qgspggeoprocessing.cpp

一个非常好的GIS开源新版本

/***************************************************************************
  qgspggeoprocessing.cpp 
  Geoprocessing plugin for PostgreSQL/PostGIS layers
Functions:
Buffer
-------------------
begin                : Jan 21, 2004
copyright            : (C) 2004 by Gary E.Sherman
email                : sherman at mrcc.com

 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
/*  $Id: qgspggeoprocessing.cpp 8053 2008-01-26 13:59:53Z timlinux $ */

// includes
#include <iostream>
#include <vector>
#include "qgisinterface.h"
#include "qgsmaplayer.h"
#include "qgsvectorlayer.h"
#include "qgsvectordataprovider.h"
#include "qgsfield.h"
#include "qgsdatasourceuri.h"
#include "qgslogger.h"

#include <QMessageBox>
#include <QAction>
#include <QApplication>
#include <QMenu>

#include "qgsdlgpgbuffer.h"
#include "qgspggeoprocessing.h"

// xpm for creating the toolbar icon
#include "icon_buffer.xpm"

static const char * const ident_ = "$Id: qgspggeoprocessing.cpp 8053 2008-01-26 13:59:53Z timlinux $";

static const QString name_ = QObject::tr("PostgreSQL Geoprocessing");
static const QString description_ = QObject::tr("Geoprocessing functions for working with PostgreSQL/PostGIS layers");
static const QString version_ = QObject::tr("Version 0.1");
static const QgisPlugin::PLUGINTYPE type_ = QgisPlugin::UI;


/**
 * Constructor for the plugin. The plugin is passed a pointer to the main app
 * and an interface object that provides access to exposed functions in QGIS.
 * @param qgis Pointer to the QGIS main window
 * @parma _qI Pointer to the QGIS interface object
 */
QgsPgGeoprocessing::QgsPgGeoprocessing(QgisInterface * _qI)
  : QgisPlugin( name_, description_, version_, type_ ),
    qgisMainWindow(_qI->getMainWindow()),
    qI(_qI)
{
}

QgsPgGeoprocessing::~QgsPgGeoprocessing()
{

}


/*
 * Initialize the GUI interface for the plugin 
 */
void QgsPgGeoprocessing::initGui()
{
  // Create the action for tool
  bufferAction = new QAction(QIcon(icon_buffer), tr("&Buffer features"), this);
  bufferAction->setWhatsThis(tr("Create a buffer for a PostgreSQL layer. " +
      tr("A new layer is created in the database with the buffered features.")));
  // Connect the action to the buffer slot
  connect(bufferAction, SIGNAL(triggered()), this, SLOT(buffer()));

  // Add the icon to the toolbar
  qI->addToolBarIcon(bufferAction);
  qI->addPluginMenu(tr("&Geoprocessing"), bufferAction);

}

// Slot called when the buffer menu item is triggered
void QgsPgGeoprocessing::buffer()
{
  // need to get a pointer to the current layer
  QgsMapLayer *layer = qI->activeLayer();
  if (layer) {
    QgsVectorLayer *lyr = (QgsVectorLayer*)layer;
    // check the layer to see if its a postgres layer
    if (layer->type() != QgsMapLayer::RASTER && 
        lyr->providerType() == "postgres") {

      QgsDataSourceURI uri( lyr->source() );

      QgsDebugMsg("data source = " + uri.connInfo() );

      // connect to the database and check the capabilities
      PGconn *capTest = PQconnectdb((const char *) uri.connInfo() );
      if (PQstatus(capTest) == CONNECTION_OK) {
        postgisVersion(capTest);
      }
      PQfinish(capTest);
      if(geosAvailable){
        // show dialog to fetch buffer distrance, new layer name, and option to
        // add the new layer to the map
        QgsDlgPgBuffer *bb = new QgsDlgPgBuffer(qI);

        // set the label
        QString lbl = tr("Buffer features in layer %1").arg( uri.table() );
        bb->setBufferLabel(lbl);
        // set a default output table name
        bb->setBufferLayerName( uri.table() + "_buffer");

        QString tableName = uri.quotedTablename();

