是否可以使用HTTP POST下载文件？

Question

Is it possible to download a file with HTTP POST? I know the "Get" way(windows.location), but in my case, there are a lot of param that should be passed to server

Answer 1

Yes, the rest of a POST request can direct a browser to download a file. The file contents would be sent as the HTTP response, same as in the GET case.

Answer 2

You mean like this ?

    function IssuePostRequest(objData) 
    {
        var strPageURL = "about:blank";
        var strAction = "@Url.Action("GetPDF", "Home")/";
        //var strAction = "/popups/delete.aspx";

        var strWindowName = "MyEvilHttpPostInAnewWindow"; // ifrmDownload
        var iWindowWidth = 805;
        var iWindowHeight = 625;



        var form = document.createElement("form");
        form.setAttribute("id", "bla");
        form.setAttribute("method", "post");
        form.setAttribute("action", strAction);
        form.setAttribute("target", strWindowName);
        form.setAttribute("style", "display: none;");
        // setting form target to a window named 'formresult'


        // Repeat for all data fields
        var hiddenField = document.createElement("input");
        hiddenField.setAttribute("name", "data");
        hiddenField.setAttribute("value", objData);
        form.appendChild(hiddenField);
        // End Repeat for all data fields


        document.body.appendChild(form);



        // creating the 'formresult' window with custom features prior to submitting the form
        //window.open(test.html, 'formresult', 'scrollbars=no,menubar=no,height=600,width=800,resizable=yes,toolbar=no,status=no');
        //JS_PopupCenterScreen(strPageURL, strWindowName, iWindowWidth, iWindowHeight);
        window.open(strPageURL, strWindowName);

        // document.forms[0].submit();
        //document.getElementById("xxx").click();
        form.submit();
    } // End Function IssuePostRequest

With this Server code:

    public FileResult GetPDF(string data)
    {
        //data = @"data:image/png;base64,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";

        string base64Data = System.Text.RegularExpressions.Regex.Match(data, @"data:image/(?<type>.+?),(?<data>.+)").Groups["data"].Value;
        byte[] binData = Convert.FromBase64String(base64Data);

        byte[] ba = PdfHandler.ImageToPdf(binData);
        //System.IO.File.WriteAllBytes(@"d:\temp\myba.pdf", ba);

        //return System.Convert.ToBase64String(ba);
        return File(ba, "application/pdf", "Chart.pdf");
    }

Answer 3

Looks like you'd like to generate the POST request from Javascript. I believe there is no way to get the browser to treat the result of an AJAX request as a download. Even if the Content-Type is set to something that browsers would normally offer as a download (eg to "application/octet-stream"), the browser will only deposit the data in the XMLHttpRequest object.

Furthermore, as you probably already know, there is no way to make window.open() issue a POST request.

I think the best way is to make an AJAX request which generates a file on the server. On the browser, when that request completes, use window.open() to download the generated file.

Answer 4

In some sense, every HTTP GET or POST is "downloading a file", but it's better to think of it as the message payload rather than a file. In most cases, the payload is an HTML document that the browser should render as a web page. But what if it's not an HTML document? What if it's a zip file for which the browser should offer the user a "Save as" dialog? Obviously, the browser must make a determination about the content type of the response and handle it correctly.

One of the most common ways that a browser determines the content type is through a HTTP header called, accordingly, "Content-Type". This header takes the value of a mime-type. This is the key to browsers doing content specific things like firing up an acrobat plugin when the response contains a pdf file, etc.

Note, not all browsers 1) determine the content type in the same way, and 2) react to the content type in the same way. Sometimes you have to toy with setting the headers to get the behaviors you want from all the browsers. All server side technologies allow you to set HTTP headers.

Answer 5

There's no difference, other than the request method and how you send data to the server. The way you process the response is the same regardless of whether you use GET or POST.

Answer 6

I managed to solve it using this:

service.js

downloadExcel : function() {
    var mapForm = document.createElement("form");
    mapForm.target ="_self"||"_blank";
    mapForm.id="stmtForm";
    mapForm.method = "POST";
    mapForm.action = "your_Controller_URL";

    var mapInput = document.createElement("input");
    mapInput.type = "hidden";
    mapInput.name = "Data";
    mapForm.appendChild(mapInput);
    document.body.appendChild(mapForm);

    mapForm.submit();
}

Spring Controller Code :

@Controller

@PostMapping(value = "/your_Controller_URL")
    public void doDownloadEmsTemplate( final HttpServletRequest request, final HttpServletResponse response)
            throws IOException, URISyntaxException {

        String filePath = "/location/zzzz.xls";
        logger.info("Excel Template File Location Path :" + filePath);
        final int BUFFER_SIZE = 4096;
        ServletContext context = request.getServletContext();
        String appPath = context.getRealPath("");
        String fullPath = appPath + filePath;
        File downloadFile = new File(fullPath);
        FileInputStream inputStream = new FileInputStream(downloadFile);
        String mimeType = context.getMimeType(fullPath);
        if (mimeType == null) {
            //mimeType = "application/octet-stream";
            mimeType = "application/vnd.ms-excel";
        }
        logger.info("MIME type: " + mimeType);
        response.setContentType(mimeType);
        response.setContentLength((int) downloadFile.length());
        String headerKey = "Content-Disposition";
        String headerValue = String.format("attachment; filename=\"%s\"", downloadFile.getName());
        logger.info("File Download Successfully : ");
        response.setHeader(headerKey, headerValue);
        OutputStream outStream = response.getOutputStream();
        byte[] buffer = new byte[BUFFER_SIZE];
        int bytesRead = -1;
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outStream.write(buffer, 0, bytesRead);
        }
        inputStream.close();
        outStream.close();
    }