(PureBasic) 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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IncludeFile "CkBinData.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRest.pb"
IncludeFile "CkAuthAzureStorage.pb"
IncludeFile "CkFileAccess.pb"

Procedure ChilkatExample()

    ; 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.

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect to the Azure Storage Blob Service
    bTls.i = 1
    port.i = 443
    bAutoReconnect.i = 1
    ; In this example, the storage account name is "chilkat".
    success.i = CkRest::ckConnect(rest,"chilkat.file.core.windows.net",port,bTls,bAutoReconnect)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; This example will upload a larger file.
    localFilePath.s = "qa_data/zips/somethingBig.zip"
    fac.i = CkFileAccess::ckCreate()
    If fac.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.
    szLocalFile.i = CkFileAccess::ckFileSize(fac,localFilePath)
    If szLocalFile < 0
        Debug CkFileAccess::ckLastErrorText(fac)
        CkRest::ckDispose(rest)
        CkFileAccess::ckDispose(fac)
        ProcedureReturn
    EndIf

    ; Provide Azure Cloud credentials for the REST calls.
    azAuth.i = CkAuthAzureStorage::ckCreate()
    If azAuth.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkAuthAzureStorage::setCkAccessKey(azAuth, "AZURE_ACCESS_KEY")
    ; The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    CkAuthAzureStorage::setCkAccount(azAuth, "chilkat")
    CkAuthAzureStorage::setCkScheme(azAuth, "SharedKey")
    CkAuthAzureStorage::setCkService(azAuth, "File")
    ; This causes the "x-ms-version: 2020-08-04" header to be automatically added.
    CkAuthAzureStorage::setCkXMsVersion(azAuth, "2020-08-04")
    success = CkRest::ckSetAuthAzureStorage(rest,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:
    CkRest::ckAddHeader(rest,"x-ms-type","file")

    ; This required header specifies the final size of the file (or the maximum size it can be).
    sbFileSize.i = CkStringBuilder::ckCreate()
    If sbFileSize.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStringBuilder::ckAppendInt(sbFileSize,szLocalFile)
    CkRest::ckAddHeader(rest,"x-ms-content-length",CkStringBuilder::ckGetAsString(sbFileSize))

    ; 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"
    responseStr.s = CkRest::ckFullRequestNoBody(rest,"PUT","/pip/somethingBig.zip")
    If CkRest::ckLastMethodSuccess(rest) <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkFileAccess::ckDispose(fac)
        CkAuthAzureStorage::ckDispose(azAuth)
        CkStringBuilder::ckDispose(sbFileSize)
        ProcedureReturn
    EndIf

    ; 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 CkRest::ckResponseStatusCode(rest) <> 201
        ; Examine the request/response to see what happened.
        Debug "response status code = " + Str(CkRest::ckResponseStatusCode(rest))
        Debug "response status text = " + CkRest::ckResponseStatusText(rest)
        Debug "response header: " + CkRest::ckResponseHeader(rest)
        Debug "response body (if any): " + responseStr
        Debug "---"
        Debug "LastRequestStartLine: " + CkRest::ckLastRequestStartLine(rest)
        Debug "LastRequestHeader: " + CkRest::ckLastRequestHeader(rest)
        CkRest::ckDispose(rest)
        CkFileAccess::ckDispose(fac)
        CkAuthAzureStorage::ckDispose(azAuth)
        CkStringBuilder::ckDispose(sbFileSize)
        ProcedureReturn
    EndIf

    Debug "Successfully created somethingBig.zip"

    ; --------------------------------------------------------------------------------
    ; Upload the file data...

