mapnik/plugins/input/postgis/postgis_datasource.cpp
2024-07-22 10:20:47 +01:00

1177 lines
44 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2024 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
#include "connection_manager.hpp"
#include "postgis_datasource.hpp"
#include "postgis_featureset.hpp"
#include "asyncresultset.hpp"
// mapnik
#include <mapnik/debug.hpp>
#include <mapnik/global.hpp>
#include <mapnik/boolean.hpp>
#include <mapnik/sql_utils.hpp>
#include <mapnik/util/conversions.hpp>
#include <mapnik/timer.hpp>
#include <mapnik/value/types.hpp>
#include <mapnik/warning.hpp>
MAPNIK_DISABLE_WARNING_PUSH
#include <mapnik/warning_ignore.hpp>
#include <boost/algorithm/string.hpp>
MAPNIK_DISABLE_WARNING_POP
// stl
#include <cfloat> // FLT_MAX
#include <memory>
#include <string>
#include <algorithm>
#include <set>
#include <sstream>
DATASOURCE_PLUGIN_IMPL(postgis_datasource_plugin, postgis_datasource);
DATASOURCE_PLUGIN_EXPORT(postgis_datasource_plugin);
DATASOURCE_PLUGIN_EMPTY_AFTER_LOAD(postgis_datasource_plugin);
DATASOURCE_PLUGIN_EMPTY_BEFORE_UNLOAD(postgis_datasource_plugin);
const std::string postgis_datasource::GEOMETRY_COLUMNS = "geometry_columns";
const std::string postgis_datasource::SPATIAL_REF_SYS = "spatial_ref_system";
using mapnik::attribute_descriptor;
using mapnik::sql_utils::identifier;
using mapnik::sql_utils::literal;
using std::shared_ptr;
postgis_datasource::postgis_datasource(parameters const& params)
: datasource(params)
, table_(*params.get<std::string>("table", ""))
, geometry_table_(*params.get<std::string>("geometry_table", ""))
, geometry_field_(*params.get<std::string>("geometry_field", ""))
, key_field_(*params.get<std::string>("key_field", ""))
, cursor_fetch_size_(*params.get<mapnik::value_integer>("cursor_size", 0))
, row_limit_(*params.get<mapnik::value_integer>("row_limit", 0))
, type_(datasource::Vector)
, srid_(*params.get<mapnik::value_integer>("srid", 0))
, extent_initialized_(false)
, simplify_geometries_(false)
, desc_(postgis_datasource::name(), "utf-8")
, creator_(params)
, pool_max_size_(*params_.get<mapnik::value_integer>("max_size", 10))
, persist_connection_(*params.get<mapnik::boolean_type>("persist_connection", true))
, extent_from_subquery_(*params.get<mapnik::boolean_type>("extent_from_subquery", false))
, max_async_connections_(*params_.get<mapnik::value_integer>("max_async_connection", 1))
, asynchronous_request_(false)
, twkb_encoding_(false)
, twkb_rounding_adjustment_(*params_.get<mapnik::value_double>("twkb_rounding_adjustment", 0.0))
, simplify_snap_ratio_(*params_.get<mapnik::value_double>("simplify_snap_ratio", 1.0 / 40.0))
,
// 1/20 of pixel seems to be a good compromise to avoid
// drop of collapsed polygons.
// See https://github.com/mapnik/mapnik/issues/1639
// See http://trac.osgeo.org/postgis/ticket/2093
simplify_dp_ratio_(*params_.get<mapnik::value_double>("simplify_dp_ratio", 1.0 / 20.0))
, simplify_dp_preserve_(false)
, simplify_clip_resolution_(*params_.get<mapnik::value_double>("simplify_clip_resolution", 0.0))
, re_tokens_("!(@?\\w+)!")
, // matches !mapnik_var! or !@user_var!
