credentials.h

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#ifndef GRPCXX_SECURITY_CREDENTIALS_H
#define GRPCXX_SECURITY_CREDENTIALS_H

#include <map>
#include <memory>

#include <grpc++/impl/codegen/grpc_library.h>
#include <grpc++/security/auth_context.h>
#include <grpc++/support/status.h>
#include <grpc++/support/string_ref.h>

struct grpc_call;

namespace grpc {
class ChannelArguments;
class Channel;
class SecureChannelCredentials;
class CallCredentials;
class SecureCallCredentials;

class ChannelCredentials : private GrpcLibraryCodegen {
 public:
  ChannelCredentials();
  ~ChannelCredentials();

 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);

  virtual SecureChannelCredentials* AsSecureCredentials() = 0;

 private:
  friend std::shared_ptr<Channel> CreateCustomChannel(
      const grpc::string& target,
      const std::shared_ptr<ChannelCredentials>& creds,
      const ChannelArguments& args);

  virtual std::shared_ptr<Channel> CreateChannel(
      const grpc::string& target, const ChannelArguments& args) = 0;
};

class CallCredentials : private GrpcLibraryCodegen {
 public:
  CallCredentials();
  ~CallCredentials();

  virtual bool ApplyToCall(grpc_call* call) = 0;

 protected:
  friend std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
      const std::shared_ptr<ChannelCredentials>& channel_creds,
      const std::shared_ptr<CallCredentials>& call_creds);

  friend std::shared_ptr<CallCredentials> CompositeCallCredentials(
      const std::shared_ptr<CallCredentials>& creds1,
      const std::shared_ptr<CallCredentials>& creds2);

  virtual SecureCallCredentials* AsSecureCredentials() = 0;
};

struct SslCredentialsOptions {
  grpc::string pem_root_certs;

  grpc::string pem_private_key;

  grpc::string pem_cert_chain;
};

// Factories for building different types of Credentials The functions may
// return empty shared_ptr when credentials cannot be created. If a
// Credentials pointer is returned, it can still be invalid when used to create
// a channel. A lame channel will be created then and all rpcs will fail on it.

std::shared_ptr<ChannelCredentials> GoogleDefaultCredentials();

std::shared_ptr<ChannelCredentials> SslCredentials(
    const SslCredentialsOptions& options);

std::shared_ptr<CallCredentials> GoogleComputeEngineCredentials();

std::shared_ptr<CallCredentials> ServiceAccountJWTAccessCredentials(
    const grpc::string& json_key, long token_lifetime_seconds);

std::shared_ptr<CallCredentials> GoogleRefreshTokenCredentials(
    const grpc::string& json_refresh_token);

std::shared_ptr<CallCredentials> AccessTokenCredentials(
    const grpc::string& access_token);

std::shared_ptr<CallCredentials> GoogleIAMCredentials(
    const grpc::string& authorization_token,
    const grpc::string& authority_selector);

std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
    const std::shared_ptr<ChannelCredentials>& channel_creds,
    const std::shared_ptr<CallCredentials>& call_creds);

std::shared_ptr<CallCredentials> CompositeCallCredentials(
    const std::shared_ptr<CallCredentials>& creds1,
    const std::shared_ptr<CallCredentials>& creds2);

std::shared_ptr<ChannelCredentials> InsecureChannelCredentials();

// User defined metadata credentials.
class MetadataCredentialsPlugin {
 public:
  virtual ~MetadataCredentialsPlugin() {}

  // If this method returns true, the Process function will be scheduled in
  // a different thread from the one processing the call.
  virtual bool IsBlocking() const { return true; }

  // Type of credentials this plugin is implementing.
  virtual const char* GetType() const { return ""; }

  // Gets the auth metatada produced by this plugin.
  // The fully qualified method name is:
  // service_url + "/" + method_name.
  // The channel_auth_context contains (among other things), the identity of
  // the server.
  virtual Status GetMetadata(
      grpc::string_ref service_url, grpc::string_ref method_name,
      const AuthContext& channel_auth_context,
      std::multimap<grpc::string, grpc::string>* metadata) = 0;
};

std::shared_ptr<CallCredentials> MetadataCredentialsFromPlugin(
    std::unique_ptr<MetadataCredentialsPlugin> plugin);

}  // namespace grpc

#endif  // GRPCXX_SECURITY_CREDENTIALS_H