Flask - 05 请求和响应

Flask提供了全局的request和 response 来封装客户端请求及服务端响应对象

request请求对象

• request.args获取通过url（如?key=value）提供的参数

from flask import Flask, request, jsonify
app = Flask(__name__)
tasks = []

@app.route('/get/'])
def get_task():
    if not request.args or 'id' not in request.args:
        # 没有指定id则返回全部
        return jsonify(tasks)
    else:
        task_id = request.args['id']
        task = list(filter(lambda t: t['id'] == int(task_id), tasks))
        return jsonify(task[0]) if len(task)>0 else jsonify({'result': 'not found'})

• request.form获取通过表单提交的参数

@app.route('/login', methods=['POST'])
def login():
   error = None
   if valid_login(request.form['username'], request.form['password']):
        return log_the_user_in(request.form['username'])
   else:
        error = 'Invalid username/password'

• request.json获取json参数

@app.route('/login', methods=['POST'])
def login():
    if not request.json:
        task = {
          "id": request.json["id"],
          "task": request.json["task"]
        }
       tasks.append(task)
       return jsonify({'result': 'add successfully'})
   else:
       return jsonify({'result': 'error'})

• request.files获取上传文件
  浏览器页面必须制定enctype="multipart/form-data"才会向服务器传送文件，已上传的文件在服务器内存，可通过save()保存文件

from flask import request

@app.route('/upload', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        f = request.files['the_file']
        f.save('/var/www/uploads/uploaded_file.txt')

详细可参加上传文件方案

• request.cookies操作cookies

读取 cookies:

from flask import request

@app.route('/')
def index():
    username = request.cookies.get('username')
    # use cookies.get(key) instead of cookies[key] to not get a
    # KeyError if the cookie is missing.

储存 cookies:

from flask import make_response

@app.route('/')
def index():
    resp = make_response(render_template(...))
    resp.set_cookie('username', 'the username')
    return resp

response响应对象

json是目前api最常用的传输格式，可通过falsk.jsonify()返回

@app.route('/get/<id>', methods=['GET'])
def get_task(id)
      task = list(filter(lambda t: t['id'] == int(id), tasks))
      return jsonify(task[0]) if len(task)>0 else jsonify({'result': 'not found'})