qgswmsprovider.cpp

一个非常好的GIS开源新版本

  }

/*
  QgsHttpTransaction http(url, httpproxyhost, httpproxyport);

  // Do a passthrough for the status bar text
  connect(
          &http, SIGNAL(setStatus        (QString)),
           this,   SLOT(showStatusMessage(QString))
         );

  bool httpOk;

  httpOk = http.getSynchronously(imagesource);

  if (!httpOk)
  {
    // We had an HTTP exception

    mErrorCaption = tr("HTTP Exception");
    mError = http.errorString();

    mError += "\n" + tr("Tried URL: ") + url;

    return 0;
  }

  if (http.responseContentType() == "application/vnd.ogc.se_xml")
  {
    // We had a Service Exception from the WMS

    QgsDebugMsg("got Service Exception as:\n"  + QString(imagesource) );

    mErrorCaption = tr("WMS Service Exception");

    // set mError with the following:
    parseServiceExceptionReportDOM(imagesource);

    mError += "\n" + tr("Tried URL: ") + url;

    QgsDebugMsg("composed error message '" + mError + "'.");
#endif

    return 0;
  }
*/

  QgsDebugMsg("Response received.");

#ifdef QGISDEBUG
  //QFile file( "/tmp/qgis-wmsprovider-draw-raw.png" );
  //if ( file.open( QIODevice::WriteOnly ) ) 
  //{
  //  file.writeBlock(imagesource);
  //  file.close();
  //}
#endif

  // Load into the final QImage.

  //bool success = i.loadFromData(imagesource);
  if (cachedImage)
  {
    delete cachedImage;
  }
  cachedImage = new QImage(imagesource);

  // Remember settings for useful caching next time.
  cachedViewExtent = viewExtent;
  cachedPixelWidth = pixelWidth;
  cachedPixelHeight = pixelHeight;

#ifdef QGISDEBUG
  // Get what we can support

// Commented out for now, causes segfaults.
//  supportedFormats();

#endif

  
  
  QgsDebugMsg("Exiting.");


  // TODO: bit depth conversion to the client's expectation
//  return *(i.convertDepth(32));
  return cachedImage;

}

/*
void QgsWmsProvider::getServerCapabilities()
{
  QgsDebugMsg("entering.");

  retrieveServerCapabilities();

  // TODO: Return generic server capabilities here

  QgsDebugMsg("exiting.");

}
*/

bool QgsWmsProvider::retrieveServerCapabilities(bool forceRefresh)
{
  QgsDebugMsg("entering.");

  if ( httpcapabilitiesresponse.isNull() ||
       forceRefresh )
  {

    QString url = baseUrl + "SERVICE=WMS&REQUEST=GetCapabilities";

    httpcapabilitiesresponse = retrieveUrl(url);

    if (httpcapabilitiesresponse.isEmpty())
    {
      return FALSE;
    }
/*
    QgsHttpTransaction http(url, httpproxyhost, httpproxyport);

    // Do a passthrough for the status bar text
    connect(
            &http, SIGNAL(setStatus        (QString)),
             this,   SLOT(showStatusMessage(QString))
           );

    bool httpOk;
    httpOk = http.getSynchronously(httpcapabilitiesresponse);

    if (!httpOk)
    {
      // We had an HTTP exception

      mErrorCaption = tr("HTTP Exception");
      mError = http.errorString();

      mError += "\n" + tr("Tried URL: ") + url;

    QgsDebugMsg("!httpOK: "  + mError );

      return FALSE;
    }
*/

    QgsDebugMsg("Converting to DOM.");

    bool domOK;
    domOK = parseCapabilitiesDOM(httpcapabilitiesresponse, mCapabilities);

    if (!domOK)
    {
      // We had an DOM exception - 
      // mErrorCaption and mError are pre-filled by parseCapabilitiesDOM

      mError += "\n" + tr("Tried URL: ") + url;

      QgsDebugMsg("!domOK: " + mError);

      return FALSE;
    }

  }

  QgsDebugMsg("exiting.");

  return TRUE;