    ; Make sure the headers from the "Create File" operation are removed.
    CkRest::ckClearAllHeaders(rest)

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

    sbRange.i = CkStringBuilder::ckCreate()
    If sbRange.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    sbResponseBody.i = CkStringBuilder::ckCreate()
    If sbResponseBody.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    bdFileData.i = CkBinData::ckCreate()
    If bdFileData.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Open the file.  We'll be reading and uploading in chunks..
    success = CkFileAccess::ckOpenForRead(fac,localFilePath)
    If success <> 1
        Debug CkFileAccess::ckLastErrorText(fac)
        CkRest::ckDispose(rest)
        CkFileAccess::ckDispose(fac)
        CkAuthAzureStorage::ckDispose(azAuth)
        CkStringBuilder::ckDispose(sbFileSize)
        CkStringBuilder::ckDispose(sbRange)
        CkStringBuilder::ckDispose(sbResponseBody)
        CkBinData::ckDispose(bdFileData)
        ProcedureReturn
    EndIf

    numBytesLeft.i = szLocalFile
    curIndex.i = 0
    While numBytesLeft > 0

        chunkSize.i = numBytesLeft
        ; Azure allows for 4MB max chunks  (4 x 1024 x 1024 = 4194304)
        If chunkSize > 4194304
            chunkSize = 4194304
        EndIf

        ; 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
        CkStringBuilder::ckClear(sbRange)
        CkStringBuilder::ckAppend(sbRange,"bytes=")
        CkStringBuilder::ckAppendInt(sbRange,curIndex)
        CkStringBuilder::ckAppend(sbRange,"-")
        CkStringBuilder::ckAppendInt(sbRange,curIndex + chunkSize - 1)

        ; This replaces the header if it already exists..
        CkRest::ckAddHeader(rest,"x-ms-range",CkStringBuilder::ckGetAsString(sbRange))

        ; Read the next chunk from the local file.
        CkBinData::ckClear(bdFileData)
        success = CkFileAccess::ckFileReadBd(fac,chunkSize,bdFileData)

        success = CkRest::ckFullRequestBd(rest,"PUT","/pip/somethingBig.zip?comp=range",bdFileData,sbResponseBody)
        If success <> 1
            ; This would indicate a failure where no response was received.
            Debug CkRest::ckLastErrorText(rest)
            CkRest::ckDispose(rest)
            CkFileAccess::ckDispose(fac)
            CkAuthAzureStorage::ckDispose(azAuth)
            CkStringBuilder::ckDispose(sbFileSize)
            CkStringBuilder::ckDispose(sbRange)
            CkStringBuilder::ckDispose(sbResponseBody)
            CkBinData::ckDispose(bdFileData)
            ProcedureReturn
        EndIf

        ; A 201 response indicates the chunk was uploaded.
        If CkRest::ckResponseStatusCode(rest) <> 201
            ; Examine the request/response to see what happened.
            Debug "response status code = " + Str(CkRest::ckResponseStatusCode(rest))
            Debug "response status text = " + CkRest::ckResponseStatusText(rest)
            Debug "response header: " + CkRest::ckResponseHeader(rest)
            Debug "response body (if any): " + responseStr
            Debug "---"
            Debug "LastRequestStartLine: " + CkRest::ckLastRequestStartLine(rest)
            Debug "LastRequestHeader: " + CkRest::ckLastRequestHeader(rest)
            CkRest::ckDispose(rest)
            CkFileAccess::ckDispose(fac)
            CkAuthAzureStorage::ckDispose(azAuth)
            CkStringBuilder::ckDispose(sbFileSize)
            CkStringBuilder::ckDispose(sbRange)
            CkStringBuilder::ckDispose(sbResponseBody)
            CkBinData::ckDispose(bdFileData)
            ProcedureReturn
        EndIf

        Debug "Uploaded chunk from " + Str(curIndex) + " to " + Str(curIndex + chunkSize - 1)

        curIndex = curIndex + chunkSize
        numBytesLeft = numBytesLeft - chunkSize
    Wend

    CkFileAccess::ckFileClose(fac)

    Debug "success."


    CkRest::ckDispose(rest)
    CkFileAccess::ckDispose(fac)
    CkAuthAzureStorage::ckDispose(azAuth)
    CkStringBuilder::ckDispose(sbFileSize)
    CkStringBuilder::ckDispose(sbRange)
    CkStringBuilder::ckDispose(sbResponseBody)
    CkBinData::ckDispose(bdFileData)


    ProcedureReturn
EndProcedure