From 9a0bb92acd2e8f28e8f183a49b7e479c9b0f512c Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@dbsgeo.com>
Date: Thu, 27 Aug 2009 03:54:52 +0000
Subject: [PATCH] Improve handling of BBOX query substitution - closes #415

---
 CHANGELOG                         |  2 ++
 plugins/input/postgis/postgis.cpp | 58 ++++++++++++++++++-------------
 plugins/input/postgis/postgis.hpp |  2 ++
 3 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 6a3157be6..2c0cf3a37 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -14,6 +14,8 @@ For a complete change history, see the SVN log.
 Mapnik 0.6.2 Release
 --------------------
 
+- PostGIS Plugin: Add bbox substitution ability in sql query string (r1292) (#415)
+
 - PostGIS Plugin: Throw and report errors if SQL execution fails (r1291) (#363)
 
 - PostGIS Plugin: Added missing support for BigInt(int8) postgres datatypes (r1250) (#384)
diff --git a/plugins/input/postgis/postgis.cpp b/plugins/input/postgis/postgis.cpp
index 9c1374123..23aa3dc91 100644
--- a/plugins/input/postgis/postgis.cpp
+++ b/plugins/input/postgis/postgis.cpp
@@ -74,7 +74,8 @@ postgis_datasource::postgis_datasource(parameters const& params)
               params.get<std::string>("port"),
               params.get<std::string>("dbname"),
               params.get<std::string>("user"),
-              params.get<std::string>("password"))    
+              params.get<std::string>("password")),
+     bbox_token_("!bbox!")
 {   
 
    boost::optional<int> initial_size = params_.get<int>("inital_size",1);
@@ -171,7 +172,8 @@ postgis_datasource::postgis_datasource(parameters const& params)
             
          // collect attribute desc
          s.str("");
-         s << "select * from " << table_ << " limit 0";
+         std::string table_with_bbox = populate_sql_bbox(table_,extent_);
+         s << "select * from " << table_with_bbox << " limit 0";
          rs=conn->executeQuery(s.str());
          int count = rs->getNumFields();
          for (int i=0;i<count;++i)
@@ -221,6 +223,27 @@ layer_descriptor postgis_datasource::get_descriptor() const
    return desc_;
 }
 
+std::string postgis_datasource::populate_sql_bbox(const std::string& sql, Envelope<double> const& box) const
+{
+    std::string sql_with_bbox = boost::algorithm::to_lower_copy(sql);
+    std::ostringstream b;
+    b << "SetSRID('BOX3D(";
+    b << std::setprecision(16);
+    b << box.minx() << " " << box.miny() << ",";
+    b << box.maxx() << " " << box.maxy() << ")'::box3d," << srid_ << ")";
+    if ( boost::algorithm::icontains(sql,bbox_token_) )
+    {
+        boost::algorithm::replace_all(sql_with_bbox,bbox_token_,b.str());
+        return sql_with_bbox;
+    }
+    else
+    {
+        std::ostringstream s;
+        s << " WHERE \"" << geometryColumn_ << "\" && " << b.str();
+        return sql_with_bbox + s.str();    
+    }
+}
+
 std::string postgis_datasource::table_from_sql(const std::string& sql)
 {
    std::string table_name = boost::algorithm::to_lower_copy(sql);
@@ -293,24 +316,9 @@ featureset_ptr postgis_datasource::features(const query& q) const
             ++pos;
          }	 
 
-         std::ostringstream b; 
-         b << "SetSRID('BOX3D(";
-         b << std::setprecision(16);
-         b << box.minx() << " " << box.miny() << ",";
-         b << box.maxx() << " " << box.maxy() << ")'::box3d,"<<srid_<<")";        
-         
-         std::string find = "!bbox!";
-         if (boost::algorithm::icontains(table_,find)) // if token used place bbox there
-         {
-             std::string table_m = boost::algorithm::to_lower_copy(table_);
-             std::string replace = b.str();
-             boost::algorithm::replace_all(table_m,find,replace);
-             s << " from " << table_m;     
-         }
-         else // otherwise append bbox query
-         {
-             s << " from " << table_ << " WHERE \"" << geometryColumn_ << "\" && "<< b.str();
-         }
+         std::string table_with_bbox = populate_sql_bbox(table_,box);
+
+         s << " from " << table_with_bbox;
 
          if (row_limit_ > 0) {
              s << " LIMIT " << row_limit_;
@@ -346,11 +354,11 @@ featureset_ptr postgis_datasource::features_at_point(coord2d const& pt) const
             ++itr;
             ++size;
          }
-            
-         s << " FROM " << table_ << " WHERE \""<<geometryColumn_<<"\" && SetSRID('BOX3D(";
-         s << std::setprecision(16);
-         s << pt.x << " " << pt.y << ",";
-         s << pt.x << " " << pt.y << ")'::box3d,"<<srid_<<")";
+
+         Envelope<double> box(pt.x,pt.y,pt.x,pt.y);
+         std::string table_with_bbox = populate_sql_bbox(table_,box);
+
+         s << " from " << table_with_bbox;
          
          if (row_limit_ > 0) {
              s << " LIMIT " << row_limit_;
diff --git a/plugins/input/postgis/postgis.hpp b/plugins/input/postgis/postgis.hpp
index 8619fb206..79e68ab1b 100644
--- a/plugins/input/postgis/postgis.hpp
+++ b/plugins/input/postgis/postgis.hpp
@@ -69,6 +69,7 @@ class postgis_datasource : public datasource
       ConnectionCreator<Connection> creator_;
       bool multiple_geometries_;
       static const std::string name_;
+      const std::string bbox_token_;
    public:
       static std::string name();
       int type() const;
@@ -79,6 +80,7 @@ class postgis_datasource : public datasource
       postgis_datasource(const parameters &params);
       ~postgis_datasource();
    private:
+      std::string populate_sql_bbox(const std::string& sql, Envelope<double> const& box) const;
       static std::string table_from_sql(const std::string& sql);
       boost::shared_ptr<IResultSet> get_resultset(boost::shared_ptr<Connection> const &conn, const std::string &sql) const;
       postgis_datasource(const postgis_datasource&);