c语言中怎么利用http请求解析表单内容

本篇文章给大家分享的是有关c语言中怎么利用http请求解析表单内容，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。

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valuechar *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);}

以上就是c语言中怎么利用http请求解析表单内容，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注亿速云行业资讯频道。