}


QByteArray QgsWmsProvider::retrieveUrl(QString url)
{
  QgsDebugMsg("WMS request Url: " + url);
  QgsHttpTransaction http(
    url,
    mHttpProxyHost,
    mHttpProxyPort,
    mHttpProxyUser,
    mHttpProxyPass);

  // Do a passthrough for the status bar text
  connect(
          &http, SIGNAL(setStatus        (QString)),
           this,   SLOT(showStatusMessage(QString))
         );

  QByteArray httpResponse;
  bool httpOk;

  httpOk = http.getSynchronously(httpResponse);

  if (!httpOk)
  {
    // We had an HTTP exception

    mErrorCaption = tr("HTTP Exception");
    mError = http.errorString();

    mError += "\n" + tr("Tried URL: ") + url;

    return QByteArray("");
  }

  if (http.responseContentType() == "application/vnd.ogc.se_xml")
  {
    // We had a Service Exception from the WMS

    QgsDebugMsg("got Service Exception as:\n" + httpResponse );

    mErrorCaption = tr("WMS Service Exception");

    // set mError with the following:
    parseServiceExceptionReportDOM(httpResponse);

    mError += "\n" + tr("Tried URL: ") + url;

    QgsDebugMsg("composed error message '" + mError + "'.");

    return QByteArray("");
  }

  return httpResponse;
}

#if 0
// deprecated
bool QgsWmsProvider::downloadCapabilitiesURI(QString const & uri)
{

  QgsDebugMsg("Entered with '"  + uri  + "'");

  QgsHttpTransaction http(uri, httpproxyhost, httpproxyport);

  // Do a passthrough for the status bar text
  connect(
          &http, SIGNAL(setStatus        (QString)),
           this,   SLOT(showStatusMessage(QString))
         );

  bool httpOk;
  httpOk = http.getSynchronously(httpcapabilitiesresponse);

  if (!httpOk)
  {
    // We had an HTTP exception

    mErrorCaption = tr("HTTP Exception");
    mError = http.errorString();

    mError += "\n" + tr("Tried URL: ") + uri;

    QgsDebugMsg("!httpOK: "  + mError );

    return FALSE;
  }

  QgsDebugMsg("Converting to DOM.");

  bool domOK;
  domOK = parseCapabilitiesDOM(httpcapabilitiesresponse, capabilities);

  if (!domOK)
  {
    // We had an DOM exception - 
    // mErrorCaption and mError are pre-filled by parseCapabilitiesDOM

    mError += "\n" + tr("Tried URL: ") + uri;

  QgsDebugMsg("!domOK: " + mError );

    return FALSE;
  }

  QgsDebugMsg("exiting.");

  return TRUE;

}
#endif

bool QgsWmsProvider::parseCapabilitiesDOM(QByteArray const & xml, QgsWmsCapabilitiesProperty& capabilitiesProperty)
{
  QgsDebugMsg("entering.");

#ifdef QGISDEBUG
  //test the content of the QByteArray.
  // There is a bug in Qt4.1.2, due for fixing in 4.2.0, where
  // QString(QByteArray) uses strlen to find the length of the
  // QByteArray. However, there are no guarantees that the QByteArray
  // has a terminating \0, and hence this can cause a crash, so we supply
  // the qbytearray to qstring in a way that ensures that there is a
  // terminating \0, and just to be safe, we also give it the actual
  // size.

  // Also, the Qt qWarning() function has a limit of 8192 bytes per
  // message, which can easily be exceeded by wms capability
  // documents, so we use the qgs logger stuff instead which doesn't
  // have that limitation.

