使用 C# 将任何图像转换为 WebP

在本教程中，我们将介绍如何实现图像转换器的异步方法。您只需将源图像发送到 SubmitWebPConversionTask 或任何其他提交 API 方法（如 SubmitBmpConversionTask、SubmitDicomConversionTask 等）即可接收任务标识符作为响应。

收到任务标识符后，您需要通过调用 GetConversionTaskStatus 方法检查任务状态。只要任务状态等于“Waiting”，您需要在几秒钟延迟后调用相同的方法。一旦您从GetConversionTaskStatus方法收到“Completed”，您就可以调用DownloadResult方法来下载最终图像。可以使用下面的 C# 实现。

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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");
    }
}