(Tcl) Download a SharePoint File by Path using HttpCurl

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This example shows how to use Chilkat's HttpCurl class to download a file from SharePoint when the file path within the document library is already known. The example uses Microsoft Graph to automatically resolve the SharePoint site name to a site ID, find the drive ID for the Documents document library, and then download the file directly by path using the Graph root:/path:/content syntax.

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load ./chilkat.dll

set success 0

# This example downloads a file from a SharePoint Documents document library
# when the file's path within the library is already known.
# 
# The file downloaded in this example is:
# 
#   images/sea_creatures/starfish.jpg
# 
# Unlike the previous example  that searched for a file by name and obtained
# its Microsoft Graph item ID, this example uses the Graph path-based API.
# 
# The example demonstrates how HttpCurl automatically resolves:
# 
#   site_name  -> site_id
#   site_id    -> document_library_id
# 
# and then uses the known file path to download the file directly.

set success 0

# --------------------------------------------------------------------------------------------------------
# Before running this example, create an Azure App Registration and grant it
# the Microsoft Graph permissions required to access SharePoint.
# 
# The application will authenticate using OAuth2 Client Credentials.
# See:
# How to Create SharePoint App Registration for OAuth 2.0 Client Credentials
# --------------------------------------------------------------------------------------------------------

# Build a JSON authentication configuration.
# HttpCurl will use this information to automatically obtain OAuth2 access tokens.
set jsonAuth [new_CkJsonObject]

# Enable secret lookup.
# 
# Instead of hard-coding sensitive values such as the client ID,
# client secret, and token endpoint, secret specification strings
# are used.  Chilkat automatically retrieves the actual values from
# Windows Credential Manager (Windows) or Apple Keychain (macOS).
# 
# See:
# Secret Specification Strings
CkJsonObject_put_EnableSecrets $jsonAuth 1

set success [CkJsonObject_UpdateString $jsonAuth "oauth2.client_id" "!!sharepoint|oauth2|client_id"]
if {$success == 1} then {
    set success [CkJsonObject_UpdateString $jsonAuth "oauth2.client_secret" "!!sharepoint|oauth2|client_secret"]
}

if {$success == 1} then {
    set success [CkJsonObject_UpdateString $jsonAuth "oauth2.token_endpoint" "!!sharepoint|oauth2|token_endpoint"]
}

if {$success == 0} then {
    puts [CkJsonObject_lastErrorText $jsonAuth]
    delete_CkJsonObject $jsonAuth
    exit
}

# Request Microsoft Graph permissions that were granted to the application.
CkJsonObject_UpdateString $jsonAuth "oauth2.scope" "https://graph.microsoft.com/.default"

# ---------------------------------------------------------------------------------------------------

set curl [new_CkHttpCurl]

# Associate the OAuth2 configuration with HttpCurl.
# 
# When the request is executed, Chilkat automatically obtains an access token
# if needed and adds the Authorization: Bearer header to the HTTP request.
CkHttpCurl_SetAuth $curl $jsonAuth

# Define values that are already known.
# 
# These variables are referenced in curl commands using
# {{variable_name}} substitution syntax.
CkHttpCurl_SetVar $curl "sharepoint_hostname" "example.sharepoint.com"
CkHttpCurl_SetVar $curl "site_name" "test"

# The download request requires a Microsoft Graph site ID.
# 
# Because the application only knows the SharePoint site name,
# define a helper function that can retrieve the site information.
CkHttpCurl_AddFunction $curl "getSite" "GET https://graph.microsoft.com/v1.0/sites/root:/sites/{{site_name}}"

# Extract the site's ID and store it in the HttpCurl variable named site_id.
CkHttpCurl_AddOutput $curl "getSite" "id" "site_id"

# The download request also requires the drive ID of the Documents
# document library.
# 
# Microsoft Graph refers to document libraries as "drives".
CkHttpCurl_AddFunction $curl "getDrives" "GET https://graph.microsoft.com/v1.0/sites/{{site_id}}/drives"

# Search the returned drives for the one named "Documents"
# and save its drive ID in the document_library_id variable.
CkHttpCurl_AddOutput2 $curl "getDrives" "value" "name" "Documents" 1 "id" "document_library_id"

# This is the target Microsoft Graph request.
# 
# GET /sites/{site-id}/drives/{drive-id}/root:/{path-to-file}:/content
# 
# The path-based API allows a file to be downloaded directly when its
# location within the document library is known.
# 
# The -L option causes HttpCurl to follow redirects.
# Microsoft Graph typically returns a redirect to the actual download URL.
# 
# The -o option specifies the output filename.
# The --output-dir option specifies the directory where the downloaded
# file will be saved.
set curlCommand "GET -L --output-dir c:/temp/qa_output -o starfish.jpg https://graph.microsoft.com/v1.0/sites/{{site_id}}/drives/{{document_library_id}}/root:/images/sea_creatures/starfish.jpg:/content"

# Execute the request.
# 
# HttpCurl examines the target request and determines that both
# site_id and document_library_id are required.
# 
# To obtain these values, it automatically builds and executes
# the following dependency chain:
# 
#   1) getSite    -> site_id
#   2) getDrives  -> document_library_id
#   3) download   -> file content
# 
# The file is streamed directly to the output file specified by
# the curl command.
set success [CkHttpCurl_DoYourThing $curl $curlCommand]
if {$success == 0} then {
    puts [CkHttpCurl_lastErrorText $curl]
    delete_CkJsonObject $jsonAuth
    delete_CkHttpCurl $curl
    exit
}

# A successful Graph response should return HTTP 200.
# Any other status code typically indicates an authentication,
# permission, site lookup, document library lookup, or file lookup error.
set statusCode [CkHttpCurl_get_StatusCode $curl]
if {$statusCode != 200} then {
    puts [CkHttpCurl_responseBodyStr $curl]
    puts "status code = $statusCode"
    delete_CkJsonObject $jsonAuth
    delete_CkHttpCurl $curl
    exit
}

# The file has been downloaded successfully and written to:
# 
#   c:/temp/qa_output/starfish.jpg
# 
puts "Success."

delete_CkJsonObject $jsonAuth
delete_CkHttpCurl $curl