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how to download data to b.csv that like a.csv format from gae localhost server .

Answer 1

A:

by loading the data into an sqlite db and then dumping that via the python csv module.

SpliFF 2010-06-19 03:40:02

-1 It looks like he already has an SQLite3 DB, *AND* the Python csv module doesn't read SQLite3 DBs!

John Machin 2010-06-19 03:43:45

don't be ridiculous, of course there's a step in reading the data and writing it through CSV but it's less than 10 lines of code. I'm not doing it for him, just pointing out it isn't difficult. I dump databases to CSV all the time.

SpliFF 2010-06-19 04:00:38

@SpliFF If you can write something that can dump _this_ sqlite DB to meaningful CSV in 10 lines of code, I'll be amazed. The database he's got is a data dump of his App Engine datastore, stored in encoded protocol buffer format. The better option is to do what gilesc demonstrates, and actually use the built in CSV dumper.

Nick Johnson 2010-06-19 17:43:24

Answer 2

A:

I strongly suggest that you dump the contents of b.csv by issuing the following command at your shell prompt

python -c"print repr(open('b.csv', 'rb').read())"

That way we can see what is actually in the file.

HOWEVER It looks very much like an SQLite3 database -- perhaps you need to explore what options the appcfg.py script has for choosing an output file format.

John Machin 2010-06-19 03:41:24

hi John, look the updated..

zjm1126 2010-06-19 04:17:05

Answer 3

+1 A:

As per http://appengine-cookbook.appspot.com/recipe/using-the-python-bulk-exporter-tool-with-a-java-application/ , first add the following to your str_loader.py:

class CollegeExporter(bulkloader.Exporter):
    def __init__(self):
        bulkloader.Exporter.__init__(self, 'College',
                                   [
                                    ('cid', str, None),
                                    ('name', lambda x: unicode(x, 'utf8'), None),
                                   ])
exporters = [CollegeExporter]

Next, run:

appcfg.py update zjm1126

appcfg.py download_data --config_file=upload/str_loader.py --application=zjm1126 --kind=College  --url=http://localhost:8100/remote_api --filename=b.csv

Of course you probably ultimately want to create a separate file for download vs. upload, but you get the idea.

gilesc 2010-06-19 03:42:05

hi gilesc, look the updated..

zjm1126 2010-06-19 04:01:58

Argh! It looks like the tuples in bulkloader.Exporter.__init__ require a third (default) argument. Try the slightly changed code above...

gilesc 2010-06-19 04:15:05

thanks very much

zjm1126 2010-06-19 04:46:50

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how to download data to b.csv that like a.csv format from gae localhost server .

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