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pythonflaskflask-sqlalchemypymssql

Output file stored in VARBINARY column with Flask

I have Flask frontend project and I use flask-sqlalchemy with pymssql database. There is existing .net tool that saves files to varbinary(max) column in sql server db and it can download files too just fine. Now I need flask view to output those files from varbinary(max) column.

I currently have the following code

// in model 

content = db.Column(VARBINARY())

// in view
query = models.File.query

f = query.filter(models.File.request_id == request_id).first_or_404()

response = Response(f.content, content_type='application/pdf')
response.headers["Content-Disposition"] = "attachment;filename={0}".format(file_name)

return response

Files are mostly pdfs and sample pdf is working just fine, but normal pdf files are corrupted, and I know they are ok in db, as .net client download them just fine.

So how to tweak f.content encoding so user would be able to open mentioned pdfs ?

Interesting that type(f.content) is returning 'str' so I belive flask-sqlalchemy internally converts array of bytes to string.

Solution

  • OK, I figured that out.

    Code I have was correct, and it outputs file in a right format.

    Problem was with freedts driver, it has limit of 64512 bytes in freedts.conf

    text size = 64512

    Changing it to something more sane fixes the error.