Showing posts with label Repository Web Service. Show all posts
Showing posts with label Repository Web Service. Show all posts

Thursday, April 16, 2009

Calling Alfresco Web Services from C#

Hi,
I am starting this topic to share my experience of calling Alfresco Web Services from .Net, the problems which you may face and the solutions.
I first started with scratch. I created a C# project and added a Web reference to AuthenticationService (authentication-service.wsdl) , and VersioningService (VersioningService.wsdl).
Then I wrote following lines of code


WindowsApplication1.AuthenticationService.AuthenticationService asvc = new WindowsApplication1.AuthenticationService.AuthenticationService();
AuthenticationResult ar = asvc.startSession("admin", "admin");

It worked fine. Examining ar showed the token returned by Alfresco.
I then wrote the following lines

VersioningService vs = new VersioningService();
string repID = ("xyz");
string docID = ("abc");
string docRefId = docID;
bool b = vs.checkOut(repID, ref docRefId);

I was expecting an exception to be generated for giving invalid parameters, but the exception generated was about target service is null. It seems VersioningService is not exposed at URL/alfresco/api/VersioningService.
I then tried to add reference to RepositoryService (repository-service.wsdl ). Visual Studio reported a problem:
The document was understood, but it could not be processed. The WSDL document contains links that could not be resolved.
The solution was to remove the nillable attributes in cml.xsd files. After doing that, it was able to add the reference. I then wrote the following lines

RepositoryService rs = new RepositoryService();
rs.Credentials = asvc.Credentials;
Store[] stores = rs.getStores();


The exception which got generated was about Unauthorization. It was simple to figure out the cause, I was not passing in the security token, it was hard to figure out how to pass that. I was stuck.
I then googled and found out that there is demo project called dotNet2 for calling Alfresco APIs from .Net. I downloaded the same and tried to build it. It turned out that there was a missing reference to Microsoft.Web.Services3 assembly. Solution was to install MS WSE 3. So well and good.
I tried building the solution and there was a problem:

Error 1 The best overloaded method match for 'WebServiceFactory.addSecurityHeader(Microsoft.Web.Services3.WebServicesClientProtocol)' has some invalid arguments
Error 2 Argument '1': cannot convert from 'Alfresco.RepositoryWebService.RepositoryService' to 'Microsoft.Web.Services3.WebServicesClientProtocol'

I tried google to find out the solution for this, and I got one but it didn't work. A close observation revealed that addSecurityHeader was expecting Microsoft.Web.Services3.WebServicesClientProtocol object the service objects which we were passing were derived from SoapHttpClientProtocol class. I found that Microsoft.Web.Services3.WebServicesClientProtocol itself derives from SoapHttpClientProtocol, so I just let the web services class derive from Microsoft.Web.Services3.WebServicesClientProtocol and it worked!!
Then I tried to call getStores() method of RepositoryWebService and I again encountered exception. There was some problem in class instantiation from the returned response. Close observation again revealed the problem. The StoreEnum of RepositoryWebService was defined like this

public enum StoreEnum {
///
workspace,
///
versionStore,
///
user,
///
search,
///
http,
///
system,
}

I extended this enum to look like this

public enum StoreEnum {
///
workspace,
///
versionStore,
///
user,
///
search,
///
http,
///
system,
archive,
avm,
}

