1.14.C++项目：仿muduo库实现并发服务器之Util模块的设计
一、Util模块
二、实现思想
（一）管理
- 实现一些工具接口
- 读取文件内容
- 向文件写入内容
- URL编码
- URL解码
- 通过HTTP状态码获取描述信息
- 通过文件后缀名获取mime
- 判断一个文件是不是目录
- 判断一个文件是否是一个普通文件
- HTTP资源路径有效性判断
（二）意义
在协议支持模块中，当需要某些零碎功能的时候，便于使用！
（三）功能设计
class Util {
public:
// 字符串分割函数
size_t Spilt();
// 读取文件内容
static bool ReadFile() {
}
// 向文件写入内容
static bool WriteFile();
// URL编码
static bool UrlEncode();
// URL解码
static bool UrlDecode();
// 通过HTTP状态码获取描述信息
static std::string StatusDesc();
// 根据文件后缀名获取文件MINE
static std::string ExtMine();
// 判断一个文件是不是目录
static bool IsDirectory();
//判断一个文件是否是一个普通文件
static bool IsRegular();
//HTTP资源路径有效性判断
static bool VaildPath();
};
三、代码
class Util {
public:
//字符串分割函数,将src字符串按照sep字符进行分割，得到的各个字串放到arry中，最终返回字串的数量
static size_t Split(const std::string &src, const std::string &sep, std::vector<std::string> *arry) {
size_t offset = 0;
// 有10个字符，offset是查找的起始位置，范围应该是0~9，offset==10就代表已经越界了
while(offset < src.size()) {
size_t pos = src.find(sep, offset);//在src字符串偏移量offset处，开始向后查找sep字符/字串，返回查找到的位置
if (pos == std::string::npos) {//没有找到特定的字符
//将剩余的部分当作一个字串，放入arry中
if(pos == src.size()) break;
arry->push_back(src.substr(offset));
return arry->size();
}
if (pos == offset) {
offset = pos + sep.size();
continue;//当前字串是一个空的，没有内容
}
arry->push_back(src.substr(offset, pos - offset));
offset = pos + sep.size();
}
return arry->size();
}
//读取文件的所有内容，将读取的内容放到一个Buffer中
static bool ReadFile(const std::string &filename, std::string *buf) {
std::ifstream ifs(filename, std::ios::binary);
if (ifs.is_open() == false) {
printf("OPEN %s FILE FAILED!!", filename.c_str());
return false;
}
size_t fsize = 0;
ifs.seekg(0, ifs.end);//跳转读写位置到末尾
fsize = ifs.tellg(); //获取当前读写位置相对于起始位置的偏移量，从末尾偏移刚好就是文件大小
ifs.seekg(0, ifs.beg);//跳转到起始位置
buf->resize(fsize); //开辟文件大小的空间
ifs.read(&(*buf)[0], fsize);
if (ifs.good() == false) {
printf("READ %s FILE FAILED!!", filename.c_str());
ifs.close();
return false;
}
ifs.close();
return true;
}
//向文件写入数据
static bool WriteFile(const std::string &filename, const std::string &buf) {
std::ofstream ofs(filename, std::ios::binary | std::ios::trunc);
if (ofs.is_open() == false) {
printf("OPEN %s FILE FAILED!!", filename.c_str());
return false;
}
ofs.write(buf.c_str(), buf.size());
if (ofs.good() == false) {
ERR_LOG("WRITE %s FILE FAILED!", filename.c_str());
ofs.close();
return false;
}
ofs.close();
return true;
}
//URL编码，避免URL中资源路径与查询字符串中的特殊字符与HTTP请求中特殊字符产生歧义
//编码格式：将特殊字符的ascii值，转换为两个16进制字符，前缀% C++ -> C%2B%2B
//不编码的特殊字符： RFC3986文档规定 . - _ ~ 字母，数字属于绝对不编码字符
//RFC3986文档规定，编码格式 %HH
//W3C标准中规定，查询字符串中的空格，需要编码为+， 解码则是+转空格
static std::string UrlEncode(const std::string url, bool convert_space_to_plus) {
std::string res;
for (auto &c : url) {
if (c == '.' || c == '-' || c == '_' || c == '~' || isalnum(c)) {
res += c;
continue;
}
if (c == ' ' && convert_space_to_plus == true) {
res += '+';
continue;
}
//剩下的字符都是需要编码成为 %HH 格式
char tmp[4] = {0};
//snprintf 与 printf比较类似，都是格式化字符串，只不过一个是打印，一个是放到一块空间中
snprintf(tmp, 4, "%%%02X", c);
res += tmp;
}
return res;
}
static char HEXTOI(char c) {
