c++实现数据存储程序第一天—读取配置文件
2019年4月11日晚上，脑子里突然间冒出个想法（用c++撸一个数据存储服务的程序），之前有用GO写过一个简单的可分布式扩展的图片存储程序。虽然还没有具体思路，但是仍然打算开始动手，走一步算一步（做着做着思路就来了呢也说不定）。
一、开发编辑器
打算用Qt Creator，之前电脑有装这个IDE，感觉还行，就继续用它吧。
二、程序取名
随便取个名字就叫daobu吧，总不能叫test吧...
ok,开始建工程了
三、第一天主要内容
- 主要内容是c++实现读取配置文件（读取的部分用了某位大佬的源码，博客上看到的还不清楚真正出处）。源码主要如下：
- configcore.h
#ifndef CONFIGCORE_H
#define CONFIGCORE_H
#pragma once
#include <string>
#include <map>
#include <iostream>
#include <fstream>
#include <sstream>
class ConfigCore
{
protected:
std::string m_Delimiter; //!< separator between key and value
std::string m_Comment; //!< separator between value and comments
std::map<std::string,std::string> m_Contents; //!< extracted keys and values
typedef std::map<std::string,std::string>::iterator mapi;
typedef std::map<std::string,std::string>::const_iterator mapci;
// Methods
public:
ConfigCore( std::string filename,std::string delimiter = "=",std::string comment = "#" );
ConfigCore();
template<class T> T Read( const std::string& in_key ) const; //!<Search for key and read value or optional default value, call as read<T>
template<class T> T Read( const std::string& in_key, const T& in_value ) const;
template<class T> bool ReadInto( T& out_var, const std::string& in_key ) const;
template<class T>
bool ReadInto( T& out_var, const std::string& in_key, const T& in_value ) const;
bool FileExist(std::string filename);
void ReadFile(std::string filename,std::string delimiter = "=",std::string comment = "#" );
// Check whether key exists in configuration
bool KeyExists( const std::string& in_key ) const;
// Modify keys and values
template<class T> void Add( const std::string& in_key, const T& in_value );
void Remove( const std::string& in_key );
// Check or change configuration syntax
std::string GetDelimiter() const { return m_Delimiter; }
std::string GetComment() const { return m_Comment; }
std::string SetDelimiter( const std::string& in_s )
{ std::string old = m_Delimiter; m_Delimiter = in_s; return old; }
std::string SetComment( const std::string& in_s )
{ std::string old = m_Comment; m_Comment = in_s; return old; }
// Write or read configuration
friend std::ostream& operator<<( std::ostream& os, const ConfigCore& cf );
friend std::istream& operator>>( std::istream& is, ConfigCore& cf );
protected:
template<class T> static std::string T_as_string( const T& t );
template<class T> static T string_as_T( const std::string& s );
static void Trim( std::string& inout_s );
// Exception types
public:
struct File_not_found {
std::string filename;
File_not_found( const std::string& filename_ = std::string() )
: filename(filename_) {} };
struct Key_not_found { // thrown only by T read(key) variant of read()
std::string key;
Key_not_found( const std::string& key_ = std::string() )
: key(key_) {} };
};
/* static */
template<class T>
std::string ConfigCore::T_as_string( const T& t )
{
// Convert from a T to a string
// Type T must support << operator
std::ostringstream ost;
ost << t;
return ost.str();
}
/* static */
template<class T>
T ConfigCore::string_as_T( const std::string& s )
{
// Convert from a string to a T
// Type T must support >> operator
T t;
std::istringstream ist(s);
ist >> t;
return t;
}
/* static */
template<>
inline std::string ConfigCore::string_as_T<std::string>( const std::string& s )
{
// Convert from a string to a string
// In other words, do nothing
return s;
}
/* static */
template<>
inline bool ConfigCore::string_as_T<bool>( const std::string& s )
{
// Convert from a string to a bool
// Interpret "false", "F", "no", "n", "0" as false
// Interpret "true", "T", "yes", "y", "1", "-1", or anything else as true
bool b = true;
std::string sup = s;
for( std::string::iterator p = sup.begin(); p != sup.end(); ++p )
*p = toupper(*p); // make string all caps
if( sup==std::string("FALSE") || sup==std::string("F") ||
