B4X

Download Photo to a File

See more Facebook Examples

Assuming we have the ID of a Photo, this example demonstrates how to download the photo image data to a file. B4X

Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  This example assumes a previously obtained an access token
Dim oauth2 As ChilkatOAuth2
oauth2.Initialize("oauth2")
oauth2.AccessToken = "FACEBOOK-ACCESS-TOKEN"

Dim rest As ChilkatRest
rest.Initialize("rest")

'  Connect to Facebook...
success = rest.Connect("graph.facebook.com", 443, True, True)
If success <> True Then
    Log(rest.LastErrorText)
    Return
End If


'  Provide the authentication credentials (i.e. the access key)
rest.SetAuthOAuth2(oauth2)

'  Assumes we've already obtained a Photo ID.
Dim photoId As String = "10210199026347451"

Dim sbPath As ChilkatStringBuilder
sbPath.Initialize
sbPath.Append("/v2.7/")
sbPath.Append(photoId)

'  First we're going to get the photo informaton so we can get the URL of the image file data.
'  Select the fields we want.
'  See https://developers.facebook.com/docs/graph-api/reference/photo/
rest.AddQueryParam("fields", "id,album,images")

Dim responseJson As String = rest.FullRequestNoBody("GET", sbPath.GetAsString)
If rest.LastMethodSuccess <> True Then
    Log(rest.LastErrorText)
    Return
End If


Dim json As ChilkatJsonObject
json.Initialize
json.EmitCompact = False
json.Load(responseJson)

'  Show the JSON in human-readable format.
Log(json.Emit)

'  Get the image URL.
Dim imageUrl As String = json.StringOf("images[0].source")
Log("Downloading from " & imageUrl)

Dim sbImageUrl As ChilkatStringBuilder
sbImageUrl.Initialize
sbImageUrl.Append(imageUrl)

'  Build the output local file path.
Dim sbToPath As ChilkatStringBuilder
sbToPath.Initialize
sbToPath.Append("qa_output/fb")
sbToPath.Append(json.StringOf("id"))
Dim bCaseSensitive As Boolean = False
If sbImageUrl.Contains(".jpg", bCaseSensitive) = True Then
    sbToPath.Append(".jpg")
Else
    sbToPath.Append(".png")
End If

Log("Downloading to " & sbToPath.GetAsString)

'  Download using Chilkat HTTP.
Dim http As ChilkatHttp
http.Initialize("http")
success = http.Download(imageUrl, sbToPath.GetAsString)
If success <> True Then
    Log(http.LastErrorText)
Else
    Log("Downloaded.")
End If