I have been looking for an example GAE script in go to get my image that I got from the resulted screenshot of PageSpeed Insights and saved it as json_decode object using Kohana/Cache to Google Cloud Storage (GCS).
The reason of this method is simply because I found this Kohana model is the most convenient way writing files to GCS, although I am seeking also other way like this to write files to GCS using Blobstore to serve them while the Go API Files has been deprecate as documented here.
Here is the form of stored object containing the screenshot image data (base64) which is saved as public in default application bucket with object name images/thumb/mythumb.jpg:
stdClass Object
(
[screenshot] => stdClass Object
(
[data] => _9j_4AAQSkZJRgABAQAAAQABAAD_...= // base64 data
[height] => 240
[mime_type] => image/jpeg
[width] => 320
)
[otherdata] => Array
(
[..] => ..
[..] => ..
)
)
I want to get this image that set as public using my customized url as below that to be proceed through go module
and also I need it to be expired in a certain time because I have managed to update the image content itself regularly:
http://myappId.appspot.com/image/thumb/mythumb.jpg
I have set in disptach.yaml to send all image request to my go module
as below:
- url: "*/images/*"
module: go
and set the handler in go.yaml to proceed the image request as below:
handlers:
- url: /images/thumb/.*
script: _go_app
- url: /images
static_dir: images
Using this directive I have got that all /images/ request (other than /images/thumb/ request) serve images from the static directory and that /images/thumb/mythumb.jpg goes to the module application.
So left what code I have to use (see ????
) in my application file named thumb.go as below:
package thumb
import(
//what to import
????
????
)
const (
googleAccessID = "<serviceAccountEmail>@developer.gserviceaccount.com"
serviceAccountPEMFilename = "YOUR_SERVICE_ACCOUNT_KEY.pem"
bucket = "myappId.appspot.com"
)
var (
expiration = time.Now().Add(time.Second * 60) //expire in 60 seconds
)
func init() {
http.HandleFunc("/images/thumb/", handleThumb)
}
func handleThumb(w http.ResponseWriter, r *http.Request) {
ctx := cloud.NewContext(appengine.AppID(c), hc)
???? //what code to get the string of 'mythumb.jpg' from url
???? //what code to get the image stored data from GCS
???? //what code to encoce base64 data
w.Header().Set("Content-Type", "image/jpeg;")
fmt.Fprintf(w, "%v", mythumb.jpg)
}
I have taken many codes from some examples like this, this or this but could not get one works so far. I have also tried a sample from this which is almost close to my case but also found no luck.
So in generally t was mainly due to lack on what are the correct code to be put on the line that I marked by ????
as well the relevant library or path to be imported. I have also checked the GCS permission if something have been missing as described here and here.
I shall thank you much for your help and advise.