388 lines
14 KiB
C
388 lines
14 KiB
C
|
/**
|
||
|
|
*
|
||
|
|
* @file DbClient.h
|
||
|
|
* @author An Tao
|
||
|
|
*
|
||
|
|
* Copyright 2018, An Tao. All rights reserved.
|
||
|
|
* https://github.com/an-tao/drogon
|
||
|
|
* Use of this source code is governed by a MIT license
|
||
|
|
* that can be found in the License file.
|
||
|
|
*
|
||
|
|
* Drogon
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include <drogon/exports.h>
|
||
|
|
#include <drogon/orm/Exception.h>
|
||
|
|
#include <drogon/orm/Field.h>
|
||
|
|
#include <drogon/orm/Result.h>
|
||
|
|
#include <drogon/orm/ResultIterator.h>
|
||
|
|
#include <drogon/orm/Row.h>
|
||
|
|
#include <drogon/orm/RowIterator.h>
|
||
|
|
#include <drogon/orm/SqlBinder.h>
|
||
|
|
#include <exception>
|
||
|
|
#include <functional>
|
||
|
|
#include <future>
|
||
|
|
#include <string>
|
||
|
|
#include <trantor/utils/Logger.h>
|
||
|
|
#include <trantor/utils/NonCopyable.h>
|
||
|
|
|
||
|
|
#ifdef __cpp_impl_coroutine
|
||
|
|
#include <drogon/utils/coroutine.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
namespace drogon
|
||
|
|
{
|
||
|
|
namespace orm
|
||
|
|
{
|
||
|
|
using ResultCallback = std::function<void(const Result &)>;
|
||
|
|
using ExceptionCallback = std::function<void(const DrogonDbException &)>;
|
||
|
|
|
||
|
|
class Transaction;
|
||
|
|
class DbClient;
|
||
|
|
|
||
|
|
namespace internal
|
||
|
|
{
|
||
|
|
#ifdef __cpp_impl_coroutine
|
||
|
|
struct [[nodiscard]] SqlAwaiter : public CallbackAwaiter<Result>
|
||
|
|
{
|
||
|
|
explicit SqlAwaiter(internal::SqlBinder &&binder)
|
||
|
|
: binder_(std::move(binder))
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
void await_suspend(std::coroutine_handle<> handle)
|
||
|
|
{
|
||
|
|
binder_ >> [handle, this](const drogon::orm::Result &result) {
|
||
|
|
setValue(result);
|
||
|
|
handle.resume();
|
||
|
|
};
|
||
|
|
binder_ >> [handle, this](const std::exception_ptr &e) {
|
||
|
|
setException(e);
|
||
|
|
handle.resume();
|
||
|
|
};
|
||
|
|
binder_.exec();
|
||
|
|
}
|
||
|
|
|
||
|
|
private:
|
||
|
|
internal::SqlBinder binder_;
|
||
|
|
};
|
||
|
|
|
||
|
|
struct [[nodiscard]] TransactionAwaiter
|
||
|
|
: public CallbackAwaiter<std::shared_ptr<Transaction> >
|
||
|
|
{
|
||
|
|
explicit TransactionAwaiter(DbClient *client) : client_(client)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
void await_suspend(std::coroutine_handle<> handle);
|
||
|
|
|
||
|
|
private:
|
||
|
|
DbClient *client_;
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|
||
|
|
} // namespace internal
|
||
|
|
|
||
|
|
/// Database client abstract class
|
||
|
|
class DROGON_EXPORT DbClient : public trantor::NonCopyable
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
virtual ~DbClient();
|
||
|
|
/// Create a new database client with multiple connections;
|
||
|
|
/**
|
||
|
|
* @param connInfo: Connection string with some parameters,
|
||
|
|
* each parameter setting is in the form keyword = value. Spaces around the
|
||
|
|
* equal sign are optional.
|
||
|
|
* To write an empty value, or a value containing spaces, surround it with
|
||
|
|
* single quotes, e.g.,
|
||
|
|
* keyword = 'a value'. Single quotes and backslashes within the value must
|
||
|
|
* be escaped with a backslash, i.e., \' and \\. Example: host=localhost
|
||
|
|
* port=5432 dbname=mydb connect_timeout=10 password='' The currently
|
||
|
|
* recognized parameter key words are:
|
||
|
|
* - host: can be either a host name or an IP address.
|
||
|
|
* - port: Port number to connect to at the server host.
|
||
|
|
* - dbname: The database name. Defaults to be the same as the user name.
|
||
|
|
* - user: user name to connect as. With PostgreSQL defaults to be the same
|
||
|
|
* as the operating system name of the user running the application.
