In this tutorial we will cover how to implement asynchronous approach of Image Converter. You only need to send source image to SubmitWebPConversionTask or any other submission API methods like SubmitBmpConversionTask, SubmitDicomConversionTask etc. to receive task identifier as response.

After receiving task identifier you need to check task status by calling GetConversionTaskStatus method. You need to call same method after a few seconds delay as long as task status equals to “Waiting”. Once you receive “Completed” from GetConversionTaskStatus method you can call DownloadResult method to download final image. You can use the C# implementation below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77

async Task<string> SubmitWebPConversionTask(string filePathToConvert, string rapidApiKey)
{
    using (HttpClient httpClient = new HttpClient())
    {
        using (MultipartFormDataContent form = new MultipartFormDataContent())
        {
            form.Headers.Add("X-RapidAPI-Key", rapidApiKey);
            form.Add(new StringContent("true"), "lossy");
            var fileBytes = await File.ReadAllBytesAsync(filePathToConvert);
            var fileName = Path.GetFileName(filePathToConvert);
            form.Add(new ByteArrayContent(fileBytes, 0, fileBytes.Length), "file", fileName);

            using (var response = await httpClient.PostAsync("https://image-converter4.p.rapidapi.com/submitWebPConversionTask", form))
            {
                response.EnsureSuccessStatusCode();
                return await response.Content.ReadAsStringAsync();
            }
        }
    }
}

async Task<string> GetConversionTaskStatus(string taskId, string rapidApiKey)
{
    using (HttpClient httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Add("X-RapidAPI-Key", rapidApiKey);

        using (var response = await httpClient.GetAsync($"https://image-converter4.p.rapidapi.com/getConversionTaskStatus?taskId={taskId}"))
        {
            response.EnsureSuccessStatusCode();
            return await response.Content.ReadAsStringAsync();
        }
    }
}

async Task<byte[]> DownloadResult(string taskId, string rapidApiKey)
{
    using (HttpClient httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Add("X-RapidAPI-Key", rapidApiKey);

        using (var response = await httpClient.GetAsync($"https://image-converter4.p.rapidapi.com/downloadResult?taskId={taskId}"))
        {
            response.EnsureSuccessStatusCode();
            return await response.Content.ReadAsByteArrayAsync();
        }
    }
}

var rapidApiKey = "<YOUR RAPIDAPI KEY HERE>";
var filePathToConvert = "WebRenderer.png";
var taskId = await SubmitWebPConversionTask(filePathToConvert, rapidApiKey);
var retryCount = 0;
while (retryCount < 100)
{
    retryCount++;
    await Task.Delay(5000);
    var status = await GetConversionTaskStatus(taskId, rapidApiKey);
    if (status == "Completed")
    {
        var fileBytes = await DownloadResult(taskId, rapidApiKey);
        await File.WriteAllBytesAsync("image.webp", fileBytes);
        break;
    }
    else if (status == "Waiting")
    {
        continue;
    }
    else if (status == "Failed")
    {
        throw new Exception("Cannot convert image");
    }
    else
    {
        throw new Exception("Invalid status");
    }
}