(Lianja) Download Object from Google Cloud Storage

Demonstrates how to download an object from Google Cloud Storage to a file.

Chilkat Lianja Extension Download Chilkat Lianja Extension

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

// This example uses a previously obtained access token having permission for the 
// scope "https://www.googleapis.com/auth/cloud-platform"

// In this example, Get Google Cloud Storage OAuth2 Access Token, 
// the service account access token was saved to a text file.  This example fetches the access token from the file..
loSbToken = createobject("CkStringBuilder")
loSbToken.LoadFile("qa_data/tokens/googleCloudStorageAccessToken.txt","utf-8")

// Send a GET equivalent to this curl command.

// curl -X GET \
//     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
//     -o "[SAVE_TO_LOCATION]" \
//     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?alt=media"

loHttp = createobject("CkHttp")

loHttp.AuthToken = loSbToken.GetAsString()

// Construct a URL to download an object named "starfish.jpg" from the "chilkat-ocean" bucket.
loHttp.SetUrlVar("bucket_name","chilkat-ocean")
loHttp.SetUrlVar("object_name","starfish.jpg")
lcUrl = "https://www.googleapis.com/storage/v1/b/{$bucket_name}/o/{$object_name}?alt=media"

// If there is an error response, then we didn't actually download the file data,
// but instead we downloaded an error response..
loFileData = createobject("CkBinData")
llSuccess = loHttp.DownloadBd(lcUrl,loFileData)
if (llSuccess = .F.) then
    ? loHttp.LastErrorText
    release loSbToken
    release loHttp
    release loFileData
    return
endif

loSbErrorResponse = createobject("CkStringBuilder")
lnResponseCode = loHttp.LastStatus
if (lnResponseCode = 401) then
    ? "If invalid credentials, then it is likely the access token expired."
    ? "Your app should automatically fetch a new access token and re-try."
endif

if (lnResponseCode <> 200) then
    // Get the error response
    loSbErrorResponse.AppendBd(loFileData,"utf-8",0,0)
    ? "Error response code = " + str(lnResponseCode)
    ? "Error:"
    ? loSbErrorResponse.GetAsString()
    release loSbToken
    release loHttp
    release loFileData
    release loSbErrorResponse
    return
endif

? "Success."

// Save the downloaded data to a file.
llSuccess = loFileData.WriteFile("qa_output/starfish.jpg")


release loSbToken
release loHttp
release loFileData
release loSbErrorResponse