And after doing this, the call succeeded
Now my task was to test checking out of a selected file and getting a previous version of a selected file. After many hit and trials, I got it working and here is the reference code (I added private AuthoringService authoringService; to Browse class)
This is the code for Checking Out a selected file:
private void CheckOut_Click(object sender, EventArgs e)
{
ListViewItem item = listViewBrowse.SelectedItems[0];
if (item != null)
{
ResultSetRowNode node = item.Tag as ResultSetRowNode;
if (node != null)
{
if (node.type.Contains("folder") == false)
{
// Create the reference for the node selected
Alfresco.AuthoringWebService.Store spacesStore2 = new Alfresco.AuthoringWebService.Store();
spacesStore2.scheme = Alfresco.AuthoringWebService.StoreEnum.workspace;
spacesStore2.address = "SpacesStore";
Alfresco.AuthoringWebService.Reference reference = new Alfresco.AuthoringWebService.Reference();
reference.store = spacesStore2;
reference.uuid = node.id;
// Lets try to check out
Alfresco.AuthoringWebService.Predicate predicate = new Alfresco.AuthoringWebService.Predicate();
predicate.Items = new Object[] { reference };
Alfresco.AuthoringWebService.ParentReference pr = new Alfresco.AuthoringWebService.ParentReference();
pr.store = spacesStore2; ;
pr.uuid = this.currentReference.uuid;
pr.associationType = Constants.ASSOC_CONTAINS;
pr.childName = Constants.createQNameString(Constants.NAMESPACE_CONTENT_MODEL,item.Text);
this.authoringService.checkout(predicate, pr);
}
else
{
// show message that a folder has been selected
}
}
}
}


And this is the code for getting the original version of a file
private void GetOriginalVersion_Click(object sender, EventArgs e)
{
Alfresco.RepositoryWebService.Store[] stores = this.repoService.getStores();
Alfresco.RepositoryWebService.Store vStore = stores[3]; // from data,I found out that this is for Versioned store
ListViewItem item = listViewBrowse.SelectedItems[0];
if (item != null)
{
ResultSetRowNode node = item.Tag as ResultSetRowNode;
if (node != null)
{
if (node.type.Contains("folder") == false)
{
// Create the reference for the node selected
Alfresco.AuthoringWebService.Store spacesStore2 = new Alfresco.AuthoringWebService.Store();
spacesStore2.scheme = Alfresco.AuthoringWebService.StoreEnum.workspace;
spacesStore2.address = "SpacesStore";
Alfresco.AuthoringWebService.Reference reference = new Alfresco.AuthoringWebService.Reference();
reference.store = spacesStore2;
reference.uuid = node.id;
VersionHistory VH = this.authoringService.getVersionHistory(reference);
int i = 0;
char[] temp = new char[1];
temp[0] = '0';
string versions = new string(temp);
Alfresco.AuthoringWebService.Version first;
foreach (Alfresco.AuthoringWebService.Version version inVH.versions)
{
if (i == 0)
first = version;
versions += version.label + (";") + version.id.uuid +(";");
}
{
// Create the reference for the node selected
Alfresco.ContentWebService.Store spacesStore3 = new Alfresco.ContentWebService.Store();
spacesStore3.scheme = Alfresco.ContentWebService.StoreEnum.versionStore;
spacesStore3.address = vStore.address;
Alfresco.ContentWebService.Reference reference1 = newAlfresco.ContentWebService.Reference();
reference1.store = spacesStore3;
reference1.uuid = VH.versions[VH.versions.GetUpperBound(0)].id.uuid;
// Lets try and get the content
Alfresco.ContentWebService.Predicate predicate = newAlfresco.ContentWebService.Predicate();
predicate.Items = new Object[] { reference1 };
Content[] contents = this.contentService.read(predicate,"{http://www.alfresco.org/model/content/1.0}content");
Content content = contents[0];
if (content.url != null && content.url.Length != 0)
{
string url = content.url + "?ticket=" + AuthenticationUtils.Ticket;
webBrowser.Url = new Uri(url);
}
}
}
else
{
// show message that a folder has been selected
}
}
}
}

Here is the link for the Holy Grail dotNet2 Demo project
http://forge.alfresco.com/frs/download.php/80/alfresco-dotNet-0.2Beta.zip

And here is the the project which will allow you to do a Check Out and Get Latest version. it is an extended version of dotNet2 Demo project. You should be able to head start with it. Change the Alfresco Server location as per your requirement.

http://cid-f49e53911f11f3b1.skydrive.live.com/self.aspx/.Public/Technical/Alfresco/alfresco-dotNet-0.2Beta-Modified.zip

Thanks,