(C# UWP/WinRT) Azure File Service: Upload Large File

Sample code to upload a large file to a directory in a share in the Azure File Service. A file is uploaded by first creating the file in the Azure share and then writing ranges of bytes to the file. Azure imposes a 4MB limit for each PUT to write a range. Files larger than 4MB need to be uploaded by making multiple "Put Range" calls. This example uploads a large file requiring multiple "Put Range" calls.

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// Azure File Service Example: Upload a large file.  
// See:  https://docs.microsoft.com/en-us/rest/api/storageservices/create-share
// also see: https://docs.microsoft.com/en-us/rest/api/storageservices/put-range

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Chilkat.Rest rest = new Chilkat.Rest();

// Connect to the Azure Storage Blob Service
bool bTls = true;
int port = 443;
bool bAutoReconnect = true;
// In this example, the storage account name is "chilkat".
bool success = await rest.ConnectAsync("chilkat.file.core.windows.net",port,bTls,bAutoReconnect);
if (success != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// This example will upload a larger file.
string localFilePath = "qa_data/zips/somethingBig.zip";
Chilkat.FileAccess fac = new Chilkat.FileAccess();
// Note: The FileSize method returns a signed 32-bit integer.  If the file is potentially larger than 2GB, call FileSizeStr instead to return
// the size of the file as a string, then convert to an integer value.
int szLocalFile = fac.FileSize(localFilePath);
if (szLocalFile < 0) {
    Debug.WriteLine(fac.LastErrorText);
    return;
}

// Provide Azure Cloud credentials for the REST calls.
Chilkat.AuthAzureStorage azAuth = new Chilkat.AuthAzureStorage();
azAuth.AccessKey = "AZURE_ACCESS_KEY";
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
azAuth.Account = "chilkat";
azAuth.Scheme = "SharedKey";
azAuth.Service = "File";
// This causes the "x-ms-version: 2020-08-04" header to be automatically added.
azAuth.XMsVersion = "2020-08-04";
success = rest.SetAuthAzureStorage(azAuth);

// Note: The application does not need to explicitly set the following
// headers: x-ms-date, Authorization.  These headers
// are automatically set by Chilkat.

// However, a few additional headers are required for the "Create File" operation:
rest.AddHeader("x-ms-type","file");

// This required header specifies the final size of the file (or the maximum size it can be).
Chilkat.StringBuilder sbFileSize = new Chilkat.StringBuilder();
sbFileSize.AppendInt(szLocalFile);
rest.AddHeader("x-ms-content-length",sbFileSize.GetAsString());

// Send a PUT request to create the file (or replace the file if it already exists).
// This will initialize the file in the Azure file storage.  To upload content, we'll need
// to do the "Put Range" operation one or more times.

// The following will create the file "somethingBig.zip" in the share "pip"
string responseStr = await rest.FullRequestNoBodyAsync("PUT","/pip/somethingBig.zip");
if (rest.LastMethodSuccess != true) {
    Debug.WriteLine(rest.LastErrorText);
    return;
}

// When successful, the Azure File Service will respond with a 201 (Created) response status code,
// with no XML response body.  If an error response is returned, there will be an XML response body.

if (rest.ResponseStatusCode != 201) {
    // Examine the request/response to see what happened.
    Debug.WriteLine("response status code = " + Convert.ToString(rest.ResponseStatusCode));
    Debug.WriteLine("response status text = " + rest.ResponseStatusText);
    Debug.WriteLine("response header: " + rest.ResponseHeader);
    Debug.WriteLine("response body (if any): " + responseStr);
    Debug.WriteLine("---");
    Debug.WriteLine("LastRequestStartLine: " + rest.LastRequestStartLine);
    Debug.WriteLine("LastRequestHeader: " + rest.LastRequestHeader);
    return;
}

Debug.WriteLine("Successfully created somethingBig.zip");

// --------------------------------------------------------------------------------
// Upload the file data...

// Make sure the headers from the "Create File" operation are removed.
rest.ClearAllHeaders();

// The x-ms-write header is required for each "Put Range" request.
rest.AddHeader("x-ms-write","update");

Chilkat.StringBuilder sbRange = new Chilkat.StringBuilder();
Chilkat.StringBuilder sbResponseBody = new Chilkat.StringBuilder();
Chilkat.BinData bdFileData = new Chilkat.BinData();

// Open the file.  We'll be reading and uploading in chunks..
success = fac.OpenForRead(localFilePath);
if (success != true) {
    Debug.WriteLine(fac.LastErrorText);
    return;
}

int numBytesLeft = szLocalFile;
int curIndex = 0;
while (numBytesLeft > 0) {

    int chunkSize = numBytesLeft;
    // Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
    if (chunkSize > 4194304) {
        chunkSize = 4194304;
    }

    // The only tricky part here is to correctly add the x-ms-range header.
    // It will be formatted like this:
    // x-ms-range: bytes=0-759623
    sbRange.Clear();
    sbRange.Append("bytes=");
    sbRange.AppendInt(curIndex);
    sbRange.Append("-");
    sbRange.AppendInt(curIndex + chunkSize - 1);

    // This replaces the header if it already exists..
    rest.AddHeader("x-ms-range",sbRange.GetAsString());

    // Read the next chunk from the local file.
    bdFileData.Clear();
    success = fac.FileReadBd(chunkSize,bdFileData);

    success = await rest.FullRequestBdAsync("PUT","/pip/somethingBig.zip?comp=range",bdFileData,sbResponseBody);
    if (success != true) {
        // This would indicate a failure where no response was received.
        Debug.WriteLine(rest.LastErrorText);
        return;
    }

    // A 201 response indicates the chunk was uploaded.
    if (rest.ResponseStatusCode != 201) {
        // Examine the request/response to see what happened.
        Debug.WriteLine("response status code = " + Convert.ToString(rest.ResponseStatusCode));
        Debug.WriteLine("response status text = " + rest.ResponseStatusText);
        Debug.WriteLine("response header: " + rest.ResponseHeader);
        Debug.WriteLine("response body (if any): " + responseStr);
        Debug.WriteLine("---");
        Debug.WriteLine("LastRequestStartLine: " + rest.LastRequestStartLine);
        Debug.WriteLine("LastRequestHeader: " + rest.LastRequestHeader);
        return;
    }

    Debug.WriteLine("Uploaded chunk from " + Convert.ToString(curIndex) + " to " + Convert.ToString(curIndex + chunkSize - 1));

    curIndex = curIndex + chunkSize;
    numBytesLeft = numBytesLeft - chunkSize;
}

fac.FileClose();

Debug.WriteLine("success.");