1. Util module
2. Implement ideas
(1) Management
- Implement some tool interfaces
- Read file contents
- Write content to file
- URL encoding
- URL decoding
- Get description information through HTTP status code
- Get mime by file extension
- Determine whether a file is a directory
- Determine whether a file is an ordinary file
- HTTP resource path validity judgment
(2) Meaning
In the protocol support module, it is easy to use when you need some fragmentary functions!
(3) Functional design
class Util {<!-- -->
public:
//String splitting function
size_t Spilt();
//Read file content
static bool ReadFile() {<!-- -->
}
//Write content to file
static bool WriteFile();
//URL encoding
static bool UrlEncode();
//URL decoding
static bool UrlDecode();
// Get description information through HTTP status code
static std::string StatusDesc();
// Get the file MINE based on the file extension name
static std::string ExtMine();
// Determine whether a file is a directory
static bool IsDirectory();
//Determine whether a file is an ordinary file
static bool IsRegular();
//Judge the validity of HTTP resource path
static bool VaildPath();
};
3. Code
class Util {<!-- -->
public:
//String splitting function, split the src string according to sep characters, put each obtained string into arry, and finally return the number of strings
static size_t Split(const std::string & amp;src, const std::string & amp;sep, std::vector<std::string> *arry) {<!-- -->
size_t offset = 0;
// There are 10 characters. Offset is the starting position of the search. The range should be 0~9. Offset==10 means it has crossed the boundary.
while(offset < src.size()) {<!-- -->
size_t pos = src.find(sep, offset);//At the src string offset offset, start searching backward for the sep character/string and return to the found position
if (pos == std::string::npos) {<!-- -->//No specific character found
//Treat the remaining part as a string and put it into arry
if(pos == src.size()) break;
arry->push_back(src.substr(offset));
return arry->size();
}
if (pos == offset) {<!-- -->
offset = pos + sep.size();
continue;//The current string is empty and has no content
}
arry->push_back(src.substr(offset, pos - offset));
offset = pos + sep.size();
}
return arry->size();
}
//Read all the contents of the file and put the read contents into a Buffer
static bool ReadFile(const std::string & amp;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);//Jump the reading and writing position to the end
fsize = ifs.tellg(); //Get the offset of the current read and write position relative to the starting position. The offset from the end is exactly the file size
ifs.seekg(0, ifs.beg);//Jump to the starting position
buf->resize(fsize); //Open up space of file size
ifs.read( & amp;(*buf)[0], fsize);
if (ifs.good() == false) {<!-- -->
printf("READ %s FILE FAILED!!", filename.c_str());
ifs.close();
return false;
}
ifs.close();
return true;
}
//Write data to the file
static bool WriteFile(const std::string & amp;filename, const std::string & amp;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 encoding to avoid ambiguity between special characters in the resource path and query string in the URL and special characters in the HTTP request
//Encoding format: Convert the ascii value of special characters into two hexadecimal characters, prefixed % C++ -> C++
//Unencoded special characters: RFC3986 document stipulates . - _ ~ Letters and numbers are absolutely unencoded characters
//RFC3986 document stipulates that the encoding format is %HH
//The W3C standard stipulates that spaces in the query string need to be encoded as + and decoded as + converted to spaces.
static std::string UrlEncode(const std::string url, bool convert_space_to_plus) {<!-- -->
std::string res;
for (auto & amp;c : url) {<!-- -->
if (c == '.' || c == '-' || c == '_' || c == '~' || isalnum(c)) {<!-- -->
res + = c;
continue;
}
if (c == ' ' & amp; & amp; convert_space_to_plus == true) {<!-- -->
res + = ' + ';
continue;
}
//The remaining characters need to be encoded into %HH format
char tmp[4] = {<!-- -->0};
//snprintf is similar to printf. They are both formatted strings, except that one is printed and the other is placed in a space.
snprintf(tmp, 4, "%% X", c);
res + = tmp;
}
return res;
}
static char HEXTOI(char c) {<!-- -->
if (c >= '0' & amp; & amp; c <= '9') {<!-- -->
return c - '0';
}else if (c >= 'a' & amp; & amp; c <= 'z') {<!-- -->
return c - 'a' + 10;
}else if (c >= 'A' & amp; & amp; c <= 'Z') {<!-- -->
return c - 'A' + 10;
}
return -1;
}
static std::string UrlDecode(const std::string url, bool convert_plus_to_space) {<!-- -->
//When % is encountered, convert the following 2 characters into numbers, shift the first number to the left by 4 bits, and then add the second number + -> 2b +->2 << 4 + 11
std::string res;
for (int i = 0; i < url.size(); i + + ) {<!-- -->
if (url[i] == ' + ' & amp; & amp; convert_plus_to_space == true) {<!-- -->
res + = ' ';
continue;
}
if (url[i] == '%' & amp; & amp; (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;
}
//Get description information of response status code
static std::string StatuDesc(int statu) {<!-- -->
auto it = _statu_msg.find(statu);
if (it != _statu_msg.end()) {<!-- -->
return it->second;
}
return "Unknow";
}
//Get the file mime based on the file suffix name
static std::string ExtMime(const std::string & amp;filename) {<!-- -->
// a.b.txt gets the file extension first
size_t pos = filename.find_last_of('.');
if (pos == std::string::npos) {<!-- -->
return "application/octet-stream";
}
//According to the extension, get the 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;
}
//Determine whether a file is a directory
static bool IsDirectory(const std::string & amp;filename) {<!-- -->
struct stat st;
int ret = stat(filename.c_str(), & amp;st);
if (ret < 0) {<!-- -->
return false;
}
return S_ISDIR(st.st_mode);
}
//Determine whether a file is an ordinary file
static bool IsRegular(const std::string & amp;filename) {<!-- -->
struct stat st;
int ret = stat(filename.c_str(), & amp;st);
if (ret < 0) {<!-- -->
return false;
}
return S_ISREG(st.st_mode);
}
//Judge the validity of the resource path of http request
// /index.html --- The / in front is called the relative root directory, which maps a subdirectory on a certain server.
// What I want to express is that the client can only request resources in the relative root directory, and resources in other places will be ignored.
// /../login, the .. in this path will cause the path search to go outside the relative root directory, which is unreasonable and unsafe.
static bool ValidPath(const std::string & amp;path) {<!-- -->
//Idea: Split the path according to /, calculate the directory depth based on how many subdirectories there are, how many layers there are, and the depth cannot be less than 0
std::vector<std::string> subdir;
Split(path, "/", & amp;subdir);
int level = 0;
for (auto & amp;dir : subdir) {<!-- -->
if (dir == "..") {<!-- -->
level--; //When any level leaves the relative root directory, it is considered a problem.
if (level < 0) return false;
continue;
}
level + + ;
}
return true;
}
};
status code:
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"}
};