public async Task <RetsResource> GetResourceMetadata(string resourceId)
{
if (string.IsNullOrWhiteSpace(resourceId))
{
throw new ArgumentNullException($"{resourceId} cannot be null.");
}
RetsResourceCollection capsule = await GetResourcesMetadata();
var resource = capsule.Get().FirstOrDefault(x => x.ResourceId.Equals(resourceId, StringComparison.CurrentCultureIgnoreCase)) ?? throw new ResourceDoesNotExists();
return(resource);
}
public async Task <RetsSystem> GetSystemMetadata()
{
var uriBuilder = new UriBuilder(GetMetadataUri);
var query = HttpUtility.ParseQueryString(uriBuilder.Query);
query.Add("Type", "METADATA-SYSTEM");
query.Add("ID", "*");
query.Add("Format", "STANDARD-XML");
uriBuilder.Query = query.ToString();
return(await Requester.Get(uriBuilder.Uri, async (response) =>
{
using (Stream stream = await GetStream(response))
{
XDocument doc = XDocument.Load(stream);
AssertValidReplay(doc.Root);
XNamespace ns = doc.Root.GetDefaultNamespace();
XElement metaData = doc.Descendants(ns + "METADATA").FirstOrDefault();
XElement metadataSystem = metaData.Elements().FirstOrDefault();
XElement systemMeta = metadataSystem.Elements().FirstOrDefault();
XElement metaDataResource = metadataSystem.Descendants("METADATA-RESOURCE").FirstOrDefault();
RetsResourceCollection resources = new RetsResourceCollection();
resources.Load(metaDataResource);
var system = new RetsSystem()
{
SystemId = systemMeta.Attribute("SystemID")?.Value,
SystemDescription = systemMeta.Attribute("SystemDescription")?.Value,
Version = metadataSystem.Attribute("Version")?.Value,
Date = DateTime.Parse(metadataSystem.Attribute("Date")?.Value),
Resources = resources
};
return system;
}
}, Session.Resource));
}
public async Task Execute()
{
// The first request we make to the RETS server is to login
await Client.Connect();
// To get to know the RETS server, we can scan the entire system to get a list of our resources, classes, object.....
RetsSystem system = await Client.GetSystemMetadata();
// We can also get a list of all available resources
RetsResourceCollection resources = await Client.GetResourcesMetadata();
// We can also get all available classes for a given resorce. Assuming your RETS server has a resource called "Property"
RetsClassCollection classes = await Client.GetClassesMetadata("Property");
// We can also get a list of all available objects on a given property.
RetsObjectCollection objects = await Client.GetObjectMetadata("Property");
// We can also get a list of all available field for the given resource and class. Assuming your RETS server has a resource called "Property" with a class called "Listing"
RetsFieldCollection fields = await Client.GetTableMetadata("Property", "Listing");
// We can also get all available lookup values on the given resource
IEnumerable <RetsLookupTypeCollection> lookupTypes = await Client.GetLookupValues("Property");
// We can also get a list of all available lookup types for a give resource and lookuptype aka fieldName
RetsLookupTypeCollection lookupType = await Client.GetLookupValues("Property", "FieldName");
// We can perform a search against the RETS server
SearchRequest searchRequest = new SearchRequest("Property", "Listing");
// Add ad many parameers to search for. Assuming the class "Listing" on the "Property" resource has a field called "matrix_unique_id" which is numeric type
// we say give me all properties where matrix_unique_id >= 0
searchRequest.ParameterGroup.AddParameter(new QueryParameter("matrix_unique_id", "0+"));
// If you like to return specific columns, you can do so like this
searchRequest.AddColumn("matrix_unique_id");
searchRequest.AddColumn("SomeOtherColumnName");
// This performs the search against the server
SearchResult result = await Client.Search(searchRequest);
// we can iterate over the results like so
foreach (SearchResultRow row in result.GetRows())
{
// Each row has multiple columns, lets loop over them
foreach (var columnName in result.GetColumns())
{
// Lets get the cell value for a given column from the current row
SearchResultCellValue value = row.Get(columnName);
// you can get the value trimmed like so
string a = value.GetTrimmed();
