为什么flask从POST请求中破坏了base64字符串？

Question

I am using Ajax to POST a base64 string to a flask backend. I am creating the base64 string using the canvas.toDataURL('image/png') to create a snapshot of the canvas. You can see the ajax request below.

img.src = canvas.toDataURL('image/png');

          $.ajax({
            url: "http://0.0.0.0:9000/postimage",
            type: "POST",
            crossDomain: true,
            processData: false,
            data: encodeURI(img.src),
            success: function (response) {
                console.log(response);
            },
            error: function (xhr, status) {
                console.log(xhr)
                console.log(status)
                console.log("error");
            }
        });

However, when the base64 is received on the backend it is corrupted. It does not have the trailing '==' and there is lots of spaces where previously there was '+' or '++'. When I try and access the string via request.data I get an empty binary string b''. I have been trying to access the base64 string via request.form but oddly that returns the base64 string in a dictionary as the KEY not the value, which is why I have image = key.

@app.route('/postimage', methods=['POST'])
def post_image():
     if request.method == 'POST':
         d = request.form
         print(d)
         for key, value in d.items():
             image = key
         image += '=='
         image = image.split(',', 1)[-1]
         imageEncoded = base64.decodestring(image.encode())
         with open("sean-sean.png", "wb") as fh:
             fh.write(imageEncoded)

Suggestions?

Answer 1

使用encodeURIComponent（）代替不编码保留字符（例如'='，'+'）的encodeURI（）