/* Httpp.c

**

** http parsing engine

** 

** This program is distributed under the GNU General Public License, version 2.

** A copy of this license is included with this source.

*/

#ifdef HAVE_CONFIG_H

 #include <config.h>

#endif

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

#ifdef HAVE_STRINGS_H

#include <strings.h>

#endif

#include <avl/avl.h>

#include "httpp.h"

#ifdef _WIN32

#define strcasecmp stricmp

#endif

#define MAX_HEADERS 32

/* internal functions */

/* misc */

static char *_lowercase(char *str);

/* for avl trees */

static int _compare_vars(void *compare_arg, void *a, void *b);

static int _free_vars(void *key);

http_parser_t *httpp_create_parser(void)

{

    return (http_parser_t *)malloc(sizeof(http_parser_t));

}

void httpp_initialize(http_parser_t *parser, http_varlist_t *defaults)

{

    http_varlist_t *list;

    parser->req_type = httpp_req_none;

    parser->uri = NULL;

    parser->vars = avl_tree_new(_compare_vars, NULL);

    parser->queryvars = avl_tree_new(_compare_vars, NULL);

    /* now insert the default variables */

    list = defaults;

    while (list != NULL) {

        httpp_setvar(parser, list->var.name, list->var.value);

        list = list->next;

    }

}

static int split_headers(char *data, unsigned long len, char **line)

{

    /* first we count how many lines there are 

    ** and set up the line[] array     

    */

    int lines = 0;

    unsigned long i;

    line[lines] = data;

    for (i = 0; i < len && lines < MAX_HEADERS; i++) {

        if (data[i] == '\r')

            data[i] = '\0';

        if (data[i] == '\n') {

            lines++;

            data[i] = '\0';

            if (lines >= MAX_HEADERS)

                return MAX_HEADERS;

            if (i + 1 < len) {

                if (data[i + 1] == '\n' || data[i + 1] == '\r')

                    break;

                line[lines] = &data[i + 1];

            }

        }

    }

    i++;

    while (i < len && data[i] == '\n') i++;

    return lines;

}

static void parse_headers(http_parser_t *parser, char **line, int lines)

{

    int i,l;

    int whitespace, where, slen;

    char *name = NULL;

    char *value = NULL;

    /* parse the name: value lines. */

    for (l = 1; l < lines; l++) {

        where = 0;

        whitespace = 0;

        name = line[l];

        value = NULL;

        slen = strlen(line[l]);

        for (i = 0; i < slen; i++) {

            if (line[l][i] == ':') {

                whitespace = 1;

                line[l][i] = '\0';

            } else {

                if (whitespace) {

                    whitespace = 0;

                    while (i < slen && line[l][i] == ' ')

                        i++;

                    if (i < slen)

                        value = &line[l][i];

                    break;

                }

            }

        }

        if (name != NULL && value != NULL) {

            httpp_setvar(parser, _lowercase(name), value);

            name = NULL; 

            value = NULL;

        }

    }

}

int httpp_parse_response(http_parser_t *parser, char *http_data, unsigned long len, char *uri)

{

    char *data;

    char *line[MAX_HEADERS];

    int lines, slen,i, whitespace=0, where=0,code;

    char *version=NULL, *resp_code=NULL, *message=NULL;

    if(http_data == NULL)

        return 0;

    /* make a local copy of the data, including 0 terminator */

    data = (char *)malloc(len+1);

    if (data == NULL) return 0;

    memcpy(data, http_data, len);

    data[len] = 0;

    lines = split_headers(data, len, line);

    /* In this case, the first line contains:

     * VERSION RESPONSE_CODE MESSAGE, such as HTTP/1.0 200 OK

     */

    slen = strlen(line[0]);

    version = line[0];

    for(i=0; i < slen; i++) {

        if(line[0][i] == ' ') {

            line[0][i] = 0;

            whitespace = 1;

        } else if(whitespace) {

            whitespace = 0;

            where++;

            if(where == 1)

                resp_code = &line[0][i];

            else {

                message = &line[0][i];

                break;

            }

        }

    }

    if(version == NULL || resp_code == NULL || message == NULL) {

        free(data);

        return 0;

    }

    httpp_setvar(parser, HTTPP_VAR_ERROR_CODE, resp_code);

    code = atoi(resp_code);

    if(code < 200 || code >= 300) {

        httpp_setvar(parser, HTTPP_VAR_ERROR_MESSAGE, message);

