发送 JSON 内容类型的 POST 请求并在 VB.NET 中显示 JSON 响应

Send a POST request of JSON content-type and display JSON response in VB.NET

提问by Anjum

I am trying to send a POST request to shapeshift which has few parameters to be sent as JSON and then wish to display part of the response in VB.NET

我正在尝试向 shapeshift 发送一个 POST 请求，该请求几乎没有要作为 JSON 发送的参数，然后希望在 VB.NET 中显示部分响应

Documentation from shapeshift: https://info.shapeshift.io/api#api-9

来自 shapeshift 的文档：https: //info.shapeshift.io/api#api-9

Below is what I have tried until now:

以下是我迄今为止所尝试的：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim request As HttpWebRequest
    Dim response As HttpWebResponse
    Dim reader As StreamReader
    Dim rawresponse As String

    Try

        request = DirectCast(WebRequest.Create("https://shapeshift.io/sendamount"), HttpWebRequest)
        request.ContentType = "application/json"
        request.Method = "POST"

        Dim postdata As String = "{""amount"":}" + TextBox1.Text + "{,""withdrawal"":}" + TextBox2.Text + "{,""pair"":""btc_eth""}" + "{,""returnAddress"":}" + TextBox3.Text
        request.ContentLength = postdata.Length

        Dim requestWriter As StreamWriter = New StreamWriter(request.GetRequestStream())
        requestWriter.Write(postdata)
        requestWriter.Close()

        response = DirectCast(request.GetResponse(), HttpWebResponse)
        reader = New StreamReader(response.GetResponseStream())


        rawresponse = reader.ReadToEnd()

   Catch ex As Exception
        Console.WriteLine(ex.ToString)
   End Try

   Dim json As String = rawresponse
   Dim jsonObject As Newtonsoft.Json.Linq.JObject = Newtonsoft.Json.Linq.JObject.Parse(json)

   Label1.Text = jsonObject("expiration").ToString

End Sub

ERROR I get is: 400 Bad Request

我得到的错误是：400 Bad Request

I think its because I have messed up something in code where JSON POST request is explained. I did a lot of research and tried few things but nothing worked :(

我认为这是因为我在解释 JSON POST 请求的代码中搞砸了一些东西。我做了很多研究并尝试了一些东西，但没有任何效果:(

回答by Ctznkane525

Try this instead:

试试这个：

Dim postdata As String = "{""amount"":" + TextBox1.Text + "},{""withdrawal"":""" + TextBox2.Text + """},{""pair"":""btc_eth""},{""returnAddress"":""" + TextBox3.Text + """}"

Your data was malformed.

您的数据格式错误。

Or here is another version with String.Format:

或者这里是另一个带有 String.Format 的版本：

Dim postdata2 As String = String.Format("{{""amount"":{0}}},{{""withdrawal"":""{1}""}},{{""pair"":""btc_eth""}},{{""returnAddress"":""{2}""}}", TextBox1.Text, TextBox2.Text, TextBox3.Text)

回答by dbl4k

WebRequest is pretty old now. You may want to use the newer System.Net.Http.HttpClient, official docs are here.

WebRequest 现在已经很老了。您可能想使用较新的 System.Net.Http.HttpClient，官方文档在此处。

Also when transforming to Json, I massively recommend using the Newtonsoft.Json nuget package's JConvert / Deserialize features with generic arguments (Of ...) to convert to a predefined object. Saves a lot of manual text parsing on the return.

同样在转换为 Json 时，我强烈建议使用 Newtonsoft.Json nuget 包的 JConvert / Deserialize 功能和通用参数 (Of ...) 来转换为预定义的对象。在返回时节省了大量手动文本解析。

Have mocked up a quick example:

模拟了一个简单的例子：

Private async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim transaction As New MyRequestData With 
    {
        .Amount = Convert.ToDecimal(TextBox1.Text),
        .Withdrawal = Convert.ToDecimal(TextBox2.Text),
        .ReturnAddress  = TextBox3.Text
    }

    Dim content = newtonsoft.Json.JsonConvert.SerializeObject(transaction)
    dim buffer = System.Text.Encoding.UTF8.GetBytes(content)
    Dim bytes = new Net.Http.ByteArrayContent(buffer)
    bytes.Headers.ContentType = new Net.Http.Headers.MediaTypeHeaderValue("application/json")

    Dim responseBody As string = nothing
    Using client As New System.Net.Http.HttpClient
        Dim response = Await client.PostAsync("https://shapeshift.io/sendamount",bytes)
        responsebody = Await response.Content.ReadAsStringAsync()
    End Using

    Dim data = Newtonsoft.Json.JsonConvert.DeserializeObject(Of MyResponseData)(responsebody)

    If data.Expiration Is Nothing
        Label1.Text = data.Error
    Else
        Label1.Text = data.Expiration
    End If
End Sub

Public class MyRequestData
    Public property Amount As Decimal
    Public property Withdrawal As Decimal
    Public property Pair As String = "btc_eth"
    Public property ReturnAddress As String
End Class

Public class MyResponseData
    Public property Expiration As String
    Public property [Error] As String
End Class

Hope this helps, good luck!

希望这有帮助，祝你好运！