/// <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"); }