// params below are for testing purposes only and may be removed at any time
intersect_min_scale_(*params.get<mapnik::value_integer>("intersect_min_scale", 0))
, intersect_max_scale_(*params.get<mapnik::value_integer>("intersect_max_scale", 0))
, key_field_as_attribute_(*params.get<mapnik::boolean_type>("key_field_as_attribute", true))
{
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats__(std::clog, "postgis_datasource::init");
#endif
if (table_.empty())
{
throw mapnik::datasource_exception("Postgis Plugin: missing <table> parameter");
}
const auto ext = params.get<std::string>("extent");
if (ext.has_value() && !ext->empty())
{
extent_initialized_ = extent_.from_string(*ext);
}
// NOTE: In multithread environment, pool_max_size_ should be
// max_async_connections_ * num_threads
if (max_async_connections_ > 1)
{
if (max_async_connections_ > pool_max_size_)
{
std::ostringstream err;
err << "PostGIS Plugin: Error: 'max_async_connections (" << max_async_connections_
<< ") must be <= max_size(" << pool_max_size_ << ")";
throw mapnik::datasource_exception(err.str());
}
asynchronous_request_ = true;
}
const auto initial_size = params.get<mapnik::value_integer>("initial_size", 1);
const auto autodetect_key_field = params.get<mapnik::boolean_type>("autodetect_key_field", false);
const auto estimate_extent = params.get<mapnik::boolean_type>("estimate_extent", false);
estimate_extent_ = estimate_extent && *estimate_extent;
const auto simplify_opt = params.get<mapnik::boolean_type>("simplify_geometries", false);
simplify_geometries_ = simplify_opt && *simplify_opt;
const auto twkb_opt = params.get<mapnik::boolean_type>("twkb_encoding", false);
twkb_encoding_ = twkb_opt && *twkb_opt;
const auto simplify_preserve_opt = params.get<mapnik::boolean_type>("simplify_dp_preserve", false);
simplify_dp_preserve_ = simplify_preserve_opt && *simplify_preserve_opt;
ConnectionManager::instance().registerPool(creator_, *initial_size, pool_max_size_);
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
shared_ptr<Connection> conn = pool->borrowObject();
if (!conn)
return;
if (conn->isOK())
{
desc_.set_encoding(conn->client_encoding());
mapnik::sql_utils::table_from_sql(geometry_table_.empty() ? table_ : geometry_table_,
parsed_schema_,
parsed_table_);
// NOTE: parsed_table_ now should ideally be a table name, but
// there are known edge cases where this will break down and
// it may even be empty: https://github.com/mapnik/mapnik/issues/2718
// If we do not know both the geometry_field and the srid
// then first attempt to fetch the geometry name from a geometry_columns entry.
// This will return no records if we are querying a bogus table returned
// from the simplistic table parsing in table_from_sql() or if
// the table parameter references a table, view, or subselect not
// registered in the geometry columns.
geometryColumn_ = mapnik::sql_utils::unquote_copy('"', geometry_field_);
if (!parsed_table_.empty() && (geometryColumn_.empty() || srid_ == 0))
{
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats2__(std::clog, "postgis_datasource::init(get_srid_and_geometry_column)");
#endif
std::ostringstream s;
try
{
s << "SELECT f_geometry_column, srid FROM " << GEOMETRY_COLUMNS
<< " WHERE f_table_name=" << literal(parsed_table_);
if (!parsed_schema_.empty())
{
s << " AND f_table_schema=" << literal(parsed_schema_);
}
if (!geometryColumn_.empty())
{
s << " AND f_geometry_column=" << literal(geometryColumn_);
}
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
if (rs->next())
{
geometryColumn_ = rs->getValue("f_geometry_column");
// only accept srid from geometry_tables if
// user has not provided as option
if (srid_ == 0)
{
const char* srid_c = rs->getValue("srid");
if (srid_c != nullptr)
{
int result = 0;
const char* end = srid_c + std::strlen(srid_c);
