PowerBuilder

Download a File from a SharePoint Documents Library

See more SharePoint Examples

This example shows how to use Chilkat's HttpCurl class to download a file from the root of a SharePoint Documents document library. The example demonstrates how HttpCurl automatically resolves the SharePoint site name to a site ID, finds the drive ID for the Documents library, locates the file by name, and then downloads the file content using Microsoft Graph.

PowerBuilder

integer li_rc
long li_Success
oleobject loo_JsonAuth
oleobject loo_Curl
string ls_CurlCommand
long li_StatusCode
oleobject loo_SbFileContents

li_Success = 0

//  This example downloads a file named "hamlet.json" from the root of the SharePoint
//  Documents document library.
//  
//  The example demonstrates how HttpCurl can automatically resolve all of the
//  information needed to locate and download a file:
//  
//    site_name            -> site_id
//    site_id              -> document_library_id
//    document_library_id  -> file_id
//    file_id              -> file content
//  
//  The application only provides the SharePoint site name and the desired
//  filename.  HttpCurl automatically executes the required Microsoft Graph
//  requests to obtain the remaining values.

li_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.
loo_JsonAuth = create oleobject
li_rc = loo_JsonAuth.ConnectToNewObject("Chilkat.JsonObject")
if li_rc < 0 then
    destroy loo_JsonAuth
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  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
loo_JsonAuth.EnableSecrets = 1

li_Success = loo_JsonAuth.UpdateString("oauth2.client_id","!!sharepoint|oauth2|client_id")
if li_Success = 1 then
    li_Success = loo_JsonAuth.UpdateString("oauth2.client_secret","!!sharepoint|oauth2|client_secret")
end if

if li_Success = 1 then
    li_Success = loo_JsonAuth.UpdateString("oauth2.token_endpoint","!!sharepoint|oauth2|token_endpoint")
end if

if li_Success = 0 then
    Write-Debug loo_JsonAuth.LastErrorText
    destroy loo_JsonAuth
    return
end if

//  Request Microsoft Graph permissions that were granted to the application.
loo_JsonAuth.UpdateString("oauth2.scope","https://graph.microsoft.com/.default")

//  ---------------------------------------------------------------------------------------------------

loo_Curl = create oleobject
li_rc = loo_Curl.ConnectToNewObject("Chilkat.HttpCurl")

//  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.
loo_Curl.SetAuth(loo_JsonAuth)

//  Define values that are already known.
//  
//  These variables are referenced in curl commands using
//  {{variable_name}} substitution syntax.
loo_Curl.SetVar("sharepoint_hostname","example.sharepoint.com")
loo_Curl.SetVar("site_name","test")

//  The first step is to obtain the Microsoft Graph site ID.
//  
//  The application only knows the SharePoint site name, so define
//  a function that can retrieve the site information.
loo_Curl.AddFunction("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.
loo_Curl.AddOutput("getSite","id","site_id")

//  The next step is to find the Documents document library.
//  
//  Microsoft Graph refers to document libraries as "drives".
loo_Curl.AddFunction("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.
loo_Curl.AddOutput2("getDrives","value","name","Documents",1,"id","document_library_id")

//  Now list the contents of the Documents document library.
loo_Curl.AddFunction("getFiles","GET https://graph.microsoft.com/v1.0/sites/{{site_id}}/drives/{{document_library_id}}/root/children")

//  Search the returned files for an item named "hamlet.json"
//  and save its Microsoft Graph item ID in the file_id variable.
loo_Curl.AddOutput2("getFiles","value","name","hamlet.json",1,"id","file_id")

//  This is the target request.
//  
//  GET -L https://graph.microsoft.com/v1.0/drives/{{document_library_id}}/items/{{file_id}}/content
//  
//  The /content endpoint returns the actual contents of the file.
//  
//  The -L option instructs HttpCurl to follow the redirect returned by
//  Microsoft Graph.  The Graph API typically responds with a redirect
//  to the actual file download URL.
ls_CurlCommand = "GET -L https://graph.microsoft.com/v1.0/drives/{{document_library_id}}/items/{{file_id}}/content"

//  Execute the request.
//  
//  HttpCurl examines the target request and determines that both
//  document_library_id and file_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) getFiles     -> file_id
//    4) download     -> file content
//  
//  The final response returned by DoYourThing is the downloaded
//  file content from the target request.
li_Success = loo_Curl.DoYourThing(ls_CurlCommand)
if li_Success = 0 then
    Write-Debug loo_Curl.LastErrorText
    destroy loo_JsonAuth
    destroy loo_Curl
    return
end if

//  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.
li_StatusCode = loo_Curl.StatusCode
if li_StatusCode <> 200 then
    Write-Debug loo_Curl.ResponseBodyStr
    Write-Debug "status code = " + string(li_StatusCode)
    destroy loo_JsonAuth
    destroy loo_Curl
    return
end if

//  The response body contains the contents of the downloaded file.
loo_SbFileContents = create oleobject
li_rc = loo_SbFileContents.ConnectToNewObject("Chilkat.StringBuilder")

loo_Curl.GetResponseSb(loo_SbFileContents)

//  Optionally save the downloaded content to a local file.
//  
//  The third argument controls whether the file is appended.
//  Passing ckfalse causes the file to be overwritten if it already exists.
li_Success = loo_SbFileContents.WriteFile("c:/temp/hamlet.json","utf-8",0)
if li_Success = 0 then
    Write-Debug loo_SbFileContents.LastErrorText
    destroy loo_JsonAuth
    destroy loo_Curl
    destroy loo_SbFileContents
    return
end if

Write-Debug "Success."


destroy loo_JsonAuth
destroy loo_Curl
destroy loo_SbFileContents