問題描述

我有點卡在這里.我知道我可以使用 canvas.toDataURL 生成一個 base64 編碼的字符串，以傳遞給我服務器上的經典 ASP 頁面.但我似乎找不到答案的問題是如何處理這些數據，以便我可以將其保存在我的服務器上的某個位置.

I'm a bit stuck here. I know that I can use the canvas.toDataURL to produce a base64 encoded string to pass to a classic ASP page on my server. But the problem I can't seem to find an answer to is how to process this data so I can save it someplace on my server.

因此，使用我的 HTML 頁面上的這段代碼，我提取了畫布數據(我從 StackOverflow 的另一篇文章中提取了這個):

So with this snippet of code on my HTML page, I pull the canvas data (I pulled this from another post here at StackOverflow):

var dataURL = renderedCanvas.toDataURL("image/png");    
dataURL = dataURL.replace('data:image/png;base64,', '');

var areturn = $.ajax({
  url: "http://127.0.0.1/mySite/saveImage.asp",
  type: "POST",
  data: '{ "imageData" : "' + dataURL + '" }',
  dataType: "json",
  beforeSend: function(x) {
      x.overrideMimeType("application/j-son;charset=UTF-8");
  }
}).done(function(result) {
    console.log("Success Done!
" + result);
}).always(function(data) {
    console.log("Always:
" + data.responseText);
}); 

但是我現在不清楚一旦我在服務器端如何處理數據......我可以提取 Request.Form 元素，但我似乎找不到任何 base64 解碼的好方法它，甚至將其輸出為二進制文件...我想我聽說經典的 ASP 不擅長進行 base64 解碼，在另一個測試中我確實找到了一個可以進行 base64 解碼的函數，但我不能不知道它是否真的有效，但它確實需要很長時間才能運行.我還在這里找到了這個鏈接:用于 ASP 經典的 base64 圖像解碼器，但我猜這是微軟不推薦使用的 32 位組件……我想我正在向社區尋求有關將 html5 畫布圖像保存到服務器上的建議.

But I'm unclear now what to do with the data once I'm on the server side... I can pull the Request.Form element, but I can't seem to find a good way to either base64 decode it, or even output it as a binary file... I guess I've heard that classic ASP isn't any good at doing base64 decoding, and in another test I did find a function that did the base64 decode, but I couldn't tell if it really worked, but it did take a long time to run. I also found this link here: base64 image decoder for ASP classic, but I guess this is a 32bit component that Microsoft doesn't recommend using... I guess I'm looking to the community here for suggestions on saving out an html5 canvas image onto the server.

推薦答案

您可以使用通過 DomDocument 實例創建的指定 bin.base64 數據類型的 XML 元素來編碼/解碼 Base64 數據.
然后，您可以使用 Stream 對象將獲得的二進制文件保存到磁盤.
這兩個庫都支持 64 位.假設您發送的內容將在服務器端的 Request 集合(沒有 json 的經典 post 方法等)中可用，下面的代碼可以解決問題，或者在最壞的情況下，我相信這會給您帶來洞察力.

You could use an XML element specifying bin.base64 data type that created through a DomDocument instance to encoding / decoding Base64 data.
Then you can save obtained binary to disk using a Stream object.
Both of these libraries are 64 bit supported. Assuming the content you sent will be available in a Request collection (classic post methods without json etc.) on the server-side, following code solves the problem or at worst I'm sure that gives you insight.

saveImage.asp

Function Base64Data2Stream(sData)
    Set Base64Data2Stream = Server.CreateObject("Adodb.Stream")
        Base64Data2Stream.Type = 1 'adTypeBinary
        Base64Data2Stream.Open
    With Server.CreateObject("MSXML2.DomDocument.6.0").createElement("b64")
        .dataType = "bin.base64"
        .text = sData
        Base64Data2Stream.Write .nodeTypedValue 'write bytes of decoded base64 to stream
        Base64Data2Stream.Position = 0
    End With
End Function

Dim CanvasStream
Set CanvasStream = Base64Data2Stream(Request.Form("imageData"))

'Write binary to Response Stream
'Response.BinaryWrite CanvasStream.Read

'Write binary to File
CanvasStream.SaveToFile Server.Mappath("imgFileFromCanvas.png"), 2 'adSaveCreateOverWrite

這篇關于如何使用經典 ASP 保存畫布圖像?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！