Question

I m trying to use compressed data with my Tasks in the Task Queue like so:

t = taskqueue.Task(url= /tasks/queue ,
                   params={ param : zlib.compress(some_string)}

However when I try to decompress it in the queue handler like so

message = self.request.get( param )
message = zlib.decompress(message)

I get this error:

UnicodeEncodeError: ascii codec can t encode character u u06b8 in position 2: ordinal not in range(128)

Anyone know of what s going on here? Is there a work around?

Answer 1

Instead of using params, use payload, which includes your data in the body of the request, unencoded. Then you can use zlib.decompress(self.request.body) to retrieve the data.

Answer 2

Read the docs... (my emphasis!):

params Dictionary of parameters to use for this Task. Values in the dictionary may be iterable to indicate repeated parameters. May not be specified for a POST request if payload is already specified. For POST requests, these params will be encoded as application/x-www-form-urlencoded and set to the payload; for all other methods, the parameters will be converted to a query string. May not be specified if the URL already contains a query string and the method is GET.

zlib.compress produces an arbitrary string of bytes... but then query-string conversion interprets it as Unicode! So, use any 1-byte codec, such as latin-1, to .encode the compressed results in order to pass (what s actually a binary) bytestring of params, and the same codec for a .decode to get back from the "unicode" string to a string of bytes that you can decompress. Phew... you sure the compression is crucial enough to your app s performance to be worth this weird set of gyrations, or wouldn t it be better to eschew it?-)

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