/// <summary>
/// Generates a WMS 1.3.0 compliant response based on a <see cref="SharpMap.Map"/> and the current HttpRequest.
/// </summary>
/// <remarks>
/// <para>
/// The Web Map Server implementation in SharpMap requires v1.3.0 compatible clients,
/// and support the basic operations "GetCapabilities" and "GetMap"
/// as required by the WMS v1.3.0 specification. SharpMap does not support the optional
/// GetFeatureInfo operation for querying.
/// </para>
/// <example>
/// Creating a WMS server in ASP.NET is very simple using the classes in the SharpMap.Web.Wms namespace.
/// <code lang="C#">
/// void page_load(object o, EventArgs e)
/// {
/// //Get the path of this page
/// string url = (Request.Url.Query.Length>0?Request.Url.AbsoluteUri.Replace(Request.Url.Query,""):Request.Url.AbsoluteUri);
/// SharpMap.Web.Wms.Capabilities.WmsServiceDescription description =
/// new SharpMap.Web.Wms.Capabilities.WmsServiceDescription("Acme Corp. Map Server", url);
///
/// // The following service descriptions below are not strictly required by the WMS specification.
///
/// // Narrative description and keywords providing additional information
/// description.Abstract = "Map Server maintained by Acme Corporation. Contact: [email protected]. High-quality maps showing roadrunner nests and possible ambush locations.";
/// description.Keywords.Add("bird");
/// description.Keywords.Add("roadrunner");
/// description.Keywords.Add("ambush");
///
/// //Contact information
/// description.ContactInformation.PersonPrimary.Person = "John Doe";
/// description.ContactInformation.PersonPrimary.Organisation = "Acme Inc";
/// description.ContactInformation.Address.AddressType = "postal";
/// description.ContactInformation.Address.Country = "Neverland";
/// description.ContactInformation.VoiceTelephone = "1-800-WE DO MAPS";
/// //Impose WMS constraints
/// description.MaxWidth = 1000; //Set image request size width
/// description.MaxHeight = 500; //Set image request size height
///
/// //Call method that sets up the map
/// //We just add a dummy-size, since the wms requests will set the image-size
/// SharpMap.Map myMap = MapHelper.InitializeMap(new System.Drawing.Size(1,1));
///
/// //Parse the request and create a response
/// SharpMap.Web.Wms.WmsServer.ParseQueryString(myMap,description);
/// }
/// </code>
/// </example>
/// </remarks>
/// <param name="map">Map to serve on WMS</param>
/// <param name="description">Description of map service</param>
public static void ParseQueryString(SharpMap.Map map, Capabilities.WmsServiceDescription description)
{
if (map == null)
throw (new ArgumentException("Map for WMS is null"));
if (map.Layers.Count == 0)
throw (new ArgumentException("Map doesn't contain any layers for WMS service"));
if (System.Web.HttpContext.Current == null)
throw (new ApplicationException("An attempt was made to access the WMS server outside a valid HttpContext"));
System.Web.HttpContext context = System.Web.HttpContext.Current;
//IgnoreCase value should be set according to the VERSION parameter
//v1.3.0 is case sensitive, but since it causes a lot of problems with several WMS clients, we ignore casing anyway.
bool ignorecase = true;
//Check for required parameters
//Request parameter is mandatory
if (context.Request.Params["REQUEST"] == null)
{ WmsException.ThrowWmsException("Required parameter REQUEST not specified"); return; }
//Check if version is supported
if (context.Request.Params["VERSION"] != null)
{
if (String.Compare(context.Request.Params["VERSION"], "1.3.0", ignorecase) != 0)
{ WmsException.ThrowWmsException("Only version 1.3.0 supported"); return; }
}
else //Version is mandatory if REQUEST!=GetCapabilities. Check if this is a capabilities request, since VERSION is null
{
if (String.Compare(context.Request.Params["REQUEST"], "GetCapabilities", ignorecase) != 0)
{ WmsException.ThrowWmsException("VERSION parameter not supplied"); return; }
}
//If Capabilities was requested
if (String.Compare(context.Request.Params["REQUEST"], "GetCapabilities", ignorecase) == 0)
{
//Service parameter is mandatory for GetCapabilities request
if (context.Request.Params["SERVICE"] == null)
{ WmsException.ThrowWmsException("Required parameter SERVICE not specified"); return; }
if (String.Compare(context.Request.Params["SERVICE"], "WMS") != 0)
WmsException.ThrowWmsException("Invalid service for GetCapabilities Request. Service parameter must be 'WMS'");
System.Xml.XmlDocument capabilities = Wms.Capabilities.GetCapabilities(map, description);
context.Response.Clear();
context.Response.ContentType = "text/xml";
System.Xml.XmlWriter writer = System.Xml.XmlWriter.Create(context.Response.OutputStream);
capabilities.WriteTo(writer);
writer.Close();
context.Response.End();
}
