Hello,
I am passing a lot of data between PHP and JavaScript. I am using JSON and json_encode in php, but the problem here is that I am passing a lot of numbers stored as strings - for example, numbers like 1.2345.
Is there a way to pass the data directly as numbers (floats, integers) and not have to convert it to ASCII and then back?
Thanks,
No. HTTP is a byte stream protocol(*); anything that goes down it has to be packed into bytes. You can certainly use a more compact packed binary representation of values if you like, but it's going to be much more work for your PHP to encode and your JS to decode.
Anyhow, for the common case of small numbers, text representations tend to be very efficient. Your example 1.2345 is actually smaller as a string (6 bytes) than a double-precision float (8 bytes).
JSON was invented precisely to allow non-string types to be transferred over the HTTP connection. It's as seamless as you're going to get. Is there any good reason to care that there was a serialise->string->parse step between the PHP float and the JavaScript Number?
(* exposed to JavaScript as a character protocol, since JS has no byte datatype. By setting the charset of the JSON response to iso-8859-1 you can make it work as if it were pure bytes, but the default utf-8 is usually more suitable.)
If you didn't want to use JSON, there are other encoding options. The data returned from an HTTP request is an octect stream (and not 7-bit clean ASCII stream -- if it were, there would be no way to server UTF-8 encoded documents or binary files, as simple counter examples).
Some binary serialization/data protocols are ASN.1, Thrift, Google Protocol Buffers, Avro, or, of course, some custom format. The advantage of JSON is "unified human-readable simplicity".
But in the end -- JSON is JSON.
Perhaps of interest to someone: JavaScript Protocol Buffer Implementation