C Language HTTP request parsing form content _mssql

Cgi.h

Copy Code code as follows:

#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

Copy Code code as follows:

#include "cgi.h"

Index *get_input () {
 //get form Send method
 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;
&NBSP;&NBSP}
  //get method, get content through environment variable
  buffer = (char *) malloc (strlen (GET_STR) + 1);
  strcpy (buffer, GET_STR); The
  //resolves the content to exist in the form of a linked list
  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 method, reading content through standard input
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);
}
Linked table Header
Input-> head = head;
The string that was received
Input-> buffer = buffer;
return input;
}

Analyze.c

Copy Code code as follows:

#include "cgi.h"
The Post method gets the content to parse
Node *analyze (char *buffer)
{
Get content Format
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) {
The format indicates that the obtained content is "name=value" form
return analy_a (buffer);
else if (strcmp ("Text/plain", c_type) = = 0) {
This encoding format is not currently discussed
} else {
The encoding format is multipart/form-data, suitable for large flow data transmission
Get the separator after the equal sign
bound = index (c_type, ' = ') + 1;
fprintf (stderr, "Debug:bound is%s\n", bound);
Return analy_m (buffer, bound);
}
}

Analy_a.c

Copy Code code as follows:

#include "cgi.h"
The content of the encoded format is ' application/x-www-form-urlencoded '
Node *analy_a (char *buffer)
{
Create a first node
Node *head = (node *) malloc (sizeof (node));
Node *temp = head;
Temp-> name = buffer;
char *b_temp = buffer;
Separating strings by moving or changing part characters
while (*buffer!= 0) {
if (*buffer = = ' = ') {
' = ' to indicate that name has ended and value will begin
*b_temp = 0;
Temp-> value = b_temp + 1;
}else if (*buffer = = ' + ') {
' + ' represents a space
*b_temp = ';
}else if (*buffer = = '% ') {
'% ' is followed by a special character in the two-bit hexadecimal notation
*b_temp = FUN1 (* (buffer + 1)) * + fun1 (* (buffer + 2));
Buffer + 2;
}
else if (*buffer = = ' & ') {
' & ' indicates that value has ended and name is about to begin
*b_temp = 0;
Re-request memory, store new content address
Temp-> Next = (node *) malloc (sizeof (node));
temp = temp-> next;
Temp-> name = b_temp + 1;
}else {
*b_temp = *buffer;
}
buffer++;
b_temp++;
}
Last Terminator
*b_temp = 0;
return head;
}

Analy_m.c

Copy Code code as follows:

#include "cgi.h"
The content of the encoded format is ' Multipart/form-data '
Node *analy_m (Char *buffer, char *bound)
{
Char *start;
Char *end;
First node
Node *head = (node*) malloc (sizeof (node));
Node *temp = head;
fprintf (stderr, "Debug:buffer is%s\n", buffer);
Start parsing content, name is between two double quotes (see encoding format)
Temp-> name = index (buffer, ' ") + 1;
End = Index (temp-> name, ' "');
*end = 0;
fprintf (stderr, "Debug:temp->name is%s\n", temp-> name);
Two "\ r \ n" in the middle interval
Temp-> value = end + 5;
Buffer = STRSTR (temp-> value, bound);
To the next spacer with two "\ r \ n" Intervals above
* (buffer-4) = 0;
fprintf (stderr, "Debug:temp->valu is%s\n", temp-> value);
while ((start = strstr (buffer, "name="))!= NULL) {
Loop to get name and value address until No Name
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

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Converts a hexadecimal character to a decimal number
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

Copy Code code as follows:

#include "cgi.h"
Get the corresponding value based on name
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

Copy Code code as follows:

#include "cgi.h"
Free dynamically acquired memory
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);
}