    }

    httpp_setvar(parser, HTTPP_VAR_URI, uri);

    httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "NONE");

    parse_headers(parser, line, lines);

    free(data);

    return 1;

}

static int hex(char c)

{

    if(c >= '0' && c <= '9')

        return c - '0';

    else if(c >= 'A' && c <= 'F')

        return c - 'A' + 10;

    else if(c >= 'a' && c <= 'f')

        return c - 'a' + 10;

    else

        return -1;

}

static char *url_escape(char *src)

{

    int len = strlen(src);

    unsigned char *decoded;

    int i;

    char *dst;

    int done = 0;

    decoded = calloc(1, len + 1);

    dst = decoded;

    for(i=0; i < len; i++) {

        switch(src[i]) {

        case '%':

            if(i+2 >= len) {

                free(decoded);

                return NULL;

            }

            if(hex(src[i+1]) == -1 || hex(src[i+2]) == -1 ) {

                free(decoded);

                return NULL;

            }

            *dst++ = hex(src[i+1]) * 16  + hex(src[i+2]);

            i+= 2;

            break;

        case '+':

            *dst++ = ' ';

            break;

        case '#':

            done = 1;

            break;

        case 0:

            free(decoded);

            return NULL;

            break;

        default:

            *dst++ = src[i];

            break;

        }

        if(done)

            break;

    }

    *dst = 0; /* null terminator */

    return decoded;

}

/** TODO: This is almost certainly buggy in some cases */

static void parse_query(http_parser_t *parser, char *query)

{

    int len;

    int i=0;

    char *key = query;

    char *val=NULL;

    if(!query || !*query)

        return;

    len = strlen(query);

    while(i

        switch(query[i]) {

        case '&':

            query[i] = 0;

            if(val && key)

                httpp_set_query_param(parser, key, val);

            key = query+i+1;

            break;

        case '=':

            query[i] = 0;

            val = query+i+1;

            break;

        }

        i++;

    }

    if(val && key) {

        httpp_set_query_param(parser, key, val);

    }

}

int httpp_parse(http_parser_t *parser, char *http_data, unsigned long len)

{

    char *data, *tmp;

    char *line[MAX_HEADERS]; /* limited to 32 lines, should be more than enough */

    int i;

    int lines;

    char *req_type = NULL;

    char *uri = NULL;

    char *version = NULL;

    int whitespace, where, slen;

    if (http_data == NULL)

        return 0;

    /* make a local copy of the data, including 0 terminator */

    data = (char *)malloc(len+1);

    if (data == NULL) return 0;

    memcpy(data, http_data, len);

    data[len] = 0;

    lines = split_headers(data, len, line);

    /* parse the first line special

    ** the format is:

    ** REQ_TYPE URI VERSION

    ** eg:

    ** GET /index.html HTTP/1.0

    */

    where = 0;

    whitespace = 0;

    slen = strlen(line[0]);

    req_type = line[0];

    for (i = 0; i < slen; i++) {

        if (line[0][i] == ' ') {

            whitespace = 1;

            line[0][i] = '\0';

        } else {

            /* we're just past the whitespace boundry */

            if (whitespace) {

                whitespace = 0;

                where++;

                switch (where) {

                case 1:

                    uri = &line[0][i];

                    break;

                case 2:

                    version = &line[0][i];

                    break;

                }

            }

        }

    }

    if (strcasecmp("GET", req_type) == 0) {

        parser->req_type = httpp_req_get;

    } else if (strcasecmp("POST", req_type) == 0) {

        parser->req_type = httpp_req_post;

    } else if (strcasecmp("HEAD", req_type) == 0) {

        parser->req_type = httpp_req_head;

    } else if (strcasecmp("SOURCE", req_type) == 0) {

        parser->req_type = httpp_req_source;

    } else if (strcasecmp("PLAY", req_type) == 0) {

        parser->req_type = httpp_req_play;

    } else if (strcasecmp("STATS", req_type) == 0) {

        parser->req_type = httpp_req_stats;

    } else {

        parser->req_type = httpp_req_unknown;

    }

    if (uri != NULL && strlen(uri) > 0) {

        char *query;

        if((query = strchr(uri, '?')) != NULL) {

            httpp_setvar(parser, HTTPP_VAR_RAWURI, uri);

            *query = 0;

            query++;

            parse_query(parser, query);

