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Accepted
Lorenzo Martín
Asked: 2020-08-23 07:31:34 +0800 CST 2020-08-23 07:31:34 +0800 CST

Problems opening a file from PHP in a new window

  • 772

I have a file on a server path and would like to be able to send it to the browser.

I have tried something like this:

<?php
$filepath = '/var/tmp/apiRest/download/'.$rst;

if(file_exists($filepath)) {
        header('Content-Description: File Transfer');
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename="'.basename($filepath).'"');
        header('Expires: 0');
        header('Cache-Control: must-revalidate');
        header('Pragma: public');
        header('Content-Length: ' . filesize($filepath));
        flush(); // Flush system output buffer
        readfile($filepath);
        exit();
    }

If the variable $filepathcontains the name of the file in the form of a variable $rst, it does not download the file, but if I put the full path by hand it does.

$filepath = '/var/tmp/apiRest/download/prueba.txt';

Doing a echoof the variable $rst, it gives me the name of the file but something fails when concatenating.

The call to PHP from the browser, using javascript, is done as follows:

function loadDoc(id){ //funcion que me carga un documento y lo guarda en download
    var parametros = {
        "id": id,
    }

    $.ajax({
        data: parametros,
        url: "php/PlnDir/load_doc.php",
        type: "POST",
        success: function (data) {
            window.open("php/PlnDir/load_doc.php");
        }
    });
}
php

2 Answers

  1. Best Answer

    XHRThe problem you have is that you areXMLHttpRequest requesting the file using the method POSTand sending the file identifier through the variable id:

    $.ajax({
    data: {
        'id': id,
    },
    url: "php/PlnDir/load_doc.php",
    type: "POST",
    success: function (data) {
        window.open("php/PlnDir/load_doc.php");
    }
});

    So far everything is fine, but you can't trigger the download of a file through a request XHRif you don't add additional code (I'll show how to do it in a future edition).

    To solve this problem you have tried to open the PHP in a new window:

    window.open("php/PlnDir/load_doc.php");

    The problem is that the opened window will load the PHP file using the GETnormal method, without sending any data in the variable id(and it doesn't do it POSTas expected either), so this new request will fail and it won't find any file to download if you try do the SQL lookup with $_POST['id'].

    To detect a failed delivery of the parameter idyou could have done the following check in the PHP file:

    <?php
if (isset($_POST['id']) === false) {
  die('Datos de "id" no recibidos');
}

    There are two solutions to the problem. The simplest is to correctly send the parameter by POSTto the new window. For this we can create a form whose field idis not visible and that it is loaded in _blank(new window):

    <form action="php/PlnDir/load_doc.php" method="post"
    name="formulario" target="_blank">
  <input type="hidden" name="id" value="" />
</form>
<script>
function loadDoc(id){ //funcion que me carga un documento y lo guarda en download
  document.formulario.id.value = id;
  document.formulario.submit();
}
</script>

    The most complex involves creating a Blobfrom the data received by XHR, loading it into a label <a>and forcing it to click. In this other answer I have created an example of how to do it.

    • 2

  2. you could include the file using the include function

    include '/var/tmp/apiRest/download/5730Turbo.txt';
    • Add, that the file must be in the same folder (as the file to which you add the include) as I have put it.
    • -1