sup==std::string("NO") || sup==std::string("N") ||
sup==std::string("0") || sup==std::string("NONE") )
b = false;
return b;
}
template<class T>
T ConfigCore::Read( const std::string& key ) const
{
// Read the value corresponding to key
mapci p = m_Contents.find(key);
if( p == m_Contents.end() ) throw Key_not_found(key);
return string_as_T<T>( p->second );
}
template<class T>
T ConfigCore::Read( const std::string& key, const T& value ) const
{
// Return the value corresponding to key or given default value
// if key is not found
mapci p = m_Contents.find(key);
if( p == m_Contents.end() ) return value;
return string_as_T<T>( p->second );
}
template<class T>
bool ConfigCore::ReadInto( T& var, const std::string& key ) const
{
// Get the value corresponding to key and store in var
// Return true if key is found
// Otherwise leave var untouched
mapci p = m_Contents.find(key);
bool found = ( p != m_Contents.end() );
if( found ) var = string_as_T<T>( p->second );
return found;
}
template<class T>
bool ConfigCore::ReadInto( T& var, const std::string& key, const T& value ) const
{
// Get the value corresponding to key and store in var
// Return true if key is found
// Otherwise set var to given default
mapci p = m_Contents.find(key);
bool found = ( p != m_Contents.end() );
if( found )
var = string_as_T<T>( p->second );
else
var = value;
return found;
}
template<class T>
void ConfigCore::Add( const std::string& in_key, const T& value )
{
// Add a key with given value
std::string v = T_as_string( value );
std::string key=in_key;
Trim(key);
Trim(v);
m_Contents[key] = v;
return;
};
#endif // CONFIGCORE_H
- configcore.cpp
#include "configcore.h"
using namespace std;
ConfigCore::ConfigCore( string filename, string delimiter,
string comment )
: m_Delimiter(delimiter), m_Comment(comment)
{
// Construct a Config, getting keys and values from given file
std::ifstream in( filename.c_str() );
if( !in ) throw File_not_found( filename );
in >> (*this);
}
ConfigCore::ConfigCore()
: m_Delimiter( string(1,'=') ), m_Comment( string(1,'#') )
{
// Construct a Config without a file; empty
}
bool ConfigCore::KeyExists( const string& key ) const
{
// Indicate whether key is found
mapci p = m_Contents.find( key );
return ( p != m_Contents.end() );
}
/* static */
void ConfigCore::Trim( string& inout_s )
{
// Remove leading and trailing whitespace
static const char whitespace[] = " \n\t\v\r\f";
inout_s.erase( 0, inout_s.find_first_not_of(whitespace) );
inout_s.erase( inout_s.find_last_not_of(whitespace) + 1U );
}
std::ostream& operator<<( std::ostream& os, const ConfigCore& cf )
{
// Save a Config to os
for( ConfigCore::mapci p = cf.m_Contents.begin();
p != cf.m_Contents.end();
++p )
{
os << p->first << " " << cf.m_Delimiter << " ";
os << p->second << std::endl;
}
return os;
}
void ConfigCore::Remove( const string& key )
{
// Remove key and its value
m_Contents.erase( m_Contents.find( key ) );
return;
}
std::istream& operator>>( std::istream& is, ConfigCore& cf )
{
// Load a Config from is
// Read in keys and values, keeping internal whitespace
typedef string::size_type pos;
const string& delim = cf.m_Delimiter; // separator
const string& comm = cf.m_Comment; // comment
const pos skip = delim.length(); // length of separator
string nextline = ""; // might need to read ahead to see where value ends
while( is || nextline.length() > 0 )
{
// Read an entire line at a time
string line;
if( nextline.length() > 0 )
{
line = nextline; // we read ahead; use it now
nextline = "";
}
else
{
std::getline( is, line );
}
// Ignore comments
line = line.substr( 0, line.find(comm) );
// Parse the line if it contains a delimiter
pos delimPos = line.find( delim );
if( delimPos < string::npos )
{
// Extract the key
string key = line.substr( 0, delimPos );
line.replace( 0, delimPos+skip, "" );
// See if value continues on the next line
