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oai_fdw.c
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oai_fdw.c
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/**********************************************************************
*
* oai_fdw - PostgreSQL Foreign Data Wrapper for OAI-PMH Repositories
*
* oai_fdw is free software: you can redistribute it and/or modify
* it under the terms of the MIT Licence.
*
* Copyright (C) 2021-2024 University of Münster, Germany
* Written by Jim Jones <[email protected]>
*
**********************************************************************/
#include "postgres.h"
#include "fmgr.h"
#include "foreign/fdwapi.h"
#include "optimizer/pathnode.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/planmain.h"
#include "utils/rel.h"
#include "miscadmin.h"
#if PG_VERSION_NUM < 120000
#include "optimizer/var.h"
#else
#include "optimizer/optimizer.h"
#endif
#include "access/htup_details.h"
#include "access/sysattr.h"
#include "access/reloptions.h"
#if PG_VERSION_NUM >= 120000
#include "access/table.h"
#endif
#include "foreign/foreign.h"
#include "commands/defrem.h"
#include "nodes/pg_list.h"
#include <stdio.h>
#include <stdlib.h>
#include <curl/curl.h>
#include <utils/builtins.h>
#include <utils/array.h>
#include <commands/explain.h>
#include <libxml/tree.h>
#include <catalog/pg_collation.h>
#include <funcapi.h>
#include "lib/stringinfo.h"
#include <utils/lsyscache.h>
#include "nodes/nodes.h"
#include "nodes/primnodes.h"
#include "utils/datetime.h"
#include "utils/timestamp.h"
#include "utils/formatting.h"
#include "catalog/pg_operator.h"
#include "utils/syscache.h"
#include "catalog/pg_foreign_table.h"
#include "catalog/pg_foreign_server.h"
#include "catalog/pg_user_mapping.h"
#include "catalog/pg_type.h"
#include "access/reloptions.h"
#include "catalog/pg_namespace.h"
#define OAI_FDW_VERSION "1.10"
#define OAI_REQUEST_LISTRECORDS "ListRecords"
#define OAI_REQUEST_LISTIDENTIFIERS "ListIdentifiers"
#define OAI_REQUEST_IDENTIFY "Identify"
#define OAI_REQUEST_LISTSETS "ListSets"
#define OAI_REQUEST_GETRECORD "GetRecord"
#define OAI_REQUEST_LISTMETADATAFORMATS "ListMetadataFormats"
#define OAI_REQUEST_LISTSETS "ListSets"
#define OAI_REQUEST_CONNECTTIMEOUT 300
#define OAI_REQUEST_MAXRETRY 3
#define OAI_USERMAPPING_OPTION_USER "user"
#define OAI_USERMAPPING_OPTION_PASSWORD "password"
#define OAI_RESPONSE_ELEMENT_RECORD "record"
#define OAI_RESPONSE_ELEMENT_METADATA "metadata"
#define OAI_RESPONSE_ELEMENT_HEADER "header"
#define OAI_RESPONSE_ELEMENT_IDENTIFIER "identifier"
#define OAI_RESPONSE_ELEMENT_DATESTAMP "datestamp"
#define OAI_RESPONSE_ELEMENT_SETSPEC "setSpec"
#define OAI_RESPONSE_ELEMENT_SETNAME "setName"
#define OAI_RESPONSE_ELEMENT_METADATANAMESPACE "metadataNamespace"
#define OAI_RESPONSE_ELEMENT_METADATAPREFIX "metadataPrefix"
#define OAI_RESPONSE_ELEMENT_METADATAFORMAT "metadataFormat"
#define OAI_RESPONSE_ELEMENT_SCHEMA "schema"
#define OAI_RESPONSE_ELEMENT_DELETED "deleted"
#define OAI_RESPONSE_ELEMENT_RESUMPTIONTOKEN "resumptionToken"
#define OAI_RESPONSE_ELEMENT_COMPLETELISTSIZE "completeListSize"
#define OAI_XML_ROOT_ELEMENT "OAI-PMH"
#define OAI_NODE_IDENTIFIER "identifier"
#define OAI_NODE_URL "url"
#define OAI_NODE_HTTP_PROXY "http_proxy"
#define OAI_NODE_HTTPS_PROXY "https_proxy"
#define OAI_NODE_PROXY_USER "proxy_user"
#define OAI_NODE_PROXY_USER_PASSWORD "proxy_user_password"
#define OAI_NODE_CONNECTTIMEOUT "connect_timeout"
#define OAI_NODE_CONNECTRETRY "connect_retry"
#define OAI_NODE_REQUEST_REDIRECT "request_redirect"
#define OAI_NODE_REQUEST_MAX_REDIRECT "request_max_redirect"
#define OAI_NODE_CONTENT "content"
