(Unicode C) Facebook Download all Photos to Local Files

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.

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#include <C_CkCacheW.h>
#include <C_CkOAuth2W.h>
#include <C_CkRestW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkStringArrayW.h>
#include <C_CkStringBuilderW.h>
#include <C_CkHttpW.h>
#include <C_CkByteData.h>
#include <C_CkFileAccessW.h>

void ChilkatSample(void)
    {
    HCkCacheW fbCache;
    HCkOAuth2W oauth2;
    HCkRestW rest;
    BOOL success;
    const wchar_t *responseJson;
    HCkJsonObjectW photoJson;
    HCkStringArrayW saPhotoUrls;
    HCkStringBuilderW sbPhotoIdPath;
    HCkJsonObjectW json;
    int i;
    const wchar_t *photoId;
    const wchar_t *imageUrl;
    const wchar_t *afterCursor;
    int numItems;
    const wchar_t *photoJsonStr;
    HCkJsonObjectW imgUrlJson;
    HCkHttpW http;
    int numUrls;
    HCkJsonObjectW urlJson;
    HCkByteData imageBytes;
    HCkFileAccessW fac;
    HCkStringBuilderW sbImageUrl;
    const wchar_t *extension;
    HCkStringBuilderW sbLocalFilePath;

    // 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 = CkCacheW_Create();
    // The cache will use 1 level of 256 sub-directories.
    CkCacheW_putLevel(fbCache,1);
    // Use a directory path that makes sense on your operating system..
    CkCacheW_AddRoot(fbCache,L"C:/fbCache");

    // This example assumes a previously obtained an access token
    oauth2 = CkOAuth2W_Create();
    CkOAuth2W_putAccessToken(oauth2,L"FACEBOOK-ACCESS-TOKEN");

    rest = CkRestW_Create();

    // Connect to Facebook.
    success = CkRestW_Connect(rest,L"graph.facebook.com",443,TRUE,TRUE);
    if (success != TRUE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkCacheW_Dispose(fbCache);
        CkOAuth2W_Dispose(oauth2);
        CkRestW_Dispose(rest);
        return;
    }

    // Provide the authentication credentials (i.e. the access key)
    CkRestW_SetAuthOAuth2(rest,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".
    CkRestW_AddQueryParam(rest,L"type",L"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.
    CkRestW_AddQueryParam(rest,L"limit",L"100");

    // Get the 1st page of photos ids.
    // See https://developers.facebook.com/docs/graph-api/reference/user/photos/ for more information.
    responseJson = CkRestW_fullRequestNoBody(rest,L"GET",L"/v2.7/me/photos");
    if (CkRestW_getLastMethodSuccess(rest) != TRUE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkCacheW_Dispose(fbCache);
        CkOAuth2W_Dispose(oauth2);
        CkRestW_Dispose(rest);
        return;
    }

    photoJson = CkJsonObjectW_Create();
    saPhotoUrls = CkStringArrayW_Create();
    sbPhotoIdPath = CkStringBuilderW_Create();

    json = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(json,FALSE);
    CkJsonObjectW_Load(json,responseJson);

    // Get the "after" cursor.
    afterCursor = CkJsonObjectW_stringOf(json,L"paging.cursors.after");
    while (CkJsonObjectW_getLastMethodSuccess(json) == TRUE) {

        wprintf(L"-------------------\n");
        wprintf(L"afterCursor = %s\n",afterCursor);

        // For each photo id in this page...
        i = 0;
        numItems = CkJsonObjectW_SizeOfArray(json,L"data");
        while (i < numItems) {
            CkJsonObjectW_putI(json,i);
            photoId = CkJsonObjectW_stringOf(json,L"data[i].id");
            wprintf(L"photoId = %s\n",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 = CkCacheW_fetchText(fbCache,photoId);
            if (CkCacheW_getLastMethodSuccess(fbCache) == FALSE) {
                // It's not locally available, so get it from Facebook..
                CkStringBuilderW_Clear(sbPhotoIdPath);
                CkStringBuilderW_Append(sbPhotoIdPath,L"/v2.7/");
                CkStringBuilderW_Append(sbPhotoIdPath,photoId);