if (mapnik::util::string2int(srid_c, end, result))
{
srid_ = result;
}
}
}
}
rs->close();
}
catch (mapnik::datasource_exception const& ex)
{
// let this pass on query error and use the fallback below
MAPNIK_LOG_WARN(postgis) << "postgis_datasource: metadata query failed: " << ex.what();
}
}
// If we still do not know the srid then we can try to fetch
// it from the 'parsed_table_' parameter, which should work even if it is
// a subselect as long as we know the geometry_field to query
if (!geometryColumn_.empty() && srid_ <= 0)
{
std::ostringstream s;
s << "SELECT ST_SRID(" << identifier(geometryColumn_) << ") AS srid FROM ";
if (!parsed_table_.empty())
{
append_geometry_table(s);
}
else
{
s << populate_tokens(table_);
}
s << " WHERE " << identifier(geometryColumn_) << " IS NOT NULL LIMIT 1";
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
if (rs->next())
{
const char* srid_c = rs->getValue("srid");
if (srid_c != nullptr)
{
int result = 0;
const char* end = srid_c + std::strlen(srid_c);
if (mapnik::util::string2int(srid_c, end, result))
{
srid_ = result;
}
}
}
rs->close();
}
// detect primary key
if (*autodetect_key_field && key_field_.empty())
{
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats2__(std::clog, "postgis_datasource::bind(get_primary_key)");
#endif
std::ostringstream s;
s << "SELECT a.attname, a.attnum, t.typname, t.typname in ('int2','int4','int8') "
"AS is_int FROM pg_class c, pg_attribute a, pg_type t, pg_namespace n, pg_index i "
"WHERE a.attnum > 0 AND a.attrelid = c.oid "
"AND a.atttypid = t.oid AND c.relnamespace = n.oid "
"AND c.oid = i.indrelid AND i.indisprimary = 't' "
"AND t.typname !~ '^geom' AND c.relname = "
<< literal(parsed_table_)
<< " "
//"AND a.attnum = ANY (i.indkey) " // postgres >= 8.1
<< "AND (i.indkey[0]=a.attnum OR i.indkey[1]=a.attnum OR i.indkey[2]=a.attnum "
"OR i.indkey[3]=a.attnum OR i.indkey[4]=a.attnum OR i.indkey[5]=a.attnum "
"OR i.indkey[6]=a.attnum OR i.indkey[7]=a.attnum OR i.indkey[8]=a.attnum "
"OR i.indkey[9]=a.attnum) ";
if (!parsed_schema_.empty())
{
s << "AND n.nspname=" << literal(parsed_schema_) << ' ';
}
s << "ORDER BY a.attnum";
shared_ptr<ResultSet> rs_key = conn->executeQuery(s.str());
if (rs_key->next())
{
unsigned int result_rows = rs_key->size();
if (result_rows == 1)
{
bool is_int = (std::string(rs_key->getValue(3)) == "t");
if (is_int)
{
const char* key_field_string = rs_key->getValue(0);
if (key_field_string)
{
key_field_ = std::string(key_field_string);
MAPNIK_LOG_DEBUG(postgis) << "postgis_datasource: auto-detected key field of '"
<< key_field_ << "' on table '" << parsed_table_ << "'";
}
}
else
{
// throw for cases like a numeric primary key, which is invalid
// as it should be floating point (int numerics are useless)
std::ostringstream err;
err << "PostGIS Plugin: Error: '" << rs_key->getValue(0) << "' on table '" << parsed_table_
<< "' is not a valid integer primary key field\n";
throw mapnik::datasource_exception(err.str());
}
}
else if (result_rows > 1)
{
std::ostringstream err;
err << "PostGIS Plugin: Error: '" << "multi column primary key detected but is not supported";
throw mapnik::datasource_exception(err.str());
}
}
rs_key->close();
}
// if a globally unique key field/primary key is required
// but still not known at this point, then throw
if (*autodetect_key_field && key_field_.empty())
{
throw mapnik::datasource_exception("PostGIS Plugin: Error: primary key required"
" but could not be detected for table '" +
parsed_table_ +
"', please supply 'key_field'"
" option to specify field to use for primary key");
}
if (srid_ == 0)
{
srid_ = -1;
MAPNIK_LOG_DEBUG(postgis) << "postgis_datasource: Table " << table_ << " is using SRID=" << srid_;
}
// At this point the geometry_field may still not be known
// but we'll catch that where more useful...