        // set the fields on the dialog box drop-down
        QgsVectorDataProvider *dp = dynamic_cast<QgsVectorDataProvider *>(lyr->getDataProvider());
        QgsFieldMap flds = dp->fields();
        for (QgsFieldMap::iterator it = flds.begin(); it != flds.end(); ++it) {
          // check the field type -- if its int we can use it
          if (it->typeName().find("int") > -1) {
            bb->addFieldItem(it->name());
          }
        }
        // connect to the database
        PGconn *conn = PQconnectdb((const char *) uri.connInfo() );
        if (PQstatus(conn) == CONNECTION_OK) {
          // populate the schema drop-down
          QString schemaSql =
            QString("select nspname from pg_namespace,pg_user where nspowner = usesysid and usename = '%1'").arg( uri.username() );
          PGresult *schemas = PQexec(conn, (const char *) schemaSql);
          if (PQresultStatus(schemas) == PGRES_TUPLES_OK) {
            // add the schemas to the drop-down, otherwise just public (the
            // default) will show up
            for (int i = 0; i < PQntuples(schemas); i++) {
              bb->addSchema(PQgetvalue(schemas, i, 0));
            }
          }
          PQclear(schemas);
          // query the geometry_columns table to get the srid and use it as default
          QString sridSql =
            QString("select srid,f_geometry_column from geometry_columns where f_table_schema='%1' and f_table_name='%2'")
            .arg( uri.schema() )
            .arg( uri.table() );

          QgsDebugMsg("SRID SQL: " + sridSql);

          QString geometryCol;
          PGresult *sridq = PQexec(conn, (const char *) sridSql);
          if (PQresultStatus(sridq) == PGRES_TUPLES_OK) {
            bb->setSrid(PQgetvalue(sridq, 0, 0));
            geometryCol = PQgetvalue(sridq, 0, 1);
            bb->setGeometryColumn(geometryCol);
          } else {
            bb->setSrid("-1");
          }
          PQclear(sridq);
          // exec the dialog and process if user selects ok
          if (bb->exec()) {
            QApplication::setOverrideCursor(Qt::WaitCursor);
            qApp->processEvents();
            // determine what column to use as the obj id
            QString objId = bb->objectIdColumn();
            QString objIdType = "int";
            QString objIdValue;
            if (objId == "Create unique object id") {
              objId = "objectid";
              objIdType = "serial";
              objIdValue = "DEFAULT";
            } else {
              objIdValue = objId;
            }
            // set the schema path (need public to find the postgis
            // functions)
            PGresult *result = PQexec(conn, "begin work");
            PQclear(result);
            QString sql;
            // set the schema search path if schema is not public
            if(bb->schema() != "public")
            {
              sql = QString("set search_path = '%1','public'").arg(bb->schema());
              result = PQexec(conn, (const char *) sql);
              PQclear(result);
 
              QgsDebugMsg("SQL: " + sql);
            }
            // first create the new table

            sql = QString("create table %1.%2 (%3 %4 PRIMARY KEY)")
              .arg(bb->schema())
              .arg(bb->bufferLayerName())
              .arg(objId)
              .arg(objIdType);
            QgsDebugMsg("SQL: " + sql);

            result = PQexec(conn, (const char *) sql);
            QgsDebugMsg( QString("Status from create table is %1").arg( PQresultStatus(result) ) );
            QgsDebugMsg( QString("Error message is %1").arg(PQresStatus(PQresultStatus(result))) );

            if (PQresultStatus(result) == PGRES_COMMAND_OK)
            {
              PQclear(result);
              // add the geometry column
              //<db_name>, <table_name>, <column_name>, <srid>, <type>, <dimension>
              sql = QString("select addgeometrycolumn('%1','%2','%3',%4,'%5',%6)")
                .arg(bb->schema())
                .arg(bb->bufferLayerName())
                .arg(bb->geometryColumn())
                .arg(bb->srid())
                .arg("POLYGON")
                .arg("2");
              QgsDebugMsg("SQL: " + sql);

              PGresult *geoCol = PQexec(conn, (const char *) sql);

            if (PQresultStatus(geoCol) == PGRES_TUPLES_OK) {
              PQclear(geoCol);
              /* The constraint naming convention has changed in PostGIS
               * from $2 to enforce_geotype_shape. This change means the