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C语言实现php服务器

时间:2021-07-01 10:21:17 帮助过:22人阅读

原理介绍

原创性申明:

HTTP协议的作用原理

连接:Web浏览器与Web服务器建立连接,打开一个称为socket(套接字)的虚拟文件,此文件的建立标志着连接建立成功。
请求:Web浏览器通过socket向Web服务器提交请求。HTTP的请求一般是GET或POST命令(POST用于FORM参数的传递)。GET命令的格式为:
GET 路径/文件名 HTTP/1.0
文件名指出所访问的文件,HTTP/1.0指出Web浏览器使用的HTTP版本。

应答:Web浏览器提交请求后,通过HTTP协议传送给Web服务器。Web服务器接到后,进行事务处理,处理结果又通过HTTP传回给Web浏览器,从而在Web浏览器上显示出所请求的页面。


然后返回 网页内容到客户端,客户端更具 Conntent-Type 来解析


代码实现

其实Web服务器也就是一个一般的Socket的服务器,只不过它遵守HTTP协议来实现的罢了


//// server.c//// David J. Malan// malan@harvard.edu//// feature test macro requirements#define _GNU_SOURCE#define _XOPEN_SOURCE 700#define _XOPEN_SOURCE_EXTENDED// limits on an HTTP request's size, based on Apache's// http://httpd.apache.org/docs/2.2/mod/core.html#define LimitRequestFields 50#define LimitRequestFieldSize 4094#define LimitRequestLine 8190// number of octets for buffered reads#define OCTETS 512// header files#include #include #include #include #include #include #include #include #include #include #include // typestypedef char octet;// prototypesbool connected(void);bool error(unsigned short code);void handler(int signal);ssize_t load(void);const char* lookup(const char* extension);ssize_t parse(void);void reset(void);void start(short port, const char* path);void stop(void);// server's rootchar* root = NULL;// file descriptor for socketsint cfd = -1, sfd = -1;// buffer for requestoctet* request = NULL;// FILE pointer for filesFILE* file = NULL;// buffer for response-bodyoctet* body = NULL;int main(int argc, char* argv[]){	// a global variable defined in errno.h that's "set by system	// calls and some library functions [to a nonzero value]	// in the event of an error to indicate what went wrong"	errno = 0;	// default to a random port	int port = 0;	// usage	const char* usage = "Usage: server [-p port] /path/to/root";	// parse command-line arguments	int opt;	while ((opt = getopt(argc, argv, "hp:")) != -1)	{		switch (opt)		{		// -h		case 'h':			printf("%s\n", usage);			return 0;			// -p port		case 'p':			port = atoi(optarg);			break;		}	}	// ensure port is a non-negative short and path to server's root is specified	if (port < 0 || port > SHRT_MAX || argv[optind] == NULL || strlen(argv[optind]) == 0)	{		// announce usage		printf("%s\n", usage);		// return 2 just like bash's builtins		return 2;	}	// start server	start(port, argv[optind]);	// listen for SIGINT (aka control-c)	signal(SIGINT, handler);	// accept connections one at a time	while (true)	{		// reset server's state		reset();		// wait until client is connected		if (connected())		{			// parse client's HTTP request			ssize_t octets = parse();			if (octets == -1)			{				continue;			}			// extract request's request-line			// http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html			const char* haystack = request;			char* needle = strstr(haystack, "\r\n");			if (needle == NULL)			{				error(400);				continue;			}			else if (needle - haystack + 2 > LimitRequestLine)			{				error(414);				continue;			}			char line[needle - haystack + 2 + 1];			strncpy(line, haystack, needle - haystack + 2);			line[needle - haystack + 2] = '\0';			// log request-line			printf("\n%s", line);			// TODO: validate request-line			char* method = line;			char* request_target;			char* version;			char* absolute_path;			char* s1;			s1 = strstr (line," ");			if (s1 == NULL || (version = strstr(s1 + 1, " ")) == NULL || strncmp(line + sizeof(line) - 2, "\r\n", 2) == 0)			{				error(400);				continue;			}			request_target = strdup(s1 + 1);			request_target[version - s1 - 1] = '\0';			//printf("request_target is %s, version is %s", request_target, version);			if (strncmp(method,"GET",3) != 0)			{				error(405);				continue;			}			if (strncmp(request_target, "/", 1) != 0)			{				error(501);				continue;			}			if (strchr(request_target, '\"') != NULL)			{				error(400);				continue;			}			if (strncmp (version + 1,"HTTP/1.1",8) != 0)			{				error(505);				continue;			}			if (strchr(request_target, '.') == NULL)			{				error(501);				continue;			}			// TODO: extract query from request-target			char *query = strchr(request_target, '?');			if (query == NULL)				query = "";			else				query = query + 1;			//printf("query is %s\n", query);			// TODO: concatenate root and absolute-path			absolute_path = strdup(request_target);//			printf("%s. %d\n", absolute_path, query-request_target);			if (strcmp(query, "") != 0)				absolute_path[query - request_target - 1] = '\0';			//printf("absolute path is %s\n", absolute_path);			char *path = (char*)malloc(1000);			strcpy(path, root);//			strcat(path, "/");			strcat(path, absolute_path);			//printf("path is %s\n", path);			// TODO: ensure path exists			if (access(path, F_OK) == -1) {				error(404);				continue;			}			// TODO: ensure path is readable			if (access(path, R_OK) == -1) {				error(403);				continue;			}			// TODO: extract path's extension			char* extension;			if ((extension = strrchr(absolute_path, '.')) == NULL) {				error(501);				continue;			}			extension = extension + 1;			//printf("extension is %s\n", extension);			// dynamic content			if (strcasecmp("php", extension) == 0)			{				// open pipe to PHP interpreter				char* format = "QUERY_STRING=\"%s\" REDIRECT_STATUS=200 SCRIPT_FILENAME=\"%s\" php-cgi";				char command[strlen(format) + (strlen(path) - 2) + (strlen(query) - 2) + 1];				sprintf(command, format, query, path);				file = popen(command, "r");				if (file == NULL)				{					error(500);					continue;				}				// load file				ssize_t size = load();				if (size == -1)				{					error(500);					continue;				}				// subtract php-cgi's headers from body's size to get content's length				haystack = body;				needle = memmem(haystack, size, "\r\n\r\n", 4);				if (needle == NULL)				{					error(500);					continue;				}				size_t length = size - (needle - haystack + 4);				// respond to client				if (dprintf(cfd, "HTTP/1.1 200 OK\r\n") < 0)				{					continue;				}				if (dprintf(cfd, "Connection: close\r\n") < 0)				{					continue;				}				if (dprintf(cfd, "Content-Length: %i\r\n", length) < 0)				{					continue;				}				if (write(cfd, body, size) == -1)				{					continue;				}			}			// static content			else			{				// look up file's MIME type				const char* type = lookup(extension);				if (type == NULL)				{					error(501);					continue;				}				// open file				file = fopen(path, "r");				if (file == NULL)				{					error(500);					continue;				}				// load file				ssize_t length = load();				if (length == -1)				{					error(500);					continue;				}				// TODO: respond to client				// respond with Status-Line				dprintf(cfd, "HTTP/1.1 200 OK\r\n");				// respond with Connection header				dprintf(cfd, "Connection: close\r\n");				// respond with Content-Length header				dprintf(cfd, "Content-Length: %i\r\n", length);				// respond with Content-Type header				dprintf(cfd, "Content-Type: text/html\r\n");				// respond with CRLF				dprintf(cfd, "\r\n");								write(cfd, body, length);			}			// announce OK			printf("\033[32m");			printf("HTTP/1.1 200 OK");			printf("\033[39m\n");		}	}}/** * Accepts a connection from a client, blocking (i.e., waiting) until one is heard. * Upon success, returns true; upon failure, returns false. */bool connected(void){	struct sockaddr_in cli_addr;	memset(&cli_addr, 0, sizeof(cli_addr));	socklen_t cli_len = sizeof(cli_addr);	cfd = accept(sfd, (struct sockaddr*) &cli_addr, &cli_len);	if (cfd == -1)	{		return false;	}	return true;}/** * Handles client errors (4xx) and server errors (5xx). */bool error(unsigned short code){	// ensure client's socket is open	if (cfd == -1)	{		return false;	}	// ensure code is within range	if (code < 400 || code > 599)	{		return false;	}	// determine Status-Line's phrase	// http://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html#sec6.1	const char* phrase = NULL;	switch (code)	{	case 400: phrase = "Bad Request"; break;	case 403: phrase = "Forbidden"; break;	case 404: phrase = "Not Found"; break;	case 405: phrase = "Method Not Allowed"; break;	case 413: phrase = "Request Entity Too Large"; break;	case 414: phrase = "Request-URI Too Long"; break;	case 418: phrase = "I'm a teapot"; break;	case 500: phrase = "Internal Server Error"; break;	case 501: phrase = "Not Implemented"; break;	case 505: phrase = "HTTP Version Not Supported"; break;	}	if (phrase == NULL)	{		return false;	}	// template	char* template = "%i %s

