Pascal (Lazarus/Delphi)
Pascal (Lazarus/Delphi)
Facebook Download all Photos to Local Files
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Demonstrates how to download all of one's Facebook photos to a local filesystem directory. This sample code keeps a local cache to avoid re-downloading the same photos twice. The program can be run again after a time, and it will download only photos that haven't yet been downloaded.Chilkat Pascal (Lazarus/Delphi) Downloads
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.Http,
Chilkat.FileAccess,
Chilkat.OAuth2,
Chilkat.Rest,
Chilkat.JsonObject,
Chilkat.StringBuilder,
Chilkat.Cache,
Chilkat.StringArray;
// ---------------------------------------------------------------------------
procedure RunDemo;
var
success: Boolean;
fbCache: TCache;
oauth2: TOAuth2;
rest: TRest;
responseJson: string;
photoJson: TJsonObject;
saPhotoUrls: TStringArray;
sbPhotoIdPath: TStringBuilder;
json: TJsonObject;
i: Integer;
photoId: string;
imageUrl: string;
afterCursor: string;
numItems: Integer;
photoJsonStr: string;
imgUrlJson: TJsonObject;
http: THttp;
numUrls: Integer;
urlJson: TJsonObject;
imageBytes: TBytes;
fac: TFileAccess;
sbImageUrl: TStringBuilder;
extension: string;
sbLocalFilePath: TStringBuilder;
begin
success := False;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
// This example will use a local disk cache to avoid re-fetching the same
// photo id after it's been fetched once.
fbCache := TCache.Create;
// The cache will use 1 level of 256 sub-directories.
fbCache.Level := 1;
// Use a directory path that makes sense on your operating system..
fbCache.AddRoot('C:/fbCache');
// This example assumes a previously obtained an access token
oauth2 := TOAuth2.Create;
oauth2.AccessToken := 'FACEBOOK-ACCESS-TOKEN';
rest := TRest.Create;
// Connect to Facebook.
success := rest.Connect('graph.facebook.com',443,True,True);
if (success <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
// Provide the authentication credentials (i.e. the access key)
rest.SetAuthOAuth2(oauth2);
// There are two choices:
// We can choose to download the photos the person is tagged in or has uploaded
// by setting type to "tagged" or "uploaded".
rest.AddQueryParam('type','uploaded');
// To download all photos, we begin with an outer loop that iterates over
// the list of photo nodes in pages. Each page returned contains a list of
// photo node ids. Each photo node id must be retrieved to get the download URL(s)
// of the actual image.
// I don't know the max limit for the number of records that can be downloaded at once.
rest.AddQueryParam('limit','100');
// Get the 1st page of photos ids.
// See https://developers.facebook.com/docs/graph-api/reference/user/photos/ for more information.
responseJson := rest.FullRequestNoBody('GET','/v2.7/me/photos');
if (rest.LastMethodSuccess <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
photoJson := TJsonObject.Create;
saPhotoUrls := TStringArray.Create;
sbPhotoIdPath := TStringBuilder.Create;
json := TJsonObject.Create;
json.EmitCompact := False;
json.Load(responseJson);
// Get the "after" cursor.
afterCursor := json.StringOf('paging.cursors.after');
while json.LastMethodSuccess = True do
begin
WriteLn('-------------------');
WriteLn('afterCursor = ' + afterCursor);
// For each photo id in this page...
i := 0;
numItems := json.SizeOfArray('data');
while i < numItems do
begin
json.I := i;
photoId := json.StringOf('data[i].id');
WriteLn('photoId = ' + photoId);
// We need to fetch the JSON for this photo. Check to see if it's in the local disk cache,
// and if not, then get it from Facebook.
photoJsonStr := fbCache.FetchText(photoId);
if (fbCache.LastMethodSuccess = False) then
begin
// It's not locally available, so get it from Facebook..
sbPhotoIdPath.Clear();
sbPhotoIdPath.Append('/v2.7/');
sbPhotoIdPath.Append(photoId);
rest.ClearAllQueryParams();
rest.AddQueryParam('fields','id,album,images');
WriteLn('Fetching photo node from Facebook...');
// This REST request will continue using the existing connection.