        }

        parser->uri = strdup(uri);

    } else {

        free(data);

        return 0;

    }

    if ((version != NULL) && ((tmp = strchr(version, '/')) != NULL)) {

        tmp[0] = '\0';

        if ((strlen(version) > 0) && (strlen(&tmp[1]) > 0)) {

            httpp_setvar(parser, HTTPP_VAR_PROTOCOL, version);

            httpp_setvar(parser, HTTPP_VAR_VERSION, &tmp[1]);

        } else {

            free(data);

            return 0;

        }

    } else {

        free(data);

        return 0;

    }

    if (parser->req_type != httpp_req_none && parser->req_type != httpp_req_unknown) {

        switch (parser->req_type) {

        case httpp_req_get:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "GET");

            break;

        case httpp_req_post:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "POST");

            break;

        case httpp_req_head:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "HEAD");

            break;

        case httpp_req_source:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "SOURCE");

            break;

        case httpp_req_play:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "PLAY");

            break;

        case httpp_req_stats:

            httpp_setvar(parser, HTTPP_VAR_REQ_TYPE, "STATS");

            break;

        default:

            break;

        }

    } else {

        free(data);

        return 0;

    }

    if (parser->uri != NULL) {

        httpp_setvar(parser, HTTPP_VAR_URI, parser->uri);

    } else {

        free(data);

        return 0;

    }

    parse_headers(parser, line, lines);

    free(data);

    return 1;

}

void httpp_setvar(http_parser_t *parser, const char *name, const char *value)

{

    http_var_t *var;

    if (name == NULL || value == NULL)

        return;

    var = (http_var_t *)malloc(sizeof(http_var_t));

    if (var == NULL) return;

    var->name = strdup(name);

    var->value = strdup(value);

    if (httpp_getvar(parser, name) == NULL) {

        avl_insert(parser->vars, (void *)var);

    } else {

        avl_delete(parser->vars, (void *)var, _free_vars);

        avl_insert(parser->vars, (void *)var);

    }

}

char *httpp_getvar(http_parser_t *parser, const char *name)

{

    http_var_t var;

    http_var_t *found;

    void *fp;

    if (parser == NULL || name == NULL)

        return NULL;

    fp = &found;

    var.name = (char*)name;

    var.value = NULL;

    if (avl_get_by_key(parser->vars, &var, fp) == 0)

        return found->value;

    else

        return NULL;

}

void httpp_set_query_param(http_parser_t *parser, char *name, char *value)

{

    http_var_t *var;

    if (name == NULL || value == NULL)

        return;

    var = (http_var_t *)malloc(sizeof(http_var_t));

    if (var == NULL) return;

    var->name = strdup(name);

    var->value = url_escape(value);

    if (httpp_get_query_param(parser, name) == NULL) {

        avl_insert(parser->queryvars, (void *)var);

    } else {

        avl_delete(parser->queryvars, (void *)var, _free_vars);

        avl_insert(parser->queryvars, (void *)var);

    }

}

char *httpp_get_query_param(http_parser_t *parser, char *name)

{

    http_var_t var;

    http_var_t *found;

    void *fp;

    fp = &found;

    var.name = name;

    var.value = NULL;

    if (avl_get_by_key(parser->queryvars, (void *)&var, fp) == 0)

        return found->value;

    else

        return NULL;

}

void httpp_clear(http_parser_t *parser)

{

    parser->req_type = httpp_req_none;

    if (parser->uri)

        free(parser->uri);

    parser->uri = NULL;

    avl_tree_free(parser->vars, _free_vars);

    avl_tree_free(parser->queryvars, _free_vars);

    parser->vars = NULL;

}

void httpp_destroy(http_parser_t *parser)

{

    httpp_clear(parser);

    free(parser);

}

static char *_lowercase(char *str)

{

    char *p = str;

    for (; *p != '\0'; p++)

        *p = tolower(*p);

    return str;

}

static int _compare_vars(void *compare_arg, void *a, void *b)

{

    http_var_t *vara, *varb;

    vara = (http_var_t *)a;

    varb = (http_var_t *)b;

    return strcmp(vara->name, varb->name);

}

static int _free_vars(void *key)

{

    http_var_t *var;

    var = (http_var_t *)key;

    if (var->name)

        free(var->name);

    if (var->value)

        free(var->value);

    free(var);

    return 1;

}