MAPNIK_LOG_DEBUG(postgis) << "postgis_datasource: Using SRID=" << srid_;
MAPNIK_LOG_DEBUG(postgis) << "postgis_datasource: Using geometry_column=" << geometryColumn_;
// collect attribute desc
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats2__(std::clog, "postgis_datasource::bind(get_column_description)");
#endif
std::ostringstream s;
s << "SELECT * FROM " << populate_tokens(table_) << " LIMIT 0";
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
int count = rs->getNumFields();
bool found_key_field = false;
for (int i = 0; i < count; ++i)
{
std::string fld_name = rs->getFieldName(i);
int type_oid = rs->getTypeOID(i);
// validate type of key_field
if (!found_key_field && !key_field_.empty() && fld_name == key_field_)
{
if (type_oid == 20 || type_oid == 21 || type_oid == 23)
{
found_key_field = true;
if (key_field_as_attribute_)
{
desc_.add_descriptor(attribute_descriptor(fld_name, mapnik::Integer));
}
}
else
{
std::ostringstream error_s;
error_s << "invalid type '";
std::ostringstream type_s;
type_s << "SELECT oid, typname FROM pg_type WHERE oid = " << type_oid;
shared_ptr<ResultSet> rs_oid = conn->executeQuery(type_s.str());
if (rs_oid->next())
{
error_s << rs_oid->getValue("typname") << "' (oid:" << rs_oid->getValue("oid") << ")";
}
else
{
error_s << "oid:" << type_oid << "'";
}
rs_oid->close();
error_s << " for key_field '" << fld_name << "' - " << "must be an integer primary key";
rs->close();
throw mapnik::datasource_exception(error_s.str());
}
}
else
{
switch (type_oid)
{
case 16: // bool
desc_.add_descriptor(attribute_descriptor(fld_name, mapnik::Boolean));
break;
case 20: // int8
case 21: // int2
case 23: // int4
desc_.add_descriptor(attribute_descriptor(fld_name, mapnik::Integer));
break;
case 700: // float4
case 701: // float8
case 1700: // numeric
desc_.add_descriptor(attribute_descriptor(fld_name, mapnik::Double));
break;
case 1042: // bpchar
case 1043: // varchar
case 25: // text
case 705: // literal
desc_.add_descriptor(attribute_descriptor(fld_name, mapnik::String));
break;
default: // should not get here
#ifdef MAPNIK_LOG
s.str("");
s << "SELECT oid, typname FROM pg_type WHERE oid = " << type_oid;
shared_ptr<ResultSet> rs_oid = conn->executeQuery(s.str());
if (rs_oid->next())
{
std::string typname(rs_oid->getValue("typname"));
if (typname != "geometry")
{
MAPNIK_LOG_WARN(postgis) << "postgis_datasource: Unknown type=" << typname
<< " (oid:" << rs_oid->getValue("oid") << ")";
}
}
else
{
MAPNIK_LOG_WARN(postgis) << "postgis_datasource: Unknown type_oid=" << type_oid;
}
rs_oid->close();
#endif
break;
}
}
}
rs->close();
}
// Close explicitly the connection so we can 'fork()' without sharing open connections
conn->close();
// Finally, add unique metadata to layer descriptor
mapnik::parameters& extra_params = desc_.get_extra_parameters();
// explicitly make copies of values due to https://github.com/mapnik/mapnik/issues/2651
extra_params["srid"] = mapnik::value_integer(srid_);
if (!key_field_.empty())
{
extra_params["key_field"] = key_field_;
}
}
}
postgis_datasource::~postgis_datasource()
{
if (!persist_connection_)
{
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
try
{
shared_ptr<Connection> conn = pool->borrowObject();
if (conn)
{
conn->close();
}
}
catch (mapnik::datasource_exception const& ex)
{
// happens when borrowObject tries to
// create a new connection and fails.
// In turn, new connection would be needed
// when our broke and was thus no good to
// be borrowed
// See https://github.com/mapnik/mapnik/issues/2191
}
}
}
}
const char* postgis_datasource::name()
{
return "postgis";
}
mapnik::datasource::datasource_t postgis_datasource::type() const
{
return type_;
}
layer_descriptor postgis_datasource::get_descriptor() const
{
return desc_;
}
std::string postgis_datasource::sql_bbox(box2d<double> const& env) const
{
std::ostringstream b;
b.precision(16);
b << "ST_MakeEnvelope(";
b << env.minx() << "," << env.miny() << ",";
b << env.maxx() << "," << env.maxy() << ",";
b << std::max(srid_, 0) << ")";
return b.str();
}
std::string postgis_datasource::populate_tokens(std::string const& sql) const
{
return populate_tokens(sql,
FLT_MAX,
box2d<double>(-FLT_MAX, -FLT_MAX, FLT_MAX, FLT_MAX),
0,
0,
mapnik::attributes{},
false);
}
std::string postgis_datasource::populate_tokens(std::string const& sql,
double scale_denom,
box2d<double> const& env,
double pixel_width,
double pixel_height,
mapnik::attributes const& vars,
bool intersect) const
{
std::ostringstream populated_sql;
std::cmatch m;
char const* start = sql.data();
char const* end = start + sql.size();
populated_sql.precision(16);
populated_sql << std::showpoint;
while (std::regex_search(start, end, m, re_tokens_))
{
populated_sql.write(start, m[0].first - start);
start = m[0].second;
auto m1 = boost::make_iterator_range(m[1].first, m[1].second);
if (m1.front() == '@')
{
std::string var_name(m1.begin() + 1, m1.end());
auto itr = vars.find(var_name);
if (itr != vars.end())
{
auto var_value = itr->second.to_string();
populated_sql << literal(var_value);
}
else
{
populated_sql << "NULL"; // undefined @variable
}
}
else if (boost::algorithm::equals(m1, "bbox"))
{
populated_sql << sql_bbox(env);
intersect = false;
}
else if (boost::algorithm::equals(m1, "pixel_height"))
{
populated_sql << pixel_height;
}
else if (boost::algorithm::equals(m1, "pixel_width"))
{
populated_sql << pixel_width;
}
else if (boost::algorithm::equals(m1, "scale_denominator"))
{
populated_sql << scale_denom;
}
else
{
populated_sql << "NULL"; // unrecognized !token!
