(PowerBuilder) 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.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_FbCache
oleobject loo_Oauth2
oleobject loo_Rest
integer li_Success
string ls_ResponseJson
oleobject loo_PhotoJson
oleobject loo_SaPhotoUrls
oleobject loo_SbPhotoIdPath
oleobject loo_Json
integer i
string ls_PhotoId
string ls_ImageUrl
string ls_AfterCursor
integer li_NumItems
string ls_PhotoJsonStr
oleobject loo_ImgUrlJson
oleobject loo_Http
integer li_NumUrls
oleobject loo_UrlJson
oleobject loo_Fac
oleobject loo_SbImageUrl
string ls_Extension
oleobject loo_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.
loo_FbCache = create oleobject
li_rc = loo_FbCache.ConnectToNewObject("Chilkat_9_5_0.Cache")
if li_rc < 0 then
    destroy loo_FbCache
    MessageBox("Error","Connecting to COM object failed")
    return
end if
// The cache will use 1 level of 256 sub-directories.
loo_FbCache.Level = 1
// Use a directory path that makes sense on your operating system..
loo_FbCache.AddRoot("C:/fbCache")

// This example assumes a previously obtained an access token
loo_Oauth2 = create oleobject
li_rc = loo_Oauth2.ConnectToNewObject("Chilkat_9_5_0.OAuth2")

loo_Oauth2.AccessToken = "FACEBOOK-ACCESS-TOKEN"

loo_Rest = create oleobject
li_rc = loo_Rest.ConnectToNewObject("Chilkat_9_5_0.Rest")

// Connect to Facebook.
li_Success = loo_Rest.Connect("graph.facebook.com",443,1,1)
if li_Success <> 1 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_FbCache
    destroy loo_Oauth2
    destroy loo_Rest
    return
end if

// Provide the authentication credentials (i.e. the access key)
loo_Rest.SetAuthOAuth2(loo_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".
loo_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.
loo_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.
ls_ResponseJson = loo_Rest.FullRequestNoBody("GET","/v2.7/me/photos")
if loo_Rest.LastMethodSuccess <> 1 then
    Write-Debug loo_Rest.LastErrorText
    destroy loo_FbCache
    destroy loo_Oauth2
    destroy loo_Rest
    return
end if

loo_PhotoJson = create oleobject
li_rc = loo_PhotoJson.ConnectToNewObject("Chilkat_9_5_0.JsonObject")

loo_SaPhotoUrls = create oleobject
li_rc = loo_SaPhotoUrls.ConnectToNewObject("Chilkat_9_5_0.StringArray")

loo_SbPhotoIdPath = create oleobject
li_rc = loo_SbPhotoIdPath.ConnectToNewObject("Chilkat_9_5_0.StringBuilder")

loo_Json = create oleobject
li_rc = loo_Json.ConnectToNewObject("Chilkat_9_5_0.JsonObject")

loo_Json.EmitCompact = 0
loo_Json.Load(ls_ResponseJson)

// Get the "after" cursor.
ls_AfterCursor = loo_Json.StringOf("paging.cursors.after")
do while loo_Json.LastMethodSuccess = 1

    Write-Debug "-------------------"
    Write-Debug "afterCursor = " + ls_AfterCursor

    // For each photo id in this page...
    i = 0
    li_NumItems = loo_Json.SizeOfArray("data")
    do while i < li_NumItems
        loo_Json.I = i
        ls_PhotoId = loo_Json.StringOf("data[i].id")
        Write-Debug "photoId = " + ls_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.
        ls_PhotoJsonStr = loo_FbCache.FetchText(ls_PhotoId)
        if loo_FbCache.LastMethodSuccess = 0 then
            // It's not locally available, so get it from Facebook..
            loo_SbPhotoIdPath.Clear()
            loo_SbPhotoIdPath.Append("/v2.7/")
            loo_SbPhotoIdPath.Append(ls_PhotoId)

            loo_Rest.ClearAllQueryParams()
            loo_Rest.AddQueryParam("fields","id,album,images")

            Write-Debug "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.
            ls_PhotoJsonStr = loo_Rest.FullRequestNoBody("GET",loo_SbPhotoIdPath.GetAsString())
            if loo_Rest.LastMethodSuccess <> 1 then
                Write-Debug loo_Rest.LastErrorText
                destroy loo_FbCache
                destroy loo_Oauth2
                destroy loo_Rest
                destroy loo_PhotoJson
                destroy loo_SaPhotoUrls
                destroy loo_SbPhotoIdPath
                destroy loo_Json
                return
            end if

            // Add the photo JSON to the local cache.
            loo_FbCache.SaveTextNoExpire(ls_PhotoId,"",ls_PhotoJsonStr)
        end if

        // 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.
        loo_PhotoJson.Load(ls_PhotoJsonStr)
        ls_ImageUrl = loo_PhotoJson.StringOf("images[0].source")
        if loo_PhotoJson.LastMethodSuccess = 1 then