// If the connection was closed, it will automatically reconnect to send the request.
photoJsonStr := rest.FullRequestNoBody('GET',sbPhotoIdPath.GetAsString());
if (rest.LastMethodSuccess <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
// Add the photo JSON to the local cache.
fbCache.SaveTextNoExpire(photoId,'',photoJsonStr);
end;
// Parse the photo JSON and add the main photo download URL to saPhotoUrls
// There may be multiple URLs in the images array, but the 1st one is the largest and main photo URL.
// The others are smaller sizes of the same photo.
photoJson.Load(photoJsonStr);
imageUrl := photoJson.StringOf('images[0].source');
if (photoJson.LastMethodSuccess = True) then
begin
// Actually, we'll add a small JSON document that contains both the image ID and the URL.
imgUrlJson := TJsonObject.Create;
imgUrlJson.AppendString('id',photoId);
imgUrlJson.AppendString('url',imageUrl);
saPhotoUrls.Append(imgUrlJson.Emit());
WriteLn('imageUrl = ' + imageUrl);
end;
i := i + 1;
end;
// Prepare for getting the next page of photos ids.
// We can continue using the same REST object.
// If already connected, we'll continue using the existing connection.
// Otherwise, a new connection will automatically be made if needed.
rest.ClearAllQueryParams();
rest.AddQueryParam('type','uploaded');
rest.AddQueryParam('limit','20');
rest.AddQueryParam('after',afterCursor);
// Get the next page of photo ids.
responseJson := rest.FullRequestNoBody('GET','/v2.7/me/photos');
if (rest.LastMethodSuccess <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
json.Load(responseJson);
afterCursor := json.StringOf('paging.cursors.after');
end;
WriteLn('No more pages of photos.');
// Now iterate over the photo URLs and download each to a file.
// We can use Chilkat HTTP. No Facebook authorization (access token) is required to download
// the photo once the URL is known.
http := THttp.Create;
// We'll cache the image data so that if run again, we don't re-download the same image again.
numUrls := saPhotoUrls.Count;
i := 0;
urlJson := TJsonObject.Create;
fac := TFileAccess.Create;
while i < numUrls do
begin
urlJson.Load(saPhotoUrls.GetString(i));
photoId := urlJson.StringOf('id');
imageUrl := urlJson.StringOf('url');
// Check the local cache for the image data.
// Only download and save if not already cached.
imageBytes := fbCache.FetchFromCache(imageUrl);
if (fbCache.LastMethodSuccess = False) then
begin
// This photo needs to be downloaded.
sbImageUrl := TStringBuilder.Create;
sbImageUrl.Append(imageUrl);
// Let's form a filename..
extension := '.jpg';
if (sbImageUrl.Contains('.gif',False) = True) then
begin
extension := '.gif';
end;
if (sbImageUrl.Contains('.png',False) = True) then
begin
extension := '.png';
end;
if (sbImageUrl.Contains('.tiff',False) = True) then
begin
extension := '.tiff';
end;
if (sbImageUrl.Contains('.bmp',False) = True) then
begin
extension := '.bmp';
end;
sbLocalFilePath := TStringBuilder.Create;
sbLocalFilePath.Append('C:/Photos/facebook/uploaded/');
sbLocalFilePath.Append(photoId);
sbLocalFilePath.Append(extension);
imageBytes := http.QuickGet(imageUrl);
if (http.LastMethodSuccess <> True) then
begin
WriteLn(http.LastErrorText);
Exit;
end;
// We've downloaded the photo image bytes into memory.
// Save it to the cache AND save it to the output file.
fbCache.SaveToCacheNoExpire(imageUrl,'',imageBytes);
fac.WriteEntireFile(sbLocalFilePath.GetAsString(),imageBytes);
WriteLn('Downloaded to ' + sbLocalFilePath.GetAsString());
end;
i := i + 1;
end;
WriteLn('Finished downloading all Facebook photos!');
fbCache.Free;
oauth2.Free;
rest.Free;
photoJson.Free;
saPhotoUrls.Free;
sbPhotoIdPath.Free;
json.Free;
imgUrlJson.Free;
http.Free;
urlJson.Free;
fac.Free;
sbImageUrl.Free;
sbLocalFilePath.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.