(Tcl) OneDrive -- Streaming REST Download to File

Downloads the contents of a DriveItem directly to a file in the local filesystem using the Chilkat REST class.

Note: This example requires Chilkat v9.5.0.69 or greater.

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load ./chilkat.dll

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

set rest [new_CkRest]

#  Use your previously obtained access token here:
#  See the following examples for getting an access token:
#     Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
#     Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
#     Refresh Access Token (Azure AD v2.0 Endpoint).
#     Refresh Access Token (Azure AD Endpoint).

#  First connect to graph.microsoft.com.  If there's a connectivity problem, we'll find out here.
set success [CkRest_Connect $rest "graph.microsoft.com" 443 1 1]
if {[expr $success != 1]} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    exit
}

#  (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
set oauth2 [new_CkOAuth2]

CkOAuth2_put_AccessToken $oauth2 "MICROSOFT_GRAPH_ACCESS_TOKEN"
CkRest_SetAuthOAuth2 $rest $oauth2

#  Send the GET request to download the file.
set uriPath "/v1.0/me/drive/root:/Misc/wildlife/penguins.jpg:/content"
set success [CkRest_SendReqNoBody $rest "GET" $uriPath]
if {[expr [CkRest_get_LastMethodSuccess $rest] != 1]} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkOAuth2 $oauth2
    exit
}

#  NOTE: This way of doing the HTTP GET (i.e. download) may be more cumbersome, but it
#  allows for finer control of handling errors.  The connection establishment, the sending of the
#  request, the reading of the response header, and the reading of the response body (i.e. the file data)
#  are handled by separate method calls.  If the response header indicates an error, we can read
#  the response body and treat it differently than if reading the file data.

#  Read the response header.
set statusCode [CkRest_ReadResponseHeader $rest]
puts "Response Status Code = $statusCode"
if {[expr $statusCode == 302]} then {
    #  This is a redirect.  Read the response body, if any, and then follow the redirect.
    #  Usually the response body will be empty for a redirect, but we need to be sure to read
    #  the response body just in case it exists.
    set discard [new_CkBinData]

    [CkRest_ReadRespBd $rest $discard]
    [CkRest_Disconnect $rest 10]

    #  For OneDrive, the redirect URL does not need authorization because the only way
    #  to have obtained the direct download URL is from an authenticated request.
    #  In fact, if we leave the authentication present, the GET request to the redirect URL will fail.

    #  Note: The ClearAuth method is introduced in v9.5.0.69.
    [CkRest_ClearAuth $rest]

    #  Follow the redirect URL...
    # redirectUrl is a CkUrl
    set redirectUrl [CkRest_RedirectUrl $rest]
    puts "Redirect Host: [CkUrl_host $redirectUrl]"
    puts "Redirect URI Path: [CkUrl_pathWithQueryParams $redirectUrl]"

    set success [CkRest_Connect $rest [CkUrl_host $redirectUrl] [CkUrl_get_Port $redirectUrl] [CkUrl_get_Ssl $redirectUrl] 1]
    if {[expr $success != 1]} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkOAuth2 $oauth2
        delete_CkBinData $discard
        exit
    }

    #  Send the request..
    set success [CkRest_SendReqNoBody $rest "GET" [CkUrl_path $redirectUrl]]
    delete_CkUrl $redirectUrl

    if {[expr [CkRest_get_LastMethodSuccess $rest] != 1]} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkOAuth2 $oauth2
        delete_CkBinData $discard
        exit
    }

    set statusCode [CkRest_ReadResponseHeader $rest]
    puts [CkRest_lastErrorText $rest]
    puts "Redirect Response Status Code = $statusCode"

}

if {[expr $statusCode >= 300]} then {

    #  Read the error response body.
    set sbJson [new_CkStringBuilder]

    set success [CkRest_ReadRespSb $rest $sbJson]
    if {[expr $success != 1]} then {
        puts [CkRest_lastErrorText $rest]
        delete_CkRest $rest
        delete_CkOAuth2 $oauth2
        delete_CkBinData $discard
        delete_CkStringBuilder $sbJson
        exit
    }

    set jsonErr [new_CkJsonObject]

    CkJsonObject_put_EmitCompact $jsonErr 0
    [CkJsonObject_LoadSb $jsonErr $sbJson]
    puts [CkJsonObject_emit $jsonErr]

    delete_CkRest $rest
    delete_CkOAuth2 $oauth2
    delete_CkBinData $discard
    delete_CkStringBuilder $sbJson
    delete_CkJsonObject $jsonErr
    exit
}

#  Stream the response body directly to a local file.
set localPath "qa_output/penguins.jpg"

set stream [new_CkStream]

CkStream_put_SinkFile $stream $localPath

set success [CkRest_ReadRespBodyStream $rest $stream 1]
if {[expr $success != 1]} then {
    puts [CkRest_lastErrorText $rest]
    delete_CkRest $rest
    delete_CkOAuth2 $oauth2
    delete_CkBinData $discard
    delete_CkStringBuilder $sbJson
    delete_CkJsonObject $jsonErr
    delete_CkStream $stream
    exit
}

puts "Successfully streamed a OneDrive file to the local filesystem."

delete_CkRest $rest
delete_CkOAuth2 $oauth2
delete_CkBinData $discard
delete_CkStringBuilder $sbJson
delete_CkJsonObject $jsonErr
delete_CkStream $stream