            // Actually, we'll add a small JSON document that contains both the image ID and the URL.
            loo_ImgUrlJson = create oleobject
            li_rc = loo_ImgUrlJson.ConnectToNewObject("Chilkat_9_5_0.JsonObject")

            loo_ImgUrlJson.AppendString("id",ls_PhotoId)
            loo_ImgUrlJson.AppendString("url",ls_ImageUrl)
            loo_SaPhotoUrls.Append(loo_ImgUrlJson.Emit())
            Write-Debug "imageUrl = " + ls_ImageUrl
        end if

        i = i + 1
    loop

    // 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.
    loo_Rest.ClearAllQueryParams()
    loo_Rest.AddQueryParam("type","uploaded")
    loo_Rest.AddQueryParam("limit","20")
    loo_Rest.AddQueryParam("after",ls_AfterCursor)

    // Get the next page of photo ids.
    ls_ResponseJson = loo_Rest.FullRequestNoBody("GET","/v2.7/me/photos")
    if loo_Rest.LastMethodSuccess <> 1 then
        Write-Debug loo_Rest.LastErrorText
        destroy loo_FbCache
        destroy loo_Oauth2
        destroy loo_Rest
        destroy loo_PhotoJson
        destroy loo_SaPhotoUrls
        destroy loo_SbPhotoIdPath
        destroy loo_Json
        destroy loo_ImgUrlJson
        return
    end if

    loo_Json.Load(ls_ResponseJson)
    ls_AfterCursor = loo_Json.StringOf("paging.cursors.after")
loop

Write-Debug "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.  
loo_Http = create oleobject
li_rc = loo_Http.ConnectToNewObject("Chilkat_9_5_0.Http")

// We'll cache the image data so that if run again, we don't re-download the same image again.
li_NumUrls = loo_SaPhotoUrls.Count
i = 0
loo_UrlJson = create oleobject
li_rc = loo_UrlJson.ConnectToNewObject("Chilkat_9_5_0.JsonObject")

loo_Fac = create oleobject
li_rc = loo_Fac.ConnectToNewObject("Chilkat_9_5_0.FileAccess")

do while i < li_NumUrls
    loo_UrlJson.Load(loo_SaPhotoUrls.GetString(i))
    ls_PhotoId = loo_UrlJson.StringOf("id")
    ls_ImageUrl = loo_UrlJson.StringOf("url")

    // Check the local cache for the image data.
    // Only download and save if not already cached.
    loo_ImageBytes = loo_FbCache.FetchFromCache(ls_ImageUrl)
    if loo_FbCache.LastMethodSuccess = 0 then
        //  This photo needs to be downloaded.

        loo_SbImageUrl = create oleobject
        li_rc = loo_SbImageUrl.ConnectToNewObject("Chilkat_9_5_0.StringBuilder")

        loo_SbImageUrl.Append(ls_ImageUrl)

        // Let's form a filename..
        ls_Extension = ".jpg"
        if loo_SbImageUrl.Contains(".gif",0) = 1 then
            ls_Extension = ".gif"
        end if

        if loo_SbImageUrl.Contains(".png",0) = 1 then
            ls_Extension = ".png"
        end if

        if loo_SbImageUrl.Contains(".tiff",0) = 1 then
            ls_Extension = ".tiff"
        end if

        if loo_SbImageUrl.Contains(".bmp",0) = 1 then
            ls_Extension = ".bmp"
        end if

        loo_SbLocalFilePath = create oleobject
        li_rc = loo_SbLocalFilePath.ConnectToNewObject("Chilkat_9_5_0.StringBuilder")

        loo_SbLocalFilePath.Append("C:/Photos/facebook/uploaded/")
        loo_SbLocalFilePath.Append(ls_PhotoId)
        loo_SbLocalFilePath.Append(ls_Extension)

        loo_ImageBytes = loo_Http.QuickGet(ls_ImageUrl)
        if loo_Http.LastMethodSuccess <> 1 then
            Write-Debug loo_Http.LastErrorText
            destroy loo_FbCache
            destroy loo_Oauth2
            destroy loo_Rest
            destroy loo_PhotoJson
            destroy loo_SaPhotoUrls
            destroy loo_SbPhotoIdPath
            destroy loo_Json
            destroy loo_ImgUrlJson
            destroy loo_Http
            destroy loo_UrlJson
            destroy loo_Fac
            destroy loo_SbImageUrl
            destroy loo_SbLocalFilePath
            return
        end if

        // We've downloaded the photo image bytes into memory.
        // Save it to the cache AND save it to the output file.
        loo_FbCache.SaveToCacheNoExpire(ls_ImageUrl,"",loo_ImageBytes)
        loo_Fac.WriteEntireFile(loo_SbLocalFilePath.GetAsString(),loo_ImageBytes)

        Write-Debug "Downloaded to " + loo_SbLocalFilePath.GetAsString()
    end if

    i = i + 1
loop

Write-Debug "Finished downloading all Facebook photos!"


destroy loo_FbCache
destroy loo_Oauth2
destroy loo_Rest
destroy loo_PhotoJson
destroy loo_SaPhotoUrls
destroy loo_SbPhotoIdPath
destroy loo_Json
destroy loo_ImgUrlJson
destroy loo_Http
destroy loo_UrlJson
destroy loo_Fac
destroy loo_SbImageUrl
destroy loo_SbLocalFilePath