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#include "response.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <lua.h>
/// Sends a response based on the current top value on the stack.
/// \param L Lua state to send response for
/// \param fd File descriptor of a socket to write to
/// \return Bytes written or -1 on error
/// \see write(2)
// TODO: Consider splitting response_send into smaller functions.
int response_send(lua_State * L, const int fd)
{
static const char * error_response =
"HTTP/1.1 500\r\n"
"Connection: close\r\n"
"\r\n";
if (0 == lua_istable(L, -1) || 0 == lua_checkstack(L, 5))
{
lua_pop(L, 1);
return write(fd, error_response, strlen(error_response));
}
int bytes_total = 2048 * sizeof(char);
int bytes_used = 0;
char * buffer = malloc(bytes_total);
char * new_buffer = NULL;
lua_pushstring(L, "status");
lua_gettable(L, -2);
const lua_Integer status = lua_tointeger(L, -1);
lua_pop(L, 1);
if (0 == status || NULL == buffer)
{
free(buffer);
lua_pop(L, 1);
return write(fd, error_response, strlen(error_response));
}
bytes_used = snprintf(buffer, bytes_total, "HTTP/1.1 %d\r\n\r\n", (int) status) - 2;
lua_pushstring(L, "headers");
lua_gettable(L, -2);
if (0 == lua_istable(L, -1))
{
const int result = write(fd, buffer, bytes_used + 2);
free(buffer);
lua_pop(L, 2);
return result;
}
static const char * header_pattern = "%s: %s\r\n";
lua_pushnil(L);
while (0 != lua_next(L, -2) && 0 != lua_isstring(L, -2))
{
const char * key = lua_tostring(L, -2);
const char * value = lua_tostring(L, -1); // TODO: Check the type of the header's value?
const int bytes_left = bytes_total - bytes_used;
int new_bytes = snprintf(buffer + bytes_used, bytes_left, header_pattern, key, value);
while (bytes_left <= new_bytes)
{
bytes_total += 2048;
if (65536 < bytes_total)
{
free(buffer);
lua_pop(L, 4);
return write(fd, error_response, strlen(error_response));
}
new_buffer = realloc(buffer, bytes_total); // TODO: Realloc and error handling involves duplication.
if (NULL == new_buffer)
{
free(buffer);
lua_pop(L, 4);
return write(fd, error_response, strlen(error_response));
}
buffer = new_buffer;
new_bytes = snprintf(buffer + bytes_used, bytes_left, header_pattern, key, value);
}
bytes_used += new_bytes;
lua_pop(L, 1);
}
if (bytes_total < bytes_used + 2)
{
bytes_total += 2;
new_buffer = realloc(buffer, bytes_total);
if (NULL == new_buffer)
{
lua_pop(L, 2);
return write(fd, error_response, strlen(error_response));
}
buffer = new_buffer;
}
lua_pop(L, 1);
buffer[bytes_used] = '\r';
buffer[bytes_used + 1] = '\n';
bytes_used += 2;
lua_pushstring(L, "data");
lua_gettable(L, -2);
size_t data_length = 0;
const char * data = lua_tolstring(L, -1, &data_length);
if (NULL != data && 0 < data_length)
{
// TODO: There are quite a few parts which could be moved out of this function.
if (bytes_total < bytes_used + (int) data_length)
{
bytes_total += data_length;
new_buffer = realloc(buffer, bytes_total);
if (NULL == new_buffer)
{
free(buffer);
lua_pop(L, 2);
return write(fd, error_response, strlen(error_response));
}
buffer = new_buffer;
}
memcpy(buffer + bytes_used, data, data_length);
bytes_used += data_length;
}
int result = write(fd, buffer, bytes_used);
free(buffer); // TODO: Don't free the buffer if EAGAIN or EWOULDBLOCK, so it can be reused.
lua_pop(L, 2);
return result;
}
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