#define OAI_NODE_DATESTAMP "datestamp"
#define OAI_NODE_SETSPEC "setspec"
#define OAI_NODE_METADATAPREFIX "metadataprefix"
#define OAI_NODE_FROM "from"
#define OAI_NODE_UNTIL "until"
#define OAI_NODE_STATUS "status"
#define OAI_NODE_OPTION "oai_node"
#define OAI_ERROR_ID_DOES_NOT_EXIST "idDoesNotExist"
#define OAI_ERROR_NO_RECORD_MATCH "noRecordsMatch"
#define OAI_SUCCESS 0
#define OAI_FAIL 1
#define OAI_MALFORMED_URL 3
#define OAI_UNKNOWN_REQUEST 2
#define ERROR_CODE_MISSING_PREFIX 1
PG_MODULE_MAGIC;
typedef struct OAIFdwState
{
int numcols; /* Total number of columns in a foreign table. */
int numfdwcols; /* Number of oai_fdw columns in a foregign table. */
int rowcount; /* Total number of OAI records retrieved. */
bool requestRedirect; /* Enables or disables URL redirecting. */
long requestMaxRedirect; /* Limit of how many times the URL redirection (jump) may occur. */
long maxretries; /* Max number of retries in case a request returns an error message. */
long connectTimeout; /* Connection timeout for OAI requests in seconds. */
char *identifier; /* The unique identifier of an item in a repository. */
char *set; /* The set membership of the item for the purpose of selective harvesting. */
char *url; /* Concatenated URL with the OAI request. */
char *metadataPrefix; /* Metadata format in OAI requests issued to the repository. */
char *proxy; /* Proxy for HTTP requests, if necessary. */
char *proxyType; /* Proxy protocol (HTTPS, HTTP). */
char *proxyUser; /* User name for proxy authentication. */
char *proxyUserPassword; /* Password for proxy authentication. */
char *from; /* Beginning of am interval to filter an OAI request. */
char *until; /* End of an interval to filter an OAI request. */
char *resumptionToken; /* Token to retrieve the next page of a result set. */
char *requestVerb; /* Type of OAI request (GetRecord, ListRecords, ListIdentifiers,
Identify, ListSets, ListMetadataFormats. */
Oid foreigntableid;
xmlDocPtr xmldoc; /* Result of an OAI request. */
MemoryContext oaicxt; /* Memory Context for data manipulation. */
List *records; /* List of OAI records retrieved. */
int pageindex; /* Index of a record within a retrieved page (list). */
int pagesize; /* Number of OAI records retrieved. */
ForeignTable *foreign_table;
ForeignServer *foreign_server;
char *user;
char *password;
} OAIFdwState;
typedef struct OAIRecord
{
char *identifier;
char *content;
char *datestamp;
char *metadataPrefix;
bool isDeleted;
ArrayType *setsArray;
} OAIRecord;
typedef struct OAIColumn
{
int id;
char *oaiNode;
char *label;
char *function;
} OAIColumn;
typedef struct OAIMetadataFormat
{
char *metadataPrefix;
char *schema;
char *metadataNamespace;
} OAIMetadataFormat;
typedef struct OAISet
{
char *setSpec;
char *setName;
} OAISet;
typedef struct OAIFdwIdentityNode
{
char *name;
char *description;
} OAIFdwIdentityNode;
struct string
{
char *ptr;
size_t len;
};
struct OAIFdwOption
{
const char *optname;
Oid optcontext; /* Oid of catalog in which option may appear */
bool optrequired; /* Flag mandatory options */
bool optfound; /* Flag whether options was specified by user */
};
struct MemoryStruct
{
char *memory;
size_t size;
};
static struct OAIFdwOption valid_options[] =
{
{OAI_NODE_URL, ForeignServerRelationId, true, false},
{OAI_NODE_METADATAPREFIX, ForeignServerRelationId, false, false},
{OAI_NODE_HTTP_PROXY, ForeignServerRelationId, false, false},
{OAI_NODE_HTTPS_PROXY, ForeignServerRelationId, false, false},
{OAI_NODE_PROXY_USER, ForeignServerRelationId, false, false},
{OAI_NODE_PROXY_USER_PASSWORD, ForeignServerRelationId, false, false},
{OAI_NODE_CONNECTTIMEOUT, ForeignServerRelationId, false, false},
{OAI_NODE_CONNECTRETRY, ForeignServerRelationId, false, false},
{OAI_NODE_REQUEST_REDIRECT, ForeignServerRelationId, false, false},
{OAI_NODE_REQUEST_MAX_REDIRECT, ForeignServerRelationId, false, false},
{OAI_NODE_IDENTIFIER, ForeignTableRelationId, false, false},
{OAI_NODE_METADATAPREFIX, ForeignTableRelationId, true, false},
{OAI_NODE_SETSPEC, ForeignTableRelationId, false, false},
{OAI_NODE_FROM, ForeignTableRelationId, false, false},
{OAI_NODE_UNTIL, ForeignTableRelationId, false, false},
{OAI_NODE_OPTION, AttributeRelationId, true, false},
/* User Mapping */
{OAI_USERMAPPING_OPTION_USER, UserMappingRelationId, false, false},
{OAI_USERMAPPING_OPTION_PASSWORD, UserMappingRelationId, false, false},
/* EOList option */
{NULL, InvalidOid, false, false}};
#define option_count (sizeof(valid_options) / sizeof(struct OAIFdwOption))
extern Datum oai_fdw_handler(PG_FUNCTION_ARGS);
extern Datum oai_fdw_validator(PG_FUNCTION_ARGS);
extern Datum oai_fdw_version(PG_FUNCTION_ARGS);
extern Datum oai_fdw_listMetadataFormats(PG_FUNCTION_ARGS);
extern Datum oai_fdw_listSets(PG_FUNCTION_ARGS);
extern Datum oai_fdw_identity(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(oai_fdw_handler);
PG_FUNCTION_INFO_V1(oai_fdw_validator);
PG_FUNCTION_INFO_V1(oai_fdw_version);
PG_FUNCTION_INFO_V1(oai_fdw_listMetadataFormats);
PG_FUNCTION_INFO_V1(oai_fdw_listSets);
PG_FUNCTION_INFO_V1(oai_fdw_identity);
static void OAIFdwGetForeignRelSize(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid);
static void OAIFdwGetForeignPaths(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid);
static ForeignScan *OAIFdwGetForeignPlan(PlannerInfo *root, RelOptInfo *baserel, Oid foreigntableid, ForeignPath *best_path, List *tlist, List *scan_clauses, Plan *outer_plan);
static void OAIFdwBeginForeignScan(ForeignScanState *node, int eflags);
static TupleTableSlot *OAIFdwIterateForeignScan(ForeignScanState *node);
static void OAIFdwReScanForeignScan(ForeignScanState *node);
static void OAIFdwEndForeignScan(ForeignScanState *node);
static TupleTableSlot *OAIFdwExecForeignUpdate(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static TupleTableSlot *OAIFdwExecForeignInsert(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static TupleTableSlot *OAIFdwExecForeignDelete(EState *estate, ResultRelInfo *rinfo, TupleTableSlot *slot, TupleTableSlot *planSlot);
static List *OAIFdwImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid);
static void appendTextArray(ArrayType **array, char *text_element);
static int ExecuteOAIRequest(OAIFdwState *state);
static void CreateOAITuple(TupleTableSlot *slot, OAIFdwState *state, OAIRecord *oai);
static OAIRecord *FetchNextOAIRecord(OAIFdwState **state);
static void LoadOAIRecords(struct OAIFdwState **state);
static void deparseExpr(Expr *expr, OAIFdwState *state);
static char *datumToString(Datum datum, Oid type);
static char *GetOAINodeFromColumn(Oid foreigntableid, int16 attnum);
static void deparseWhereClause(OAIFdwState *state, List *conditions);
static void deparseSelectColumns(OAIFdwState *state, List *exprs);
static void OAIRequestPlanner(OAIFdwState *state, RelOptInfo *baserel);
static char *deparseTimestamp(Datum datum);
static int CheckURL(char *url);
static OAIFdwState *GetServerInfo(const char *srvname);
static List *GetMetadataFormats(OAIFdwState *state);
static List *GetIdentity(OAIFdwState *state);
static List *GetSets(OAIFdwState *state);
static void RaiseOAIException(xmlNodePtr error);
static Datum CreateDatum(HeapTuple tuple, int pgtype, int pgtypmod, char *value);
static void LoadOAIUserMapping(OAIFdwState *state);
static void InitSession(OAIFdwState *state, RelOptInfo *baserel);
Datum oai_fdw_handler(PG_FUNCTION_ARGS)
{
FdwRoutine *fdwroutine = makeNode(FdwRoutine);
fdwroutine->GetForeignRelSize = OAIFdwGetForeignRelSize;
fdwroutine->GetForeignPaths = OAIFdwGetForeignPaths;
fdwroutine->GetForeignPlan = OAIFdwGetForeignPlan;
fdwroutine->BeginForeignScan = OAIFdwBeginForeignScan;
fdwroutine->IterateForeignScan = OAIFdwIterateForeignScan;
fdwroutine->ReScanForeignScan = OAIFdwReScanForeignScan;
fdwroutine->EndForeignScan = OAIFdwEndForeignScan;
fdwroutine->ExecForeignUpdate = OAIFdwExecForeignUpdate;
fdwroutine->ExecForeignDelete = OAIFdwExecForeignDelete;
fdwroutine->ExecForeignInsert = OAIFdwExecForeignInsert;
fdwroutine->ImportForeignSchema = OAIFdwImportForeignSchema;
PG_RETURN_POINTER(fdwroutine);
}
Datum oai_fdw_version(PG_FUNCTION_ARGS)
{
StringInfoData buffer;
initStringInfo(&buffer);
appendStringInfo(&buffer, "oai fdw = %s,", OAI_FDW_VERSION);
appendStringInfo(&buffer, " libxml = %s,", LIBXML_DOTTED_VERSION);
appendStringInfo(&buffer, " libcurl = %s", curl_version());
PG_RETURN_TEXT_P(cstring_to_text(buffer.data));
}
/**
* Retrieves all information configured in the CREATE SERVER statement.
*/
OAIFdwState *GetServerInfo(const char *srvname)
{
OAIFdwState *state = (OAIFdwState *)palloc0(sizeof(OAIFdwState));
ForeignServer *server = GetForeignServerByName(srvname, true);
state->requestRedirect = false;
state->requestMaxRedirect = 0L;
elog(DEBUG1, "%s called: '%s'", __func__, srvname);
if (server)
{
ListCell *cell;
foreach (cell, server->options)
{
DefElem *def = lfirst_node(DefElem, cell);
elog(DEBUG1, " %s parsing node '%s': %s", __func__, def->defname, defGetString(def));
if (strcmp(def->defname, OAI_NODE_URL) == 0)
{
state->url = defGetString(def);
}
if (strcmp(def->defname, OAI_NODE_HTTP_PROXY) == 0)
{
state->proxy = defGetString(def);
state->proxyType = OAI_NODE_HTTP_PROXY;
}
if (strcmp(def->defname, OAI_NODE_PROXY_USER) == 0)
{
state->proxyUser = defGetString(def);
}
if (strcmp(def->defname, OAI_NODE_PROXY_USER_PASSWORD) == 0)
{
state->proxyUserPassword = defGetString(def);
}
if (strcmp(def->defname, OAI_NODE_CONNECTTIMEOUT) == 0)
{
char *tailpt;
char *timeout_str = defGetString(def);
state->connectTimeout = strtol(timeout_str, &tailpt, 0);
}
if (strcmp(def->defname, OAI_NODE_REQUEST_REDIRECT) == 0)
{
state->requestRedirect = defGetBoolean(def);
elog(DEBUG1, " %s: setting \"%s\": %d", __func__, OAI_NODE_REQUEST_REDIRECT, state->requestRedirect);
}
if (strcmp(def->defname, OAI_NODE_REQUEST_MAX_REDIRECT) == 0)
{
char *tailpt;
char *maxredirect_str = defGetString(def);
state->requestMaxRedirect = strtol(maxredirect_str, &tailpt, 10);
elog(DEBUG1, " %s: setting \"%s\": %ld", __func__, OAI_NODE_REQUEST_MAX_REDIRECT, state->requestMaxRedirect);
if (strcmp(defGetString(def), "0") != 0 && state->requestMaxRedirect == 0)
{
elog(ERROR, "invalid value for \"%s\"", OAI_NODE_REQUEST_MAX_REDIRECT);
}
}
}
}
else
{
ereport(ERROR,
(errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
errmsg("FOREIGN SERVER does not exist: '%s'", srvname)));
}
return state;
}
Datum oai_fdw_identity(PG_FUNCTION_ARGS)
{
text *srvname_text = PG_GETARG_TEXT_P(0);
const char *srvname = text_to_cstring(srvname_text);
OAIFdwState *state = GetServerInfo(srvname);
FuncCallContext *funcctx;
AttInMetadata *attinmeta;
TupleDesc tupdesc;
int call_cntr;
int max_calls;
MemoryContext oldcontext;
List *identity;
if (SRF_IS_FIRSTCALL())
{
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
identity = GetIdentity(state);
funcctx->user_fctx = identity;
if (identity)
funcctx->max_calls = identity->length;
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that cannot accept type record")));
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls)
{
Datum values[23];
bool nulls[23];
HeapTuple tuple;
Datum result;
OAIFdwIdentityNode *identity_node = (OAIFdwIdentityNode *)list_nth((List *)funcctx->user_fctx, call_cntr);
memset(nulls, 0, sizeof(nulls));
for (size_t i = 0; i < funcctx->attinmeta->tupdesc->natts; i++)
{
Form_pg_attribute att = TupleDescAttr(funcctx->attinmeta->tupdesc, i);
if(strcmp(NameStr(att->attname),"name")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, identity_node->name);
else if(strcmp(NameStr(att->attname),"description")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, identity_node->description);
else
nulls[i] = true;
}
elog(DEBUG2, " %s: creating heap tuple", __func__);
tuple = heap_form_tuple(funcctx->attinmeta->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else
{
SRF_RETURN_DONE(funcctx);
}
}
Datum oai_fdw_listSets(PG_FUNCTION_ARGS)
{
text *srvname_text = PG_GETARG_TEXT_P(0);
char *srvname = text_to_cstring(srvname_text);
OAIFdwState *state = GetServerInfo(srvname);
MemoryContext oldcontext;
FuncCallContext *funcctx;
AttInMetadata *attinmeta;
TupleDesc tupdesc;
int call_cntr;
int max_calls;
if (SRF_IS_FIRSTCALL())
{
List *sets;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
sets = GetSets(state);
funcctx->user_fctx = sets;
if (sets)
funcctx->max_calls = sets->length;
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that cannot accept type record")));
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls)
{
Datum values[23];
bool nulls[23];
HeapTuple tuple;
Datum result;
OAISet *set_node = (OAISet *)list_nth((List *)funcctx->user_fctx, call_cntr);
memset(nulls, 0, sizeof(nulls));
for (size_t i = 0; i < funcctx->attinmeta->tupdesc->natts; i++)
{
Form_pg_attribute att = TupleDescAttr(funcctx->attinmeta->tupdesc, i);
if(strcmp(NameStr(att->attname),"setname")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, set_node->setName);
else if(strcmp(NameStr(att->attname),"setspec")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, set_node->setSpec);
else
nulls[i] = true;
}
elog(DEBUG2, " %s: creating heap tuple", __func__);
tuple = heap_form_tuple(funcctx->attinmeta->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else
{
SRF_RETURN_DONE(funcctx);
}
}
Datum oai_fdw_listMetadataFormats(PG_FUNCTION_ARGS)
{
text *srvname_text = PG_GETARG_TEXT_P(0);
const char *srvname = text_to_cstring(srvname_text);
OAIFdwState *state = GetServerInfo(srvname);
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
MemoryContext oldcontext;
/* stuff done only on the first call of the function */
if (SRF_IS_FIRSTCALL())
{
List *formats;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
formats = GetMetadataFormats(state);
funcctx->user_fctx = formats;
if (formats)
funcctx->max_calls = formats->length;
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context that cannot accept type record")));
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every function call */
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
attinmeta = funcctx->attinmeta;
/* do when there is more left to send */
if (call_cntr < max_calls)
{
Datum values[23];
bool nulls[23];
HeapTuple tuple;
Datum result;
OAIMetadataFormat *format = (OAIMetadataFormat *)list_nth((List *)funcctx->user_fctx, call_cntr);
memset(nulls, 0, sizeof(nulls));
for (size_t i = 0; i < funcctx->attinmeta->tupdesc->natts; i++)
{
Form_pg_attribute att = TupleDescAttr(funcctx->attinmeta->tupdesc, i);
if(strcmp(NameStr(att->attname),"metadataprefix")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, format->metadataPrefix);
else if(strcmp(NameStr(att->attname),"schema")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, format->schema);
else if(strcmp(NameStr(att->attname),"metadatanamespace")==0)
values[i] = CreateDatum(tuple, att->atttypid, att->atttypmod, format->metadataNamespace);
else
nulls[i] = true;
}
elog(DEBUG2, " %s: creating heap tuple", __func__);
tuple = heap_form_tuple(funcctx->attinmeta->tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
else /* do when there is no more left */
{
SRF_RETURN_DONE(funcctx);
}
}
Datum oai_fdw_validator(PG_FUNCTION_ARGS)
{
List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
Oid catalog = PG_GETARG_OID(1);
ListCell *cell;
struct OAIFdwOption *opt;
/* Initialize found state to not found */
for (opt = valid_options; opt->optname; opt++)
{
opt->optfound = false;
}
foreach (cell, options_list)
{
DefElem *def = (DefElem *)lfirst(cell);
bool optfound = false;
for (opt = valid_options; opt->optname; opt++)
{
if (catalog == opt->optcontext && strcmp(opt->optname, def->defname) == 0)
{
/* Mark that this user option was found */
opt->optfound = optfound = true;
if (strlen(defGetString(def)) == 0)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("empty value in option '%s'", opt->optname)));
}
if (strcmp(opt->optname, OAI_NODE_URL) == 0 || strcmp(opt->optname, OAI_NODE_HTTP_PROXY) == 0 || strcmp(opt->optname, OAI_NODE_HTTPS_PROXY) == 0)
{
int return_code = CheckURL(defGetString(def));
if (return_code != OAI_SUCCESS)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid %s: '%s'", opt->optname, defGetString(def))));
}
}
if (strcmp(opt->optname, OAI_NODE_CONNECTTIMEOUT) == 0)
{
char *endptr;
char *timeout_str = defGetString(def);
long timeout_val = strtol(timeout_str, &endptr, 0);
if (timeout_str[0] == '\0' || *endptr != '\0' || timeout_val < 0)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid %s: %s", def->defname, timeout_str),
errhint("expected values are positive integers (timeout in seconds)")));
}
}
if (strcmp(opt->optname, OAI_NODE_CONNECTRETRY) == 0)
{
char *endptr;
char *retry_str = defGetString(def);
long retry_val = strtol(retry_str, &endptr, 0);
if (retry_str[0] == '\0' || *endptr != '\0' || retry_val < 0)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_ATTRIBUTE_VALUE),
errmsg("invalid %s: %s", def->defname, retry_str),
errhint("expected values are positive integers (retry attempts in case of failure)")));
}
}
if (strcmp(opt->optname, OAI_NODE_OPTION) == 0)
{
if (strcmp(defGetString(def), OAI_NODE_IDENTIFIER) != 0 &&
strcmp(defGetString(def), OAI_NODE_METADATAPREFIX) != 0 &&
strcmp(defGetString(def), OAI_NODE_SETSPEC) != 0 &&
strcmp(defGetString(def), OAI_NODE_DATESTAMP) != 0 &&
strcmp(defGetString(def), OAI_NODE_CONTENT) != 0 &&
strcmp(defGetString(def), OAI_NODE_STATUS) != 0)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
errmsg("invalid %s option '%s'", OAI_NODE_OPTION, defGetString(def)),
errhint("Valid column options for oai_fdw are:\nCREATE SERVER: '%s', '%s'\nCREATE TABLE: '%s','%s', '%s', '%s' and '%s'",
OAI_NODE_URL,
OAI_NODE_METADATAPREFIX,
OAI_NODE_METADATAPREFIX,
OAI_NODE_SETSPEC,
OAI_NODE_FROM,
OAI_NODE_UNTIL,
OAI_NODE_STATUS)));
}
}
break;
}
}
if (!optfound)
{
ereport(ERROR,
(errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
errmsg("invalid oai_fdw option \"%s\"", def->defname)));
}
}
for (opt = valid_options; opt->optname; opt++)
{
/* Required option for this catalog type is missing? */
if (catalog == opt->optcontext && opt->optrequired && !opt->optfound)
{
ereport(ERROR, (
errcode(ERRCODE_FDW_DYNAMIC_PARAMETER_VALUE_NEEDED),
errmsg("required option '%s' is missing", opt->optname)));
}
}
PG_RETURN_VOID();
}
/*
* Parses information from the OAI Identify request.
