将图像作为base64string发送到WebAPI;base64字符串太长

Question

我最近学习了Ahsan Siddique 的这些教程

利用Azure数据库在ASP.Net中开发RESTful API。

第1部分https://www.c-sharpcorner.com/article/creating-sql-database-in-azure-portal/

第2部分https://www.c-sharpcorner.com/article/developing-restful-api-in-asp-net-with-add-method/

第3部分https://www.c-sharpcorner.com/article/developing-restful-apis-in-asp-net-with-retrieve-update-and-delete-functions/

在Xamarin.Android 中消费RESTful API

第4部分https://www.c-sharpcorner.com/article/consuming-restful-apis-in-xamarin-android/

我设法让所有的代码都能工作，但我在试图将base64字符串传递给web api的部分遇到了麻烦。教程中没有我遇到的部分。我在Postman上测试了POST API，得到了错误消息"HTTP错误414"。请求URL太长。">

下面你可以看到我的代码的一部分：

public String BitmapToBase64(Bitmap bitmap)
{
//Java.IO.ByteArrayOutputStream byteArrayOutputStream = new Java.IO.ByteArrayOutputStream();
MemoryStream memStream = new MemoryStream();
bitmap.Compress(Bitmap.CompressFormat.Jpeg, 100, memStream);
byte[] byteArray = memStream.ToArray();
return Base64.EncodeToString(byteArray, Base64Flags.Default);
}
User user = new User ();
user.ID = "1";
user.name = "Kelly";
user.profilepic = BitmapToBase64(NGetBitmap(uri)); //this is the part where base64string is too long
HttpClient client = new HttpClient();
string url = $"http://test.azurewebsites.net/api/User/{user.ID}?name={user.name}&profilepic={user.profilepic}";
var uri1 = new System.Uri(url); //base64
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response;
var json = JsonConvert.SerializeObject(feedback);
var content = new StringContent(json, Encoding.UTF8, "application/json");
response = await client.PostAsync(uri1, content);
if (response.StatusCode == System.Net.HttpStatusCode.Accepted)
{
Toast.MakeText(this, "Your profile is updated.", ToastLength.Long).Show();
}
else
{
Toast.MakeText(this, "Your profile is not updated." + feedback.profilepic, ToastLength.Long).Show();
}

我需要帮助！提前谢谢！

更新：这就是我的控制器类目前看起来像的样子

public HttpResponseMessage Update_User(int ID, string name, string profilepic)
{
if (!ModelState.IsValid)
{
return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
}
UserTable newUser = new UserTable();
var entry = db.Entry<UserTable>(newUser);
entry.Entity.ID = ID;
entry.Entity.name = name;
entry.Entity.profilepic = profilepic;
entry.State = EntityState.Modified;
try
{
db.SaveChanges();
}
catch (DbUpdateConcurrencyException ex)
{
return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
}
return Request.CreateResponse(HttpStatusCode.Accepted, "Your profile is updated.");
}

Answer 1

如注释中所述，不要将base64图像作为url/GET参数的一部分发送。

而是将它附加到POST请求的主体。

var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("profilepic", user.profilepic)
});
var result = await client.PostAsync(url, content);