如何设置FlaskAPI以将数据从python函数返回到flask路由

Question

我试图在一个名为poemBot.py的文件中显示python函数输出的一些数据，并使用一个简单的flask应用程序在网页中显示该输出。这里是到github repo的链接：https://github.com/nditanaka/flask_poembot_app我的路由设置如下：

import time
from flask import Flask, request, render_template, jsonify
from poemBot import tap

app = Flask(__name__)


@app.route('/')
def hello():
    return tap()


@app.route('/time')
def get_current_time():
    return {'time': time.time()}


@app.route('/api/about')
def about():
    return 'This is the about page'


@app.route('/api/poem')
def get_random_poem():
    return tap()

调用tap（）函数的poemBot文件如下所示：

#!/usr/bin/python
# main.py
from __future__ import print_function
import subprocess
import time
import socket
import csv
import textwrap
import random


def printPoem():
    # get a random poem
    randPoem = random.choice(allPoems)
    # nicely wrap the content for the printer
    # Title and Author are printed in 'M' medium font, limit is 32 character per line
    # poem is printed in 'S' small font, limit is 32 characters per line
    # book and publisher are in "fontB", limit is 42 character per line
    wrappedTitle = textwrap.fill(randPoem[1], width=32)
    wrappedAuthor = textwrap.fill(randPoem[2], width=32)
    wrappedPoem = ""
    for line in randPoem[3].splitlines():
        wrappedLine = textwrap.fill(line, width=32, subsequent_indent="    ")
        wrappedPoem += wrappedLine + "\n"
    # print the poem
    # return (wrappedTitle, '\n', wrappedPoem, '\n',
        # wrappedAuthor, '\n', randPoem[4], '\n', randPoem[0])
    years = str(randPoem[4])
    author = str(wrappedTitle)
    poem = wrappedAuthor
    url = str(randPoem[3])

    return {author, poem, years, url}
# Print random poem, called on tap


def tap():
    # print a random poem
    return printPoem()


def hold():
    return ('Goodbye!')


# Load up all poems from CSV
# poem CSV is structured with the columns: number,title,author,poem,book
# goldenTreasuryPoems.csv was parsed from the text of Project Gutenberg EBook #19221
# http://www.gutenberg.org/ebooks/19221
# the poem column contains the full text of the poem with no markup, only \n
# the CSV is in PC437 encoding since the printer only supports this character set
with open('poembot_poems_2020.csv') as csvPoems:
    allPoems = list(csv.reader(csvPoems, delimiter=','))

# Start printing
print('Hello!')
print('Ready to print')
tap()

poemBot.py文件的工作原理是读取csv文件，然后通过printpoom（）函数输出该文件的内容。我怀疑我的printpooth（）返回了错误类型的对象，或者我在main.py中的routes中调用tap（）的方式是错误的

当我使用flask run运行flask应用程序时，得到的错误是

"The view function did not return a valid response. The" TypeError: The view function did not return a valid response. The function either returned None or ended without a return statement.

编辑：修改了文件，现在的错误是：

TypeError: The view function did not return a valid response tuple. The tuple must have the form (body, status, headers), (body, status), or (body, headers).

Answer 1

您的代码中有许多内容需要更改：
1）创建路由函数时，它必须返回渲染模板对象或字符串。 应该是这样的：

@app.route('/api/poem')
def get_random_poem():
    return tap() 
    # tap() as to be a string

2）如果知道将导入文件，则应使用“名称””变量：

if __name__ == "__main__":
    # execute only if run as a script
    print('Hello!')
    print('Ready to print')
    tap()
    

3）使用逗号“”返回值时，它将类型转换为元组。如果希望它是字符串，则必须使用操作数“+”

return "line1" + "\n" + "line2...

希望对你有帮助