if (c >= '0' && c <= '9') {
return c - '0';
}else if (c >= 'a' && c <= 'z') {
return c - 'a' + 10;
}else if (c >= 'A' && c <= 'Z') {
return c - 'A' + 10;
}
return -1;
}
static std::string UrlDecode(const std::string url, bool convert_plus_to_space) {
//遇到了%，则将紧随其后的2个字符，转换为数字，第一个数字左移4位，然后加上第二个数字 + -> 2b %2b->2 << 4 + 11
std::string res;
for (int i = 0; i < url.size(); i++) {
if (url[i] == '+' && convert_plus_to_space == true) {
res += ' ';
continue;
}
if (url[i] == '%' && (i + 2) < url.size()) {
char v1 = HEXTOI(url[i + 1]);
char v2 = HEXTOI(url[i + 2]);
char v = v1 * 16 + v2;
res += v;
i += 2;
continue;
}
res += url[i];
}
return res;
}
//响应状态码的描述信息获取
static std::string StatuDesc(int statu) {
auto it = _statu_msg.find(statu);
if (it != _statu_msg.end()) {
return it->second;
}
return "Unknow";
}
//根据文件后缀名获取文件mime
static std::string ExtMime(const std::string &filename) {
// a.b.txt 先获取文件扩展名
size_t pos = filename.find_last_of('.');
if (pos == std::string::npos) {
return "application/octet-stream";
}
//根据扩展名，获取mime
std::string ext = filename.substr(pos);
auto it = _mime_msg.find(ext);
if (it == _mime_msg.end()) {
return "application/octet-stream";
}
return it->second;
}
//判断一个文件是否是一个目录
static bool IsDirectory(const std::string &filename) {
struct stat st;
int ret = stat(filename.c_str(), &st);
if (ret < 0) {
return false;
}
return S_ISDIR(st.st_mode);
}
//判断一个文件是否是一个普通文件
static bool IsRegular(const std::string &filename) {
struct stat st;
int ret = stat(filename.c_str(), &st);
if (ret < 0) {
return false;
}
return S_ISREG(st.st_mode);
}
//http请求的资源路径有效性判断
// /index.html --- 前边的/叫做相对根目录 映射的是某个服务器上的子目录
// 想表达的意思就是，客户端只能请求相对根目录中的资源，其他地方的资源都不予理会
// /../login, 这个路径中的..会让路径的查找跑到相对根目录之外，这是不合理的，不安全的
static bool ValidPath(const std::string &path) {
//思想：按照/进行路径分割，根据有多少子目录，计算目录深度，有多少层，深度不能小于0
std::vector<std::string> subdir;
Split(path, "/", &subdir);
int level = 0;
for (auto &dir : subdir) {
if (dir == "..") {
level--; //任意一层走出相对根目录，就认为有问题
if (level < 0) return false;
continue;
}
level++;
}
return true;
}
};
状态码：
std::unordered_map<int, std::string> _statu_msg = {
{100, "Continue"},
{101, "Switching Protocol"},
{102, "Processing"},
{103, "Early Hints"},
{200, "OK"},
{201, "Created"},
{202, "Accepted"},
{203, "Non-Authoritative Information"},
{204, "No Content"},
{205, "Reset Content"},
{206, "Partial Content"},
{207, "Multi-Status"},
{208, "Already Reported"},
{226, "IM Used"},
{300, "Multiple Choice"},
{301, "Moved Permanently"},
{302, "Found"},
{303, "See Other"},
{304, "Not Modified"},
{305, "Use Proxy"},
{306, "unused"},
{307, "Temporary Redirect"},
{308, "Permanent Redirect"},
{400, "Bad Request"},
{401, "Unauthorized"},
{402, "Payment Required"},
{403, "Forbidden"},
{404, "Not Found"},
{405, "Method Not Allowed"},
{406, "Not Acceptable"},
{407, "Proxy Authentication Required"},
{408, "Request Timeout"},
{409, "Conflict"},
{410, "Gone"},
{411, "Length Required"},
{412, "Precondition Failed"},
{413, "Payload Too Large"},
{414, "URI Too Long"},
