flask使用原生ajax、不使用表单(Form)上传文件

2024-07-04 13:28| 来源: 网络整理| 查看: 265

〇、知识点

jquery ajax 文档告诉你可以使用默认的　application/x-www-form-urlencoded, multipart/form-data, or text/plain 这三种，其它的也可以，但是需要告诉ajax 的怎样序列化它。——这句话来源于：https://www.cnblogs.com/htoooth/p/7242217.html

一、原生ajax、不使用表单(Form)

app.py

import os from flask import Flask, request, jsonify, render_template from werkzeug import secure_filename UPLOAD_FOLDER = 'uploads' ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif']) app = Flask(__name__) app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER def allowed_file(filename): return '.' in filename and \ filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS @app.route('/') def index(): return render_template('index.html') @app.route('/uploadfile', methods=['POST']) def upload_file(): if requesthod == 'POST': print('request.files', dir(request.files)) file = request.files['file'] if file and allowed_file(file.filename): filename = secure_filename(file.filename) url = os.path.join(app.config['UPLOAD_FOLDER'], filename) file.save(url) return jsonify(dict(url=url,)), 201 if __name__ == "__main__": app.run(debug=True)

index.html

DOCTYPE html> Flask上传图片演示三 Flask上传本地图片示例三不使用表单Form，原生javascript实现ajax，返回上传的图片所保存的位置 var file = document.querySelector('input[type="file"]'); var btn = document.querySelector('input[type="button"]'); //ajax btn.addEventListener('click', function(event){ event.preventDefault(); var data = new FormData(); data.append(file.name, file.files[0]);var xhr = new XMLHttpRequest(); xhr.open('POST', '/uploadfile', true); //xhr.setRequestHeader("Content-Type", "multipart\/form-data;"); //千万不能要这一句，否则后台request.files读不到file xhr.send(data); xhr.addEventListener('loadend', function(){ if(xhr.status == 201){ var res_json = JSON.parse(xhr.responseText); document.querySelector('#res').innerHTML = "上传的图片保存在：" + res_json.url; } }, false); }, false);

二、原生ajax、使用表单(Form)

app.py

import os from flask import Flask, request, jsonify, render_template from werkzeug import secure_filename UPLOAD_FOLDER = 'uploads' ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif']) app = Flask(__name__) app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER def allowed_file(filename): return '.' in filename and \ filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS @app.route('/') def index(): return render_template('index.html') @app.route('/uploadfile', methods=['POST']) def upload_file(): if requesthod == 'POST': file = request.files['file'] if file and allowed_file(file.filename): filename = secure_filename(file.filename) url = os.path.join(app.config['UPLOAD_FOLDER'], filename) file.save(url) return jsonify(dict(url=url,)), 201 if __name__ == "__main__": app.run(debug=True)

index.html

DOCTYPE html> Flask上传图片演示二 Flask上传本地图片示例二使用表单Form，原生javascript实现ajax，返回上传的图片所保存的位置 var form = document.querySelector('form'); //ajax form.addEventListener('submit', function(event){ event.preventDefault(); var xhr = new XMLHttpRequest(); xhr.open('POST', '/uploadfile', true); xhr.send(new FormData(form)); //注意：不需要设置Content-Type xhr.addEventListener('loadend', function() { if(xhr.status == 201){ var res_json = JSON.parse(xhr.responseText); document.querySelector('#res').innerHTML = "上传的图片保存在：" + res_json.url; } }, false); }, false);

三、无ajax、只使用表单(Form)

app.py

import os from flask import Flask, request, redirect, url_for, render_template from werkzeug import secure_filename UPLOAD_FOLDER = 'uploads' ALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif']) app = Flask(__name__) app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER def allowed_file(filename): return '.' in filename and \ filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS @app.route('/') def index(): return render_template('index.html') @app.route('/uploadfile', methods=['POST']) def upload_file(): if requesthod == 'POST': file = request.files['file'] if file and allowed_file(file.filename): filename = secure_filename(file.filename) file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename)) return redirect(url_for('uploaded_file', filename=filename)) from flask import send_from_directory @app.route('/uploads/') def uploaded_file(filename): return send_from_directory(app.config['UPLOAD_FOLDER'], filename) if __name__ == "__main__": app.run(debug=True)

index.html

DOCTYPE html> Flask上传图片演示一 Flask上传本地图片示例一使用表单Form，无javascript，跳转显示上传的图片

四、预览、无Form、原生ajax

index.html

DOCTYPE html> Flask上传图片演示四 Flask上传本地图片示例四上传前预览图片，不使用表单Form，原生ajax，返回上传的图片所保存的位置 var base64image = document.querySelector('#base64image'); var fileElement = document.querySelector('input[type="file"]'); var btnElement = document.querySelector('input[type="button"]'); //预览 fileElement.addEventListener('change', function(event){ if (!event.target.files || !event.target.files[0]) { return; } var reader = new FileReader(); reader.readAsDataURL(event.target.files[0]); reader.addEventListener("load", function(e){ base64image.src = e.target.result; //base64编码 }, false); },false); //ajax btnElement.addEventListener('click', function(event){ event.preventDefault(); var data = new FormData(); data.append(fileElement.name, fileElement.files[0]); //添加图片信息 var xhr = new XMLHttpRequest(); xhr.open("post", "/uploadfile", true);//true即异步 //xhr.setRequestHeader('Content-Type', 'multipart/form-data'); //千万别写这句！！ xhr.send(data); xhr.addEventListener("loadend", function(event){ if(xhr.status == 201){ // 201，去看app.py！！ var res = JSON.parse(xhr.responseText); //接收的是json数据 console.log(res); } }, false); },false);

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