* https://www.openarchives.org/OAI/openarchivesprotocol.html#Identify
*/
static List *GetIdentity(OAIFdwState *state)
{
int oaiExecuteResponse;
List *result = NIL;
elog(DEBUG1, "%s called", __func__);
state->requestVerb = OAI_REQUEST_IDENTIFY;
oaiExecuteResponse = ExecuteOAIRequest(state);
if (!state->xmldoc)
elog(ERROR, "invalid %s response from '%s'", state->requestVerb, state->url);
xmlInitParser();
if (oaiExecuteResponse == OAI_SUCCESS)
{
xmlNodePtr oai_root;
xmlNodePtr Identity;
xmlNodePtr xmlroot = xmlDocGetRootElement(state->xmldoc);
for (oai_root = xmlroot->children; oai_root != NULL; oai_root = oai_root->next)
{
if (oai_root->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(oai_root->name, (xmlChar *)OAI_REQUEST_IDENTIFY) != 0)
continue;
for (Identity = oai_root->children; Identity != NULL; Identity = Identity->next)
{
OAIFdwIdentityNode *node = (OAIFdwIdentityNode *)palloc0(sizeof(OAIFdwIdentityNode));
if (Identity->type != XML_ELEMENT_NODE)
continue;
node->name = pstrdup((char *)Identity->name);
node->description = pstrdup((char *)xmlNodeGetContent(Identity));
result = lappend(result, node);
}
}
}
xmlFreeDoc(state->xmldoc);
xmlCleanupParser();
elog(DEBUG1, "%s => finished", __func__);
return result;
}
/*
* Parses information from the OAI ListSets request.
* https://www.openarchives.org/OAI/openarchivesprotocol.html#ListSets
*/
static List *GetSets(OAIFdwState *state)
{
int oaiExecuteResponse;
List *result = NIL;
elog(DEBUG1, "%s called", __func__);
state->requestVerb = OAI_REQUEST_LISTSETS;
oaiExecuteResponse = ExecuteOAIRequest(state);
if (!state->xmldoc)
elog(ERROR, "invalid %s response from '%s'", state->requestVerb, state->url);
xmlInitParser();
if (oaiExecuteResponse == OAI_SUCCESS)
{
xmlNodePtr oai_root;
xmlNodePtr ListSets;
xmlNodePtr SetElement;
xmlNodePtr xmlroot = xmlDocGetRootElement(state->xmldoc);
for (oai_root = xmlroot->children; oai_root != NULL; oai_root = oai_root->next)
{
if (oai_root->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(oai_root->name, (xmlChar *)OAI_REQUEST_LISTSETS) != 0)
continue;
for (ListSets = oai_root->children; ListSets != NULL; ListSets = ListSets->next)
{
OAISet *set = (OAISet *)palloc0(sizeof(OAISet));
if (ListSets->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(ListSets->name, (xmlChar *)"set") != 0)
continue;
for (SetElement = ListSets->children; SetElement != NULL; SetElement = SetElement->next)
{
if (SetElement->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(SetElement->name, (xmlChar *)OAI_RESPONSE_ELEMENT_SETSPEC) == 0)
{
set->setSpec = pstrdup((char *)xmlNodeGetContent(SetElement));
}
else if (xmlStrcmp(SetElement->name, (xmlChar *)OAI_RESPONSE_ELEMENT_SETNAME) == 0)
{
set->setName = pstrdup((char *)xmlNodeGetContent(SetElement));
}
}
result = lappend(result, set);
}
}
}
xmlFreeDoc(state->xmldoc);
xmlCleanupParser();
elog(DEBUG1, "%s => finished", __func__);
return result;
}
/*
* Parses information from the OAI ListMetadataFormats request.
