在视图函数中，有没有一种方法可以将字符串与响应对象一起返回？

Question

以下代码段将文件发送到浏览器。你知道吗

# Prepare selected file for download...
filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

如果我想在发送文件之前打印一些行，如：

# Prepare selected file for download...
pdata = pdata + '''Your file will be ready for download'''
padata = pdata + '''it will just atake a moment'''

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

如果我尝试添加pdata+response，比如：

return pdata + send_from_directory( filepath, filename )

我得到一个错误，return应该只返回字符串，而不是string+response

Answer 1

如果要同时返回字符串和响应对象，请尝试以下操作：

return (pdata, send_from_directory(filepath, filename))

这将返回一个包含两种数据类型的元组。不能使用+符号，除非有两个兼容的对象，例如"string" + "string"或(tuple,) + (tuple,)

Answer 2

为什么不在你回来之前打印呢？你知道吗

def add(a, b):
    print(f"{a} is being added...")
    print(f"{b} is being added..")
    return a + b

c = add(1, 2)
print(c)

(xenial)vash@localhost:~/python/stack_overflow$ python3.7 strings.py
1 is being added...
2 is being added..
3

建议：

print(f'{pdata} "Your file will be ready for download..."')
print(f'{pdata} "it will just atake a moment..."')

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )

旧版Python：

print(f'{} "Your file will be ready for download..."'.format(pdata))
print(f'{} "it will just atake a moment..."'.format(pdata))

filename = request.form.get('filename')
filepath = '/home/nikos/wsgi/static/files/'

return send_from_directory( filepath, filename )