public Customer AddCustomer(Customer customer)
{
lock (writeLock)
{
string id = (++counter).ToString();
// Set the Uri of the customer and add it to the colleciton
UriTemplate itemTemplate = WebOperationContext.Current.GetUriTemplate("GetCustomer");
customer.Uri = itemTemplate.BindByPosition(WebOperationContext.Current.IncomingRequest.UriTemplateMatch.BaseUri, id);
customers[id] = customer;
// initialize an etag for the newly added customer
long newEtag = DateTime.UtcNow.Ticks;
customerEtags[id] = newEtag;
// set the new etag in the response
WebOperationContext.Current.OutgoingResponse.SetETag(newEtag);
// update the etag for the customer collection since the list has changed (item added to it)
this.customerListEtag = DateTime.UtcNow.Ticks;
WebOperationContext.Current.OutgoingResponse.SetStatusAsCreated(customer.Uri);
}
return customer;
}
static void Main(string[] args)
{
using (WebServiceHost host = new WebServiceHost(typeof(Service), new Uri("http://localhost:8000/Customers")))
{
//WebServiceHost will automatically create a default endpoint at the base address using the WebHttpBinding
//and the WebHttpBehavior, so there's no need to set it up explicitly
host.Open();
Uri baseAddress = new Uri("http://localhost:8000/Customers");
Console.WriteLine("Service is hosted at: " + baseAddress.AbsoluteUri);
Console.WriteLine("Service help page is at: " + baseAddress.AbsoluteUri + "/help");
Console.WriteLine("");
Console.WriteLine("Adding some customers with POST:");
Customer alice = new Customer("Alice", "123 Pike Place", null);
Uri aliceLocation = PostCustomer(baseAddress, alice);
Customer bob = new Customer("Bob", "2323 Lake Shore Drive", null);
Uri bobLocation = PostCustomer(baseAddress, bob);
Console.WriteLine("");
Console.WriteLine("Using PUT to update a customer without specifying an Etag in the request. This will fail with error PreconditionFailed");
alice.Name = "Charlie";
alice.Uri = aliceLocation;
string aliceEtag = null;
try
{
PutCustomer(aliceLocation, alice, aliceEtag);
}
catch (WebException ex)
{
HttpWebResponse response = (HttpWebResponse)ex.Response;
Console.WriteLine("Request failed with error '{0}'", response.StatusCode);
aliceEtag = response.Headers[HttpResponseHeader.ETag];
}
Console.WriteLine("Retrying PUT to update a customer after specifying the latest Etag in the request. This will succeed");
PutCustomer(aliceLocation, alice, aliceEtag);
Console.WriteLine("");
Console.WriteLine("Using GET to retrieve the list of customers");
string customerListEtag = null;
List<Customer> customers = GetCustomers(baseAddress, ref customerListEtag);
foreach (Customer c in customers)
{
Console.WriteLine(c.ToString());
}
Console.WriteLine("Doing a conditional GET to retrieve the list of customers again. This will return NotMofified");
try
{
GetCustomers(baseAddress, ref customerListEtag);
}
catch (WebException ex)
{
HttpWebResponse response = (HttpWebResponse)ex.Response;
Console.WriteLine("Request failed with error '{0}'", response.StatusCode);
}
Console.WriteLine("");
Console.WriteLine("Using DELETE to delete a customer without specifying an Etag in the request. This will fail with error PreconditionFailed");
string bobEtag = null;
try
{
DeleteCustomer(bobLocation, bobEtag);
}
catch (WebException ex)
{
HttpWebResponse response = (HttpWebResponse)ex.Response;
Console.WriteLine("Request failed with error '{0}'", response.StatusCode);
bobEtag = response.Headers[HttpResponseHeader.ETag];
}
Console.WriteLine("Retrying DELETE with the latest Etag in the request. This will succeed");
DeleteCustomer(bobLocation, bobEtag);
Console.WriteLine("");
Console.WriteLine("Doing a conditional GET for final list of customers. This will not return NotModified since the etag for the customer list is stale");
customers = GetCustomers(baseAddress, ref customerListEtag);
foreach (Customer c in customers)
{
Console.WriteLine(c.ToString());
}
Console.WriteLine("");
Console.WriteLine("Press any key to terminate");
Console.ReadLine();
}
}
static void PutCustomer(Uri uri, Customer customer, string etag)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = "PUT";
request.ContentType = "application/xml";
request.Headers[HttpRequestHeader.IfMatch] = etag;
using (Stream requestStream = request.GetRequestStream())
{
customerSerializer.WriteObject(requestStream, customer);
}
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (Stream responseStream = response.GetResponseStream())
{
Customer updatedItem = (Customer)customerSerializer.ReadObject(responseStream);
Console.WriteLine(updatedItem.ToString());
}
response.Close();
}
static Uri PostCustomer(Uri uri, Customer customer)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = "POST";
request.ContentType = "application/xml";
using (Stream requestStream = request.GetRequestStream())
{
customerSerializer.WriteObject(requestStream, customer);
}
HttpWebResponse response = (HttpWebResponse) request.GetResponse();
using (Stream responseStream = response.GetResponseStream())
{
Customer createdItem = (Customer) customerSerializer.ReadObject(responseStream);
Console.WriteLine(createdItem.ToString());
}
response.Close();
return new Uri(response.Headers[HttpResponseHeader.Location]);
}
public Customer UpdateCustomer(string id, Customer newCustomer)
{
lock (writeLock)
{
// return NotFound if there is no item with the specified id.
object itemEtag = customerEtags[id];
if (itemEtag == null)
{
throw new WebFaultException(HttpStatusCode.NotFound);
}
// Return PreconditionFailed if the client request does not have an etag or has an old etag for the item
WebOperationContext.Current.IncomingRequest.CheckConditionalUpdate((long)itemEtag);
customers[id] = newCustomer;
// update the etag for the item since it has changed
long newEtag = DateTime.UtcNow.Ticks;
customerEtags[id] = newEtag;
// update the customer list etag since the item in the list has changed
this.customerListEtag = DateTime.UtcNow.Ticks;
// set the updated etag in the response
WebOperationContext.Current.OutgoingResponse.SetETag(newEtag);
return newCustomer;
}
}