}
}
populated_sql.write(start, end - start);
if (intersect)
{
if (intersect_min_scale_ > 0 && (scale_denom <= intersect_min_scale_))
{
populated_sql << " WHERE ST_Intersects(" << identifier(geometryColumn_) << ", " << sql_bbox(env) << ")";
}
else if (intersect_max_scale_ > 0 && (scale_denom >= intersect_max_scale_))
{
// do no bbox restriction
}
else
{
populated_sql << " WHERE " << identifier(geometryColumn_) << " && " << sql_bbox(env);
}
}
return populated_sql.str();
}
void postgis_datasource::append_geometry_table(std::ostream& os) const
{
if (!geometry_table_.empty())
{
os << geometry_table_; // assume datasource parameter is valid SQL
}
else if (!parsed_schema_.empty())
{
os << identifier(parsed_schema_) << '.' << identifier(parsed_table_);
}
else if (!parsed_table_.empty())
{
os << identifier(parsed_table_);
}
else
{
os << table_; // assume datasource parameter is valid SQL
}
}
std::shared_ptr<IResultSet> postgis_datasource::get_resultset(std::shared_ptr<Connection>& conn,
std::string const& sql,
CnxPool_ptr const& pool,
processor_context_ptr ctx) const
{
if (!ctx)
{
// ! asynchronous_request_
if (cursor_fetch_size_ > 0)
{
// cursor
std::ostringstream csql;
std::string cursor_name = conn->new_cursor_name();
csql << "DECLARE " << cursor_name << " BINARY INSENSITIVE NO SCROLL CURSOR WITH HOLD FOR " << sql
<< " FOR READ ONLY";
if (!conn->execute(csql.str()))
{
// TODO - better error
throw mapnik::datasource_exception("Postgis Plugin: error creating cursor for data select.");
}
return std::make_shared<CursorResultSet>(conn, cursor_name, cursor_fetch_size_);
}
else
{
// no cursor
return conn->executeQuery(sql, 1);
}
}
else
{ // asynchronous requests
std::shared_ptr<postgis_processor_context> pgis_ctxt = std::static_pointer_cast<postgis_processor_context>(ctx);
if (conn)
{
// lauch async req & create asyncresult with conn
conn->executeAsyncQuery(sql, 1);
return std::make_shared<AsyncResultSet>(pgis_ctxt, pool, conn, sql);
}
else
{
// create asyncresult with null connection
std::shared_ptr<AsyncResultSet> res = std::make_shared<AsyncResultSet>(pgis_ctxt, pool, conn, sql);
pgis_ctxt->add_request(res);
return res;
}
}
}
processor_context_ptr postgis_datasource::get_context(feature_style_context_map& ctx) const
{
if (!asynchronous_request_)
{
return processor_context_ptr();
}
std::string ds_name(name());
feature_style_context_map::const_iterator itr = ctx.find(ds_name);
if (itr != ctx.end())
{
return itr->second;
}
else
{
return ctx.emplace(ds_name, std::make_shared<postgis_processor_context>()).first->second;
}
}
featureset_ptr postgis_datasource::features(query const& q) const
{
// if the driver is in asynchronous mode, return the appropriate fetaures
if (asynchronous_request_)
{
return features_with_context(q, std::make_shared<postgis_processor_context>());
}
else
{
return features_with_context(q, processor_context_ptr());
}
}