{415, "Unsupported Media Type"},
{416, "Range Not Satisfiable"},
{417, "Expectation Failed"},
{418, "I'm a teapot"},
{421, "Misdirected Request"},
{422, "Unprocessable Entity"},
{423, "Locked"},
{424, "Failed Dependency"},
{425, "Too Early"},
{426, "Upgrade Required"},
{428, "Precondition Required"},
{429, "Too Many Requests"},
{431, "Request Header Fields Too Large"},
{451, "Unavailable For Legal Reasons"},
{501, "Not Implemented"},
{502, "Bad Gateway"},
{503, "Service Unavailable"},
{504, "Gateway Timeout"},
{505, "HTTP Version Not Supported"},
{506, "Variant Also Negotiates"},
{507, "Insufficient Storage"},
{508, "Loop Detected"},
{510, "Not Extended"},
{511, "Network Authentication Required"}
};
std::unordered_map<std::string, std::string> _mime_msg = {
{".aac", "audio/aac"},
{".abw", "application/x-abiword"},
{".arc", "application/x-freearc"},
{".avi", "video/x-msvideo"},
{".azw", "application/vnd.amazon.ebook"},
{".bin", "application/octet-stream"},
{".bmp", "image/bmp"},
{".bz", "application/x-bzip"},
{".bz2", "application/x-bzip2"},
{".csh", "application/x-csh"},
{".css", "text/css"},
{".csv", "text/csv"},
{".doc", "application/msword"},
{".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
{".eot", "application/vnd.ms-fontobject"},
{".epub", "application/epub+zip"},
{".gif", "image/gif"},
{".htm", "text/html"},
{".html", "text/html"},
{".ico", "image/vnd.microsoft.icon"},
{".ics", "text/calendar"},
{".jar", "application/java-archive"},
{".jpeg", "image/jpeg"},
{".jpg", "image/jpeg"},
{".js", "text/javascript"},
{".json", "application/json"},
{".jsonld", "application/ld+json"},
{".mid", "audio/midi"},
{".midi", "audio/x-midi"},
{".mjs", "text/javascript"},
{".mp3", "audio/mpeg"},
{".mpeg", "video/mpeg"},
{".mpkg", "application/vnd.apple.installer+xml"},
{".odp", "application/vnd.oasis.opendocument.presentation"},
{".ods", "application/vnd.oasis.opendocument.spreadsheet"},
{".odt", "application/vnd.oasis.opendocument.text"},
{".oga", "audio/ogg"},
{".ogv", "video/ogg"},
{".ogx", "application/ogg"},
{".otf", "font/otf"},
{".png", "image/png"},
{".pdf", "application/pdf"},
{".ppt", "application/vnd.ms-powerpoint"},
{".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
{".rar", "application/x-rar-compressed"},
{".rtf", "application/rtf"},
{".sh", "application/x-sh"},
{".svg", "image/svg+xml"},
{".swf", "application/x-shockwave-flash"},
{".tar", "application/x-tar"},
{".tif", "image/tiff"},
{".tiff", "image/tiff"},
{".ttf", "font/ttf"},
{".txt", "text/plain"},
{".vsd", "application/vnd.visio"},
{".wav", "audio/wav"},
{".weba", "audio/webm"},
{".webm", "video/webm"},
{".webp", "image/webp"},
{".woff", "font/woff"},
{".woff2", "font/woff2"},
{".xhtml", "application/xhtml+xml"},
{".xls", "application/vnd.ms-excel"},
{".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
{".xml", "application/xml"},
{".xul", "application/vnd.mozilla.xul+xml"},
{".zip", "application/zip"},
{".3gp", "video/3gpp"},
{".3g2", "video/3gpp2"},
{".7z", "application/x-7z-compressed"}
};