Access VBA上传JPG至自建服务器报错（PHP错误码3）求帮助

问题描述 #

用户编写Access VBA代码上传JPG文件至自建Web服务器，服务器端PHP返回$_FILES错误码3（文件仅部分上传），具体返回信息如下：

Array
(
    [fileToUpload] => Array
        (
            [name] => testimage.jpg
            [full_path] => testimage.jpg
            [type] => 
            [tmp_name] => 
            [error] => 3
            [size] => 0
        )

)

用户的VBA代码：

Sub UploadJPGWithCURL()
    Dim winHttpReq As Object
    Dim fileData As String
    Dim boundary As String

    Dim fileName As String
    Dim filePath As String
    
    filePath = "Z:\Desktop\testimage.jpg"
    fileName = "testimage.jpg"

    boundary = "----------------------------" & Format(Now, "ddmmyyyyhhmmss")
    
    fileData = "--" & boundary & vbCrLf
    fileData = fileData & "Content-Disposition: form-data; name=""fileToUpload""; filename=""" & fileName & """" & vbCrLf
    fileData = fileData & "Content-Type: image/jpeg" & vbCrLf & vbCrLf
    'fileData = fileData & filePath & vbCrLf
    fileData = fileData & getBinaryFile(filePath) & vbCrLf
    fileData = fileData & "--" & boundary & "--" & vbCrLf
    
    Debug.Print fileData
    
    Set winHttpReq = CreateObject("WinHttp.WinHttpRequest.5.1")
    
    winHttpReq.Open "POST", "[THE URL TO MY WEBSERVER PHP PAGE THAT IS GOING TO PROCESS THE UPLOAD]", False
    winHttpReq.setRequestHeader "Content-Type", "multipart/form-data; boundary=" & boundary
    winHttpReq.send (fileData)
    
    If winHttpReq.Status = 200 Then
      Debug.Print winHttpReq.ResponseText
    Else
      Debug.Print "Request failed with status code: " & winHttpReq.Status
    End If
End Sub

Function getBinaryFile(filePath)
  Dim binaryStream
  Set binaryStream = CreateObject("ADODB.Stream")
  binaryStream.Type = 1
  binaryStream.Open
  binaryStream.LoadFromFile filePath
  getBinaryFile = binaryStream.Read
  binaryStream.Close
End Function

错误原因分析 #

• 二进制数据转字符串丢失：VBA的String是Unicode编码，无法正确存储二进制字节（如JPG中的非ASCII字节），直接将二进制文件内容赋值给fileData会导致数据损坏。
• 请求体拼接方式错误：用字符串拼接边界、头部和二进制内容，会破坏二进制流的完整性，导致服务器无法识别完整文件。
• Send方法参数类型错误：WinHttpRequest的send方法传入字符串时会按文本发送，而二进制文件需要以字节流形式传输。

修正后的代码 #

核心修改 #

• 用ADODB.Stream构建完整的二进制请求体，避免字符串转换丢失数据
• 所有边界、头部信息和文件内容均以二进制方式写入流
• 直接发送二进制流而非字符串

Sub UploadJPGWithWinHttp()
    Dim winHttpReq As Object
    Dim requestStream As Object
    Dim boundary As String
    Dim fileName As String
    Dim filePath As String
    
    filePath = "Z:\Desktop\testimage.jpg"
    fileName = "testimage.jpg"
    boundary = "----------------------------" & Format(Now, "ddmmyyyyhhmmss")
    
    ' 创建二进制请求流
    Set requestStream = CreateObject("ADODB.Stream")
    requestStream.Type = 1 ' 二进制类型
    requestStream.Open
    
    ' 写入边界和表单头部（转二进制）
    WriteBinaryString requestStream, "--" & boundary & vbCrLf
    WriteBinaryString requestStream, "Content-Disposition: form-data; name=""fileToUpload""; filename=""" & fileName & """" & vbCrLf
    WriteBinaryString requestStream, "Content-Type: image/jpeg" & vbCrLf & vbCrLf
    
    ' 写入文件二进制内容
    Dim fileStream As Object
    Set fileStream = CreateObject("ADODB.Stream")
    fileStream.Type = 1
    fileStream.Open
    fileStream.LoadFromFile filePath
    fileStream.CopyTo requestStream
    fileStream.Close
    Set fileStream = Nothing
    
    ' 写入结束边界
    WriteBinaryString requestStream, vbCrLf & "--" & boundary & "--" & vbCrLf
    
    ' 初始化并发送请求
    Set winHttpReq = CreateObject("WinHttp.WinHttpRequest.5.1")
    winHttpReq.Open "POST", "[你的服务器PHP处理页面URL]", False
    winHttpReq.setRequestHeader "Content-Type", "multipart/form-data; boundary=" & boundary
    
    requestStream.Position = 0 ' 重置流指针到开头
    winHttpReq.send requestStream
    
    ' 处理响应
    If winHttpReq.Status = 200 Then
        Debug.Print winHttpReq.ResponseText
    Else
        Debug.Print "请求失败，状态码: " & winHttpReq.Status
    End If
    
    ' 清理资源
    requestStream.Close
    Set requestStream = Nothing
    Set winHttpReq = Nothing
End Sub

' 辅助函数：将字符串转为二进制并写入流
Sub WriteBinaryString(stream As Object, text As String)
    Dim textStream As Object
    Set textStream = CreateObject("ADODB.Stream")
    textStream.Type = 2 ' 文本类型
    textStream.Charset = "utf-8"
    textStream.Open
    textStream.WriteText text
    textStream.Position = 0
    textStream.Type = 1 ' 转为二进制
    textStream.CopyTo stream
    textStream.Close
    Set textStream = Nothing
End Sub

额外检查项 #

• 确认服务器PHP配置中upload_max_filesize和post_max_size值足够大，避免文件大小限制导致部分上传
• 检查服务器临时目录（upload_tmp_dir）是否有读写权限
• 确保本地文件路径正确，且文件未被其他程序占用

内容的提问来源于stack exchange，提问作者Chris Lydon