featureset_ptr postgis_datasource::features_with_context(query const& q, processor_context_ptr proc_ctx) const
{
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats__(std::clog, "postgis_datasource::features_with_context");
#endif
box2d<double> const& box = q.get_bbox();
double scale_denom = q.scale_denominator();
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
shared_ptr<Connection> conn;
if (asynchronous_request_)
{
// limit use to num_async_request_ => if reached don't borrow the last connexion object
std::shared_ptr<postgis_processor_context> pgis_ctxt =
std::static_pointer_cast<postgis_processor_context>(proc_ctx);
if (pgis_ctxt->num_async_requests_ < max_async_connections_)
{
conn = pool->borrowObject();
pgis_ctxt->num_async_requests_++;
}
}
else
{
// Always get a connection in synchronous mode
conn = pool->borrowObject();
if (!conn)
{
throw mapnik::datasource_exception("Postgis Plugin: Null connection");
}
}
if (geometryColumn_.empty())
{
std::ostringstream s_error;
s_error << "PostGIS: geometry name lookup failed for table '";
append_geometry_table(s_error);
s_error << "'. Please manually provide the 'geometry_field' parameter or add an entry "
<< "in the geometry_columns for '";
append_geometry_table(s_error);
s_error << "'.";
throw mapnik::datasource_exception(s_error.str());
}
std::ostringstream s;
const double px_gw = 1.0 / std::get<0>(q.resolution());
const double px_gh = 1.0 / std::get<1>(q.resolution());
const double px_sz = std::min(px_gw, px_gh);
if (twkb_encoding_)
{
// This will only work against PostGIS 2.2, or a back-patched version
// that has (a) a ST_Simplify with a "preserve collapsed" flag and
// (b) a ST_RemoveRepeatedPoints with a tolerance parameter and
// (c) a ST_AsTWKB implementation
// What number of decimals of rounding does the pixel size imply?
const int twkb_rounding = -1 * std::lround(log10(px_sz) + twkb_rounding_adjustment_) + 1;
// And what's that in map units?
const double twkb_tolerance = pow(10.0, -1.0 * twkb_rounding);
s << "SELECT ST_AsTWKB(";
s << "ST_Simplify(";
s << "ST_RemoveRepeatedPoints(";
if (simplify_clip_resolution_ > 0.0 && simplify_clip_resolution_ > px_sz)
{
s << "ST_ClipByBox2D(";
}
s << identifier(geometryColumn_);
// ! ST_ClipByBox2D()
if (simplify_clip_resolution_ > 0.0 && simplify_clip_resolution_ > px_sz)
{
s << "," << sql_bbox(box) << ")";
}
// ! ST_RemoveRepeatedPoints()
s << "," << twkb_tolerance << ")";
// ! ST_Simplify(), with parameter to keep collapsed geometries
s << "," << twkb_tolerance << ",true)";
// ! ST_TWKB()
s << "," << twkb_rounding << ") AS geom";
}
else
{
s << "SELECT ST_AsBinary(";
if (simplify_geometries_)
{
s << "ST_Simplify(";
}
if (simplify_clip_resolution_ > 0.0 && simplify_clip_resolution_ > px_sz)
{
s << "ST_ClipByBox2D(";
}
if (simplify_geometries_ && simplify_snap_ratio_ > 0.0)
{
s << "ST_SnapToGrid(";
}
// Geometry column!
