#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

#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; }

#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);  } }

#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; }

#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; }

//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;  }

#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; }

#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); }