创建和下载一个csv文件 [英] Create and download a csv file
本文介绍了创建和下载一个csv文件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
解决方案
使用 csv.writer
和流响应。使用 StringIO 写入内存缓冲区,而不是生成中间文件。
以下是一个简单的例子。
import csv
from datetime import datetime
from cstringio import StringIO
从烧瓶导入Flask,stream_with_context
from werkzeug.datastructures import标题
from werkzeug.wrappers import Response
app = Flask(__ name__)
#示例数据,这可能来自存储日志的任何位置
log = [
('login'日期时间(2015,1,10,5,30)),
('deposit',datetime(2015,1,10,5,35)),
('order',datetime(2015, 1,10,5,50)),
('withdraw',datetime(2015,1,10,6,10)),
('logout',datetime(2015,1,10,
]
@ app.route('/')
def download_log():
def generate():
data = Stri ngIO()
w = csv.writer(data)
#write header
w.writerow(('action','timestamp'))
yield data。 getvalue()
data.seek(0)
data.truncate(0)
#写每个日志项
对于日志中的项:
w .writerow((
item [0],
item [1] .isoformat()#format datetime as string
))
yield data.getvalue()
data.seek(0)
data.truncate(0)
#添加文件名
headers = Headers()
headers.set('Content-Disposition' ,'attachment',filename ='log.csv')
#生成数据时生成的响应
返回响应(
stream_with_context(generate()),
mimetype ='text / csv',headers = headers
)
app.run()
My Flask application is deployed on Google App Engine. I am trying to allow the user to download a csv file with data defined by their actions. How can I do this in Flask?
解决方案
Generate the data with csv.writer
and stream the response. Use StringIO to write to an in-memory buffer rather than generating an intermediate file.
The following is a short example of how to do this.
import csv
from datetime import datetime
from cstringio import StringIO
from flask import Flask, stream_with_context
from werkzeug.datastructures import Headers
from werkzeug.wrappers import Response
app = Flask(__name__)
# example data, this could come from wherever you are storing logs
log = [
('login', datetime(2015, 1, 10, 5, 30)),
('deposit', datetime(2015, 1, 10, 5, 35)),
('order', datetime(2015, 1, 10, 5, 50)),
('withdraw', datetime(2015, 1, 10, 6, 10)),
('logout', datetime(2015, 1, 10, 6, 15))
]
@app.route('/')
def download_log():
def generate():
data = StringIO()
w = csv.writer(data)
# write header
w.writerow(('action', 'timestamp'))
yield data.getvalue()
data.seek(0)
data.truncate(0)
# write each log item
for item in log:
w.writerow((
item[0],
item[1].isoformat() # format datetime as string
))
yield data.getvalue()
data.seek(0)
data.truncate(0)
# add a filename
headers = Headers()
headers.set('Content-Disposition', 'attachment', filename='log.csv')
# stream the response as the data is generated
return Response(
stream_with_context(generate()),
mimetype='text/csv', headers=headers
)
app.run()
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