Issue #6 Help using RSA public/private keypairs to sign #6

examples/simple_ex3_rsa.cc

@@ -0,0 +1,82 @@
+#include <chrono>
+#include <cassert>
+#include <fstream>
+#include <string>
+#include <iostream>
+#include "jwt/jwt.hpp"
+
+/***
+ * STEPS TO GENERATE RSA PRIVATE PUBLIC KEYPAIR.
+ *
+ * 1. openssl genrsa -out jwtRS256.key 1024
+ * 2. openssl rsa -in jwtRS256.key -pubout -outform PEM -out jwtRS256.key.pub
+ */
+
+std::string read_from_file(const std::string& path)
+{
+  std::string contents;
+  std::ifstream is{path, std::ifstream::binary};
+
+  if (is) {
+    // get length of file:
+    is.seekg (0, is.end);
+    auto length = is.tellg();
+    is.seekg (0, is.beg);
+    contents.resize(length);
+
+    is.read(&contents[0], length);
+    if (!is) {
+      is.close();
+      return {};
+    }
+  } else {
+    std::cerr << "FILE not FOUND!!" << std::endl;
+  }
+
+  is.close();
+  return contents;
+}
+
+int main() {
+  using namespace jwt::params;
+  const std::string priv_key_path =  std::string{CERT_ROOT_DIR} + "/jwtRS256.key";
+  const std::string pub_key_path = std::string{CERT_ROOT_DIR} + "/jwtRS256.key.pub";
+
+  auto priv_key = read_from_file(priv_key_path);
+
+  jwt::jwt_object obj{algorithm("rs256"), secret(priv_key), payload({{"user", "admin"}})};
+
+  //Use add_claim API to add claim values which are
+  // _not_ strings.
+  // For eg: `iat` and `exp` claims below.
+  // Other claims could have been added in the payload
+  // function above as they are just stringy things.
+  obj.add_claim("iss", "arun.muralidharan")
+     .add_claim("sub", "test")
+     .add_claim("id", "a-b-c-d-e-f-1-2-3")
+     .add_claim("iat", 1513862371)
+     .add_claim("exp", std::chrono::system_clock::now() + std::chrono::seconds{10})
+     ;
+
+  //Use `has_claim` to check if the claim exists or not
+  assert (obj.has_claim("iss"));
+  assert (obj.has_claim("exp"));
+
+  //Use `has_claim_with_value` to check if the claim exists
+  //with a specific value or not.
+  assert (obj.payload().has_claim_with_value("id", "a-b-c-d-e-f-1-2-3"));
+  assert (obj.payload().has_claim_with_value("iat", 1513862371));
+
+  auto pub_key = read_from_file(pub_key_path);
+
+  std::error_code ec{};
+  auto sign = obj.signature(ec);
+  if (ec) {
+    std::cerr << ec.message() << std::endl;
+    return 1;
+  }
+
+  auto dec_obj = jwt::decode(sign, algorithms({"rs256"}), verify(false), secret(pub_key));
+
+  return 0;
+}