How to convert php blob to base64

How to convert php blob to base64: 1. Open the corresponding code file; 2. Modify the PHP content to "fetch("/path/to/server", {method: "POST" body: files[i ]})..." That's it.

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

How to convert php blob to base64?

Convert local image blob to base64 in PHP

Specific problem description:

I am writing a (HTML) form for an internal tool. Users can fill in the relevant questions data and attach a screenshot. This form is then submitted via Ajax to PHPMailer for sending. The problem is with the screenshot. Due to system limitations, I cannot let the user actually upload the file to the server.

Currently, I am using HTML5 file reader to select the file. I then converted the image blob to base64 and sent it to PHPMailer to be converted to an attachment. This actually worked fine. However, I ran into file size issues. Specifically That's a test image of 1000px x 1000px (402KB). The resulting base64 string is over a million characters, and the request returns 413 (Request entity too large).

I know base64 is not efficient for transferring large images method, and I've seen various articles about retrieving/converting image blobs from the database. What I can't find is information about retrieving local image blobs and converting them to base64.

My Image Blob The URL looks like this: blob: http://example.com/18960927-e220-4417-93a4-edb608e5b8b3

Is it possible to get this local image data in PHP and then convert it to base64?

I can't post a lot of source code, however, the following will give you an idea of ​​how I use FileReader

window.onload=function(){
window.URL = window.URL || window.webkitURL;
var fileSelect = document.getElementById("fileSelect"),
    fileElem = document.getElementById("fileElem"),
    fileList = document.getElementById("fileList");
fileSelect.addEventListener("click", function (e) {
  if (fileElem) {
    fileElem.click();
  }
  e.preventDefault(); // prevent navigation to "#"
}, false);
}
function handleFiles(files) {
  if (!files.length) {
    fileList.innerHTML = "<p>No files selected!</p>";
  } else {
    fileList.innerHTML = "";
    var list = document.createElement("ul");
    fileList.appendChild(list);
    for (var i = 0; i < files.length; i++) {
        if(files[i].size > 1000000) {
            alert(files[i].name + &#39; is too big. Please resize it and try again.&#39;);
        } else {
        var li = document.createElement("li");
      list.appendChild(li);
      var img = document.createElement("img");
      img.src = window.URL.createObjectURL(files[i]);
      img.height = 60;
      img.setAttribute("class", "shotzPrev");
      img.onload = function() {
        window.URL.revokeObjectURL(this.src);
      }
      li.appendChild(img);
      var info = document.createElement("span");
      info.innerHTML = files[i].name + "<br>" + files[i].size + " bytes";
      li.appendChild(info);
        }
    }
  }
}

Solution:

You can POST a File object to php

fetch("/path/to/server", {
  method: "POST"
  body: files[i]
})
.then(response => console.log(response.ok))
.catch(err => console.error(err));

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