flask小记

小APP代码
小坑
flask jinja模板显示图片
flask ajax操作
部署

TOC

小APP代码

import os
from flask import Flask, flash, request, redirect, url_for, render_template, send_from_directory, jsonify, json
from werkzeug.utils import secure_filename
import time
from os.path import join, getsize
from utils import allowed_file, get_hash, unzip_file
import shutil


import process


ALLOWED_EXTENSIONS = {'zip'}


app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = './resources/source/'
app.config['ANALYZE_FOLDER'] = './resources/analyze/'


@app.route('/', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
# check if the post request has the file part
        if 'file' not in request.files:
            flash('No file part')
            return redirect(request.url)
        file = request.files['file']
# if user does not select file, browser also    
# submit an empty part without filename
        if file.filename == '':    
            return render_template('404.html')
        if file and allowed_file(file.filename, ALLOWED_EXTENSIONS):
            filename = secure_filename(file.filename)
            filePath = os.path.join(app.config['UPLOAD_FOLDER'], filename)
            file.save(filePath)
            file.close()


            f = open(filePath, 'rb')
            md5 = str(get_hash(f))
            f.close()
            workfile = app.config['ANALYZE_FOLDER'] + md5 + '/'
            is_file_exist = os.path.exists(workfile)            
            if not is_file_exist:
                unzip_file(filePath, workfile)
            os.remove(filePath)


            workpath = app.config['ANALYZE_FOLDER'] + md5 + '/'
            analyze = process.Process(workpath)
            ret = analyze.stat()


            success_json = {
                'url': '/' + md5,
                'stat': ret,
            }
            return jsonify(success_json)
        else:
            ret = {
                'init': {
                    'stat': False,
                    'msg': '文件格式错误，请上传正确格式的文件'
                        }
                    }
            success_json = {
                'stat': ret,
                }
            return jsonify(success_json)
    return render_template('index.html',
        allowedFile=ALLOWED_EXTENSIONS,
        val=int(time.time()))




@app.route('/<md5>/')
def uploaded_file(md5):
    return render_template('analyze.html',
    val=int(time.time()))


@app.route( "/<md5>/", methods = [ "POST", "GET" ])
def getDataSet(md5):
    send_data = {}
    with open(app.config['ANALYZE_FOLDER'] + md5 + '/' + 'analyze.json', 'r') as load_json:
        send_data = json.load(load_json)
        load_json.close()
    return jsonify(send_data)


if __name__=="__main__":
    app.run(host='0.0.0.0',port=8080, threaded=True, debug=True)

小坑

flask jinja模板显示图片

直接把图片路径填入jinja模板似乎是不行的，目前还没找到方法。能做的是在jinja模板中写入固定的url；或者将图片在后台解析成字符流，在传输给前端，不过这样造成的影响是，前端“不认为”这是一个图片。

• 后台

def return_img_stream(img_local_path):
    import base64
        img_stream = ''
        with open(img_local_path, 'rb') as img_f:
            img_stream = img_f.read()
            img_stream = base64.b64encode(img_stream)
    return img_stream

• 前端

<img src="data:;base64, {{ FrameRateImg }}", alt="***" >

但是因为是只需要展示图表，所以最后改成在后台做数据解析和整理的工作，再将数据发送到前端，由前端的d3.js做数据可视化工作。

flask ajax操作

尽量以json格式做数据传递的格式。

• 后台

@app.route( "/<md5>/", methods = [ "POST", "GET" ])
def getDataSet(md5):
    send_data = {}
    with open(app.config['ANALYZE_FOLDER'] + md5 + '/' + 'analyze.json', 'r') as load_json:
        send_data = json.load(load_json)
        load_json.close()
    return jsonify(send_data)

• 前端

var analyze_path = window.location.pathname;
var request_data = {
"data": "reserved",
}
$.ajax({
type: 'POST',
url: analyze_path,
data: JSON.stringify(request_data),
contentType: 'application/json; charset=UTF-8',
dataType: 'json',
success: function(data) {
draw(data);
},
error: function(xhr, type) {
console.log("can not get ajax retured");
}
});

部署

使用 gunicorn gevent docker

pip install gunicorn gevent

在gunicorn.conf.py中配置

workers = 5
worker_class = "gevent"
bind = "0.0.0.0:8080"

使用docker，在dockerfile中配置

FROM python:3.6
WORKDIR /www/
COPY requirements.txt .
RUN pip3 install -r requirements.txt -i https://mirrors.aliyun.com/pypi/simple/
COPY . .
CMD ["gunicorn", "app:app", "-c", "./gunicorn.conf.py"]

来自为知笔记(Wiz)