【Python】Web学习笔记_flask(3)——上传文件

用GET、POST请求上传图片并呈现出来

首先还是创建文件上传的模板

    
    



    

        上传图片
        
    
    提交

然后需要定义几个函数：

upload()：路由函数，接收GET请求时，显示模板文件内容，接收post请求时，上传图片

allowed_file()：检测上传的文件是否满足设置的类型

random_file()：为上传的文件重新创建随机的不重复文件名

uploaded_file()：显示图片内容

import os.path
import uuid
import config

from flask import Flask,url_for,redirect,request,render_template,send_from_directory

ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif','PNG', 'JPG', 'JPEG', 'GIF',}

app=Flask(__name__)
UPLOAD_FOLDER = os.path.join(app.root_path,'uploads')
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
@app.route('/upload',methods=['GET','POST'])
#创建路由函数，接收GET请求时，显示模板文件内容，接收post请求时，上传图片
def upload():
    """
    #头像上传表单页面
    :return:
    """
    if request.method=='POST':
        #接受头像字段
        avatar=request.files['avatar']
        #判断头像是否上传
        if avatar and allowed_file(avatar.filename):
            filename=random_file(avatar.filename)
            avatar.save(os.path.join(app.config['UPLOAD_FOLDER'],filename))
            return redirect(url_for('uploaded_file',filename=filename))
    return render_template('upload.html')

def allowed_file(filename):
    """
    #判断上传文件类型是否允许
    :param filename 文件名
    :return: 布尔值 TRUE or False
    """
    print(filename)
    return '.' in filename and filename.rsplit('.',1)[1] in ALLOWED_EXTENSIONS

def random_file(filename):
    """
    生成随机文件名
    :param filename: 文件名
    :return:随机文件名
    """
    ext=os.path.splitext(filename)[1]
    #使用uuid生成随机字符
    new_filename=uuid.uuid4().hex+ext
    return new_filename

@app.route('/uploads/')
def uploaded_file(filename):
    """
    显示上传头像
    :param filename:文件名
    :return: 真实文件路径
    """
    return send_from_directory(app.config['UPLOAD_FOLDER'],filename)


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

需要单独设置的内容：

ALLOWED_EXTENSIONS：文件后缀类型

UPLOAD_FOLDER：上传文件的路径，如果不设置，会报错：

                                KeyError: 'UPLOAD_FOLDER'

ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif','PNG', 'JPG', 'JPEG', 'GIF',}

UPLOAD_FOLDER = os.path.join(app.root_path,'uploads')
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER