c语言http请求解析表单内容
cgi.h
代码如下:
#ifndef CGI_H #define CGI_H #include <stdio.h> #include <string.h> #include <stdlib.h> typedef struct Node{ char *name; char *value; struct Node *next; }Node; typedef struct Index{ Node *head; char *buffer; }Index; Index *get_input(); void free_input(Index *); Node *analyze(char *); Node *analy_a(char *); Node *analy_m(char *, char *); char *get_value(Node *, char *); char fun1(char); #endif
get_input.c
代码如下:
#include "cgi.h" Index *get_input() { //获得表单发送方法 char *get_method = getenv("REQUEST_METHOD"); Index *input = (Index *)malloc(sizeof(Index)); Node *head; char *buffer; if (strcmp(get_method,"GET") == 0) { char *get_str = getenv("QUERY_STRING"); if (get_str == NULL || *get_str == 0) { return NULL; } //get方法,通过环境变量得到内容 buffer = (char *)malloc(strlen(get_str) + 1); strcpy(buffer, get_str); //对内容进行解析,以链表的形式存在 head = analy_a(buffer); } else if (strcmp(get_method,"POST") == 0){ int get_len = atoi(getenv("CONTENT_LENGTH")); if (get_len == 0) { return NULL; } //post方法,通过标准输入读取内容 buffer = (char *)malloc(get_len + 1); memset(buffer,0,get_len + 1); int n = fread(buffer, 1,get_len, stdin); if (n != get_len) { fprintf(stderr,"Read error!"); } head = analyze(buffer); } //链表头 input -> head = head; //接受到的字符串 input -> buffer = buffer; return input; }
analyze.c
代码如下:
#include "cgi.h" //post方法获取的内容进行解析 Node *analyze(char *buffer) { //获取内容格式 char *c_type = getenv("CONTENT_TYPE"); char *bound; fprintf(stderr,"debug:c_type is %s\n",c_type); if (strcmp("application/x-www-form-urlencoded",c_type) == 0) { //该格式表明获取内容为"name=value"形式 return analy_a(buffer); } else if (strcmp("text/plain", c_type) == 0) { //此种编码格式暂不讨论 } else { //编码格式为multipart/form-data,适用大流量数据传送 //获取等号后面的分隔符 bound = index(c_type,'=') + 1; fprintf(stderr,"debug:bound is %s\n",bound); return analy_m(buffer, bound); } }
analy_a.c
代码如下:
#include "cgi.h" //编码格式为'application/x-www-form-urlencoded'的内容 Node *analy_a(char *buffer) { //创建第一个节点 Node *head = (Node *)malloc(sizeof(Node)); Node *temp = head; temp -> name = buffer; char *b_temp = buffer; //通过移动、改变部分字符来分离字符串 while (*buffer != 0) { if (*buffer == '=') { //'=',则表示name已经结束,value将开始 *b_temp = 0; temp -> value = b_temp + 1; }else if (*buffer == '+') { //'+'代表空格 *b_temp = ' '; }else if (*buffer == '%') { //'%'则紧跟两位十六进制表示的特殊字符 *b_temp = fun1(*(buffer + 1)) * 16 + fun1(*(buffer + 2)); buffer += 2; } else if (*buffer == '&') { //'&'表示value已经结束,name即将开始 *b_temp = 0; //重新申请内存,存储新内容地址 temp -> next = (Node *)malloc(sizeof(Node)); temp = temp -> next; temp -> name = b_temp + 1; }else { *b_temp = *buffer; } buffer++; b_temp++; } //最后一个结束符 *b_temp = 0; return head; }
analy_m.c
代码如下:
#include "cgi.h" //编码格式为'multipart/form-data'的内容 Node *analy_m(char *buffer, char *bound) { char *start; char *end; //第一个节点 Node *head = (Node*)malloc(sizeof(Node)); Node *temp = head; fprintf(stderr,"debug:buffer is %s\n", buffer); //开始解析内容,name在两个双引号之间(详见编码格式) temp -> name = index(buffer, '"') + 1; end = index(temp -> name, '"'); *end = 0; fprintf(stderr,"debug:temp->name is %s\n", temp -> name); //中间间隔了两个"\r\n" temp -> value = end + 5; buffer = strstr(temp -> value, bound); //到下一个间隔符,上面间隔两个"\r\n" *(buffer - 4) = 0; fprintf(stderr,"debug:temp->valu is %s\n", temp -> value); while ((start = strstr(buffer,"name=")) != NULL) { //循环获取name与value地址,直到没有name为止 temp -> next = (Node *)malloc(sizeof(Node)); temp = temp -> next; temp -> name = index(start, '"') + 1; end = index(temp -> name, '"'); *end = 0; fprintf(stderr,"debug:temp->name is %s\n", temp -> name); temp -> value = end + 5; buffer = strstr(temp -> value, bound); *(buffer - 4) = 0; fprintf(stderr,"debug:temp->valu is %s\n", temp -> value); } return head; }
fun1.c
代码如下:
//将十六进制字符转化为十进制数 char fun1(char ch) { char buffer; if (ch < 'A') { buffer = ch - 48; }else if (ch < 'a'){ buffer = ch - 55; }else { buffer = ch - 87; } return buffer; }
get_value.c
代码如下:
#include "cgi.h" //根据name获取相应的value char *get_value(Node *head, char *name) { Node *p; while (head != NULL) { if (strcmp(head -> name, name) == 0) { return head -> value; } p = head -> next; head = p; } return NULL; }
free_input.c
代码如下:
#include "cgi.h" //释放动态获取的内存 void free_input(Index *index) { Node *temp = index -> head; Node *p; while (temp != NULL) { p = temp -> next; free(temp); temp = p; } free(index -> buffer); free(index); }
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