Pascal (Lazarus/Delphi)

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.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.HttpCurl,
  Chilkat.StringBuilder,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  jsonAuth: TJsonObject;
  curl: THttpCurl;
  curlCommand: string;
  statusCode: Integer;
  sbFileContents: TStringBuilder;

begin
  success := False;

  //  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.

  success := False;

  //  --------------------------------------------------------------------------------------------------------
  //  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.
  jsonAuth := TJsonObject.Create;

  //  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
  jsonAuth.EnableSecrets := True;

  success := jsonAuth.UpdateString('oauth2.client_id','!!sharepoint|oauth2|client_id');
  if (success = True) then
    begin
      success := jsonAuth.UpdateString('oauth2.client_secret','!!sharepoint|oauth2|client_secret');
    end;
  if (success = True) then
    begin
      success := jsonAuth.UpdateString('oauth2.token_endpoint','!!sharepoint|oauth2|token_endpoint');
    end;
  if (success = False) then
    begin
      WriteLn(jsonAuth.LastErrorText);
      Exit;
    end;

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

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

  curl := THttpCurl.Create;

  //  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.
  curl.SetAuth(jsonAuth);

  //  Define values that are already known.
  //  
  //  These variables are referenced in curl commands using
  //  {{variable_name}} substitution syntax.
  curl.SetVar('sharepoint_hostname','example.sharepoint.com');
  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.
  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.
  curl.AddOutput('getSite','id','site_id');

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

  //  Now list the contents of the Documents document library.
  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.
  curl.AddOutput2('getFiles','value','name','hamlet.json',True,'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.
  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.
  success := curl.DoYourThing(curlCommand);
  if (success = False) then
    begin
      WriteLn(curl.LastErrorText);
      Exit;
    end;

  //  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.
  statusCode := curl.StatusCode;
  if (statusCode <> 200) then
    begin
      WriteLn(curl.ResponseBodyStr);
      WriteLn('status code = ' + statusCode);
      Exit;
    end;

  //  The response body contains the contents of the downloaded file.
  sbFileContents := TStringBuilder.Create;
  curl.GetResponseSb(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.
  success := sbFileContents.WriteFile('c:/temp/hamlet.json','utf-8',False);
  if (success = False) then
    begin
      WriteLn(sbFileContents.LastErrorText);
      Exit;
    end;

  WriteLn('Success.');


  jsonAuth.Free;
  curl.Free;
  sbFileContents.Free;

end;

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

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.