[question] Can I add claims without id?

[MountainNine]

For example, I want to add payload claims with this JSON format. {'test':'hello', 'test2':123} I looked jwt.h, and I found 'set_payload_claim' function. But this function needs 'id' parameter, and I don't want to contain id. Can I add this payload_claim without adding id? Thank you.

[prince-chrismc]

Hmm 🤔 I am not sure I understood your question so let me know if I missed the mark.

So JWT are JSON object those are key value pairs. If youd like to add a claim it needs to have a key (the API id might be unclear, let us know).

So if you use

https://github.com/Thalhammer/jwt-cpp/blob/9d1a010fea3ed3293112edec9745dc435a85a849/include/jwt-cpp/jwt.h#L2702

Like so

https://github.com/Thalhammer/jwt-cpp/blob/9d1a010fea3ed3293112edec9745dc435a85a849/example/private-claims.cpp#L30

You are able to add any JSON value for the id you want to access it with.

And for completeness, here's how youd access the value

https://github.com/Thalhammer/jwt-cpp/blob/9d1a010fea3ed3293112edec9745dc435a85a849/example/traits/kazuho-picojson.cpp#L36-L37

By passing the id... here's he output

https://github.com/Thalhammer/jwt-cpp/runs/5156063883?check_suite_focus=true#step:11:1605

[MountainNine]

What I want to do is to set payload claim without id.

According to the link,

https://github.com/Thalhammer/jwt-cpp/blob/9d1a010fea3ed3293112edec9745dc435a85a849/example/private-claims.cpp#L30

payload_claims variable is set to this.

{'object':{'test':'hello', 'test2':123}}

But I want to set payload_claims like this.

{'test':'hello', 'test2':123}

More specifically, I looked jwt.h, and found this code.

https://github.com/Thalhammer/jwt-cpp/blob/9d1a010fea3ed3293112edec9745dc435a85a849/include/jwt-cpp/jwt.h#L2702-L2705

What I want to do is to set payload_claims itself, not payload_claims[id], like this.

payload_claims = std::move(c)

How to implement this?

I apologize about Insufficient explanation.

[MountainNine]

Never Mind, I solved it by adding the function in jwt.h

        builder& set_payload(typename json_traits::object_type jsonStr) {
            payload_claims = std::move(jsonStr);
            return *this;
        }

Thanks for help, prince.

[prince-chrismc]

Ohh!

You could have called the method twice.

builder.set_payload_claim("test", /* json string hello */);
builder.set_payload_claim("test2", /* other */);

Thanks for sharing your solution!

PS you might be missing some other claims that are recommended like issuer. Not sure your application or situation but wanted to throw that in.

[Thalhammer]

@MountainNine If I understood correctly what you wanted to do is replace the payload claims entirely. You are right that this is not supported by default and the reason for this is simple: JWT requires certain claims to be present and set to correct values. Otherwise its not a valid jwt and jwt-cpp (or any other jwt library) will not correctly verify it. If you have a third party application that requires exactly this, then your way is probably fine, however if you control the layout of the jwt I highly recommend sticking with the defaults.

[atlantis013]

Never Mind, I solved it by adding the function in jwt.h

      builder& set_payload(typename json_traits::object_type jsonStr) {
          payload_claims = std::move(jsonStr);
          return *this;
        }

Thanks for help, prince.

̶C̶a̶n̶ ̶y̶o̶u̶ ̶s̶h̶o̶w̶ ̶h̶o̶w̶ ̶s̶e̶t̶_̶p̶a̶y̶l̶o̶a̶d̶ ̶i̶s̶ ̶c̶a̶l̶l̶e̶d̶?̶ ̶M̶y̶ ̶p̶r̶o̶b̶l̶e̶m̶ ̶i̶s̶ ̶t̶o̶ ̶p̶a̶s̶s̶ ̶t̶o̶ ̶t̶h̶e̶ ̶f̶u̶n̶c̶t̶i̶o̶n̶ ̶t̶h̶e̶ ̶j̶s̶o̶n̶ ̶t̶h̶a̶t̶ ̶I̶ ̶r̶e̶c̶e̶i̶v̶e̶d̶ ̶a̶s̶ ̶s̶t̶d̶:̶:̶s̶t̶r̶i̶n̶g̶.̶ ̶T̶h̶a̶n̶k̶ ̶y̶o̶u̶.̶

Solved.

std::string payload = "{'test':'hello', 'test2':123}";
picojson::value json_value;
std::string err = picojson::parse(json_value, payload);
if (!err.empty()) {
    std::cout << err << std::endl;
    return false;
}
auto token = jwt::create()
    .set_type("JWT")
    .set_payload(jwt::traits::kazuho_picojson::as_object(json_value))
    .sign(jwt::algorithm::rs256("", private_key, "", ""));