如何在 Unity 中获取 Firebase 应用程序目录中的文件列表

Question

I am trying to get a list of all files in a directory of the Firebase app. It seems that this is possible on all platforms but Unity. All platforms excluding Unity have an option of "List Files" here . Is there some other way to get a list of all the files?

I also tried to maintain a text file with such entry but it takes a long time to first download the text file, upload the video and again upload the updated text file. (There some other issues as well due to download being async).

Basically my code currently looks like this:

public void UploadVideoandUpdateText()
{
    //Downloading Text file
    details_text_ref.GetFileAsync(local_text_url).ContinueWith(task => {
            if (!task.IsFaulted && !task.IsCanceled)
            {
                Debug.Log("File downloaded.");
            }
        });

    //Updating local_text_url and downloading it again
    details_text_ref.PutFileAsync(local_text_url).ContinueWith((Task<StorageMetadata> task) => {
            if (task.IsFaulted || task.IsCanceled)
            {
                Debug.Log(task.Exception.ToString());
                // Uh-oh, an error occurred!
            }
            else
            {
                // Metadata contains file metadata such as size, content-type, and download URL.
                Firebase.Storage.StorageMetadata metadata = task.Result;
                string download_url = details_text_ref.GetDownloadUrlAsync().ToString();
                Debug.Log("Finished uploading...");
                Debug.Log("download url = " + download_url);
            }
        });

    //Finally uploading the video
    video_ref.PutFileAsync(full_path_video).ContinueWith((Task<StorageMetadata> task) => {
            if (task.IsFaulted || task.IsCanceled)
            {
                Debug.Log(task.Exception.ToString());
                // Uh-oh, an error occurred!
            }
            else
            {
                // Metadata contains file metadata such as size, content-type, and download URL.
                Firebase.Storage.StorageMetadata metadata = task.Result;
                string download_url = video_ref.GetDownloadUrlAsync().ToString();
                Debug.Log("Finished uploading...");
                Debug.Log("download url = " + download_url);
            }
        });
}

The above is not working due to the downloads being in async. Is there a solution to make the function wait till the Details txt file is downloaded. Or even better, to have a direct method to view all uploaded files in a directory.

Answer 1

Anyone else coming across this issue, I've managed to find a solution.

Note: This doesn't answer the original question specifically, but general to what the question is asking without any description

How to get all objects within a Firebase folder

Seems easy enough right? Just request to get an object array of the data. Wrong... If the data is kept in a format like this:

Folder
-- 0
---- Name: "Bob"
---- Age: 26
-- 1
---- Name: "Me"
---- Age: 29
-- 2
---- Name: "Jeff"
---- Age: 24

Then it can be retrieved into an object array.

But notice that the sub folders within the folders need to be indexes in order for Firebase to recognize it as an array. This isn't normally how people might keep data. A normal Firebase structure might look like this:

Folder
-- Bob
---- Name: "Bob"
---- Age: 26
-- Me
---- Name: "Me"
---- Age: 29
-- Jeff
---- Name: "Jeff"
---- Age: 24

Notice that now, the sub folders aren't indexed, and so the JSON isn't an array anymore, but another folder. This cannot be read as an array of objects. So what do we do?

We can simply get a dictionary containing keys of type string, and values of type object . This way, we can keep the names of the sub folders, and not have to change them into array index numbers.

However to do this, we need to get the raw JSON first. Here's a way of doing it in C# using a WebClient:

static string GetJson(string url)
{
    using (var w = new WebClient())
    {
        var json_data = string.Empty;

        // attempt to download JSON data as a string
        try
        {
            json_data = w.DownloadString(url);
            Debug.Log(json_data);
        }
        catch (Exception) { }

        return json_data;
    }
}

The 'url' parameter is the link to our firebase database, alongside our folder name. For example: "https://myprojectid.firebaseio.com/Folder.json". Remember to add .json at the end to get the raw json data.

Next, we need a JSON deserializer to convert our json data into our dictionary. I'm using the Newtonsoft.Json NuGet package, which you can install and place the .dll file into your Assets/Plugins folder. Create it if you haven't already.

Then, to convert it into an object, we just write:

static Dictionary<string, Person> GetObjects(string json)
{
    var values = JsonConvert.DeserializeObject<Dictionary<string, Person>>(json);
    return values;
}

This should return a dictionary containing all objects within your folder, hopefully. The object class is called person. Quite simple:

public class Person
{
    public string Name;
    public int Age;

    public Person(string name, int age)
    {
        Name = name;
        Age = age;
    }  
}

Hopefully this helps someone down the line. Tag me if you have any issues.

Update

There is a much simpler and faster way to do this. I've managed to find an article explaining the usage of a REST API to put and get objects from a Firebase database.

It also explains how to get a collection of objects from a folder using a custom serializer. It's a lot quicker than the WebClient solution above. Here's the link:

Firebase in Unity with REST API

Answer 2

If you use unity after 2017.3 and use .Net 4.x Scripting Backend, use async/await.

Then your code will be like this

public async void UploadVideoandUpdateText()
{
    await details_text_ref.GetFileAsync(local_text_url);
    var metadata = await details_text_ref.PutFileAsync(local_text_url);
    string download_url = (awit details_text_ref.GetDownloadUrlAsync()).ToString();
    await video_ref.PutFileAsync(full_path_video);
}

See this article for async / await. https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/

but in case you can't use async/await, seperate each async operation to function and connect with ContinueWith().

public void UploadVideoandUpdateText()
{
    GetFile.ContinueWith(PutText).ContinueWith(PutVideo);
}

private Task GetFile()
{
    return details_text_ref.GetFileAsync(local_text_url);
}
private Task<StorageMetadata> GetText()
{
    return details_text_ref.PutFileAsync(local_text_url);
}
private Task<StorageMetadata> PutText()
{
    return details_text_ref.PutFileAsync(local_text_url);
}
private Task<StorageMetadata> PutVideo()
{
    return details_text_ref.PutFileAsync(full_path_video);
}