string b = value.NullOrValue();
// Assuming you know the type of the returned data, you can cast the values like so
// Of cource you must know that the column is int type befor eyou call this
//int castedToIntValue = value.Get<int>();
//you can also do something like
//int? castedToIntValue = value.GetNullable<int>();
//DateTime? castedToIntValue = value.GetNullable<DateTime>();
// you can also check if the value is restricted like this
bool restrictedValue = value.IsRestricted;
// you can check if this value is a primary key
bool primaryKey = value.IsPrimaryKeyValue;
bool c = value.IsNullOrEmpty();
bool d = value.IsNullOrWhiteSpace();
bool e = value.IsNull();
}
}
// Also you can extract only all value for a given column like this
IEnumerable <SearchResultCellValue> createdAtCells = result.Pluck("CreatedAt");
// you can also result cast the values of a given field like this
// this will result an IEnumerable<> of all values found in the CreatedAt column
IEnumerable <DateTime> createdAtvalues = result.Pluck <DateTime>("CreatedAt");
// We can also download photos
// This will return all photos for property with the primarykey 1234
IEnumerable <FileObject> files = await Client.GetObject("Property", "Photo", new PhotoId(1234), false);
// Here is how we can iterate over the fields
foreach (FileObject file in files)
{
var filePath = $"{file.ContentId}/{file.ObjectId}{file.Extension}";
using (FileStream output = File.Create("../../../Downloads/" + filePath))
{
// file.Content has the stream object where you can write it your storage
file.Content.CopyTo(output);
// IMPORTANT: Make sure you dispose the stram after finising using it
file.Dispose();
}
}
// you can get a specific image for a given primary key like so
IEnumerable <FileObject> files2 = await Client.GetObject("Property", "Photo", new PhotoId(1234, 1), false);
// you can get also get images for multiple primary keys at the same time like this
List <PhotoId> photoIds = new List <PhotoId>()
{
new PhotoId(1234), new PhotoId(5678), new PhotoId(2255)
};
IEnumerable <FileObject> files3 = await Client.GetObject("Property", "Photo", photoIds, false);
// When you are trying to download lots of images you must be very carfult. If you send the server too many ids at the same time
// the server may return 404, 414, 500 or something along these lines because the request is too long.
// Also, the server may take long time to response which will case the HTTP request to timeout.
// So solve for the timeout issue we can increate the HTTP timeout from ConnectionOptions() object.
// However, there is a better more reliable solution to this prblem which is the ability to batch the request into multiple request
// Assume we want to download images for 1000 properties. Assume that each property on average has 15 photos, this will result in downloading 1000 x 15 = 15,000 images
// We can split the 1000 properties into a smaller number like 100. This will make 10 (i.e 1000/100) request to the RETS server then return you an object of 15,000 images
// You may want to still be careful because there will be 15,000 stored in the memory, so make sure you're not going to run our of memory
// Anyhow, batching can easily be done like this
IEnumerable <FileObject> batchedFiles = await Client.GetObject("Property", "Photo", photoIds, batchSize : 100);
// Finally we can disconect
await Client.Disconnect();
// The above code require us to First connect, then Disconnect when we are done. Not too bad, but we can simplfy the call by using
// a method called RoundTrip() which will first connect, execure out code, then disconnect
// to save some code you can do call RoundTrip() which will connect, call out method, then discconnect();
IEnumerable <FileObject> files4 = await Client.RoundTrip(async() =>
{
// Each batch will cause a round trip. In other words, each batch will connect, download a batch, then disconnect.
return(await Client.GetObject("Property", "Photo", photoIds, batchSize: 20));
});
}
public async Task <RetsResourceCollection> GetResourcesMetadata()
{
RetsResourceCollection capsule = await MakeMetadataRequest <RetsResourceCollection>("METADATA-RESOURCE", "0");
return(capsule);
}