s << identifier(geometryColumn_);
// ! ST_SnapToGrid()
if (simplify_geometries_ && simplify_snap_ratio_ > 0.0)
{
const double tolerance = px_sz * simplify_snap_ratio_;
s << "," << tolerance << ")";
}
// ! ST_ClipByBox2D()
if (simplify_clip_resolution_ > 0.0 && simplify_clip_resolution_ > px_sz)
{
s << "," << sql_bbox(box) << ")";
}
// ! ST_Simplify()
if (simplify_geometries_)
{
const double tolerance = px_sz * simplify_dp_ratio_;
s << ", " << tolerance;
// Add parameter to ST_Simplify to keep collapsed geometries
if (simplify_dp_preserve_)
{
s << ", true";
}
s << ")";
}
// ! ST_AsBinary()
s << ") AS geom";
}
mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
std::set<std::string> const& props = q.property_names();
std::set<std::string>::const_iterator pos = props.begin();
std::set<std::string>::const_iterator end = props.end();
if (!key_field_.empty())
{
s << ',' << identifier(key_field_);
if (key_field_as_attribute_)
{
ctx->push(key_field_);
}
for (; pos != end; ++pos)
{
if (*pos != key_field_)
{
s << ',' << identifier(*pos);
ctx->push(*pos);
}
}
}
else
{
for (; pos != end; ++pos)
{
s << ',' << identifier(*pos);
ctx->push(*pos);
}
}
std::string table_with_bbox = populate_tokens(table_, scale_denom, box, px_gw, px_gh, q.variables());
s << " FROM " << table_with_bbox;
if (row_limit_ > 0)
{
s << " LIMIT " << row_limit_;
}
std::shared_ptr<IResultSet> rs = get_resultset(conn, s.str(), pool, proc_ctx);
return std::make_shared<postgis_featureset>(rs,
ctx,
desc_.get_encoding(),
!key_field_.empty(),
key_field_as_attribute_,
twkb_encoding_);
}
return mapnik::make_invalid_featureset();
}
featureset_ptr postgis_datasource::features_at_point(coord2d const& pt, double tol) const
{
#ifdef MAPNIK_STATS
mapnik::progress_timer __stats__(std::clog, "postgis_datasource::features_at_point");
#endif
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
shared_ptr<Connection> conn = pool->borrowObject();
if (!conn)
return mapnik::make_invalid_featureset();
if (conn->isOK())
{
if (geometryColumn_.empty())
{
std::ostringstream s_error;
s_error << "PostGIS: geometry name lookup failed for table '";
append_geometry_table(s_error);
s_error << "'. Please manually provide the 'geometry_field' parameter or add an entry "
<< "in the geometry_columns for '";
append_geometry_table(s_error);
s_error << "'.";
throw mapnik::datasource_exception(s_error.str());
}
std::ostringstream s;
s << "SELECT ST_AsBinary(" << identifier(geometryColumn_) << ") AS geom";
mapnik::context_ptr ctx = std::make_shared<mapnik::context_type>();
auto const& desc = desc_.get_descriptors();
if (!key_field_.empty())
{
s << ',' << identifier(key_field_);
if (key_field_as_attribute_)
{
ctx->push(key_field_);
}
for (auto const& attr_info : desc)
{
std::string const& name = attr_info.get_name();
if (name != key_field_)
{
s << ',' << identifier(name);
ctx->push(name);
}
}
}
else
{
for (auto const& attr_info : desc)
{
std::string const& name = attr_info.get_name();
s << ',' << identifier(name);
ctx->push(name);
}
}
box2d<double> box(pt.x - tol, pt.y - tol, pt.x + tol, pt.y + tol);
std::string table_with_bbox = populate_tokens(table_, FLT_MAX, box, 0, 0, mapnik::attributes{});
s << " FROM " << table_with_bbox;
if (row_limit_ > 0)
{
s << " LIMIT " << row_limit_;
}
std::shared_ptr<IResultSet> rs = get_resultset(conn, s.str(), pool);
return std::make_shared<postgis_featureset>(rs,
ctx,
desc_.get_encoding(),
!key_field_.empty(),
key_field_as_attribute_,
twkb_encoding_);
}
}
return mapnik::make_invalid_featureset();
}
box2d<double> postgis_datasource::envelope() const
{
if (extent_initialized_)
{
return extent_;
}
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
shared_ptr<Connection> conn = pool->borrowObject();
if (!conn)
return extent_;
if (conn->isOK())
{
std::ostringstream s;
if (geometryColumn_.empty())
{
std::ostringstream s_error;
s_error << "PostGIS: unable to query the layer extent of table '";
append_geometry_table(s_error);
s_error << "' because we cannot determine the geometry field name."
