Setting and Retrieving the Properties of a Job
The owner of the job or a user with administrator privileges can set and retrieve the properties of the job at any time. For a complete list of properties that you can set and retrieve, see the IBackgroundCopyJob, IBackgroundCopyJob2, IBackgroundCopyJob3, and IBackgroundCopyJob4 interfaces.
Files also contain properties. For information on how to retrieve a file and its properties from a job, see Enumerating Files in a Job.
To transfer files, you do not need to change the default values of the job's properties—BITS uses default values that are appropriate for the typical application.
Setting the properties of a job
The following example shows how to set the properties that your application is most likely to change: priority, notify interface, notify flags, and reply file name. The example assumes the IBackgroundCopyJob interface pointer, pJob, is valid.
HRESULT hr;
IBackgroundCopyJob* pJob;
IBackgroundCopyJob4* pJob4 = NULL;
CNotifyInterface *pNotify = new CNotifyInterface();
hr = pJob->QueryInterface(__uuidof(IBackgroundCopyJob4), (void**)&pJob4);
pJob->Release();
//The default priority level for a job is BG_JOB_PRIORITY_NORMAL.
hr = pJob4->SetPriority(BG_JOB_PRIORITY_HIGH);
if (FAILED(hr))
{
//Handle error
}
//By default, an application must poll BITS for the status of a job.
//To specify an IBackgroundCopyCallback interface pointer that receives event
//notification based on the value of the notify flags property, set the notify
//interface property. For details on the CNotifyInterface example class, see the
//IBackgroundCopyCallback interface in the reference section.
hr = pJob4->SetNotifyInterface(pNotify);
if (SUCCEEDED(hr))
{
hr = pJob4->SetNotifyFlags(BG_NOTIFY_JOB_TRANSFERRED |
BG_NOTIFY_JOB_ERROR);
}
pNotify->Release();
if (FAILED(hr))
{
//Handle error - failed to setup notification callbacks
}
//Only set the reply file name if the job's type is BG_JOB_TYPE_UPLOAD_REPLY.
//If you do not set the file name before calling the IBackgroundCopyJob::Resume
//method, BITS generates a file name for you; the directory is the same as that
//specified for the local file name (the file being uploaded). To retrieve the
//file name, call the IBackgroundCopyJob2::GetReplyFileName method.
hr = pJob4->SetReplyFileName(L"<REPLYPATHGOESHERE>");
if (FAILED(hr))
{
//Handle error
}
pJob4->Release();
By default, BITS downloads content from the origin server. To download content from a peer, both the computer and the job must enable peer caching. To enable peer caching on the computer, set the EnablePeerCaching group policy setting. You can also call the IBitsPeerCacheAdministration::SetConfigurationFlags method to enable peer caching on the computer; however, the preference setting is overridden by the policy, if set. To enable peer caching for the job, you must call the IBackgroundCopyJob4::SetPeerCachingFlags method.
To specify custom headers, a client certificate for client authentication, and HTTP options like redirection policy, CRL checking, and specifying which certificate errors to ignore, use the IBackgroundCopyJobHttpOptions interface. To get the IBackgroundCopyJobHttpOptions interface, query any of the IBackgroundCopyJob interfaces.
Retrieving the properties of a job
The following example shows how to retrieve the display name, owner, progress, and state property values of a job. The example assumes the IBackgroundCopyJob interface pointer, pJob, is valid.
HRESULT hr;
IBackgroundCopyJob* pJob;
WCHAR* pszJobName = NULL;
WCHAR* pszOwnerSid = NULL;
BOOL bResult;
DWORD dwNameSize = 0;
DWORD dwDomainSize = 0;
WCHAR* pszName = NULL;
WCHAR* pszDomain = NULL;
WCHAR* pszFullOwnerName = NULL;
PSID pSid = NULL;
SID_NAME_USE eNameUse;
BG_JOB_PROGRESS Progress;
int PercentOfFiles = 0;
BG_JOB_PRIORITY Priority;
BG_JOB_STATE State;
//WCHAR *JobStates[] = { L"Queued", L"Connecting", L"Transferring",
// L"Suspended", L"Error", L"Transient Error",
// L"Transferred", L"Acknowledged", L"Canceled"
// };
//Name of the job to use in the user interface. The name is set when you
//create the job. You can use the SetDisplayName method to change the name.
hr = pJob->GetDisplayName(&pszJobName);
if (SUCCEEDED(hr))
{
//Use the name in a user interface or output.
CoTaskMemFree(pszJobName);
}
//The owner property contains the SID of the job's owner. The following code
//shows how to get the domain and user names associated with the SID.
hr = pJob->GetOwner(&pszOwnerSID);
if (SUCCEEDED(hr))
{
bResult = ConvertStringSidToSid(pszOwnerSid, &pSid);
CoTaskMemFree(pszOwnerSid);
if (bResult)
{
//Call LookupAccountSid twice. The first call retrieves the buffer size
//for name and domain and the second call retrieves the actual name and domain.
LookupAccountSid(NULL, pSid, NULL, &cbNameSize,
NULL, &cbDomainSize, &eNameUse);
LastError = GetLastError();
if (ERROR_INSUFFICIENT_BUFFER == LastError)
{
pszName = (WCHAR*)malloc(sizeof(WCHAR) * cbNameSize);
pszDomain = (WCHAR*)malloc(sizeof(WCHAR) * cbDomainSize);
if (pszName && pszDomain)
{
bResult = LookupAccountSid(NULL, pSid, pszName, &cbNameSize,
pszDomain, &cbDomainSize, &eNameUse);
if (bResult)
{
pszFullName = (WCHAR*)malloc(sizeof(WCHAR)*(cbDomainSize+1+cbNameSize+1));
if (pszFullName)
{
StringCchPrintf(pszFullName, cbDomainSize+1+cbNameSize+1, L"%s\\%s", pszDomain, pszName);
//Do something with pszFullName.
free(pszFullName);
}
}
}
if (pszDomain)
free(pszDomain);
if(pszName)
free(pszName);
}
else
{
//Handle error - most likely ERROR_NONE_MAPPED, could not find the SID.
}
LocalFree(pSid);
}
}
//The state property identifies the current state of the job. For example, the
//state of the job is BG_JOB_STATE_TRANSFERRING or BG_JOB_STATE_ERROR.
hr = pJob->GetState(&State);
if (SUCCEEDED(hr))
{
//Use JobStates[State] to set the text representation of the job's
//state in a user interface.
}
//Use the information contained in the BG_JOB_PROGRESS structure to determine the
//overall progress of the job. The structure contains information on the number of
//bytes and files transferred.
hr = pJob->GetProgress(&Progress);
if (SUCCEEDED(hr))
{
//Determine the progress of the job based on the number of files transferred.
if (Progress.FilesTotal > 0)
{
PercentOfFiles = 100*Progress.FilesTransferred/Progress.FilesTotal
}
//For an example that shows determining the progress of the job based on the
//number of bytes transferred, see the topic Determing the Progress of a Job.
}