                CkRestW_ClearAllQueryParams(rest);
                CkRestW_AddQueryParam(rest,L"fields",L"id,album,images");

                wprintf(L"Fetching photo node from Facebook...\n");

                // This REST request will continue using the existing connection.
                // If the connection was closed, it will automatically reconnect to send the request.
                photoJsonStr = CkRestW_fullRequestNoBody(rest,L"GET",CkStringBuilderW_getAsString(sbPhotoIdPath));
                if (CkRestW_getLastMethodSuccess(rest) != TRUE) {
                    wprintf(L"%s\n",CkRestW_lastErrorText(rest));
                    CkCacheW_Dispose(fbCache);
                    CkOAuth2W_Dispose(oauth2);
                    CkRestW_Dispose(rest);
                    CkJsonObjectW_Dispose(photoJson);
                    CkStringArrayW_Dispose(saPhotoUrls);
                    CkStringBuilderW_Dispose(sbPhotoIdPath);
                    CkJsonObjectW_Dispose(json);
                    return;
                }

                // Add the photo JSON to the local cache.
                CkCacheW_SaveTextNoExpire(fbCache,photoId,L"",photoJsonStr);
            }

            // 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.
            CkJsonObjectW_Load(photoJson,photoJsonStr);
            imageUrl = CkJsonObjectW_stringOf(photoJson,L"images[0].source");
            if (CkJsonObjectW_getLastMethodSuccess(photoJson) == TRUE) {

                // Actually, we'll add a small JSON document that contains both the image ID and the URL.
                imgUrlJson = CkJsonObjectW_Create();
                CkJsonObjectW_AppendString(imgUrlJson,L"id",photoId);
                CkJsonObjectW_AppendString(imgUrlJson,L"url",imageUrl);
                CkStringArrayW_Append(saPhotoUrls,CkJsonObjectW_emit(imgUrlJson));
                wprintf(L"imageUrl = %s\n",imageUrl);
            }

            i = i + 1;
        }

        // 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.
        CkRestW_ClearAllQueryParams(rest);
        CkRestW_AddQueryParam(rest,L"type",L"uploaded");
        CkRestW_AddQueryParam(rest,L"limit",L"20");
        CkRestW_AddQueryParam(rest,L"after",afterCursor);

        // Get the next page of photo ids.
        responseJson = CkRestW_fullRequestNoBody(rest,L"GET",L"/v2.7/me/photos");
        if (CkRestW_getLastMethodSuccess(rest) != TRUE) {
            wprintf(L"%s\n",CkRestW_lastErrorText(rest));
            CkCacheW_Dispose(fbCache);
            CkOAuth2W_Dispose(oauth2);
            CkRestW_Dispose(rest);
            CkJsonObjectW_Dispose(photoJson);
            CkStringArrayW_Dispose(saPhotoUrls);
            CkStringBuilderW_Dispose(sbPhotoIdPath);
            CkJsonObjectW_Dispose(json);
            CkJsonObjectW_Dispose(imgUrlJson);
            return;
        }

        CkJsonObjectW_Load(json,responseJson);
        afterCursor = CkJsonObjectW_stringOf(json,L"paging.cursors.after");
    }

    wprintf(L"No more pages of photos.\n");

    // 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 = CkHttpW_Create();

    // We'll cache the image data so that if run again, we don't re-download the same image again.
    numUrls = CkStringArrayW_getCount(saPhotoUrls);
    i = 0;
    urlJson = CkJsonObjectW_Create();
    imageBytes = CkByteData_Create();
    fac = CkFileAccessW_Create();

    while (i < numUrls) {
        CkJsonObjectW_Load(urlJson,CkStringArrayW_getString(saPhotoUrls,i));
        photoId = CkJsonObjectW_stringOf(urlJson,L"id");
        imageUrl = CkJsonObjectW_stringOf(urlJson,L"url");