* https://www.openarchives.org/OAI/openarchivesprotocol.html#ListMetadataFormats
*/
static List *GetMetadataFormats(OAIFdwState *state)
{
int oaiExecuteResponse;
List *result = NIL;
elog(DEBUG1, " %s called", __func__);
state->requestVerb = OAI_REQUEST_LISTMETADATAFORMATS;
oaiExecuteResponse = ExecuteOAIRequest(state);
if (!state->xmldoc)
elog(ERROR, "invalid %s response from '%s'", state->requestVerb, state->url);
xmlInitParser();
if (oaiExecuteResponse == OAI_SUCCESS)
{
xmlNodePtr oai_root;
xmlNodePtr ListMetadataFormats;
xmlNodePtr MetadataElement;
xmlNodePtr xmlroot = xmlDocGetRootElement(state->xmldoc);
for (oai_root = xmlroot->children; oai_root != NULL; oai_root = oai_root->next)
{
if (oai_root->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(oai_root->name, (xmlChar *)OAI_REQUEST_LISTMETADATAFORMATS) != 0)
continue;
for (ListMetadataFormats = oai_root->children; ListMetadataFormats != NULL; ListMetadataFormats = ListMetadataFormats->next)
{
OAIMetadataFormat *format = (OAIMetadataFormat *)palloc0(sizeof(OAIMetadataFormat));
if (ListMetadataFormats->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(ListMetadataFormats->name, (xmlChar *)OAI_RESPONSE_ELEMENT_METADATAFORMAT) != 0)
continue;
for (MetadataElement = ListMetadataFormats->children; MetadataElement != NULL; MetadataElement = MetadataElement->next)
{
if (MetadataElement->type != XML_ELEMENT_NODE)
continue;
if (xmlStrcmp(MetadataElement->name, (xmlChar *)OAI_RESPONSE_ELEMENT_METADATAPREFIX) == 0)
{
format->metadataPrefix = pstrdup((char *)xmlNodeGetContent(MetadataElement));
}
else if (xmlStrcmp(MetadataElement->name, (xmlChar *)OAI_RESPONSE_ELEMENT_SCHEMA) == 0)
{
format->schema = pstrdup((char *)xmlNodeGetContent(MetadataElement));
}
else if (xmlStrcmp(MetadataElement->name, (xmlChar *)OAI_RESPONSE_ELEMENT_METADATANAMESPACE) == 0)
{
format->metadataNamespace = pstrdup((char *)xmlNodeGetContent(MetadataElement));
}
}
result = lappend(result, format);
}
}
}
xmlFreeDoc(state->xmldoc);
xmlCleanupParser();
elog(DEBUG1, " %s => finished.", __func__);
return result;
}
/**
* Checks if a given URL is valid.
*/
static int CheckURL(char *url)
{
CURLUcode code;
CURLU *handler = curl_url();
elog(DEBUG1, "%s called > '%s'", __func__, url);
code = curl_url_set(handler, CURLUPART_URL, url, 0);
curl_url_cleanup(handler);
elog(DEBUG1, " %s handler return code: %u", __func__, code);
if (code != 0)
{
elog(DEBUG1, "%s: invalid URL (%u) > '%s'", __func__, code, url);
return code;
}
return OAI_SUCCESS;
}
static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
{
size_t realsize = size * nmemb;
struct MemoryStruct *mem = (struct MemoryStruct *)userp;
char *ptr = repalloc(mem->memory, mem->size + realsize + 1);