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add wrappers for db

This commit is contained in:
jie 2021-08-09 15:07:09 +08:00
parent b36d999300
commit 3006214897
3 changed files with 257 additions and 85 deletions
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148
bserv/database.hpp
View File

@ -16,16 +16,61 @@
namespace bserv {
using raw_db_connection_type = pqxx::connection;
using raw_db_transaction_type = pqxx::work;
class db_field {
private:
pqxx::field field_;
public:
db_field(const pqxx::field& field) : field_{field} {}
const char* c_str() const { return field_.c_str(); }
template <typename Type>
Type as() const { return field_.as<Type>(); }
};
class db_row {
private:
pqxx::row row_;
public:
db_row(const pqxx::row& row) : row_{row} {}
std::size_t size() const { return row_.size(); }
db_field operator[](std::size_t idx) const { return row_[idx]; }
};
class db_result {
private:
pqxx::result result_;
public:
class const_iterator {
private:
pqxx::result::const_iterator iterator_;
public:
const_iterator(
const pqxx::result::const_iterator& iterator
) : iterator_{iterator} {}
const_iterator& operator++() { ++iterator_; return *this; }
bool operator==(const const_iterator& rhs) const { return iterator_ == rhs.iterator_; }
bool operator!=(const const_iterator& rhs) const { return iterator_ != rhs.iterator_; }
db_row operator*() const { return *iterator_; }
};
db_result() = default;
db_result(const pqxx::result& result) : result_{result} {}
const_iterator begin() const { return result_.begin(); }
const_iterator end() const { return result_.end(); }
std::string query() const { return result_.query(); }
};
class db_connection_manager;
class db_connection {
private:
db_connection_manager& mgr_;
std::shared_ptr<pqxx::connection> conn_;
std::shared_ptr<raw_db_connection_type> conn_;
public:
db_connection(
db_connection_manager& mgr,
std::shared_ptr<pqxx::connection> conn)
std::shared_ptr<raw_db_connection_type> conn)
: mgr_{mgr}, conn_{conn} {}
// non-copiable, non-assignable
db_connection(const db_connection&) = delete;
@ -33,13 +78,13 @@ public:
// during the destruction, it should put itself back to the
// manager's queue
~db_connection();
pqxx::connection& get() { return *conn_; }
raw_db_connection_type& get() { return *conn_; }
};
// provides the database connection pool functionality
class db_connection_manager {
private:
std::queue<std::shared_ptr<pqxx::connection>> queue_;
std::queue<std::shared_ptr<raw_db_connection_type>> queue_;
// this lock is for manipulating the `queue_`
mutable std::mutex queue_lock_;
// since C++ 17 doesn't provide the semaphore functionality,
@ -52,7 +97,7 @@ public:
db_connection_manager(const std::string& conn_str, int n) {
for (int i = 0; i < n; ++i)
queue_.emplace(
std::make_shared<pqxx::connection>(conn_str));
std::make_shared<raw_db_connection_type>(conn_str));
}
// if there are no available database connections, this function
// blocks until there is any;
@ -68,7 +113,7 @@ public:
// `queue_lock_` is acquired so that only one thread will
// modify the `queue_`
std::lock_guard<std::mutex> lg{queue_lock_};
std::shared_ptr<pqxx::connection> conn = queue_.front();
std::shared_ptr<raw_db_connection_type> conn = queue_.front();
queue_.pop();
// if there are no connections in the `queue_`,
// `counter_lock_` remains to be locked
@ -93,7 +138,7 @@ inline db_connection::~db_connection() {
class db_parameter {
public:
virtual ~db_parameter() = default;
virtual std::string get_value(pqxx::work&) = 0;
virtual std::string get_value(raw_db_transaction_type&) = 0;
};
class db_name : public db_parameter {
@ -102,8 +147,8 @@ private:
public:
db_name(const std::string& value)
: value_{value} {}
std::string get_value(pqxx::work& w) {
return w.quote_name(value_);
std::string get_value(raw_db_transaction_type& tx) {
return tx.quote_name(value_);
}
};
@ -114,7 +159,7 @@ private:
public:
db_value(const Type& value)
: value_{value} {}
std::string get_value(pqxx::work&) {
std::string get_value(raw_db_transaction_type&) {
return std::to_string(value_);
}
};
@ -126,8 +171,8 @@ private:
public:
db_value(const std::string& value)
: value_{value} {}
std::string get_value(pqxx::work& w) {
return w.quote(value_);
std::string get_value(raw_db_transaction_type& tx) {
return tx.quote(value_);
}
};
@ -138,7 +183,7 @@ private:
public:
db_value(const bool& value)
: value_{value} {}
std::string get_value(pqxx::work&) {
std::string get_value(raw_db_transaction_type&) {
return value_ ? "true" : "false";
}
};
@ -169,8 +214,8 @@ inline std::shared_ptr<db_parameter> convert_parameter(
template <typename ...Params>
std::vector<std::string> convert_parameters(
pqxx::work& w, std::shared_ptr<Params>... params) {
return {params->get_value(w)...};
raw_db_transaction_type& tx, std::shared_ptr<Params>... params) {