        // Check the local cache for the image data.
        // Only download and save if not already cached.
        success = CkCacheW_FetchFromCache(fbCache,imageUrl,imageBytes);
        if (CkCacheW_getLastMethodSuccess(fbCache) == FALSE) {
            //  This photo needs to be downloaded.

            sbImageUrl = CkStringBuilderW_Create();
            CkStringBuilderW_Append(sbImageUrl,imageUrl);

            // Let's form a filename..
            extension = L".jpg";
            if (CkStringBuilderW_Contains(sbImageUrl,L".gif",FALSE) == TRUE) {
                extension = L".gif";
            }

            if (CkStringBuilderW_Contains(sbImageUrl,L".png",FALSE) == TRUE) {
                extension = L".png";
            }

            if (CkStringBuilderW_Contains(sbImageUrl,L".tiff",FALSE) == TRUE) {
                extension = L".tiff";
            }

            if (CkStringBuilderW_Contains(sbImageUrl,L".bmp",FALSE) == TRUE) {
                extension = L".bmp";
            }

            sbLocalFilePath = CkStringBuilderW_Create();
            CkStringBuilderW_Append(sbLocalFilePath,L"C:/Photos/facebook/uploaded/");
            CkStringBuilderW_Append(sbLocalFilePath,photoId);
            CkStringBuilderW_Append(sbLocalFilePath,extension);

            success = CkHttpW_QuickGet(http,imageUrl,imageBytes);
            if (CkHttpW_getLastMethodSuccess(http) != TRUE) {
                wprintf(L"%s\n",CkHttpW_lastErrorText(http));
                CkCacheW_Dispose(fbCache);
                CkOAuth2W_Dispose(oauth2);
                CkRestW_Dispose(rest);
                CkJsonObjectW_Dispose(photoJson);
                CkStringArrayW_Dispose(saPhotoUrls);
                CkStringBuilderW_Dispose(sbPhotoIdPath);
                CkJsonObjectW_Dispose(json);
                CkJsonObjectW_Dispose(imgUrlJson);
                CkHttpW_Dispose(http);
                CkJsonObjectW_Dispose(urlJson);
                CkByteData_Dispose(imageBytes);
                CkFileAccessW_Dispose(fac);
                CkStringBuilderW_Dispose(sbImageUrl);
                CkStringBuilderW_Dispose(sbLocalFilePath);
                return;
            }

            // We've downloaded the photo image bytes into memory.
            // Save it to the cache AND save it to the output file.
            CkCacheW_SaveToCacheNoExpire(fbCache,imageUrl,L"",imageBytes);
            CkFileAccessW_WriteEntireFile(fac,CkStringBuilderW_getAsString(sbLocalFilePath),imageBytes);

            wprintf(L"Downloaded to %s\n",CkStringBuilderW_getAsString(sbLocalFilePath));
        }

        i = i + 1;
    }

    wprintf(L"Finished downloading all Facebook photos!\n");


    CkCacheW_Dispose(fbCache);
    CkOAuth2W_Dispose(oauth2);
    CkRestW_Dispose(rest);
    CkJsonObjectW_Dispose(photoJson);
    CkStringArrayW_Dispose(saPhotoUrls);
    CkStringBuilderW_Dispose(sbPhotoIdPath);
    CkJsonObjectW_Dispose(json);
    CkJsonObjectW_Dispose(imgUrlJson);
    CkHttpW_Dispose(http);
    CkJsonObjectW_Dispose(urlJson);
    CkByteData_Dispose(imageBytes);
    CkFileAccessW_Dispose(fac);
    CkStringBuilderW_Dispose(sbImageUrl);
    CkStringBuilderW_Dispose(sbLocalFilePath);

    }