Bottom line: If you keep getting “No JSON object could be decoded” when loading JSON objects in django that look perfectly valid then make sure that you are using ASCII encoding.

I have been experimenting with django’s test framework and I recently hit a wall while creating a JSON fixture. Django wouldn’t like my JSON file and keep spitting out…

Problem installing fixture 'thebitguru/nodes/fixtures/nofmt_nodes.json': No JSON object could be decoded

The fixture was very simple and for the longest time I couldn’t figure out what was wrong. I had used the code>dumpdata command to dump the JSON in the first place, but after Magus- on #django (IRC) asked me if that’s what I had done, I decided to do it again. This time somehow magically it worked! I used TortoiseMerge to diff the two files and it claimed that they were exactly the same. Obviously, they weren’t!

I, being I who I am, wasn’t satisfied without finding out really why my initial export was not working. So, off I went to do some investigation. After about fifteen minutes and several different hex dumps and google searches I was looking at this wikipedia entry. Yes, 0xFEFF! That was the key to this puzzle. So, somehow my initial export had ended up in UTF-16 Big Endian encoding. A quick encoding change in VIM, set fileencoding=ascii, and everything was back to normal.

I took a trip down the memory lane and realized that I was using PowerShell at the time, and considering that it is fairly new and fancy shell I guessed that it must probably is using Unicode as the default output. If you look through the PowerShell User Guide you will see this specifically mentioned…

By default, the Out-File cmdlet creates a Unicode file. This is the best default in the long run, but it means that tools that expect ASCII files will not work correctly with the default output format. You can change the default output format to ASCII by using the Encoding parameter:

PS> Get-Process | Out-File -FilePath C:\temp\processlist.txt -Encoding ASCII

Another quick test verified that this was in fact the cause. Whew! Finally, another mystery solved!

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