return {params->get_value(tx)...};
}
// *************************************
@ -183,7 +228,7 @@ public:
: name_{name} {}
virtual ~db_field_holder() = default;
virtual void add(
const pqxx::row& row, size_t field_idx,
const db_row& row, std::size_t field_idx,
boost::json::object& obj) = 0;
};
@ -192,7 +237,7 @@ class db_field : public db_field_holder {
public:
using db_field_holder::db_field_holder;
void add(
const pqxx::row& row, size_t field_idx,
const db_row& row, std::size_t field_idx,
boost::json::object& obj) {
obj[name_] = row[field_idx].as<Type>();
}
@ -203,7 +248,7 @@ class db_field<std::string> : public db_field_holder {
public:
using db_field_holder::db_field_holder;
void add(
const pqxx::row& row, size_t field_idx,
const db_row& row, std::size_t field_idx,
boost::json::object& obj) {
obj[name_] = row[field_idx].c_str();
}
@ -234,49 +279,63 @@ public:
const std::initializer_list<
std::shared_ptr<db_internal::db_field_holder>>& fields)
: fields_{fields} {}
boost::json::object convert_row(const pqxx::row& row) {
boost::json::object convert_row(const db_row& row) {
boost::json::object obj;
for (size_t i = 0; i < fields_.size(); ++i)
for (std::size_t i = 0; i < fields_.size(); ++i)
fields_[i]->add(row, i, obj);
return obj;
}
std::vector<boost::json::object> convert_to_vector(
const pqxx::result& result) {
const db_result& result) {
std::vector<boost::json::object> results;
for (const auto& row : result)
results.emplace_back(convert_row(row));
return results;
}
std::optional<boost::json::object> convert_to_optional(
const pqxx::result& result) {
if (result.size() == 0) return std::nullopt;
if (result.size() == 1) return convert_row(result[0]);
const db_result& result) {
// result.size() == 0
if (result.begin() == result.end()) return std::nullopt;
auto iterator = result.begin();
auto first = iterator;
// result.size() == 1
if (++iterator == result.end())
return convert_row(*first);
// result.size() > 1
throw invalid_operation_exception{
"too many objects to convert"};
}
};
// Usage:
// db_exec(tx, "select * from ? where ? = ? and first_name = 'Name??'",
// db_name("auth_user"), db_name("is_active"), db_value<bool>(true));
// -> SQL: select * from "auth_user" where "is_active" = true and first_name = 'Name?'
// ======================================================================================
// db_exec(tx, "select * from ? where ? = ? and first_name = ?",
// db_name("auth_user"), db_name("is_active"), false, "Name??");
// -> SQL: select * from "auth_user" where "is_active" = false and first_name = 'Name??'
// ======================================================================================
// Note: "?" is the placeholder for parameters, and "??" will be converted to "?" in SQL.
// But, "??" in the parameters remains.
template <typename ...Params>
pqxx::result db_exec(pqxx::work& w,
const std::string& s, const Params&... params) {
class db_transaction {
private:
raw_db_transaction_type tx_;
public:
db_transaction(
std::shared_ptr<db_connection> connection_ptr
) : tx_{connection_ptr->get()} {}
// non-copiable, non-assignable
db_transaction(const db_transaction&) = delete;
db_transaction& operator=(const db_transaction&) = delete;
// Usage:
// exec("select * from ? where ? = ? and first_name = 'Name??'",
// db_name("auth_user"), db_name("is_active"), db_value<bool>(true));
// -> SQL: select * from "auth_user" where "is_active" = true and first_name = 'Name?'
// ======================================================================================
// exec("select * from ? where ? = ? and first_name = ?",
// db_name("auth_user"), db_name("is_active"), false, "Name??");
// -> SQL: select * from "auth_user" where "is_active" = false and first_name = 'Name??'
// ======================================================================================
// Note: "?" is the placeholder for parameters, and "??" will be converted to "?" in SQL.
// But, "??" in the parameters remains.
template <typename ...Params>
db_result exec(const std::string& s, const Params&... params) {
std::vector<std::string> param_vec =
db_internal::convert_parameters(
w, db_internal::convert_parameter(params)...);
size_t idx = 0;
tx_, db_internal::convert_parameter(params)...);
std::size_t idx = 0;
std::string query;
for (size_t i = 0; i < s.length(); ++i) {
for (std::size_t i = 0; i < s.length(); ++i) {
if (s[i] == '?') {
if (i + 1 < s.length() && s[i + 1] == '?') {
query += s[++i];
@ -289,8 +348,11 @@ pqxx::result db_exec(pqxx::work& w,
}
if (idx != param_vec.size())
throw invalid_operation_exception{"too many parameters"};
return w.exec(query);
}
return tx_.exec(query);
}
void commit() { tx_.commit(); }
void abort() { tx_.abort(); }
};
// TODO: add support for time conversions between postgresql and c++, use timestamp?

