如何在 VB.NET 中使用授权令牌和 JSON 参数进行 HTML 发布

Question

我正在创建一个 VB.NET 程序，我想与 dropbox 交互。我从“list_folder”命令开始，它将返回指定路径上的内容。这是您可以使用该命令的 URL：

https://dropbox.github.io/dropbox-api-v2-explorer/#files_list_folder

提供的HTTP请求语法如下：

 POST /2/files/list_folder
 Host: https://api.dropboxapi.com
 User-Agent: api-explorer-client
 Authorization: Bearer HBNBvdIls8AA12AAFTvyzhNJrdwwpQcswxpRVjmwRIJANPIea7Jc1Ke
 Content-Type: application/json
 {
     "path": "/Backups"
 }

我想做的相当于 VB.NET 命令。这是我到目前为止所拥有的：

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

    Dim uri As String = "https://api.dropboxapi.com/2/files/list_folder"
    Dim request As Net.HttpWebRequest = Net.HttpWebRequest.Create(uri)

    request.Method = "POST"
    request.UserAgent = "api-explorer-client"

    ' this is wrong, need to supply an 'authorization token' somehow:
    Dim credentials As New Net.NetworkCredential("username", "password")
    request.Credentials = credentials

    request.ContentType = "application/json"

    'request.ContentLength  = ???
    ' how do I set content to the "path: backups" data?

    Dim response As Net.HttpWebResponse = request.GetResponse

    Debug.Print(response.StatusDescription)

    Dim dataStream As IO.Stream = response.GetResponseStream()
    Dim reader As New IO.StreamReader(dataStream)          ' Open the stream using a StreamReader for easy access.
    Dim responseFromServer As String = reader.ReadToEnd()  ' Read the content.

    MsgBox(responseFromServer)  ' Display the content.

    ' Cleanup the streams and the response.
    reader.Close()
    dataStream.Close()
    response.Close()

End Sub

我缺少的是以某种方式将文档指定的“path”：“/Backups”数据编码到请求对象中。我还缺少如何将“授权”访问令牌编码到请求中。 （上面我使用了用户名/密码，但这可能是错误的。）

有人可以帮我完成 VB.NET HTTP 请求吗？非常感谢。

** 根据 the_lotus 的有用链接更新新代码——这有效，谢谢！:

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

    Dim uri As String = "https://api.dropboxapi.com/2/files/list_folder"
    Dim request As Net.HttpWebRequest = Net.HttpWebRequest.Create(uri)

    request.Method = "POST"
    request.UserAgent = "api-explorer-client"

    request.Headers.Add("Authorization", "Bearer HBN-BvdIlsAAAFTyAQzhNJrBNINPIea7Jc1Ke")

    '{
    '"path": "/Backups"
    '}

    Dim json_data As String = "{"+ Chr(34) + "path" + Chr(34) + ": " + Chr(34) + "/Backups" + Chr(34) + "}"
    request.ContentType = "application/json"
    Dim json_bytes() As Byte = System.Text.Encoding.ASCII.GetBytes(json_data)
    request.ContentLength = json_bytes.Length

    Dim stream As IO.Stream = request.GetRequestStream

    stream.Write(json_bytes, 0, json_bytes.Length)


    Dim response As Net.HttpWebResponse = request.GetResponse

    Debug.Print(response.StatusDescription)

    Dim dataStream As IO.Stream = response.GetResponseStream()
    Dim reader As New IO.StreamReader(dataStream)          ' Open the stream using a StreamReader for easy access.
    Dim responseFromServer As String = reader.ReadToEnd()  ' Read the content.

    MsgBox(responseFromServer)  ' Display the content.

    ' Cleanup the streams and the response.
    reader.Close()
    dataStream.Close()
    response.Close()

End Sub

Answer 1

您可以使用 request.Headers 添加自定义标头。

request.Headers.Add("Authorization", "Bearer HBN-BvdIlsAAAFTyAQzhNJrBNINPIea7Jc1Ke")

要发送POST信息，可以使用request.GetRequestStream。

此外，请确保 POST 中发送的数据格式正确为 JSON。