else if (String.Compare(context.Request.Params["REQUEST"], "GetMap", ignorecase) == 0) //Map requested
{
//Check for required parameters
if (context.Request.Params["LAYERS"] == null)
{ WmsException.ThrowWmsException("Required parameter LAYERS not specified"); return; }
if (context.Request.Params["STYLES"] == null)
{ WmsException.ThrowWmsException("Required parameter STYLES not specified"); return; }
if (context.Request.Params["CRS"] == null)
{ WmsException.ThrowWmsException("Required parameter CRS not specified"); return; }
else if (context.Request.Params["CRS"] != "EPSG:" + map.Layers[0].SRID.ToString())
{ WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidCRS, "CRS not supported"); return; }
if (context.Request.Params["BBOX"] == null)
{ WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidDimensionValue, "Required parameter BBOX not specified"); return; }
if (context.Request.Params["WIDTH"] == null)
{ WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidDimensionValue, "Required parameter WIDTH not specified"); return; }
if (context.Request.Params["HEIGHT"] == null)
{ WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidDimensionValue, "Required parameter HEIGHT not specified"); return; }
if (context.Request.Params["FORMAT"] == null)
{ WmsException.ThrowWmsException("Required parameter FORMAT not specified"); return; }
//Set background color of map
if (String.Compare(context.Request.Params["TRANSPARENT"], "TRUE", ignorecase) == 0)
map.BackColor = System.Drawing.Color.Transparent;
else if (context.Request.Params["BGCOLOR"] != null)
{
try { map.BackColor = System.Drawing.ColorTranslator.FromHtml(context.Request.Params["BGCOLOR"]); }
catch { WmsException.ThrowWmsException("Invalid parameter BGCOLOR"); return; };
}
else
map.BackColor = System.Drawing.Color.White;
//Get the image format requested
System.Drawing.Imaging.ImageCodecInfo imageEncoder = GetEncoderInfo(context.Request.Params["FORMAT"]);
if (imageEncoder == null)
{
WmsException.ThrowWmsException("Invalid MimeType specified in FORMAT parameter");
return;
}
//Parse map size
int width = 0;
int height = 0;
if (!int.TryParse(context.Request.Params["WIDTH"], out width))
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidDimensionValue, "Invalid parameter WIDTH");
return;
}
else if (description.MaxWidth > 0 && width > description.MaxWidth)
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.OperationNotSupported, "Parameter WIDTH too large");
return;
}
if (!int.TryParse(context.Request.Params["HEIGHT"], out height))
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.InvalidDimensionValue, "Invalid parameter HEIGHT");
return;
}
else if (description.MaxHeight > 0 && height > description.MaxHeight)
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.OperationNotSupported, "Parameter HEIGHT too large");
return;
}
map.Size = new System.Drawing.Size(width, height);
IEnvelope bbox = ParseBBOX(context.Request.Params["bbox"]);
if (bbox == null)
{
WmsException.ThrowWmsException("Invalid parameter BBOX");
return;
}
map.PixelAspectRatio = ((double)width / (double)height) / (bbox.Width / bbox.Height);
map.Center = bbox.Centre;
map.Zoom = bbox.Width;
//Set layers on/off
if (!String.IsNullOrEmpty(context.Request.Params["LAYERS"])) //If LAYERS is empty, use default layer on/off settings
{
string[] layers = context.Request.Params["LAYERS"].Split(new char[] { ',' });
if(description.LayerLimit>0)
{
if (layers.Length == 0 && map.Layers.Count > description.LayerLimit ||
layers.Length > description.LayerLimit)
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.OperationNotSupported, "Too many layers requested");
return;
}
}
foreach (SharpMap.Layers.ILayer layer in map.Layers)
layer.Enabled = false;
foreach (string layer in layers)
{
//SharpMap.Layers.ILayer lay = map.Layers.Find(delegate(SharpMap.Layers.ILayer findlay) { return findlay.LayerName == layer; });
SharpMap.Layers.ILayer lay = null;
for (int i = 0; i < map.Layers.Count; i++)
if (String.Equals(map.Layers[i].Name, layer, StringComparison.InvariantCultureIgnoreCase))
lay = map.Layers[i];
if (lay == null)
{
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.LayerNotDefined, "Unknown layer '" + layer + "'");
return;
}
else
lay.Enabled = true;
}
}
//Render map
System.Drawing.Image img = map.Render();
//Png can't stream directy. Going through a memorystream instead
System.IO.MemoryStream MS = new System.IO.MemoryStream();
img.Save(MS, imageEncoder, null);
img.Dispose();
byte[] buffer = MS.ToArray();
context.Response.Clear();
context.Response.ContentType = imageEncoder.MimeType;
context.Response.OutputStream.Write(buffer, 0, buffer.Length);
context.Response.End();
}
else
WmsException.ThrowWmsException(WmsException.WmsExceptionCode.OperationNotSupported, "Invalid request");
}