%i %s

"; char content[strlen(template) + 2 * ((int) log10(code) + 1 - 2) + 2 * (strlen(phrase) - 2) + 1]; int length = sprintf(content, template, code, phrase, code, phrase); // respond with Status-Line if (dprintf(cfd, "HTTP/1.1 %i %s\r\n", code, phrase) < 0) { return false; } // respond with Connection header if (dprintf(cfd, "Connection: close\r\n") < 0) { return false; } // respond with Content-Length header if (dprintf(cfd, "Content-Length: %i\r\n", length) < 0) { return false; } // respond with Content-Type header if (dprintf(cfd, "Content-Type: text/html\r\n") < 0) { return false; } // respond with CRLF if (dprintf(cfd, "\r\n") < 0) { return false; } // respond with message-body if (write(cfd, content, length) == -1) { return false; } // announce Response-Line printf("\033[31m"); printf("HTTP/1.1 %i %s", code, phrase); printf("\033[39m\n"); return true;}/** * Loads file into message-body. */ssize_t load(void){ // ensure file is open if (file == NULL) { return -1; } // ensure body isn't already loaded if (body != NULL) { return -1; } // buffer for octets octet buffer[OCTETS]; // read file ssize_t size = 0; while (true) { // try to read a buffer's worth of octets ssize_t octets = fread(buffer, sizeof(octet), OCTETS, file); // check for error if (ferror(file) != 0) { if (body != NULL) { free(body); body = NULL; } return -1; } // if octets were read, append to body if (octets > 0) { body = realloc(body, size + octets); if (body == NULL) { return -1; } memcpy(body + size, buffer, octets); size += octets; } // check for EOF if (feof(file) != 0) { break; } } return size;}/** * Handles signals. */void handler(int signal){ // control-c if (signal == SIGINT) { // ensure this isn't considered an error // (as might otherwise happen after a recent 404) errno = 0; // announce stop printf("\033[33m"); printf("Stopping server\n"); printf("\033[39m"); // stop server stop(); }}/** * Returns MIME type for supported extensions, else NULL. */const char* lookup(const char* extension){ // TODO if (strcasecmp(extension, "css")) return "text/css"; if (strcasecmp(extension, "html")) return "text/html"; if (strcasecmp(extension, "gif")) return "image/gif"; if (strcasecmp(extension, "ico")) return "image/x-icon"; if (strcasecmp(extension, "jpg")) return "image/jpeg"; if (strcasecmp(extension, "js")) return "text/javascript"; if (strcasecmp(extension, "png")) return "image/png"; return NULL;}/** * Parses an HTTP request. */ssize_t parse(void){ // ensure client's socket is open if (cfd == -1) { return -1; } // ensure request isn't already parsed if (request != NULL) { return -1; } // buffer for octets octet buffer[OCTETS]; // parse request ssize_t length = 0; while (true) { // read from socket ssize_t octets = read(cfd, buffer, sizeof(octet) * OCTETS); if (octets == -1) { error(500); return -1; } // if octets have been read, remember new length if (octets > 0) { request = realloc(request, length + octets); if (request == NULL) { return -1; } memcpy(request + length, buffer, octets); length += octets; } // else if nothing's been read, socket's been closed else { return -1; } // search for CRLF CRLF int offset = (length - octets < 3) ? length - octets : 3; char* haystack = request + length - octets - offset; char* needle = memmem(haystack, request + length - haystack, "\r\n\r\n", 4); if (needle != NULL) { // trim to one CRLF and null-terminate length = needle - request + 2 + 1; request = realloc(request, length); if (request == NULL) { return -1; } request[length - 1] = '\0'; break; } // if buffer's full and we still haven't found CRLF CRLF, // then request is too large if (length - 1 >= LimitRequestLine + LimitRequestFields * LimitRequestFieldSize) { error(413); return -1; } } return length;}/** * Resets server's state, deallocating any resources. */void reset(void){ // free response's body if (body != NULL) { free(body); body = NULL; } // close file if (file != NULL) { fclose(file); file = NULL; } // free request if (request != NULL) { free(request); request = NULL; } // close client's socket if (cfd != -1) { close(cfd); cfd = -1; }}/** * Starts server. */void start(short port, const char* path){ // path to server's root root = realpath(path, NULL); if (root == NULL) { stop(); } // ensure root exists if (access(root, F_OK) == -1) { stop(); } // ensure root is executable if (access(root, X_OK) == -1) { stop(); } // announce root printf("\033[33m"); printf("Using %s for server's root, size is %ld", root, sizeof(root)); printf("\033[39m\n"); // create a socket sfd = socket(AF_INET, SOCK_STREAM, 0); if (sfd == -1) { stop(); } // allow reuse of address (to avoid "Address already in use") int optval = 1; setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)); // assign name to socket struct sockaddr_in serv_addr; memset(&serv_addr, 0, sizeof(serv_addr)); serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(port); serv_addr.sin_addr.s_addr = htonl(INADDR_ANY); if (bind(sfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) == -1) { stop(); } // listen for connections if (listen(sfd, SOMAXCONN) == -1) { stop(); } // announce port in use struct sockaddr_in addr; socklen_t addrlen = sizeof(addr); if (getsockname(sfd, (struct sockaddr*) &addr, &addrlen) == -1) { stop(); } printf("\033[33m"); printf("Listening on port %i", ntohs(addr.sin_port)); printf("\033[39m\n");}/** * Stop server, deallocating any resources. */void stop(void){ // preserve errno across this function's library calls int errsv = errno; // reset server's state reset(); // free root, which was allocated by realpath if (root != NULL) { free(root); } // close server socket if (sfd != -1) { close(sfd); } // terminate process if (errsv == 0) { // success exit(0); } else { // announce error printf("\033[33m"); printf("%s", strerror(errsv)); printf("\033[39m\n"); // failure exit(1); }}


编译方法
gcc -o server server.c -lm

运行方法

./server -p 8080 public 

其中public目录是存放html和php文件的

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