|
||
|
|
* - password: Password to be used if the server demands password
|
||
|
|
* authentication.
|
||
|
|
* - client_encoding: The character set to be used on database connections.
|
||
|
|
*
|
||
|
|
* For other key words on PostgreSQL, see the PostgreSQL documentation.
|
||
|
|
* Only a pair of key values is valid for Sqlite3, and its keyword is
|
||
|
|
* 'filename'.
|
||
|
|
*
|
||
|
|
* @param connNum: The number of connections to database server;
|
||
|
|
*/
|
||
|
|
static std::shared_ptr<DbClient> newPgClient(const std::string &connInfo,
|
||
|
|
size_t connNum,
|
||
|
|
bool autoBatch = false);
|
||
|
|
static std::shared_ptr<DbClient> newMysqlClient(const std::string &connInfo,
|
||
|
|
size_t connNum);
|
||
|
|
static std::shared_ptr<DbClient> newSqlite3Client(
|
||
|
|
const std::string &connInfo,
|
||
|
|
size_t connNum);
|
||
|
|
|
||
|
|
/// Async and nonblocking method
|
||
|
|
/**
|
||
|
|
* @param sql is the SQL statement to be executed;
|
||
|
|
* @param FUNCTION1 is usually the ResultCallback type;
|
||
|
|
* @param FUNCTION2 is usually the ExceptionCallback type;
|
||
|
|
* @param args are parameters that are bound to placeholders in the sql
|
||
|
|
* parameter;
|
||
|
|
*
|
||
|
|
* @note
|
||
|
|
*
|
||
|
|
* If the number of args parameters is not zero, make sure that all criteria
|
||
|
|
* in the sql parameter set by bind parameters, for example:
|
||
|
|
*
|
||
|
|
* 1. select * from users where user_id > 10 limit 10 offset 10; //Not
|
||
|
|
* bad, no bind parameters are used.
|
||
|
|
* 2. select * from users where user_id > ? limit ? offset ?; //Good,
|
||
|
|
* fully use bind parameters.
|
||
|
|
* 3. select * from users where user_id > ? limit ? offset 10; //Bad,
|
||
|
|
* partially use bind parameters.
|
||
|
|
*
|
||
|
|
* Strictly speaking, try not to splice SQL statements dynamically, Instead,
|
||
|
|
* use the constant sql string with placeholders and the bind parameters to
|
||
|
|
* execute sql. This rule makes the sql execute faster and more securely,
|
||
|
|
* and users should follow this rule when calling all methods of DbClient.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
template <typename FUNCTION1, typename FUNCTION2, typename... Arguments>
|
||
|
|
void execSqlAsync(const std::string &sql,
|
||
|
|
FUNCTION1 &&rCallback,
|
||
|
|
FUNCTION2 &&exceptCallback,
|
||
|
|
Arguments &&...args) noexcept
|
||
|
|
{
|
||
|
|
auto binder = *this << sql;
|
||
|
|
(void)std::initializer_list<int>{
|
||
|
|
(binder << std::forward<Arguments>(args), 0)...};
|
||
|
|
binder >> std::forward<FUNCTION1>(rCallback);
|
||
|
|
binder >> std::forward<FUNCTION2>(exceptCallback);
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Async and nonblocking method
|
||
|
|
template <typename... Arguments>
|
||
|
|
std::future<Result> execSqlAsyncFuture(const std::string &sql,
|
||
|
|
Arguments &&...args) noexcept
|
||
|
|
{
|
||
|
|
auto binder = *this << sql;
|
||
|
|
(void)std::initializer_list<int>{
|
||
|
|
(binder << std::forward<Arguments>(args), 0)...};
|
||
|
|
std::shared_ptr<std::promise<Result> > prom =
|
||
|
|
std::make_shared<std::promise<Result> >();
|
||
|
|
binder >> [prom](const Result &r) { prom->set_value(r); };
|
||
|
|
binder >>
|
||
|
|
[prom](const std::exception_ptr &e) { prom->set_exception(e); };
|
||
|
|
binder.exec();
|
||
|
|
return prom->get_future();
|
||
|
|
}
|
||
|
|
|
||
|
|
// Sync and blocking method
|
||
|
|
template <typename... Arguments>
|
||
|
|
Result execSqlSync(const std::string &sql,
|
||
|
|
Arguments &&...args) noexcept(false)
|
||
|
|
{
|
||
|
|
Result r(nullptr);
|
||
|
|
{
|
||
|
|
auto binder = *this << sql;
|
||
|
|
(void)std::initializer_list<int>{
|
||
|
|
(binder << std::forward<Arguments>(args), 0)...};
|
||
|
|
// Use blocking mode
|
||
|
|
binder << Mode::Blocking;
|
||
|
|
|
||
|
|
binder >> [&r](const Result &result) { r = result; };
|
||
|
|
binder.exec(); // exec may be throw exception;
|
||
|
|
}
|
||
|
|
return r;
|
||
|
|
}
|
||
|
|
|
||
|
|
#ifdef __cpp_impl_coroutine
|
||
|
|
template <typename... Arguments>
|
||
|
|
internal::SqlAwaiter execSqlCoro(const std::string &sql,
|
||
|
|
Arguments &&...args) noexcept
|
||
|
|
{
|
||
|
|
auto binder = *this << sql;
|
||
|
|
(void)std::initializer_list<int>{
|
||
|
|
(binder << std::forward<Arguments>(args), 0)...};
|
||
|
|
return internal::SqlAwaiter(std::move(binder));
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/// Streaming-like method for sql execution. For more information, see the
|
||
|
|
/// wiki page.
