[英]How can I generate file on the fly and delete it after download?
here's my function that creates file on the fly(when the user clicks proper link) 这是我的功能,即动创建文件(当用户点击正确的链接时)
@app.route('/survey/<survey_id>/report')
def survey_downloadreport(survey_id):
survey, bsonobj = survey_get(survey_id) #get object
resps = response_get_multi(survey_id) #get responses to the object
fields = ["_id", "sid", "date", "user_ip"] #meta-fields
fields.extend(survey.formfields) #survey-specific fields
randname = "".join(random.sample(string.letters + string.digits, 15)) + ".csv" #some random file name
with open("static//" + randname, "wb") as csvf:
wr = csv.DictWriter(csvf, fields, encoding = 'cp949')
wr.writerow(dict(zip(fields, fields))) #dummy, to explain what each column means
for resp in resps :
wr.writerow(resp)
return send_from_directory("static", randname, as_attachment = True)
I'd like to have file to be deleted after completing of the download. 我想在完成下载后删除文件。 How can I do it?
我该怎么做?
On Linux, if you have an open file you can still read it even when deleted. 在Linux上,如果您有一个打开的文件,即使删除它也仍然可以读取它。 Do this:
做这个:
import tempfile
from flask import send_file
csvf = tempfile.TemporaryFile()
wr = csv.DictWriter(csvf, fields, encoding = 'cp949')
wr.writerow(dict(zip(fields, fields))) #dummy, to explain what each column means
for resp in resps :
wr.writerow(resp)
wr.close()
csvf.seek(0) # rewind to the start
send_file(csvf, as_attachment=True, attachment_filename='survey.csv')
The csvf
file is deleted as soon as it is created; csvf
文件一旦创建就会被删除; the OS will reclaim the space once the file is closed (which cpython will do for you as soon as the request is completed and the last reference to the file object is deleted). 一旦文件关闭,操作系统将回收空间(一旦请求完成并且删除了对文件对象的最后一个引用,cpython将为您完成)。 Optionally, you could use the
after_this_request
hook to explicitly close the file object. (可选)您可以使用
after_this_request
挂钩显式关闭文件对象。
I've used os.unlink for a while with success: 我已经成功地使用了os.unlink一段时间了:
import os
os.unlink(os.path.join('/path/files/csv/', '%s' % file))
Hope it helps. 希望能帮助到你。
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