Flask - 如何使用蓝图提供静态文件？答案

【问题标题】：Flask - How to serve static files with Blueprint?Flask - 如何使用蓝图提供静态文件？
【发布时间】：2017-03-24 06:37:50
【问题描述】：

我无法使用 Flask 从蓝图中提供静态文件。我知道这个问题已经被问过很多次了，但感觉说明不清楚。另外，我无法让它工作。我有以下文件结构：

  FlaskApp
    ├──__init__.py # Let's call it OuterInit.
    └── FlaskApp
        ├──__init__.py # Let's call it InnerInit.
        ├── modulo
        │   └── main.py #My blueprint
        ├── mongo
        │   └── otherBlueprint... Still not developed.
        ├── __pycache__
        ├── resources
        ├── static
        │   ├── public
        │   │   └── SomePublicFiles...
        │   └── R
        |       └── TheFileIWant.R #I want to serve this file
        └── templates
             └── index.html #I serve this template from my Blueprint. (it works)

外部初始化：这个文件只是启动服务。这就像我的主要。有人告诉我这是一个很好的做法。

from FlaskApp import app
app.run()

InnerInit：此文件注册蓝图并创建应用程序。

from flask import Flask, render_template
app = Flask(__name__)
from FlaskApp.modulo.main import map_module
app.register_blueprint(map_module)

Main.py：这里我暴露了这个模块的API服务。

import os
otherImports...

static_folder = os.path.join(os.pardir, 'static')
map_module = Blueprint('map_module', __name__, static_folder=static_folder, static_url_path="/static")

@map_module.route("/map")
def map():
    return render_template("index.html")

@map_module.route("/serviceData")
def serviceData():
    r = robjects.r
    r.source("R/TheFileIWant.R")
    return "Ok."

我可以提供 index.html 文件，它实际上显示了许多动态元素...但我无法使用 rpy2 访问 R 文件。我确信这与蓝图有关，因为在创建蓝图（使程序更加模块化）之前它已经工作了。

这是我访问“http://localhost:5000/serviceData”时得到的结果

(flaskEnv) python_user@Pipepc:~/Documents/FlaskApp$ python __init__.py 
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning: Error in file(filename, "r", encoding = encoding) : 
  cannot open the connection

  warnings.warn(x, RRuntimeWarning)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning: In addition: 
  warnings.warn(x, RRuntimeWarning)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning: Warning message:

  warnings.warn(x, RRuntimeWarning)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning: In file(filename, "r", encoding = encoding) :
  warnings.warn(x, RRuntimeWarning)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning: 

  warnings.warn(x, RRuntimeWarning)
/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/rinterface/__init__.py:186: RRuntimeWarning:  cannot open file 'R/rmethod.R': No such file or directory

  warnings.warn(x, RRuntimeWarning)
[2017-03-24 01:36:28,320] ERROR in app: Exception on /serviceData [GET]
Traceback (most recent call last):
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/python_user/Documents/FlaskApp/FlaskApp/modulo/main.py", line 19, in serviceData
    r.source("R/rmethod.R")
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/robjects/functions.py", line 178, in __call__
    return super(SignatureTranslatedFunction, self).__call__(*args, **kwargs)
  File "/home/python_user/Documents/flaskEnv/local/lib/python3.4/site-packages/rpy2/robjects/functions.py", line 106, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
rpy2.rinterface.RRuntimeError: Error in file(filename, "r", encoding = encoding) : 
  cannot open the connection

【问题讨论】：

Python 提供了获取当前模块目录的方法。请改用它们。
能否请您进一步解释并给出解决方案。我对 webframeworks 很陌生，使用 Flask 提供文件并不是很简单。
请学习阅读docs。谢谢。
我确实阅读了它们，但我无法让它仍然工作......
我假设您知道您将相对路径传递给 r.path 并且您已修复它。

标签： python flask

【解决方案1】：

问题在于您对 R 的调用：

@map_module.route("/serviceData")
def serviceData():
r = robjects.r
r.source("R/TheFileIWant.R")
return "Ok."

改成这样：

r.source(map_module.root_path + "/R/TheFileIWant.R)

另外，将 R 文件移动到蓝图下的文件夹中。它根本不是一个静态文件（定义是“由 Web 服务器按原样提供”）。

【讨论】：