|
||
|
|
internal::SqlBinder operator<<(const std::string &sql);
|
||
|
|
internal::SqlBinder operator<<(std::string &&sql);
|
||
|
|
template <int N>
|
||
|
|
internal::SqlBinder operator<<(const char (&sql)[N])
|
||
|
|
{
|
||
|
|
return internal::SqlBinder(sql, N - 1, *this, type_);
|
||
|
|
}
|
||
|
|
internal::SqlBinder operator<<(const string_view &sql)
|
||
|
|
{
|
||
|
|
return internal::SqlBinder(sql.data(), sql.length(), *this, type_);
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Create a transaction object.
|
||
|
|
/**
|
||
|
|
* @param commitCallback: the callback with which user can get the
|
||
|
|
* submitting result, The Boolean type parameter in the callback function
|
||
|
|
* indicates whether the transaction was submitted successfully.
|
||
|
|
*
|
||
|
|
* @note The callback only indicates the result of the 'commit' command,
|
||
|
|
* which is the last step of the transaction. If the transaction has been
|
||
|
|
* automatically or manually rolled back, the callback will never be
|
||
|
|
* executed. You can also use the setCommitCallback() method of a
|
||
|
|
* transaction object to set the callback.
|
||
|
|
* @note A TimeoutError exception is thrown if the operation is timed out.
|
||
|
|
*/
|
||
|
|
virtual std::shared_ptr<Transaction> newTransaction(
|
||
|
|
const std::function<void(bool)> &commitCallback =
|
||
|
|
std::function<void(bool)>()) noexcept(false) = 0;
|
||
|
|
|
||
|
|
/// Create a transaction object in asynchronous mode.
|
||
|
|
/**
|
||
|
|
* @note An empty shared_ptr object is returned via the callback if the
|
||
|
|
* operation is timed out.
|
||
|
|
*/
|
||
|
|
virtual void newTransactionAsync(
|
||
|
|
const std::function<void(const std::shared_ptr<Transaction> &)>
|
||
|
|
&callback) = 0;
|
||
|
|
|
||
|
|
#ifdef __cpp_impl_coroutine
|
||
|
|
orm::internal::TransactionAwaiter newTransactionCoro()
|
||
|
|
{
|
||
|
|
return orm::internal::TransactionAwaiter(this);
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Check if there is a connection successfully established.
|
||
|
|
*
|
||
|
|
* @return true
|
||
|
|
* @return false
|
||
|
|
*/
|
||
|
|
virtual bool hasAvailableConnections() const noexcept = 0;
|
||
|
|
|
||
|
|
ClientType type() const
|
||
|
|
{
|
||
|
|
return type_;
|
||
|
|
}
|
||
|
|
const std::string &connectionInfo() const
|
||
|
|
{
|
||
|
|
return connectionInfo_;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Set the Timeout value of execution of a SQL.
|
||
|
|
*
|
||
|
|
* @param timeout in seconds, if the SQL result is not returned from the
|
||
|
|
* server within the timeout, a TimeoutError exception with "SQL execution
|
||
|
|
* timeout" string is generated and returned to the caller.
|
||
|
|
* @note set the timeout value to zero or negative for no limit on time. The
|
||
|
|
* default value is -1.0, this means there is no time limit if this method
|
||
|
|
* is not called.
|
||
|
|
*/
|
||
|
|
virtual void setTimeout(double timeout) = 0;
|
||
|
|
/**
|
||
|
|
* @brief Close all connections in the client. usually used by Drogon in the
|
||
|
|
* quit() method.
|
||
|
|
* */
|
||
|
|
virtual void closeAll() = 0;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @brief Enable auto-batch mode.
