Figured it out: streams have this builtin position attr which bytesIO uses
to keep track of to know where to insert data. Reportlab simpledoctemplate
writes to the stream object, but when it completes pdf generation at
doc.build(story), it doesn't reset the stream position back to the
beginning of the file. as a result the s3 put_object method writes only the
portion of the file from where the position is at currently, through to the
end, resulting in corrupt file. all that was neeeded was to reset the
stream position just before writing to s3 using stream.seek(0)
On Monday, 22 April 2019 21:18:14 UTC+10, Danny Blaker wrote:
>
> I'm trying to generate a PDF using reportlab and write to s3 bucket
> without saving locally
>
> I know I'm missing something simple:
>
> # create a stream
> stream = io.BytesIO()
>
> # generate PDF
> doc = SimpleDocTemplate(stream, pagesize=letter,
> rightMargin=72, leftMargin=72,
> topMargin=72, bottomMargin=18)
> Story = []
>
> styles = getSampleStyleSheet()
>
> Story.append(Paragraph('<font size=11>This is a PDF</font>',
> styles["Normal"]))
>
> doc.build(Story)
>
> # get buffer
> pdf_buffer = stream.getbuffer()
>
> filename = "new.pdf"
> bucket_name = 'insert_bucket_name'
> object_name = bucket_name
>
> # here is where I get stuck - how should be passing the pdf_buffer to s3?
>
> # how you typically write to s3 :
> # Method 1
>
> s3 = boto3.client('s3')
> with open(filename, "rb") as f:
> s3.upload_fileobj(f, bucket_name, object_name)
>
> # Method 2
> s3.Bucket(bucket_name).put_object(Key=filename, Body=file)
>
> Any ideas most appreciated!
>
> Thanks!
>
> here are some related resources:
>
>
> https://stackoverflow.com/questions/43373006/django-reportlab-save-generated-pdf-directly-to-filefield-in-aws-s3
> https://sciwiki.fredhutch.org/compdemos/aws-python/#about-pandas-and-dask
>
> https://stackoverflow.com/questions/12570465/how-to-upload-a-file-to-s3-without-creating-a-temporary-local-file
>
>
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