Add SetContext on Builder interface and GetContext on Biscuit struct.

[Benoit12345]

To be able to set a context and retrieve it form a biscuit.

[seh]

What is a "context" in this context?

[Benoit12345]

"context" is the second field of the block liked it is indicated into the spec:

message Block {
  repeated string symbols = 1;
  optional string context = 2;
  optional uint32 version = 3;
  repeated FactV2 facts_v2 = 4;
  repeated RuleV2 rules_v2 = 5;
  repeated CheckV2 checks_v2 = 6;
  repeated Scope scope = 7;
  repeated PublicKey publicKeys = 8;
}

And the goal is to be able to be equivalent to the java biscuit library (https://github.com/biscuit-auth/biscuit-java/blob/a863cd8c0bd45ad1e36390ce777741e49417da0e/src/main/java/org/biscuitsec/biscuit/token/builder/Biscuit.java#L119)

if you're question is "are you talking about a Go std context ?", the answer is no but the context from biscuit specification.

[seh]

"context" is the second field of the block liked it is indicated into the spec:

I did see that field in the IDL before asking the question here, but I'm wondering what a typical value would be for such a "context", who sets it, who consumes it, and why.

[divarvel]

"context" is the second field of the block liked it is indicated into the spec:

I did see that field in the IDL before asking the question here, but I'm wondering what a typical value would be for such a "context", who sets it, who consumes it, and why.

It is intended as a way to embed a payload outside datalog. so something freeform that would not be directly used in the authorization context. It’s a remnant of early biscuit days, meant as some kind of escape hatch.