|
||
|
|
* This feature is available only for PostgreSQL 14+ version and the
|
||
|
|
* LIBPQ_BATCH_MODE option is CMakeLists.txt is ON.
|
||
|
|
* When auto-batch mode is disabled (by default), every SQL query
|
||
|
|
* pipelined in a connection is automatically executed in an individual
|
||
|
|
* implicit transaction, this behavior ensures that SQL queries cannot make
|
||
|
|
* side-effects to each other. Most databases client drivers execute SQL
|
||
|
|
* queries in this way.
|
||
|
|
* When auto-batch mode is enabled, SQL queries are batched automatically to
|
||
|
|
* an implicit transaction, the synchronization point as the end of the
|
||
|
|
* transaction is inserted when:
|
||
|
|
* 1. The number of queries in the transaction has reached the upper limit;
|
||
|
|
* 2. The last SQL query in the transaction contains some key words shows
|
||
|
|
* that the query make some changes on the database server;
|
||
|
|
* 3. All SQL queries that are in the same call stack of the current
|
||
|
|
* event-loop are sent to the server;
|
||
|
|
* @note the auto-batch mode is unsafe for general purpose scenarios.
|
||
|
|
* While the framework is doing its best to reduce the side effects of this
|
||
|
|
* implicit transaction, there are some risks that cannot be avoided, for
|
||
|
|
* example:
|
||
|
|
* if a command is executed which happens to SELECT from a function (it
|
||
|
|
* makes some changes but don't cause a synchronization point), and around
|
||
|
|
* the same time another unrelated command is executed which produces an
|
||
|
|
* error (e.g. unique constraint violation), then any side-effects from the
|
||
|
|
* function may get rolled back, without any indication to the program that
|
||
|
|
* this happened. That is, the user code executing the function will
|
||
|
|
* continue as if the function completed successfully and its side effects
|
||
|
|
* were committed, when in fact they were silently rolled back.
|
||
|
|
*
|
||
|
|
* So, users should ensure that all SQL requests sent by database clients
|
||
|
|
* with auto-batch mode are mutually safe, a viable strategy is to ensure
|
||
|
|
* that all SQL is read-only and does not interrupt the current transaction.
|
||
|
|
* Benefiting from the reduction in the number of transactions, the
|
||
|
|
* automatic batch mode has a certain performance improvement for some
|
||
|
|
* high-concurrency scenarios. The auto-batch mode can only be enabled
|
||
|
|
* before the client is used, and enabling it during use will have uncertain
|
||
|
|
* side effects. This feature can be enabled in the configuration file.
|
||
|
|
* */
|
||
|
|
// virtual void enableAutoBatch() = 0;
|
||
|
|
|
||
|
|
private:
|
||
|
|
friend internal::SqlBinder;
|
||
|
|
virtual void execSql(
|
||
|
|
const char *sql,
|
||
|
|
size_t sqlLength,
|
||
|
|
size_t paraNum,
|
||
|
|
std::vector<const char *> &¶meters,
|
||
|
|
std::vector<int> &&length,
|
||
|
|
std::vector<int> &&format,
|
||
|
|
ResultCallback &&rcb,
|
||
|
|
std::function<void(const std::exception_ptr &)> &&exceptCallback) = 0;
|
||
|
|
|
||
|
|
protected:
|
||
|
|
ClientType type_;
|
||
|
|
std::string connectionInfo_;
|
||
|
|
};
|
||
|
|
using DbClientPtr = std::shared_ptr<DbClient>;
|
||
|
|
|
||
|
|
class Transaction : public DbClient
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
virtual void rollback() = 0;
|
||
|
|
// virtual void commit() = 0;
|
||
|
|
virtual void setCommitCallback(
|
||
|
|
const std::function<void(bool)> &commitCallback) = 0;
|
||
|
|
void closeAll() override
|
||
|
|
{
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
#ifdef __cpp_impl_coroutine
|
||
|
|
inline void internal::TransactionAwaiter::await_suspend(
|
||
|
|
std::coroutine_handle<> handle)
|
||
|
|
{
|
||
|
|
assert(client_ != nullptr);
|
||
|
|
client_->newTransactionAsync(
|
||
|
|
[this, handle](const std::shared_ptr<Transaction> &transaction) {
|
||
|
|
if (transaction == nullptr)
|
||
|
|
setException(std::make_exception_ptr(TimeoutError(
|
||
|
|
"Timeout, no connection available for transaction")));
|
||
|
|
else
|
||
|
|
setValue(transaction);
|
||
|
|
handle.resume();
|
||
|
|
});
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
} // namespace orm
|
||
|
|
} // namespace drogon
|