从Webservice StreamReader返回一个System.Drawing.Image

本文关键字：一个 System Drawing Image Webservice StreamReader 返回 | 更新日期: 2023-09-27 18:12:14

我写了一个webservice，其中一个函数需要返回一个System.Drawing.Image

我的服务功能如下:

public class GetVisitorImageController : ApiController
{
    [Route("GetVisitorImage/{id}")]
    [HttpGet]
    public System.Drawing.Image Get(string id)
    {
        string[] authorization = Request.Headers.Authorization.ToString().Split('|');
        string PartnerId = Request.Headers.GetValues("PartnerId").First();
        string DeviceId = Request.Headers.GetValues("DeviceId").First();
        try
        {
            return VisitorFunctions.GetVisitorImage(authorization[0], authorization[1], id, PartnerId, DeviceId);
        }
        catch
        {
            throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NoContent));
        }
    }
}
下面是我的客户端函数: 
public static System.Drawing.Image GetVisitorImage(NetworkInfo networkInfo, string partnerId, string deviceId, string visitorId)
{
    ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(AcceptAllCertifications);
    var httpWebRequest = (HttpWebRequest)WebRequest.Create(networkInfo.baseUrl + "GetVisitorImage" + "/" + visitorId);
    httpWebRequest.ContentType = "application/json";
    httpWebRequest.Method = "GET";
    httpWebRequest.Headers.Add("Authorization", "" + networkInfo.userName + "|" + networkInfo.userPassword + "");
    httpWebRequest.Headers.Add("PartnerId", partnerId);
    httpWebRequest.Headers.Add("DeviceId", deviceId);
    httpWebRequest.Proxy = ConfigureProxy(networkInfo);
    var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
    using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
    {
        var result = streamReader.ReadToEnd();
        return JsonConvert.DeserializeObject<System.Drawing.Image>(result);
    }
}

正如你可能看到的，我已经尝试使用Json库将StreamReader的结果转换为System.Drawing.Image

我感觉json库不能做我想做的事情。

我可以转换StreamReader字符串"结果"并将其作为System.Drawing.Image返回吗?

谢谢

从Webservice StreamReader返回一个System.Drawing.Image

你不能简单地将System.Drawing.Image序列化为Json，然后将Json反序列化回System.Drawing.Image。Json只是序列化对象的公共属性，System.Drawing.Image是GDI2库的包装器。

相反，你应该保存你的System.Drawing.Image到一个字节数组，使用一些图像编码器(jpg或png)，并从GetVisitorImage操作返回字节数组。在客户端，你读取所有的字节(在ResponseStream上使用ReadToEnd)并渲染它们，或者你仍然可以选择从你的流中重建你的System.Drawing.Image -如果你真的需要一个System.Drawing.Image.

我完全不熟悉webAPI，所以我不完全确定在你的webAPI方法中声明这个的最好方法是什么。

以防有人像我一样被卡住。

这是我如何修复它。

基本上，在服务中，我将图像转换为base64字符串并返回。

在客户端，我将返回的base64字符串转换回System.Drawing.Image

这是新的Service controller:

public class GetVisitorImageController : ApiController
{
    [Route("GetVisitorImage/{id}")]
    [HttpGet]
    public string Get(string id)
    {
        string[] authorization = Request.Headers.Authorization.ToString().Split('|');
        string PartnerId = Request.Headers.GetValues("PartnerId").First();
        string DeviceId = Request.Headers.GetValues("DeviceId").First();
        System.Drawing.Image visitorimage = VisitorFunctions.GetVisitorImage(authorization[0], authorization[1], id, PartnerId, DeviceId);
        MemoryStream memStream = new MemoryStream();
        visitorimage.Save(memStream, ImageFormat.Jpeg);
        byte[] imageBytes = memStream.ToArray();
        string base64String = Convert.ToBase64String(imageBytes);
        return base64String;
    }
}

这是新的客户端函数

public static System.Drawing.Image GetVisitorImage(NetworkInfo networkInfo, string partnerId, string deviceId, string visitorId)
    {
        ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(AcceptAllCertifications);
        var httpWebRequest = (HttpWebRequest)WebRequest.Create(networkInfo.baseUrl + "GetVisitorImage" + "/" + visitorId);
        httpWebRequest.ContentType = "application/json";
        httpWebRequest.Method = "GET";
        httpWebRequest.Headers.Add("Authorization", "" + networkInfo.userName + "|" + networkInfo.userPassword + "");
        httpWebRequest.Headers.Add("PartnerId", partnerId);
        httpWebRequest.Headers.Add("DeviceId", deviceId);
        httpWebRequest.Proxy = ConfigureProxy(networkInfo);
        var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            var result = streamReader.ReadToEnd();
            result = result.Remove(0, 1); // remove first character
            result = result.Remove(result.Length - 1); // remove last character
            byte[] imageBytes = Convert.FromBase64String(result);
            MemoryStream ms = new MemoryStream(imageBytes, 0, imageBytes.Length);
            ms.Write(imageBytes, 0, imageBytes.Length);
            Image image = Image.FromStream(ms, true);
            return image;
        }
    }
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