(PureBasic) Get RSA Public Key in JWK Format (JSON Web Key)

Demonstrates how to get an RSA public key in JWK (JSON Web Key) format.

Note: This example requires Chilkat v9.5.0.66 or later.

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IncludeFile "CkStringBuilder.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkPublicKey.pb"

Procedure ChilkatExample()

    ; Note: This example requires Chilkat v9.5.0.66 or later.

    ; Load a PEM file into memory.
    sbPem.i = CkStringBuilder::ckCreate()
    If sbPem.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkStringBuilder::ckLoadFile(sbPem,"qa_data/pem/rsa_public.pem","utf-8")
    If success <> 1
        Debug "Failed to load PEM file."
        CkStringBuilder::ckDispose(sbPem)
        ProcedureReturn
    EndIf

    ; Load the PEM into a public key object.
    pubKey.i = CkPublicKey::ckCreate()
    If pubKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPublicKey::ckLoadFromString(pubKey,CkStringBuilder::ckGetAsString(sbPem))
    If success <> 1
        Debug CkPublicKey::ckLastErrorText(pubKey)
        CkStringBuilder::ckDispose(sbPem)
        CkPublicKey::ckDispose(pubKey)
        ProcedureReturn
    EndIf

    ; Get the public key in JWK format:
    jwk.s = CkPublicKey::ckGetJwk(pubKey)

    ; The GetJwk method will return the JWK in the most compact JSON format possible,
    ; as a single line with no extra whitespace.  To get a more human-readable JWK (for this example),
    ; load into a Chilkat JSON object and emit non-compact:

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckLoad(json,jwk)
    CkJsonObject::setCkEmitCompact(json, 0)
    Debug "RSA Public Key in JWK format:"
    Debug CkJsonObject::ckEmit(json)

    ; Sample output:
    ; { 
    ;   "kty": "RSA",
    ;   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
    ;   "e": "AQAB"
    ; }

    ; Additional information can be added like this:
    CkJsonObject::ckAppendString(json,"use","enc")
    CkJsonObject::ckAppendString(json,"kid","123ABC")

    ; Now examine the JSON:
    Debug CkJsonObject::ckEmit(json)

    ; { 
    ;   "kty": "RSA",
    ;   "n": "33TqqLR3eeUmDtHS89qF3p4MP7Wfqt2Zjj3lZjLjjCGDvwr9cJNlNDiuKboODgUiT4ZdPWbOiMAfDcDzlOxA04DDnEFGAf-kDQiNSe2ZtqC7bnIc8-KSG_qOGQIVaay4Ucr6ovDkykO5Hxn7OU7sJp9TP9H0JH8zMQA6YzijYH9LsupTerrY3U6zyihVEDXXOv08vBHk50BMFJbE9iwFwnxCsU5-UZUZYw87Uu0n4LPFS9BT8tUIvAfnRXIEWCha3KbFWmdZQZlyrFw0buUEf0YN3_Q0auBkdbDR_ES2PbgKTJdkjc_rEeM0TxvOUf7HuUNOhrtAVEN1D5uuxE1WSw",
    ;   "e": "AQAB",
    ;   "use": "enc",
    ;   "kid": "123ABC"
    ; }


    CkStringBuilder::ckDispose(sbPem)
    CkPublicKey::ckDispose(pubKey)
    CkJsonObject::ckDispose(json)


    ProcedureReturn
EndProcedure