29
handlers.hpp
View File

@ -8,8 +8,6 @@
#include <vector>
#include <optional>
#include <pqxx/pqxx>
#include "bserv/common.hpp"
// register an orm mapping (to convert the db query results into
@ -35,9 +33,9 @@ bserv::db_relation_to_object orm_user{
};
std::optional<boost::json::object> get_user(
pqxx::work& tx,
bserv::db_transaction& tx,
const std::string& username) {
pqxx::result r = bserv::db_exec(tx,
bserv::db_result r = tx.exec(
"select * from auth_user where username = ?", username);
lginfo << r.query(); // this is how you log info
return orm_user.convert_to_optional(r);
@ -58,10 +56,20 @@ std::nullopt_t hello(
bserv::session_type& session = *session_ptr;
boost::json::object obj;
if (session.count("user")) {
// NOTE: modifications to sessions must be performed
// BEFORE referencing objects in them. this is because
// modifications might invalidate referenced objects.
// in this example, "count" might be added to `session`,
// which should be performed first.
// then `user` can be referenced safely.
if (!session.count("count")) {
session["count"] = 0;
}
auto& user = session["user"].as_object();
session["count"] = session["count"].as_int64() + 1;
obj = {
{"msg", std::string{"welcome, "}
+ user["username"].as_string().c_str() + "!"}
{"welcome", user["username"]},
{"count", session["count"]}
};
} else {
obj = {{"msg", "hello, world!"}};
@ -97,7 +105,7 @@ boost::json::object user_register(
};
}
auto username = params["username"].as_string();
pqxx::work tx{conn->get()};
bserv::db_transaction tx{conn};
auto opt_user = get_user(tx, username.c_str());
if (opt_user.has_value()) {
return {
@ -106,7 +114,7 @@ boost::json::object user_register(
};
}
auto password = params["password"].as_string();
pqxx::result r = bserv::db_exec(tx,
bserv::db_result r = tx.exec(
"insert into ? "
"(?, password, is_superuser, "
"first_name, last_name, email, is_active) values "
@ -147,7 +155,7 @@ boost::json::object user_login(
};
}
auto username = params["username"].as_string();
pqxx::work tx{conn->get()};
bserv::db_transaction tx{conn};
auto opt_user = get_user(tx, username.c_str());
if (!opt_user.has_value()) {
return {
@ -182,7 +190,7 @@ boost::json::object user_login(
boost::json::object find_user(
std::shared_ptr<bserv::db_connection> conn,
const std::string& username) {
pqxx::work tx{conn->get()};
bserv::db_transaction tx{conn};
auto user = get_user(tx, username);
if (!user.has_value()) {
return {
@ -190,6 +198,7 @@ boost::json::object find_user(
{"message", "requested user does not exist"}
};
}
user.value().erase("id");
user.value().erase("password");
return {
{"success", true},

101
scripts/db_test.py Normal file
View File

@ -0,0 +1,101 @@
import uuid
import string
import secrets
import random
import requests
from multiprocessing import Process
from pprint import pprint
from time import time
char_string = string.ascii_letters + string.digits
def get_password(n):
return ''.join(secrets.choice(char_string) for _ in range(n))
def get_string(n):
return ''.join(random.choice(char_string) for _ in range(n))
def create_user():
return {
"username": str(uuid.uuid4()),
"password": get_password(16),
"first_name": get_string(5),
"last_name": get_string(5),
"email": get_string(5) + "@" + get_string(5) + ".com"
}
# pprint(create_user())
# exit()
def session_test():
session = requests.session()
user = create_user()
res = session.post("http://localhost:8080").json()
if res != {'msg': 'hello, world!'}:
print('test failed')
# print(res)
res = session.post("http://localhost:8080/register", json=user).json()
if res != {'success': True, 'message': 'user registered'}:
print('test failed')
# print(res)
res = session.post("http://localhost:8080/login", json={
"username": user["username"],
"password": user["password"]
}).json()
if res != {'success': True, 'message': 'login successfully'}:
print('test failed')
# print(res)
n = random.randint(1, 5)
for i in range(1, n + 1):
res = session.post("http://localhost:8080").json()
if res != {'welcome': user["username"], 'count': i}:
print('test failed')
# print(res)
res = session.post("http://localhost:8080/find/" + user["username"]).json()
if res != {
'success': True,
'user': {
'username': user["username"],
'is_active': True,
'is_superuser': False,
'first_name': user["first_name"],
'last_name': user["last_name"],
'email': user["email"]
}}:
print('test failed')
# print(res)
res = session.post("http://localhost:8080/logout").json()
if res != {'success': True, 'message': 'logout successfully'}:
print('test failed')
# print(res)
res = session.post("http://localhost:8080").json()
if res != {'msg': 'hello, world!'}:
print('test failed')
# print(res)
# session_test()
# exit()
P = 1000 # number of concurrent processes
processes = [Process(target=session_test) for i in range(P)]
print('starting')
start = time()
for p in processes:
p.start()
for p in processes:
p.join()
end = time()
print('test ended')
print('elapsed: ', end - start)