How can I put binary data in a json string?
The binary data can't be encoded in a base64 string or something like that. Basically I need to know how to put a raw byte array as-is inside a json string.
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1 Answer
The JSON format natively doesn't support binary data. You have to encode it in some ways to convert binary data into text strings that can be accepted as a JSON string.
The most common way of doing so is Base64 encoding
{
"this_is_base_64": "aGVsbG8hIHVuZGVydGhldm9pZCEgSGVyZSBjYW4gYmUgc29tZSBCaW5hcnkgRGF0YSE="
}
Or alternatively, you can store individual bytes as a number array if the data you're willing to encode is not terribly large.
{
"my_data": [127, 21, 62, 31, 0, 16, 71, 23, 44, 51, 14, 61, 41, 65]
}
7 Comments
Miigon
You can try putting binary data between two double quotes in a JSON text. But I doubt it would be any useful since most parser won't be able to parse it.
Chris Dodd
Another common way of encoding it is as a hex string -- a string of (an even number of) hex digits.
Miigon
@underthevoid It shouldn't have. Which base64 library/method are you using to encode the data? Some library might try to be smart and handle charset/CRLF for you, which ruins binary data. However base64 is perfectly capable of encoding and decoding binary data with the right setting for your base64 library (or method).
Miigon
@underthevoid In fact, a lot of RESTful apis encodes files and images into base64 for transmission within http, then decodes it at the other end to get back the original file or image,
Miigon
@underthevoid Yes. You can. That's one major use case of base64 :-) The format itself doesn't change anything about the original data. But beware how you encode it though. If you're using C/C++ and uses a encode method that takes only a
const char *, but no length, as input, than that's most likely not gonna work. Since it likely assumed a zero-terminated string and not binary data. Your binary data can get chopped off in this case but still, it's not the fault of base64. |