader)
RDMHeader_SetType(RDMHeader,RDMType)
RDMHeader_SetVersion(RDMHeader,stringvalue)
RDMHeader_SetQueryLanguage(RDMHeader,stringvalue)
RDMHeader_SetCSID(RDMHeader,stringvalue)
RDMHeader_SetResponseInterpret(RDMHeader,stringvalue)
RDMHeader_SetErrorMessage(RDMHeader,stringvalue)
RDMHeader_SetErrorNumber(RDMHeader,stringvalue)
RDMHeader_Parse
NSAPI_PUBLIC RDMHeader *RDMHeader_Parse(SOIFStream *ss);
RDMHeader_Create
NSAPI_PUBLIC RDMHeader *RDMHeader_Create(RDMType t);
RDMHeader_CreateRequest
NSAPI_PUBLIC RDMHeader *RDMHeader_CreateRequest(RDMType, char *ql, CSID *)
RDMHeader_CreateResponse
NSAPI_PUBLIC RDMHeader *RDMHeader_CreateResponse(RDMType, char *ri, CSID *);
RDMHeader_Free
NSAPI_PUBLIC int RDMHeader_Free(RDMHeader *r);
RDMHeader_Merge
NSAPI_PUBLIC int RDMHeader_Merge(RDMHeader *, SOIF *)
Merges data from a SOIF object into the RDMHeader object.
RDMQuery
An RDMQuery represents the body of an RDM. An RDMQuery structure has one public field, soif, which is a SOIF containing a collection of attribute-value pairs. The allowable attribute names of the attribute-value pairs in the SOIF are:
You can use the following macros to get and set the string values of these attributes:
RDMQuery_GetScope(query)
RDMQuery_GetViewAttr(query)
RDMQuery_GetViewHits(query)
RDMQuery_GetViewOrder(query)
RDMQuery_GetViewTemplate(query)
RDMQuery_SetScope(query, value)
RDMQuery_SetViewAttr(query,value-list)
RDMQuery_SetViewHits(query,value)
RDMQuery_SetViewOrder(query,value-list)
RDMQuery_SetViewTemplate(query,value)
RDMQuery_Parse
NSAPI_PUBLIC RDMQuery *RDMQuery_Parse(SOIFStream *ss);
RDMQuery_Create
NSAPI_PUBLIC RDMQuery *RDMQuery_Create(const char *scope);
RDMQuery_Free
NSAPI_PUBLIC int RDMQuery_Free(RDMQuery *);
RDMQuery_Merge
NSAPI_PUBLIC int RDMQuery_Merge(RDMQuery *, SOIF *);
Other RDM Structures
In addition to RDMHeader and RDMQuery, the file rdm.h provides definitions and functions for the following auxiliary objects. See the file rdm.h in portal-server-install-root/SUNWps/sdk/rdm/include for details.