<< "\nPlease provide either an 'extent' parameter to skip this query, "
<< "a 'geometry_field' and/or 'geometry_table' parameter, or add a "
<< "record to the 'geometry_columns' for your table.";
throw mapnik::datasource_exception("Postgis Plugin: " + s_error.str());
}
if (estimate_extent_)
{
s << "SELECT ST_XMin(ext),ST_YMin(ext),ST_XMax(ext),ST_YMax(ext)"
<< " FROM (SELECT ST_EstimatedExtent(";
if (!parsed_schema_.empty())
{
s << literal(parsed_schema_) << ',';
}
s << literal(parsed_table_) << ',' << literal(geometryColumn_) << ") as ext) as tmp";
}
else
{
s << "SELECT ST_XMin(ext),ST_YMin(ext),ST_XMax(ext),ST_YMax(ext)" << " FROM (SELECT ST_Extent("
<< identifier(geometryColumn_) << ") as ext from ";
if (extent_from_subquery_)
{
// if a subselect limits records then calculating the extent upon the
// subquery will be faster and the bounds will be more accurate
s << populate_tokens(table_) << ") as tmp";
}
else
{
// but if the subquery does not limit records then querying the
// actual table will be faster as indexes can be used
append_geometry_table(s);
s << ") as tmp";
}
}
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
if (rs->next() && !rs->isNull(0))
{
double lox, loy, hix, hiy;
if (mapnik::util::string2double(rs->getValue(0), lox) &&
mapnik::util::string2double(rs->getValue(1), loy) &&
mapnik::util::string2double(rs->getValue(2), hix) &&
mapnik::util::string2double(rs->getValue(3), hiy))
{
extent_.init(lox, loy, hix, hiy);
extent_initialized_ = true;
}
else
{
MAPNIK_LOG_DEBUG(postgis)
<< "postgis_datasource: Could not determine extent from query: " << s.str();
}
}
rs->close();
}
}
return extent_;
}
std::optional<mapnik::datasource_geometry_t> postgis_datasource::get_geometry_type() const
{
std::optional<mapnik::datasource_geometry_t> result;
CnxPool_ptr pool = ConnectionManager::instance().getPool(creator_.id());
if (pool)
{
shared_ptr<Connection> conn = pool->borrowObject();
if (!conn)
return result;
if (conn->isOK())
{
std::ostringstream s;
std::string g_type;
try
{
s << "SELECT lower(type) as type FROM " << GEOMETRY_COLUMNS
<< " WHERE f_table_name=" << literal(parsed_table_);
if (!parsed_schema_.empty())
{
s << " AND f_table_schema=" << literal(parsed_schema_);
}
if (!geometryColumn_.empty())
{
s << " AND f_geometry_column=" << literal(geometryColumn_);
}
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
if (rs->next())
{
g_type = rs->getValue("type");
if (boost::algorithm::contains(g_type, "line"))
{
result = mapnik::datasource_geometry_t::LineString;
return result;
}
else if (boost::algorithm::contains(g_type, "point"))
{
result = mapnik::datasource_geometry_t::Point;
return result;
}
else if (boost::algorithm::contains(g_type, "polygon"))
{
result = mapnik::datasource_geometry_t::Polygon;
return result;
}
else // geometry
{
g_type = "";
}
}
}
catch (mapnik::datasource_exception const& ex)
{
// let this pass on query error and use the fallback below
MAPNIK_LOG_WARN(postgis) << "postgis_datasource: metadata query failed: " << ex.what();
}
// fallback to querying first several features
if (g_type.empty() && !geometryColumn_.empty())
{
s.str("");
std::string prev_type("");
s << "SELECT ST_GeometryType(" << identifier(geometryColumn_) << ") AS geom" << " FROM "
<< populate_tokens(table_);
if (row_limit_ > 0 && row_limit_ < 5)
{
s << " LIMIT " << row_limit_;
}
else
{
s << " LIMIT 5";
}
shared_ptr<ResultSet> rs = conn->executeQuery(s.str());
while (rs->next() && !rs->isNull(0))
{
const char* data = rs->getValue(0);
if (boost::algorithm::icontains(data, "line"))
{
g_type = "linestring";
result = mapnik::datasource_geometry_t::LineString;
}
else if (boost::algorithm::icontains(data, "point"))
{
g_type = "point";
result = mapnik::datasource_geometry_t::Point;
}
else if (boost::algorithm::icontains(data, "polygon"))
{
g_type = "polygon";
result = mapnik::datasource_geometry_t::Polygon;
}
else // geometry
{
result = mapnik::datasource_geometry_t::Collection;
return result;
}
if (!prev_type.empty() && g_type != prev_type)
{
result = mapnik::datasource_geometry_t::Collection;
return result;
}
prev_type = g_type;
}
}
}
}
return result;
}