下载类型为“application/octet-stream”的文件并将其保存到下载文件夹以进行安装

Question

I'm currently doing a proof of concept for my application to check for updates and if their is a new version then download that version and install it (prompt the user to install?).

I'm stuck on implementing the download part of the problem, I have an AJAX call with PHP that just returns a file but the type is "application/octet-stream".

<?php @session_start();

$filename = "\\xxx\x\Application\ka-v1.0.0.0.txt";

header("X-Sendfile: $filename");
header("Content-type: application/octet-stream");
header('Content-Disposition: attachment; filename="' . basename($filename) . '"');

?>

The idea is to expand this and check the database what is the latest version and based on that it will form the filename. Originally the plan is to do a scandir on the directory to get all filenames and check for the latest and compare that to the application.

On the Xamarin.Form my code is

        _client = new HttpClient();
    public async void GetUpdate(string uri)
    {
        var bytesme = await DownloadFile("https://10.0.2.2:8080/apps/x/ajax/ajax.get_download.php");
        File.WriteAllBytes(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), bytesme);
    }
    
    public static Task<byte[]> DownloadFile(string url)
    {
        if (!url.Trim().StartsWith("https", StringComparison.OrdinalIgnoreCase))
            throw new Exception("iOS and Android Require Https");

        return _client.GetByteArrayAsync(url);

    }

So the idea is that when the user starts the application then it will call GetUpdates. For now GetUpdate is tied to a button click event. So the idea on the code is that it will download the file via HTTPClient then write it on a Downloads folder.

In this state that code doesn't work

The next step that I haven't research is automatically opening the file to prompt the user to install the new update

Answer 1

Since doing byte download with content-type 'application/octet-stream' is unreliable on Xamarin.Forms I came up with an alternative way of downloading and installing a apk file.

Instead of capturing the data, storing it locally then running it afterwards, I changed that sequence to the API call to a default browser

        try
        {
            await Browser.OpenAsync("https://10.0.2.2/apps/x/ajax/ajax.get_download.php", BrowserLaunchMode.SystemPreferred);
        }
        catch (Exception ex)
        {
            // An unexpected error occured. No browser may be installed on the device.
        }

So the idea is that the application will get downloaded in the browser and will give the user to open it and install the update.