Question

我是前端开发的初学者，必须在Flask中为项目做一个小型Web应用程序。

我编写了一个Flask应用程序，可让您使用HTML表单上传图像，然后在点击上传时将图像显示回用户。我需要对其进行修改，以便每次用户上传图像时都不会将图像保存到项目目录中的文件夹中。基本上，应用程序应该将上传的图像发回到响应正文中。

到目前为止，这是我的代码：

UploadTest.py

import os


from uuid import uuid4

from flask import Flask, request, render_template, send_from_directory

app = Flask(__name__)
# app = Flask(__name__, static_folder="images")



APP_ROOT = os.path.dirname(os.path.abspath(__file__))

@app.route("/")
def index():
    return render_template("upload.html")

@app.route("/upload", methods=["POST"])
def upload():
    target = os.path.join(APP_ROOT, 'images/')
    print(target)
    if not os.path.isdir(target):
            os.mkdir(target)
    else:
        print("Couldn't create upload directory: {}".format(target))
    print(request.files.getlist("file"))
    for upload in request.files.getlist("file"):
        print(upload)
        print("{} is the file name".format(upload.filename))
        filename = upload.filename
        destination = "/".join([target, filename])
        print ("Accept incoming file:", filename)
        print ("Save it to:", destination)
        upload.save(destination)

    return render_template("complete.html", image_name=filename)

@app.route('/upload/<filename>')
def send_image(filename):
    return send_from_directory("images", filename)

if __name__ == "__main__":
    app.run(port=8080, debug=True)

upload.html - 创建上传表单

<!DOCTYPE html>
<html>
<head>
<title>Upload</title>
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.0/jquery.min.js"></script>
</head>
<body>

<form id="upload-form" action="{{ url_for('upload') }}" method="POST" enctype="multipart/form-data">

    <strong>Files:</strong><br>
    <input id="file-picker" type="file" name="file" accept="image/*" multiple>
    <div id="msg"></div>
    <input type="submit" value="Upload!" id="upload-button">
</form>
</body>
<script>

    $("#file-picker").change(function(){

        var input = document.getElementById('file-picker');

        for (var i=0; i<input.files.length; i++)
        {

            var ext= input.files[i].name.substring(input.files[i].name.lastIndexOf('.')+1).toLowerCase()

            if ((ext == 'jpg') || (ext == 'png'))
            {
                $("#msg").text("Files are supported")
            }
            else
            {
                $("#msg").text("Files are NOT supported")
                document.getElementById("file-picker").value ="";
            }

        }


    } );

</script>
</html>

complete.html - 在用户点击“上传”后显示保存文件夹中的图片

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
Uploaded
<img src=" {{url_for('send_image', filename=image_name)}}">
</body>
</html>

我已经尝试过相当多的研究，但除了在文件夹显示后删除文件夹之外，我找不到任何其他内容（我认为这不是解决手头问题的正确方法）。我真的很感激这方面的任何帮助，如果有比我目前的代码更好的解决方案，我想了解更多！

谢谢！：）

Answer 1

请检查以下代码是否对您有帮助。将以下代码复制到upload.html文件夹中的templates中。

<!DOCTYPE html>

<html>
<head>
<link class="jsbin" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1/themes/base/jquery-ui.css" rel="stylesheet" type="text/css" />
<script class="jsbin" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script class="jsbin" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.0/jquery-ui.min.js"></script>
<meta charset=utf-8 />

 <script src="{{ url_for('static', filename='upload.js') }}"></script>

<style>
  article, aside, figure, footer, header, hgroup, 
  menu, nav, section { display: block; }
</style>
</head>
<body>
<form action = "http://127.0.0.1:5000/uploader" method = "POST" 
 enctype = "multipart/form-data">
  <input type='file' name = 'file' onchange="readURL(this);" />
    <img id="blah" src="#" alt="your image" />
 <input type = "submit"/>
</form>
</body>
</html>

将以下代码复制到upload.js文件夹中的static文件中

function readURL(input) {
if (input.files && input.files[0]) {
    var reader = new FileReader();

    reader.onload = function (e) {
        $('#blah')
            .attr('src', e.target.result)
            .width(150)
            .height(200);
    };

    reader.readAsDataURL(input.files[0]);
}
}

现在将以下代码复制到python文件中

from flask import Flask, render_template, request
from werkzeug import secure_filename
import os 

app = Flask(__name__)

app.config['UPLOAD_FOLDER'] = 'D:/Projects/flask/image_upload/images/'

@app.route('/')
def upload_f():
   return render_template('upload.html')

@app.route('/uploader', methods = ['GET', 'POST'])
def upload_file():
   if request.method == 'POST':
      f = request.files['file']
      f.save(os.path.join(app.config['UPLOAD_FOLDER'],secure_filename(f.filename)))
      return 'file uploaded successfully'

# if __name__ == '__main__':
app.run(debug = True)

以上代码段将帮助您浏览和显示html页面上的图像，以及将图像保存在磁盘上的所需位置。

Answer 2

如果您想将图像发送回客户端，有两种方法，

您可以将图像作为文件 url 发送到客户端
您需要将图像转换为 blob 或 base64 图像并显示图像

使用Flask上传图像并将其显示为响应

2 个答案: