RJSON: compress JSON to JSON

#1

Post by dogada » Tue, Jun 05, 2012, 12:41 PM UTC

Re: RJSON: compress JSON to JSON

#2

Post by ZenPsycho » Tue, Jun 05, 2012, 1:07 PM UTC

I see a pretty major problem with this. It seems to depend on the order of key value pairs in object literals being defined. The order is not defined by the JSON or the ecmascript standards. So you can't really depend on the order of keys in a json object, unless you explicitly define some order (like alphabetical, for instance). I like the basic concept of compressing json to json but this is not a particularly good way to do it- since the order of those keys may not be preserved in round trips through json encoders and decoders in various languages.

Re: RJSON: compress JSON to JSON

#3

Post by perfunctory » Tue, Jun 05, 2012, 1:10 PM UTC

How would it compress and then decompress the following document?

  {"users": [
    {"first": "Homer", "last": "Simpson"},
    {"first": "Hank", "last": "Hill"},
    [2, "Peter", "Griffin"]
  }

Re: RJSON: compress JSON to JSON

#4

Post by [deleted] » Tue, Jun 05, 2012, 1:13 PM UTC

ZenPsycho wrote: post #2

I see a pretty major problem with this. It seems to depend on the order of key value pairs in object literals being defined. The order is not defined by the JSON or the ecmascript standards. So you can't really depend on the order of keys in a json object, unless you explicitly define some order (like alphabetical, for instance). I like the basic concept of compressing json to json but this is not a particularly good…

[deleted]

Re: RJSON: compress JSON to JSON

#5

Post by ZenPsycho » Tue, Jun 05, 2012, 1:19 PM UTC

[deleted] wrote: post #4

ZenPsycho wrote: post #2

I see a pretty major problem with this. It seems to depend on the order of key value pairs in object literals being defined. The order is not defined by the JSON or the ecmascript standards. So you can't really depend on the order of keys in a json object, unless you explicitly define some order (like alphabetical, for instance). I like the basic concept of compressing json to json but this is not a particularly good…

[deleted]

that is only enough to make it seem like it works okay. But as I said, there's nothing in the JSON spec that obligates any intervening party to preserve the order of the keys in the object.

Re: RJSON: compress JSON to JSON

#6

Post by asdfaoeu » Tue, Jun 05, 2012, 1:24 PM UTC

perfunctory wrote: post #3

How would it compress and then decompress the following document? {"users": [ {"first": "Homer", "last": "Simpson"}, {"first": "Hank", "last": "Hill"}, [2, "Peter", "Griffin"] }

    {
        "users": [
            {
                "first": "Homer",
                "last": "Simpson"
            },
            [
                2,
                "Hank",
                "Hill"
            ],
            [
                0,
                2,
                "Peter",
                "Griffin"
            ]
        ]
    }

There was a tester linked from the site. Looks like he added the [0, to handle that case.

Re: RJSON: compress JSON to JSON

#7

Post by judofyr » Tue, Jun 05, 2012, 1:24 PM UTC

perfunctory wrote: post #3

How would it compress and then decompress the following document? {"users": [ {"first": "Homer", "last": "Simpson"}, {"first": "Hank", "last": "Hill"}, [2, "Peter", "Griffin"] }

There's a demo here: http://www.cliws.com/p/rjson/

It comes it to:

    {
      "users": [
        {
          "first": "Homer",
          "last": "Simpson"
        },
        [
          2,
          "Hank",
          "Hill"
        ],
        [
          0,
          2,
          "Peter",
          "Griffin"
        ]
      ]
    }

Re: RJSON: compress JSON to JSON

#8

Post by jimktrains2 » Tue, Jun 05, 2012, 1:25 PM UTC

> reduce JSON data size and network traffic when gzip isn't available. For example, in-browser 3D-modeling tools like Mydeco 3D-planner may process and send to server megabytes of JSON-data;

`Content-encoding: gzip` anyone?

Re: RJSON: compress JSON to JSON

#9

Post by whalesalad » Tue, Jun 05, 2012, 1:26 PM UTC

ZenPsycho wrote: post #2

I see a pretty major problem with this. It seems to depend on the order of key value pairs in object literals being defined. The order is not defined by the JSON or the ecmascript standards. So you can't really depend on the order of keys in a json object, unless you explicitly define some order (like alphabetical, for instance). I like the basic concept of compressing json to json but this is not a particularly good…

I saw the same thing right away. Seems like the first item in the array would have to be used as a hash of key/index pairs to be used for the following items. I guess this would only be useful with large sets of data, the examples makes them look kind of silly =)

So this:

    "users": [
        {"first": "Homer", "last": "Simpson"},
        {"first": "Hank", "last": "Hill"},
        {"first": "Peter", "last": "Griffin"}
    ],

Becomes:

    "users": [
        ["first", "last"],
        ["Homer", "Simpson"],
        ["Hank", "Hill"],
        ["Peter", "Griffin"]
    ],

Re: RJSON: compress JSON to JSON

#10

Post by mhansen » Tue, Jun 05, 2012, 1:34 PM UTC

jimktrains2 wrote: post #8

> reduce JSON data size and network traffic when gzip isn't available. For example, in-browser 3D-modeling tools like Mydeco 3D-planner may process and send to server megabytes of JSON-data; `Content-encoding: gzip` anyone?

I don't believe that browsers let uploads be gzipped, as it can't be sure that the server supports gzipped requests.