(Go) Download Photo to a File

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

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

    // 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
    oauth2 := chilkat.NewOAuth2()
    oauth2.SetAccessToken("FACEBOOK-ACCESS-TOKEN")

    rest := chilkat.NewRest()

    // Connect to Facebook...
    success := rest.Connect("graph.facebook.com",443,true,true)
    if success != true {
        fmt.Println(rest.LastErrorText())
        oauth2.DisposeOAuth2()
        rest.DisposeRest()
        return
    }

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

    // Assumes we've already obtained a Photo ID.
    photoId := "10210199026347451"

    sbPath := chilkat.NewStringBuilder()
    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")

    responseJson := rest.FullRequestNoBody("GET",*sbPath.GetAsString())
    if rest.LastMethodSuccess() != true {
        fmt.Println(rest.LastErrorText())
        oauth2.DisposeOAuth2()
        rest.DisposeRest()
        sbPath.DisposeStringBuilder()
        return
    }

    json := chilkat.NewJsonObject()
    json.SetEmitCompact(false)
    json.Load(*responseJson)

    // Show the JSON in human-readable format.
    fmt.Println(*json.Emit())

    // Get the image URL.
    imageUrl := json.StringOf("images[0].source")
    fmt.Println("Downloading from ", *imageUrl)

    sbImageUrl := chilkat.NewStringBuilder()
    sbImageUrl.Append(*imageUrl)

    // Build the output local file path.
    sbToPath := chilkat.NewStringBuilder()
    sbToPath.Append("qa_output/fb")
    sbToPath.Append(*json.StringOf("id"))
    bCaseSensitive := false
    if sbImageUrl.Contains(".jpg",bCaseSensitive) == true {
        sbToPath.Append(".jpg")
    }
    else {
        sbToPath.Append(".png")
    }

    fmt.Println("Downloading to ", *sbToPath.GetAsString())

    // Download using Chilkat HTTP.
    http := chilkat.NewHttp()
    success = http.Download(*imageUrl,*sbToPath.GetAsString())
    if success != true {
        fmt.Println(http.LastErrorText())
    }
    else {
        fmt.Println("Downloaded.")
    }


    oauth2.DisposeOAuth2()
    rest.DisposeRest()
    sbPath.DisposeStringBuilder()
    json.DisposeJsonObject()
    sbImageUrl.DisposeStringBuilder()
    sbToPath.DisposeStringBuilder()
    http.DisposeHttp()