Facebook 批量请求

Question

我正在尝试构建一个 VB.net 应用程序，该应用程序将通过 Graph API 批量请求方法从 facebook 检索各种用户。我的问题似乎是在执行实际请求时。当我尝试检索响应时，我从服务器返回 400 错误，指出“错误请求”。我不确定这是否意味着我的请求正文形成得不好，或者我是否在代码中附加了错误的内容。

这是我的请求代码：

    Dim sURL As String
    sURL = "https://graph.facebook.com"

    Dim wrGETURL As WebRequest
    wrGETURL = WebRequest.Create(sURL)
    wrGETURL.Method = "POST"
    wrGETURL.Proxy = WebRequest.DefaultWebProxy
    Dim reqStream As IO.Stream = wrGETURL.GetRequestStream()

    Dim access_token As String = "..." ' Access token removed, but it is valid

    Dim jsonReq As String = """access_token"": """ + access_token + """"
    jsonReq = jsonReq + """batch"": ["

    AddBatchRequest(jsonReq, "[email protected]")
    AddBatchRequest(jsonReq, "[email protected]")

    jsonReq = jsonReq + "]"

    Dim enc As New System.Text.UTF8Encoding()
    Dim jsonBytes As Byte() = enc.GetBytes(jsonReq)

    reqStream.Write(jsonBytes, 0, jsonBytes.Length)

    reqStream.Close()

    Dim oLabel As Label = output_label

    Dim objStream As Stream
    Try
        objStream = wrGETURL.GetResponse.GetResponseStream() '<<<<Crashes here

        Dim objReader As New StreamReader(objStream)
        Dim sLine As String = ""
        Dim i As Integer = 0

        Dim ostr As String = ""

        Do While Not sLine Is Nothing
            i += 1
            sLine = objReader.ReadLine
            If Not sLine Is Nothing Then
                ostr = ostr + sLine

            End If
        Loop

        oLabel.Text = ostr
    Catch ex As Exception
        oLabel.Text = ex.Message
    End Try

Private Sub AddBatchRequest(ByRef json As String, ByVal email As String)
    If json.EndsWith("}") Then
        json = json + ","
    End If
    json = json + "{""method: ""GET"", ""relative_url"": ""search?q=" + email + "&type=user""}"
End Sub

我已经尝试了很多关于如何形成字符串主体的变体，但它们都不起作用，这让我相信我没有正确添加主体。

Answer 1

最简单的方法是使用 Facebook SDK，它支持 批量请求。 你会做类似的事情：

Dim fb = New FacebookClient(accessToken)
Dim results = fb.Batch(New FacebookBatchParameter("[email protected]&type=user"), New FacebookBatchParameter("[email protected]&type=user"))

我认为你的问题是 jsonReq 不是格式正确的 POST 身体。将该值粘贴到此处，我相信有人可以具体指出问题所在。我没有安装VB.NET。