// Stop at blank line, next line with a key, end of stream,
// or end of file sentry
bool terminate = false;
while( !terminate && is )
{
std::getline( is, nextline );
terminate = true;
string nlcopy = nextline;
ConfigCore::Trim(nlcopy);
if( nlcopy == "" ) continue;
nextline = nextline.substr( 0, nextline.find(comm) );
if( nextline.find(delim) != string::npos )
continue;
nlcopy = nextline;
ConfigCore::Trim(nlcopy);
if( nlcopy != "" ) line += "\n";
line += nextline;
terminate = false;
}
// Store key and value
ConfigCore::Trim(key);
ConfigCore::Trim(line);
cf.m_Contents[key] = line; // overwrites if key is repeated
}
}
return is;
}
bool ConfigCore::FileExist(std::string filename)
{
bool exist= false;
std::ifstream in( filename.c_str() );
if( in )
exist = true;
return exist;
}
void ConfigCore::ReadFile( string filename, string delimiter,
string comment )
{
m_Delimiter = delimiter;
m_Comment = comment;
std::ifstream in( filename.c_str() );
if( !in ) throw File_not_found( filename );
in >> (*this);
}
- config.h
#ifndef CONFIG_H
#define CONFIG_H
#include "configcore.h"
#include <map>
#include <vector>
#include <string>
using namespace std;
class Config
{
public:
Config(string direct,string suffix);
Config();
void getFilesFromDirect(); // 获取某路径下所有符合后缀名的配置文件
bool readFileToMemory(); // 读取文件数据到内存
ConfigCore Config_Core; // 读取配置文件的核心
private:
string confDirect; // 配置文件的路径
string confSuffix; // 配置文件后缀名
vector<string> allFiles; // 符合条件的所有配置文件
};
#endif // CONFIG_
- config.cpp
#include "config.h"
#include <string>
#include <iostream>
#include <dirent.h>
#include <regex>
using namespace std;
Config::Config()
{
// // 默认配置文件路径
// this->confDirect = "../../conf";
// // 设置配置文件后缀名
// this->confSuffix = ".conf";
}
/**
* @brief config::config
* @param direct
* @param suffix
*/
Config::Config(string direct,string suffix)
{
// 设置配置文件路径
this->confDirect = direct;
// 设置配置文件后缀名
this->confSuffix = suffix;
}
/**
* 获取目录下所有符合后缀的文件名
*
* @brief Config::getFilesFromDirect
*/
void Config::getFilesFromDirect() {
struct dirent *ptr;
DIR *dir = opendir(this->confDirect.c_str());
string::size_type idx;
string dirName;
while( (ptr=readdir(dir)) != NULL ) {
// 4 表示目录; 8 表示文件; 0 表示未知
if(ptr->d_type == 8) {
//跳过'.'和'..'两个目录
if(ptr->d_name[0] == '.') {
continue;
}
// 符合后缀名的文件名加入到迭代器中去
dirName = ptr->d_name;
idx = dirName.find(this->confSuffix);
if(idx != string::npos) {
this->allFiles.push_back(dirName);
}
}
}
closedir(dir);
}
/**
* 读取文件内容到内存
*
* @brief config::readFileToMemory
* @return
*/
bool Config::readFileToMemory() {
this->getFilesFromDirect();
int fileSize = this->allFiles.size();
if (fileSize == 0) {
throw "No right config file!";
} else if (fileSize == 1) {
this->Config_Core.ReadFile(this->confDirect +"/"+ this->allFiles[0]);
} else if (fileSize > 1) {
for (int i=0; i<fileSize; i++) {
this->Config_Core.ReadFile(this->confDirect +"/"+ this->allFiles[i]);
}
}
return true;
}
- 测试入口main.cpp
#include <iostream>
#include <libs/config/config.h>
#include <libs/config/configcore.h>
#include <unistd.h>
using namespace std;
#define MAX_PATH_LENGTH 150
int main()
{
// 获取当前路径
char cwd[MAX_PATH_LENGTH];
getcwd(cwd, MAX_PATH_LENGTH);
string cwdString = cwd;
cwdString += "/conf";
Config conf = Config(cwdString,".conf");
try {
conf.readFileToMemory();
} catch (char const* e) {
cout << e << endl;
return 0;
}
conf.Config_Core.Add<int>("test",1099999);
cout << "add:" << conf.Config_Core.Read<int>("add") << endl;
cout << "ipAddress:" << conf.Config_Core.Read<string>("ipAddress") << endl;
cout << "username:" << conf.Config_Core.Read<string>("username") << endl;
cout << "test:" << conf.Config_Core.Read<int>("test") << endl;
return 0;
}
运行结果
- .conf配置文件的内容如下：
add=1234
username1=3333
ipAddress=10.10.90.125
port=3001
username=mark
password=2d2df5a
- 程序输出
add:1234
ipAddress:10.10.90.125
username:mark
test:1099999
