Do some browsers encode cookies?

Question

This is sort of a follow-up to http://stackoverflow.com/questions/2329395/why-are-my-cookies-containing-json-occasionally-malformed, which we have resolved.

I have a 3-value cookie, and we're url encoding the main value. The other two values are a timestamp and a hash. It looks like this in our response header:

foo=d=634027688530013385&v=%7b%22HasDog%22%3afalse%2c%22Greeting%22%3anull%2c%22RecentRecipes%22%3a%5b%5d%2c%22Remember%22%3afalse%7d&h=ARv5QGf4Cnftc4tFaPoy/VH8Pbo=; path=/; HttpOnly

In our logs, we see cases where we can't parse the three values correctly because the entire cookie is now encoded:

Cookie looks mangled: d%3D634027653097874122%26v%3D%7B%22HasAcceptedTerms%22%3Afalse%2C%22RecipeBoxCount%22%3A0%2C%22Remember%22%3Afalse%7D%26h%3DR85mJ%2FTdA6yrVe5pVCVpfG2jumM%3D

Unfortunately, we're not capturing the user agent to see if this is related to a specific browser.

I have several options to fix this. I just think the behavior is odd enough to warrant a question.

Answer 1

This may not be an answer but....

This is interesting and warrants a deeper look.

I would like to see a public facing test page that shows red or green with the cookie in bold text and then run it through http://browsercam.com.

I did this when I thought I had found a bug in mozilla's native json support. turns out I was right.

Get your testpage working for sure for sure before you fill out the form for a free trial (200 shots), set the resolution to 640/480 and select all browsers/platform, 182 distinct combinations, set a delay to allow the redirection to set the cookie and track down the culprit.

Or take the time and get on http://testswarm.com/.

Please do follow up on this.