  QString responsestring(QString::fromAscii(xml.constData(), xml.size()));
  QgsLogger::debug("QgsWmsProvider::parseCapabilitiesDOM, received the following data: "+responsestring);
  
  //QFile file( "/tmp/qgis-wmsprovider-capabilities.xml" );
  //if ( file.open( QIODevice::WriteOnly ) ) 
  //{
  //  file.writeBlock(xml);
  //  file.close();
  //}
#endif
  
  // Convert completed document into a DOM
  QString errorMsg;
  int errorLine;
  int errorColumn;
  bool contentSuccess = capabilitiesDOM.setContent(xml, false, &errorMsg, &errorLine, &errorColumn);

  if (!contentSuccess)
  {
    mErrorCaption = tr("DOM Exception");
    mError = QString(tr("Could not get WMS capabilities: %1 at line %2 column %3")
                .arg(errorMsg)
                .arg(errorLine)
                .arg(errorColumn) );

    mError += "\n" + tr("This is probably due to an incorrect WMS Server URL.");

  QgsLogger::debug("DOM Exception: "+mError);

    return FALSE;
  }

  QDomElement docElem = capabilitiesDOM.documentElement();

  // Assert that the DTD is what we expected (i.e. a WMS Capabilities document)
  QgsDebugMsg("testing tagName " + docElem.tagName() );

  if (!
      (
       (docElem.tagName() == "WMS_Capabilities")     // (1.3 vintage)
       ||
       (docElem.tagName() == "WMT_MS_Capabilities")  // (1.1.1 vintage)
      )
     )
  {
    mErrorCaption = tr("DOM Exception");
    mError = QString(tr("Could not get WMS capabilities in the "
                        "expected format (DTD): no %1 or %2 found")
                .arg("WMS_Capabilities")
                .arg("WMT_MS_Capabilities")
             );

    mError += "\n" + tr("This is probably due to an incorrect WMS Server URL.");

  QgsLogger::debug("DOM Exception: "+mError);

    return FALSE;
  }

  capabilitiesProperty.version = docElem.attribute("version");

  // Start walking through XML.
  QDomNode n = docElem.firstChild();

  while( !n.isNull() ) {
      QDomElement e = n.toElement(); // try to convert the node to an element.
      if( !e.isNull() ) {
          //QgsDebugMsg(e.tagName() ); // the node really is an element.

          if      (e.tagName() == "Service")
          {
            QgsDebugMsg("  Service.");
            parseService(e, capabilitiesProperty.service);
          }
          else if (e.tagName() == "Capability")
          {
            QgsDebugMsg("  Capability.");
            parseCapability(e, capabilitiesProperty.capability);
          }

      }
      n = n.nextSibling();
  }

  QgsDebugMsg("exiting.");

  return TRUE;
}


void QgsWmsProvider::parseService(QDomElement const & e, QgsWmsServiceProperty& serviceProperty)
{
  QgsDebugMsg("entering.");

  QDomNode n1 = e.firstChild();
  while( !n1.isNull() ) {
      QDomElement e1 = n1.toElement(); // try to convert the node to an element.
      if( !e1.isNull() ) {
          //QgsDebugMsg("  "  + e1.tagName() ); // the node really is an element.

          if      (e1.tagName() == "Title")
          {
            serviceProperty.title = e1.text();
          }
          else if (e1.tagName() == "Abstract")
          {
            serviceProperty.abstract = e1.text();
          }
          else if (e1.tagName() == "KeywordList")
          {
            parseKeywordList(e1, serviceProperty.keywordList);
          }
          else if (e1.tagName() == "OnlineResource")
          {
            parseOnlineResource(e1, serviceProperty.onlineResource);
          }
          else if (e1.tagName() == "ContactInformation")
          {
            parseContactInformation(e1, serviceProperty.contactInformation);
          }
          else if (e1.tagName() == "Fees")
          {
            serviceProperty.fees = e1.text();
          }
          else if (e1.tagName() == "AccessConstraints")
          {
            serviceProperty.accessConstraints = e1.text();
          }
          else if (e1.tagName() == "LayerLimit")
          {
            serviceProperty.layerLimit = e1.text().toUInt();
          }
          else if (e1.tagName() == "MaxWidth")
          {
            serviceProperty.maxWidth = e1.text().toUInt();
          }
          else if (e1.tagName() == "MaxHeight")
          {
            serviceProperty.maxHeight = e1.text().toUInt();
          }
      }
      n1 = n1.nextSibling();
  }