Sharepoint Client Object Model Beginners Guide.

Recently I have been playing around with Sharepoint 2010 Client Object Model. To get started you will need to access and reference the client dll. They are

Microsoft.SharePoint.Client                                       

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\ISAPI\Microsoft.SharePoint.Client.dll

Microsoft.SharePoint.Client.Runtime                    

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\ISAPI\Microsoft.SharePoint.Client.Runtime.dll

Then to access the library

using Microsoft.SharePoint.Client;

When using this library to access Sharepoint you first create a ClientContext. Then you use the client context to load the queries. Once you are done doing this you then call the method ExecuteQuery.

Here is an example.

ClientContext clientContext = new ClientContext("http://intranet.contoso.com");

Web website = clientContext.Web;

WebCollection websiteCollections = clientContext.Web.Webs;

           

clientContext.Load(website);

clientContext.Load(websiteCollections);

clientContext.ExecuteQuery();

Console.WriteLine("Title: {0}", website.Title);

To recursive list through each folder we can do the following:

foreach (Web websubsites in websiteCollections)

{

Console.WriteLine("Web Sub Sites Title: {0} {1}", websubsites.Title, websubsites.ServerRelativeUrl);

FolderCollection websubsitesfolderCollection = websubsites.Folders;

clientContext.Load(websubsitesfolderCollection);

clientContext.ExecuteQuery();

webSubFolder(clientContext, websubsitesfolderCollection);

}

public static void webSubFolder(ClientContext clientContext, FolderCollection websubsitesfolderCollection)

{

foreach (Folder websubsitefolder in websubsitesfolderCollection)

{

Console.WriteLine("Web Sub Sites Folder:{0} Url:{1}", websubsitefolder.Name, websubsitefolder.ServerRelativeUrl);

FolderCollection websubsitesubfolderCollection = websubsitefolder.Folders;

clientContext.Load(websubsitesubfolderCollection);

clientContext.ExecuteQuery();

webSubFolder(clientContext, websubsitesubfolderCollection);

}

}

To upload a file to the Sharepoint Document Library we can use the code outlined below. Initially we will need FileCreationInformation. Then we attach the file by webSubsiteFolder.Files.Add

if (websubsitefolder.Name == "Shared Documents")

{

FileCreationInformation flciNewFile = new FileCreationInformation();

flciNewFile.Content = WriteSomeData().ToArray();

flciNewFile.Url = "UploadFile.txt";

flciNewFile.Overwrite = true;

File uploadFile = websubsitefolder.Files.Add(flciNewFile);

clientContext.Load(uploadFile);

clientContext.ExecuteQuery();

ListItem fileUploadedItem = uploadFile.ListItemAllFields;

fileUploadedItem["Title"] = "Breeze Document Upload";

fileUploadedItem.Update();

clientContext.ExecuteQuery();

}

public static System.IO.MemoryStream WriteSomeData()

{

System.IO.MemoryStream ms = new System.IO.MemoryStream();

System.IO.TextWriter txtw = new System.IO.StreamWriter(ms);

for (int i = 1;  i <= 20; i++)

{

txtw.WriteLine(string.Format("This is line {0}", i));

}

txtw.Flush();

ms.Seek(0, IO.SeekOrigin.Begin);

return ms;

}

WCF Proxy External to Internal and Avoid Serialization Overheads

In the past on numerous projects I had to consider application security as part of my overall software design and implementation. All internal systems that are required for the service are located in Internal Network layer protected by a firewall. The external world would not have direct access to the internal systems except via proxy from an designated external server to internal server.

The diagram below is a typical example of what this entails.

The External servers would only have access to the designated Internal Servers and from there the internal servers would do the processing and communicating to backend systems before responding back via the external systems.

The most efficient way I found to do this is to effect create a proxy External WCF service that would then forward that request to the internal systems without any serialization.

Essentially the method here being demonstrated is GetPrices.

Externally it will be exposed as

Message GetPrices(Message value);

Internally it will be the deserialized form of

GetPricesResponse GetPrices(GetPricesRequest request)

The conversion is done automatically by wcf. There are a few gotchas so please read the implementation especially around the message http headers. This is specific for wcf – rest services.

Let me demonstrate

First lets create an Interface called IGetPrices. It will be a REST WCF Service for this demonstration. It will have a method called GetPrices.

    [ServiceContract]

    public interface IGetPrices

    {

        [OperationContract(Action = "*", ReplyAction = "*")]

        [WebInvoke(Method = "POST", UriTemplate="", BodyStyle = WebMessageBodyStyle.Bare, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]

        Message GetPrices(Message value);

    }

Then the implementation will be as follows

        public Message GetPrices(Message msgRequest)

        {

     //THE EXTERNAL WCF SERVICE WILL CREATE NOW ACT AS A CLIENT TO CALL INTERNAL GETPRICES     

            InternalGetPricesClient igpcGetPrices = new InternalGetPricesClient();

            HttpRequestMessageProperty reqProperty = (HttpRequestMessageProperty)msgRequest.Properties[HttpRequestMessageProperty.Name];

            string strHeaderValue = "";

            for (int ihKey = 0; ihKey < reqProperty.Headers.Count; ihKey++)

            {

                strHeaderValue += reqProperty.Headers[ihKey];

            }

            System.Diagnostics.Debug.WriteLine("[GetPrices].External.Headers", strHeaderValue);

            //SOMETIMES EXTRA HEADERS CAN CAUSE AN ISSUE

            int ihFoundKey = 0;

            while (ihFoundKey < reqProperty.Headers.Count)

            {

                if ((reqProperty.Headers.GetKey(ihFoundKey).ToUpper() == "CONTENT-LENGTH") || (reqProperty.Headers.GetKey(ihFoundKey).ToUpper() == "CONTENT-TYPE"))

                {

                    ihFoundKey++;

                }

                else

                {

                    reqProperty.Headers.Remove(reqProperty.Headers.GetKey(ihFoundKey));

                    ihFoundKey = 0;

                }

            }

            //PASS CUSTOMISED HEADER TO INTERNAL CLIENT

            //WebOperationContext.Current.IncomingRequest.Headers.Add("AppFabricID", appFabric.ActivityID);

            msgRequest.Headers.To = igpcGetPrices.Endpoint.Address.Uri;

            msgRequest.Properties.Via = igpcGetPrices.Endpoint.Address.Uri;

            Message rspResponse = igpcGetPrices.GetPrices(msgRequest);

            //CAN CHECK RESPONSE HEADER TO SEE IF THERE IS AN ERROR

            HttpResponseMessageProperty respProperty = (HttpResponseMessageProperty)rspResponse.Properties[HttpResponseMessageProperty.Name];

            //if (respProperty.Headers["ERROR"] != null)

            //{

            //    throw new Exception(respProperty.Headers["ERROR"], HttpStatusCode.InternalServerError);

            //}

            rspResponse.Properties[HttpResponseMessageProperty.Name] = null;

            return rspResponse;

        }

Then the implementation for the external to internal client for InternalGetPricesClient igpcGetPrices = new InternalGetPricesClient(); will be.

    public partial class InternalGetPricesClient :  System.ServiceModel.ClientBase<IGetPrices>, IGetPrices

    {

        public InternalGetPricesClient()

        {

        }

        public InternalGetPricesClient(string endpointConfigurationName) :

            base(endpointConfigurationName)

        {

        }

        public InternalGetPricesClient(string endpointConfigurationName, string remoteAddress) :

            base(endpointConfigurationName, remoteAddress)

        {

        }

        public InternalGetPricesClient(string endpointConfigurationName, System.ServiceModel.EndpointAddress remoteAddress) :

            base(endpointConfigurationName, remoteAddress)

        {

        }

        public InternalGetPricesClient(System.ServiceModel.Channels.Binding binding, System.ServiceModel.EndpointAddress remoteAddress) :

            base(binding, remoteAddress)

        {

        }

        public Message GetPrices(Message request)

        {

            return base.Channel.GetPrices(request);

        }

    }

ALSO 

The Web.Config needs to be configured accordingly to configure the client accordingly.

<?xml version="1.0" encoding="utf-8"?>

<system.serviceModel>

       <serviceHostingEnvironment aspNetCompatibilityEnabled="true" />

       <bindings>

              <basicHttpBinding>

                     <binding name="soapBinding">

                           <security mode="None">

                           </security>

                     </binding>

              </basicHttpBinding>

              <webHttpBinding>

                     <binding name="webBinding">

                     </binding>

              </webHttpBinding>

       </bindings>

       <client>

              <endpoint name="Centrebet.PYOF.External.WCF.Interfaces.ExternalGetPricesClient"

                                  address="http://localhost:24984/GetPrices"

                                  binding="webHttpBinding"

                                  bindingConfiguration="webBinding"

                                  behaviorConfiguration="poxBehavior"

                                  contract="Centrebet.PYOF.External.Interfaces.IGetPrices"/>

       </client>

       <behaviors>

              <endpointBehaviors>

                     <!-- plain old XML -->

                     <behavior name="poxBehavior">

                           <webHttp/>

                     </behavior>

                     <!-- JSON -->

                     <behavior name="jsonBehavior">

                           <enableWebScript/>

                     </behavior>

                     <!-- <behavior name="ProtoBufSerializationBehavior">

                                  <ProtoBufSerialization/>

                                  </behavior> -->

              </endpointBehaviors>

              <serviceBehaviors>

                     <behavior>

                           <serviceThrottling maxConcurrentCalls="200" maxConcurrentSessions="200" maxConcurrentInstances="200"/>

                           <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->

                           <serviceMetadata httpGetEnabled="true"/>

                           <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->

                           <serviceDebug includeExceptionDetailInFaults="false"/>

                     </behavior>

              </serviceBehaviors>

       </behaviors>

</system.serviceModel>

Now for the Internal Server

It will now deserialize the following way

namespace Internal.WCF.Interfaces

{

    [ServiceBehavior(ConcurrencyMode=ConcurrencyMode.Multiple, InstanceContextMode=InstanceContextMode.PerCall)]

    [ServiceErrorBehavior(typeof(GetPricesErrorHandler))]

    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

    public class GetPricesService : IGetPrices

    {

        public GetPricesResponse GetPrices(GetPricesRequest request)

        {

            GetPricesResponse gprResponse = new GetPricesResponse();

            return gprResponse;

        }    

    }

}

Here is the implementation class.

namespace Internal.Interfaces

{

    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.

    [ServiceContract]

    public interface IGetPrices

    {

        [OperationContract(Action = "*", ReplyAction = "*")]

        [WebInvoke(Method = "POST", UriTemplate = "", BodyStyle = WebMessageBodyStyle.Bare, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]

        GetPricesResponse GetPrices(GetPricesRequest request);

    }

}

There you have it how to create a WCF Proxy External to Internal and Avoid Serialization Overheads